"Creating a Healthful Food System: Linking Agriculture to
Human Needs"
AAAS Symposium, Seattle, WA, Feb. 1997
In considering how diet affects health in North America, it is useful to understand the several contexts in which nutritionists approach the question.
We see food as . . .
Food provides the fire of life that maintains body and cellular processes and provides the energy to do physical work;
Food provides nutrients that are important for the prevention of specific deficiency diseases such as scurvy (due to vitamin C deficiency) and pellagra (due to niacin deficiency);
Food provides both energy and essential nutrients in amounts essential for good child growth and successful reproductive outcomes, in other words, healthy babies and healthy moms;
Foods contain nutrients and, perhaps, other substances that may play important roles in preventing or mitigating chronic diseases of aging; and
Food or diet have roles in the treatment of many diseases and of preventing their sequella. In epidemiology, such uses of diet are frequently called "secondary prevention".
EVALUATING POPULATION HEALTH STATUS
The health of populations can be assessed by tracking infant and childhood
mortality rates; by comparing the 
incidences of low birth weights
between populations; by assessing the growth status of children on the basis
of their weight for height, their height for age and their weight for age;
by tracking life expectancy and the median age at death; by assessing the
prevalence of different deficiency diseases in the population. Such parameters
are used to tease out the contributions of various factors to major diseases
by estimating "attributable risk". On a population basis, we can
assess the costs to society (e.g., for health care expenditures) of the
burden of diet-related disease.
Probably the most fundamental question about diet and health is whether we producing enough food to feed our growing population? For most of the world, the answer is "yes". Global food production has out-stripped population growth since the 1960's and this trend is projected to continue through the end of the century. However, this is not true in some areas of the world, particularly in sub-Saharan Africa where food production has lagged behind population growth. In that region, lagging food production, as well as associated mal-distribution of food, has resulted in high childhood mortality rates which can be made to drop sharply with improved nutritional status. This is because mild to moderate protein-energy malnutrition and micronutrient (vitamins and minerals) deficiencies place children at greater risk of death from such infectious diseases as measles, the various diarrheal and respiratory diseases, tuberculosis and malaria.
In contrast, infant mortality in the United States have been declining for the last twenty-five years; this is largely attributable to better pre-natal care including better maternal nutrition. Despite these gains, mortality rates differ among racial groups, with the rates for blacks being 17.6 deaths/1000 live births, over twice that for whites (7.3 deaths/1000 live births) in the most recent year reported. Undernutrition during pregnancy contributes to low birth weight. While that severe maternal malnutrition is seldom observed in the United States, we do have substantial racial and ethnic differences in the incidence of low birth weight, with the incidence blacks being 13.6% of live births, compared to 5.8% for whites.
The World Bank attempted to summarize the direct and the indirect contributions of malnutrition to the global burden of disease in its report "Investing in Health - World Development Indicators". That report concluded that malnutrition contributed very little, either directly or indirectly, to the burden of disease in the established market countries. However, in sub-Saharan Africa, Asia, China, other Asian countries and Latin America, the direct effects of malnutrition (i.e., protein-energy malnutrition, vitamin A deficiency, iodine deficiency and anemia) were estimated as contributing substantially to disease burden, accounting for the estimated losses of 5.6 disability-adjusted life years (DALYs) in China and 18.3 DALYs in India. Indirect contributions of malnutrition to disease accounted for the losses of 2.4 additional DALYs in Latin America, 13 additional DALYs in India and 23 additional DALYs in sub-Saharan Africa.
Blood hemoglobin level is the most frequently used parameter for detecting anemia, although in industrialized countries such as the United States it is probably not the best indicator of iron deficiency anemia because it can be affected by inflammation and recent infection. With that caveat, the nationwide Health and Nutrition Examination Survey 1988-1991 (NHANES III) showed low hemoglobin levels in women aged 12-49 yeas to be most prevalent among non-Hispanic blacks, least prevalent among non-Hispanic whites and of intermediate prevalence among Mexican-Americans. Using multivariate models to control for the effects of infection and inflammation, these data show the overall prevalence of iron deficiency anemia among women of child-bearing age in the US to be at the most 12% and perhaps as low as less than 5%. The NHANES III data for males shows a different picture: higher prevalences among the younger age groups dropping significantly during the school-age years and the third decade and thereafter increasing with age.
EFFECTS OF NUTRITION ON THE CHRONIC DISEASES OF AGING
The elderly population of the US is growing both in numbers as well as in age. During the twentieth century, the number of Americans under the age of 65 years has tripled, but the number of people over that age has increased by a factor of 11. Life expectancy has increased from 47 years at the beginning of this century to 76 years today. Thus, we are seeing an increase in the prevalence of diseases of aging. The major causes of death in the United States are now heart disease (particularly coronary heart disease), cancer, stroke, chronic obstructive pulmonary diseases; these are followed by accidents, pneumonia, diabetes, HIV infection and suicide. Four of these leading causes of death (heart disease, cancer, stroke and diabetes) have clear associations with poor diet and/or inadequate physical activity. Some of the 300,000 American deaths per year, about 14% of the total, have been attributed to poor diet and to lack of physical activity.
Life expectancy is increasing not only in the market economies, but also worldwide. Thus, many developing countries are experiencing what has been called the "epidemiological transition", the co-occurrence of diseases of under-nutrition with chronic diseases associated with aging many of which involve problems of over-nutrition. It is expected that all regions of the world will undergo the epidemiological transition but that the times at which countries will experience the phenomenon will vary.
For example, in 1950 in each region of the developing world (sub-Saharan Africa, Middle East, India, Latin America, China) half of all deaths occurred by age 20 years. Those figures have since improved in all regions except in sub-Saharan Africa. In the United States, life expectancy continues to rise for women and for white men, while for black men it has plateaued largely due to violent deaths.
AWARENESS OF DIET-HEALTH RELATIONSHIPS
There has been a growing public awareness of the relationship between diet and health in the United States. This has been particularly true in recent years in the impacts of diet on the development of the chronic diseases of aging. Through public education programs, a large proportion of the population has become aware of these relationships. Studies by the USDA have shown that 40-80% of the American population are able to associate correctly salt/sodium intakes with a increased risk of hypertension, cholesterol, fat and saturated fat intakes with higher blood cholesterol levels and risk of coronary heart disease, and fiber with risk of bowel diseases.
There also is a growing use of medical services for the treatment of diet-related diseases, which now consume a growing proportion of physician time. The National Ambulatory Medical Care Survey estimated that in the 1.4 billion office visits to physicians in 1989 and 1990, physicians ordered blood cholesterol test in 4% of visits and counseled on weight reduction in 6% of visits. The latter figure is still amazingly low proportion given that a third of adult Americans is overweight. Physicians counseled patients on how to reduce blood cholesterol in about 3% of visits.
We know that more people need medical care and intervention than are currently getting it. A study (Sympos et al) conducted of the National Probability Sample of Americans estimated that about 40% of white and black persons, and about a third of Hispanics, Mexican Americans, Puerto Ricans and Cubans, had high blood cholesterol levels, marginally high cholesterol levels plus coronary heart disease or two other coronary heart disease risk factors which placed them at high risk of coronary heart disease. Overall, 37% of the whites, 35% of the blacks and 23% of the Mexican Americans over the age of 20 years needed medical advice and intervention because of their high blood cholesterol levels and their risk of coronary heart disease. Such results indicate that a substantial proportion of the population is in need of medical intervention and treatment.
COST-EFFECTIVENESS OF NUTRITION INTERVENTIONS
A series of studies conducted in developing countries have shown that the supplementation of women with iron during pregnancy costs about $800/death averted. Fortification of entire populations costs somewhat more per death averted, but less per DALY. In the case of iodine-supplementation of women of reproductive age, the cost is about $1,2500/death averted; but the costs of iodized salt or water for entire populations are less ($1,000/death averted). The cost of vitamin A supplementation for children under 5 years of age is $50/death averted; population-wide vitamin A fortification cost $154/death averted (Table 1). In the United States, the overall costs to society associated with diet-related diseases are estimated to be about $250 billion dollars per year (Table 2).
FINAL REMARKS
Two points are clear. First, that nutrition clearly is important to maintaining good health throughout life. This is demonstrated by observations from both developing and industrialize countries. Second, that the costs to society from not providing adequate, health-promoting food supplies are very high.
Q: What mechanisms are available for extending information about diet and health to the health care community?
A: There are a variety of different routes through which this information gets out. Within the Public Health Service in the Department of Health and Human Services, there is an Office of Health Promotion and Disease Prevention that has had a series of physician-oriented publications on the general subject of improving health and preventing disease. There is also a physicians task force that has issued in the major medical journals a series of publications that review particular interventions and advice. Publicly oriented information and public education programs are other ways in which such information is summarized and presented. Within the Departments of Agriculture and Health and Human Services, a series of expert panels have been named to provide advice that is put into brochures and educational materials for the public. An example is the "Dietary Guidelines for Americans" which is updated and issued every five years; another example is the Food Guide Pyramid which advises about the number of servings of different kinds of foods to have on a daily basis. These instruments are parts of an attempt to provide the public with easy-to-follow, practical advice concerning the things that can be done to help reduce risk to chronic disease.
Q: How aware is the general public about the relationships of diet and health status?
A: Several surveys have shown that a very large proportion of the American public is aware of these relationships. As much as 80% of the population knows that fat, saturated fat and cholesterol are related to coronary heart disease; however, as national probability samples have indicated, only about a third of the adult population is actually doing something with this knowledge. When probed about the things that they're doing, it is clear that many of the behaviors that American are using are not necessarily the most appropriates one to lower their intakes of fat, saturated fat and cholesterol. Thus, population survey data show great discrepancies between knowledge and the actual desire to act on it and between the desire to act and whether the chosen behavior is appropriate. A series of surveys over the last twenty years have shown the dietary levels of total fat, saturated fat and cholesterol to be coming down slowly in the US population; so there is some indication that we're moving in the right direction.
Q: Are any trends in medical education towards greater emphasis on nutrition and dietary treatment?
A: The unfortunate answer is "no". Surveys by the American Society for Clinical Nutrition have shown that the numbers of contact hours in medical colleges that are devoted to nutrition education have not been increasing and, in recent years, have shown somewhat of a decrease. An effort by the American Society for Clinical Nutrition led by Dr. Michael Hambich had pushed for the funding of positions in medical colleges that would be devoted to nutrition education as part of the undergraduate curriculum for medical doctors. Whether that effort will be successful remains to be seen. But there is a lot of concern that we've been losing ground, not gaining ground in this area
Q: What is the status of knowledge regarding the health implications of vegetarian diets?
A: There have been a number of studies of the nutritional implications of adhering to various diets, including vegan and strict vegetarian diets. Studies of vegetarian populations indicate some health-promoting effects of vegetarian diets, which tend to be associated with lower prevalences of chronic diseases of aging. Very strictly vegetarian diets, however, also tend to have prevalent problems among children and reproductive outcomes, and studies of American adherents of these types of diets have shown higher incidences of malnutrition among children. Therefore, despite the health-promoting effects of vegetable-based diets, one needs to be very careful with respect to children and women of child-bearing age. Children have much higher requirements for nutrients for their body size than do adults.
Studies supported by the U.S. Agency for International Development have indicated that in areas of the world where the dominant dietary patterns are vegetarian, the health of children and women of child-bearing age are much better with supplementation with at least some animal products, meats and milk in particular, which provide the additional nutrients that they need to meet their life process requirements. However, to avoid chronic diseases of aging, a diet that is perhaps lower in total fat, saturated fat and cholesterol, also things found in animal products, is most appropriate.
"Creating a Healthful Food System: Linking Agriculture to
Human Needs"
AAAS Symposium, Seattle, WA, Feb. 1997
Agriculture functions to provide food energy and nutrients for people, thus supporting their health and well-being. Therefore, fashioning healthy, healthful agricultural systems means developing ways to improve the ability of agriculture to support human health and well-being.
Agricultural development has been among the greatest of human achievements. The world now produces ample food for almost six billion people. In the developing world, particularly in South Asia and sub-Saharan Africa, the "green revolution", which involved the development of improved agricultural technologies and the introduction of high-yielding cereal cultivars, succeeded in increasing grain yields by 2-4-fold during the last three decades.
SHORTCOMINGS OF PRESENT FOOD SYSTEMS
Despite these impressive gains in agricultural production, the case can be made that, globally, our food systems are failing us. In south Asia, for example, the introduction of green revolution crops (high-yielding varieties of rice and wheat) has displaced traditional crops that contain far greater amounts of critical micronutrients. Indeed, the global prevalence of iron deficiency anemia has increased from 30% to 40% among women of child-bearing age in recent decades. In India, anemia has gone from 40% to 70% of women during the green revolution years. This revolution, of course, was designed to enhance the production of food energy and not micronutrients. Accordingly, the iron density (amount per food calorie) of south Asian diets has declined steadily after the introduction of high yielding cereal crops. Hence, an unfortunate outcome of the green revolution has been increasing micronutrient malnutrition globally. While global agriculture currently produces ample food energy, there are now two billion people, i.e., some 40% of the world population, that are now deficient in iron, vitamin A and iodine (Fig. 1) and deficiencies of zinc, selenium and other micronutrient vitamins are of growing concern. The persistence of micronutrient malnutrition evidences failures in global food systems to provide adequate nutrition for all people.
It is also apparent that the food systems of the industrialized world are in need of improvement. A large portion of national health costs in North America is related to the food system through diet and nutrition. It is estimated that at least 20% and perhaps as much as 50% of the societal costs of coronary heart disease, cancer, stroke, diabetes and osteoporosis could be prevented by changes in diet and nutrition. The diets of teenage girls within the USA are of concern, as only 21% meet Recommended Dietary Allowances (RDAs) for iron, only 16% meet RDAs for calcium, and many do not meet RDAs for vitamins A, E, magnesium, phosphorous or zinc.
Sub-optimal iron status is a concern in the United States
(Fig. 2), which continues to have a prevalence of low hemoglobin among pre-menopausal
women of 14-20%. Certain population groups, especially poor, pregnant African
American women show a prevalence of over 40%. Recent reports indicate that
iron deficiency during pregnancy can lead to impaired cognitive development
of young children.
Evidence is mounting that nutritional zinc deficiency may also be prevalent. An intervention trial in Birmingham, Ala. found that pregnant women supplemented with 25 mg zinc/day had significantly greater neonatal birth weights and head circumferences than controls (Goldenberg et al., 1995). Other studies have reported marginal zinc deficiency, as indicated by low plasma zinc levels and rapid plasma zinc disappearance rates, to be fairly common among the elderly and pre-menopausal women. Studies (Gibson et al., 1991; Hambidge et al, 1972 ), have shown low intakes of zinc to be growth-limiting in some otherwise healthy infants, pre-school children and adolescents.
Other elements are also of concern in the United States. Osteoporosis, the progressive demineralization of bone to which chronic sub-optimal calcium intakes contribute, is estimated to cost the American economy $13-18 billion per annum.
DYSLINKAGE OF AGRICULTURE AND HEALTH
The USDA has led efforts to improve the healthfulness outcome of American diets by, among other things, producing the Food Guide Pyramid as a means of communicating current understanding about healthy diets. That instrument reflects the Dietary Goals of increasing intakes of foods containing complex carbohydrates and fibers, e.g., vegetables, beans and fruits. Targets call for Americans to double their average daily intakes of grains from about 3 to 6 servings per day.
American agriculture does not appear to be producing foods, particularly vegetables and fruits, in sufficient amounts to support wide-scale consumption according to these guidelines (Fig. 3). Studies by the USDA, show that the United States currently produces 93% of meats and beans and about 100% of the grains and dairy products, but only 80% of the vegetables and about 50% of the fruits that would be needed to allow every American to eat according to the Food Guide Pyramid. On the other hand, the US over produces 133% of fats and 270% of sugars and sweeteners needed to meet the guidelines. Thus, it appears that, at present, American agricultural production is not aligned with American diet and health objectives. Of course, agriculture has been driven primarily by production, with little concern for the nutritional quality or health impact of the products produced. This speaks to a dyslinkage within the USA food system between production, the food supply and nutrition and health goals.
On the other hand, nutrition and health efforts have relied primarily on medical approaches to solve diet-related health problems. That is, efforts have been focused mainly on the identification of proximate causes of illness; in the developing world. This focus has led to the use of nutrient supplements and food fortificants as the means of redressing malnutrition. Such approaches tend to be reductionist by nature, viewing problems very narrowly; hence, they tend to ignore larger issues within food systems that may offer more sustainable and effective solutions to diet-related problems. Exploitation of agriculture/food systems to improve health and well-being calls for holistic, generalized thinking.
USING AGRICULTURE TO IIMPROVE HUMAN HEALTH
There are many ways in which agriculture can help achieve
our food and health goal by improving the nutrient outputs and balance of
agricultural systems and, thus, improve the healthfulness of food supplies:
The nutritional quality of food crops can be greatly affected by the type of fertilizer used in their production and fertilizer placement within the soil. Fertilization can significantly increase the plant tissue levels of vitamins because a well nourished plant produces more vitamins than a poorly nourished one. Additionally, certain micronutrient fertilizers are well suited to increasing the density of micronutrients in plant foods. For example, the use of zinc-fertilizers can increase the contents of zinc in seeds and grains. In most plants, that response depends on, and is greatly influenced by the level of phosphorus fertilizer used; application of phosphorus without zinc can decrease zinc concentrations in seeds, while application of both nutrients increase seed-zinc (Welch, 1993). Iron constitutes a different problem, as the iron levels in plant tissues are difficult to change with fertilization at levels greater than those that satisfy plant nutritional needs for the element because of tightly controlled iron homoeostatic regulatory mechanisms within the plant.
Fertilizer placement is also important. For example, subsoil zinc fertilization is much more effective at changing the zinc concentration of cereal grains then is surface soil applications of zinc fertilizers. Probably, available subsoil zinc is more important then available surface soil zinc during grain development because surface soils become dryer during plant development while subsoils remain more moist and fertilizer zinc is fairly immobile in soils. Thus, root activity is greater in the subsoil during seed filling while roots in the surface soil become inactive in acquiring zinc during this phase of plant development.
Low micronutrient metal availability in alkaline soils can be made more available to plant roots by adding soil amendments that acidify the soil, such as gypsum or elemental sulfur. Excessive liming of acid soils can reduce the availability of many micronutrient metals to roots by increasing the pH thereby decreasing the solubility of the micronutrient metals present, making them unavailable for absorption by roots. Use of sufficient quantities of high quality organic matter can improve soil physical properties, nutrient availability and increase root distribution within the soil leading to more efficient plant use of micronutrient stores within the soil profile. Furthermore, organic matter may contribute to increased activity of beneficial soil flora, fauna, and microorganisms that improve micronutrient availability to roots. However, much needs to be learned about the beneficial effects of organic matter on micronutrient availability to plant roots.
Nutrient output per acre can be improved through judicious selection of crops used in crop rotations with improved nutritional quality as an explicit aim in the crop selection process. For example, including edible seed-legumes in rice/wheat cropping systems can improve the micronutrient output per acre because these plant foods are richer sources of micronutrients then are the cereal grains especially after grain milling and/or polishing operations. Furthermore crops grown during one season can alter the micronutrient content of subsequent crops. For instance, planting barley before wheat will decrease the zinc content of the wheat grain produced unless zinc fertilizers are used. However, planting white lupin before wheat can enhance the zinc content of the subsequent wheat grain. More needs to be learned about how changing crops in rotations effect the nutritional quality of subsequent crops and what are the mechanisms involved to more fully use this important agronomic tool to improve the nutritional quality of plant foods.
Recent studies have demonstrated that it is possible to breed varieties of staple grains that can utilize forms of micronutrient elements otherwise poorly available in soils (Graham and Welch, 1996). In the Anatolia Plateau of central Turkey, for example, an area of extreme zinc-deficient soils, genotypes of wheat have shown marked differences in their abilities to thrive without zinc fertilization, i.e., genotypes differ in their ability (zinc efficiency) to extract zinc from zinc-poor soil (Cakmak et al., 1996), indicating that within the wheat genome there is also ample ability to breed for improvements in the efficiencies with which plants obtain trace elements from soils. Research at the International Rice Research Institute (unpublished data) has shown that the iron content of rice grain is associated with aromaticity: aromatic rices are more than twice as iron-dense as the commonly used non-aromatic varieties.
The opaque-2 gene, introduced into maize to improve its lysine content, has been shown to impart the ability to accumulate iron in the grain under some circumstances (Gupta et al., 1980). The multiple aleurone layer (MAL) gene, also in maize, can increase the calcium content of that grain by as much as 135% (Welch et al., 1993). Work in this area will need to determine whether micronutrient-efficient varieties retain those trace elements in the edible portions of their milled grains; but such varieties may offer important agronomic benefits by having improved yields on micronutrient-deficient soils, by not requiring micronutrient fertilizers, and by having improved seedling viability and vigor. By realizing such benefits, it may be possible to develop micronutrient-efficient varieties of plants for use in "field fortification" programs.
The nutritional qualities of plant foods can be enhanced by breeding plants for reduced amounts of "anti-nutrients" (e.g., phytic acid, tannins, goitrogens), for increased amounts of trace element promoter substances (ascorbic acid, sulfur-containing amino acids), anti-carcinogens (e.g., selenium-compounds, S-methyl-L-cysteine sulfoxide, methyl methanethiosulfinate) and antioxidants (tocopherol and carotenoids), and for improved fatty acid composition. For example, the sulfur-containing amino acids, methionine and cystine, may enhance the enteric absorption and post-absorptive utilization of iron and zinc from plant food sources . Possibly, these amino acids may account for at least a portion of the known activity of meat in promoting the utilization of iron and zinc by humans and monogastrics animals (Welch and House, 1995). Thus, the three-fold increase (from 1.3 to 3.9 % of total protein) in the methionine content of maize grain achieved by may prove to be important in enhancing trace element utilization. A plant storage form of iron, phytoferritin, present in many plant tissues, was shown to be highly bioavailable to rats (Beard et al., 1996); it may be possible to increase its level in edible tissues of seeds either through traditional plant breeding techniques or, perhaps, to use biotechnology to increase the expression of the genes responsible for its biosynthesis in edible plant organs in order to increase its content in these organs. There is similar potential in livestock breeding to develop stock with increased carcass lean tissue and less fat, and it may be possible to increase milk's content of conjugated linoleic acid, a potently anti-carcinogenic factor.
By using these kinds of production approaches, it should be possible to design agricultural systems in ways that will assure adequate and balanced nutrient outputs to support human health and well-being by means that are lasting and that reach all people, especially those most at risk.
ACHIEVING SUSTAINABLE FOOD SYSTEMS
Nutrient supplementation and food fortification, in many cases, has been successful in addressing micronutrient malnutrition. Unfortunately, these approaches have not proven to be sustainable for political, social, logistic and other reasons. Efficacy with sustainability calls for the exploitation of opportunities available within the food system to produce food of high quality and to assure balanced nutrient output from these systems. Such efforts will require thinking about agriculture in ways that are informed by human nutrition and health needs, and that appreciates the essential roles of and opportunities offered by food systems through the participation of agriculture directed at human health and well being. That is a new paradigm of agriculture and nutrition - one that holds adequate nutrition and health as explicit goals of agriculture and that recognizes that agriculture is an important tool in the fight against malnutrition and poor health globally.
Q: Could you elaborate on the agronomic benefits of the plant breeding approaches you mentioned?
A: Improving plants as sources of nutrients is really a "win-win-win" situation. First, it's win in that many micronutrient metals impart increased disease resistance and increased drought tolerance to plants, which allows the use of fewer pesticides and herbicides. Second, increased efficiency of use of soil micronutrients would reduce needs for micronutrient inputs in the form of chemical fertilizers, particularly, zinc-, iron- and manganese-fertilizers. Third, increasing the density of micronutrients in edible tissues will benefit human health. This last benefit may be of greatest importance for staple foods because underprivileged populations depend on them for sustenance. Even without this nutritional benefit, the first two, production and environmental concerns, may be sufficiently important to justify such breeding efforts.
Q: Are our research and educational institutions able to accept the new paradigm for agriculture that you describe?
A: Many institutions are already heading in this direction; but that is not to say that this paradigmatic shift will come easily. An example of such an effort is the Food Systems for Improved Health (FSIH) Program initiated by Cornell University and the USDA-ARS, U.S. Plant, Soil and Nutrition Laboratory. Among the goals of FSIH is the building of a global Strategic Alliance for Food Systems and Health bringing together leading institutions involved in food systems research and training as a means of changing the dominant paradigms for agriculture and nutrition. Of course, efforts such as this face a kind of structural problem in that our institutions have been designed largely along disciplinary lines, while systems approaches to agriculture, food, nutrition and health are, by definition, multi- or trans-disciplinary and call for holistic thinking about these problems. This means that there are important barriers to trans-disciplinary programing which must be addressed; these involve not only the institutional structures and boundaries, but their reward and personnel development systems.
Q: Will micronutrient-efficient plants hasten the depletion of soil minerals?
A: This is the issue referred to as "soil mining". Of course, it is true that plants must remove nutrients from the soil; the question is how long this can be done before the soil has been seriously depleted in nutrient. In general, soil contents of nitrogen, potassium and phosphorus are limited; these elements must be replaced in some manner, either through the use of fertilizers, animal wastes or "green manure". But for the trace elements such as iron and zinc, data show that soil contents are ample, in most cases sufficient to meets plant needs for hundreds, if not thousands, of years. For these micronutrients, the limitations involve the abilities of plant roots to obtain the forms present in soils. This follows from the fact that current varieties have been bred on optimally fertilized soils in high-input agricultural systems. When they are grown on micronutrient-poor soils, those varieties can't tap existing soil pools of micronutrients. Still, it is clear that it is possible to breed for abilities to tap those sources.
Q: Which approach is more effective in addressing malnutrition, fortifying foods or increasing their nutrient contents through agricultural methods?
A: I think we need to employ several approaches. The problem is that, even with our current abilities to provide nutrient supplements and nutrient-fortified foods, some two billion people continue to suffer from malnutrition. Even in the United States, where these approaches are very highly developed, nearly a fifth of women are iron-deficient. The scope of these problems, in my opinion, calls for additional approaches including the better exploitation of our agricultural system to the end of finding sustainable solutions. Agricultural approaches, in my opinion, offer the best chances for sustainable solutions to malnutrition.
"Creating a Healthful Food System: Linking Agriculture to
Human Needs"
AAAS Symposium, Seattle, WA, Feb. 1997
There is an ever-increasing interest in health-promoting
foods in the American market place. Such foods are described by several
different terms (functional, designer, medicinal, pharma, etc.)
which tend to be used interchangeably, adding to the confusion in this
field. The term "neutriceuticals" has been defined as
describing any food or food ingredient considered to provide medical or
health benefits, including the prevention and treatment of disease (Food
Focus, 1997). This would include foods that are low in total fat, saturated
fat and cholesterol in the sense that they are foods that provide definite
medical or health benefits.
Interest in "designer foods" originated in the National Cancer Institute, which had a major project to add phytochemicals to the food supply. This was envisioned as a massive, nation-wide experiment in which millions of people would be fed designer foods to determine whether cancer risk might be reduced as had been indicated in preliminary studies. This proposal was probably well ahead of its time. While it was not implemented, the label nonetheless has stuck and designer foods and phytochemicals are now popularly talked about as though they've been proven to prevent cancer - nothing could be further from the truth.
THE REGULATORY ENVIRONMENT FOR HEALTH-PROMOTING FOODS
Two very different regulatory schemes control food in the United States and relate to food industry responses to consumer interests in nutrition and health (McNamara, 1997). The first is the Nutrition and Education Act, NLEA, which deals with the labeling of foods commonly found in the market place. The NLEA puts significant constraints on the claims that manufacturers can make for their products, how well substantiated those claims must be, and the nutritional information that must be declared for the product. The second is the Dietary Supplement Health and Education Act (DSHEA), which differs from the NLEA primarily by requiring that a manufacturer must be able to prove that a health claim is true. Under DSHEA, the responsibility is placed on the Food and Drug Administration to prove a claim wrong. This contrasts to NLEA, under which a manufacturer is required to demonstrate that a claim is correct - a not so subtle but very important distinction. For nutrient supplements, it is important to know both whether a supplement does what is claimed and whether there are associated risks. The case of foods, however, is quite different. For foods the established requirement is that a food be safe. Risks associated with products in the conventional food supply are, and must be, minuscule indeed.
CONSIDERING THE EVIDENCE FOR HEALTH BENEFITS
Antioxidants have been widely discussed as having putative roles in the prevention of cancer, cardiovascular disease and cataracts; the latter relationship is probably best supported in the scientific literature. The apparent antioxidant relationships with cancer and heart disease are interesting but require much more evidence to establish the relationship. These associations originated with observations that individuals who consume relatively large amounts of fruits and vegetables have lower cancer risks. An obvious research question has become whether this relationship involves the food antioxidants some other factor(s) in those foods. The "hardening" of the antioxidant association in popular thinking constitutes a leap of faith, if you will, from food having a health effect (foods known to contain antioxidants such as vitamin C, vitamin E and selenium) to the assumption that those antioxidants are, in fact, responsible for the observed effect. Along these lines are proposed relationships between linseed oil and breast cancer risk, components of citrus fruits and cancer prevention, flavinoids and cold prevention. Each of these puported relationships comes from similar leaps from observations that fruits seem to be associated with positive health effects; preliminary results tend to become exaggerated.
A lot of research has been reported on the effects of
different types of pectin on glycemic control and cholesterol lowering.
The evidence for these effects seem to be good; however; the quantities
required to obtain such benefits remain to be shown. Many other health claims
are far less supportable. An example is conjugated linoleic acid (CLA),
a fatty acid isomer that is generated in the rumen, is found in relatively
high concentrations in milk and dairy products, particularly the milk of
cows on pasture. Some work (Ip et al, 1994; Parodi, 1994) has demonstrated
that conjugated linoleic acid can prevent the in vitro mutagenic activities
of certain chemicals. There is also evidence for in vivo anti-carcinogenic
effects of CLA in rodent models. Certainly, CLA deserves a lot more research
investment, but despite the incomplete nature of our knowledge, CLA is being
sold in the marketplace.
THE NURTACEUTICAL MARKET
The US nutraceutical market in 1988 was estimated to have a volume of $2.5 billion, i.e., some ten times the estimated cost of preventing all diet-related diseases ($250 billion) in the United States. By 1995, the market had grown dramatically; estimates range from $9 billion to over $17 billion (Tomomatsu, 1994). Consumer sales of vitamin supplements alone was $4.3 billion. It has been estimated that by 2010, the US nutraceutical market will approach $500 billion (Furukawa, 1993). This is not small business; it is going to be a progressively important segment of our food system.
Among the new products introduced in 1989-1995 with specific health claims, those introduced in 1989 were mostly fat-reduced, low-calorie foods, high-fiber foods, and low-sodium foods. These kinds of foods reached a peak in 1992 after which low-cholesterol foods dropped (Friedman, 1996). There's a very good reason for that: it was at about that time that cholestrol-lowering drugs became available. Instead of counseling dieting patients to reduce their blood cholesterol levels, physicians prescribed a cholesterol-lowering drug that was very effective, was a lot easier, took a lot less time than modifying dietary habits.
Weight control is still a problem and consumers remain concerned with fat and calories. It took some time for consumers to recognize that low-fat did not necessarily mean low-calorie. In the market place reduced-fat foods are now beginning to plateau and drop a bit, but low-calorie foods continue to increase. In consumers' minds, these are healthy foods.
HOW ARE NUTRACEUTICALS MARKETED?
Best (1996) wrote about the marketing of nutraceuticals,
outlining a three-point approach: 1) begin by building on a good image;
2) then promote the product; and 3) create consumer awareness. As an example,
he cites the case of cranberries versus blueberries which both contain benzoic
acid and an unidentified polymeric compound that appears to prevent urinary
tract infections by inhibiting the adherence of bacteria to the bladder
and urinary tract. Cranberry producers, being well organized, mounted a
good campaign and created consumer awareness of this health benefit (in
fact, awareness of this attribute of cranberries is now impressively widespread)
and cranberry sales increased dramatically. Blueberries also have that health
effect - in fact, blueberries contain greater concentrations of the active
ingredients than cranberries; but blueberries have not been very well promoted.
The result is that few people know that blueberries have any health benefit.
Thus, awareness becomes very critical. Best (1996) points our that the effective
marketing of nutraceuticals depends on an image: if there is one, it must
be built upon; if there is none, one must be created.
Best (1996) also points out that many nutraceuticals are used as ingredients and not as foods. An example of effective promotion is for pea flour. The finding that the soluble fiber of field peas supports fermentation in the colon, generating short-chain fatty acids associated with health of the colonic mucosa has been fairly well popularized. Products containing pea fiber have tended to be well accepted. Wheat fiber, on the other hand, is an insoluble fiber that is promoted principally on the basis of it's laxative effects. Claims about laxation offer promotional advantages, as the consumer can observe the effect almost immediately and become a believer.
Recently, Childs (1997) summed up the marketing issues when she stated that "functional foods succeed as an extension of quality and taste for an eligible and interested consumer."
Changing food habits and patterns
Sigman-Grant (1996) proposed a five-stage model for
dietary change (Fig.1). This involves a pre-contemplation stage in
which an individual becomes aware of some diet issue. As awareness increases,
the individual becomes a little more serious and enters a contemplation
stage, usually, after about six months. In Sigman-Grant's experience,
most people must reach a preparation stage before being ready to
make a dietary change. Individuals show varying stages of readiness, but
within about a month they make some dietary change (action stage)
which, if sustained for about six months, will place them in a maintenance
phase. Sigma-Grant's model allows that a person can slip back to any
of the prior stages.
Sigman-Grant (1996) examined the change in fat intake with this model. She found that people in the pre-contemplation stage were consuming about 37-38% of their calories from fat. Although they think about it, they don't do much about it. Their fat intakes don't change appreciably until they get a little more serious and prepare to change; then there is a slight decrease. Finally, they get into an action stage and show a significant reduction to about 35% of calories. If they persist in the behavior, their fats intakes will drop to slightly more than 30% of calories. Observations show that the nature of the change will greatly influence how quickly one moves through this model. In the case of eating more fiber, which might include merely changing the brand of breakfast cereal that one consumes, one can be expected to move more quickly than in the case of making a significant reduction in total fat which will call for changes in both the number and types of foods one consumes. Significant behavioral changes, such as the latter case, will occur much more slowly and will be less likely to be sustained. It becomes incumbent upon manufactures to recognize this process and to determine where in the sequence they can intervene in ways that make the change most acceptable.
WHAT NEEDS TO BE DONE TO DEVELOP NUTRACEUTICALS FURTHER?
The development of nutraceuticals for improving health and well-being will call for efforts in several areas:
It will be of utmost importance to continue our record of food safety. That means that DSHEA probably needs to be re-examined. The burden of proof needs to be shifted back to the manufacturer and not laid at the feet of government. That will happen only if consumers feel a need for it.
This will requires a lot of research and it is an area that is not adequately funded at present.
Any scenario for changing the food system must consider market forces, e.g., consumer demand drives what we do in this country. If consumer demand does not exist, it will need to be created in order to "pull" the market to change. In order to create consumer demand for healthy foods, the benefits must be communicated to targeted consumers much more effectively.
Denke (1993) pointed out that the equation describing the expected change in serum cholesterol level according to the type of dietary fat is based solely on saturated and polyunsaturated fatty acids, i.e., the only fat information given on nutrition food labels. According to that equation, all saturated fats are equally bad. In fact, stearic acid, one of the major saturated fatty acids in common fats has been found to be neutral in terms of changing blood cholesterol. Other equations (Hegstead et al, 1965) which take into account the neutrality of stearic acid indicate that the equation based on saturated fat alone overestimates the cholesterol-raising effect of dairy fat by 60%, of cocoa butter by over 120%, of lard by about 60%, and of beef fat by over 60%. The two approaches predict similar effects for coconut and palm oils, which contain relatively little stearic acid. Denke (1993 ) suggested that the current labeling does not accurately inform consumers about the importance of fats as determinants of serum cholesterol levels. This problem also puts marketers of cocoa butter at a clear disadvantage relative to those selling other fats.
Many pharmaceutical companies are really pushing the limits in terms of health claims for nutritional supplements, while the regulatory constraints on conventional food manufacturers restrict they abilities to make health claims for foods. This disconnect needs to be brought closer together; FDA and USDA must find ways of creating incentives for research in this area by food and pharmaceutical manufacturers who, after all, will be the beneficiaries of a healthy food market. But there must be incentives to the private sector to make the investment necessary to insure progress.
Improved research collaborations among government, academic institutions and private industry will help this effort. Research in the food industry has a high failure rate. Sloan (1994) estimated that only 8% of new product projects in the food industry generated a product that ultimately reached the market place. Further, of the products that reach the market place, only 17% are successful in attaining the business objective in terms of sales and profits. Putting these figures together, it can be seen that food industryresearch has a failure rate of about 99%!
FINAL REMARK
The whole healthy food area, including nutrqceuticals, is an important area that is growing very rapidly. Unfortunately, it is growing in an uncontrolled way.
Q: What nutrient losses can be expected in processed foods?
A: Nutrient losses vary a great deal, depending on both the nutrient and product. In the case of ascorbic acid in heat-processed food, a significant amount, probably as much as 25-30% might be lost. On the other hand, in cold-processed, pasteurized products like orange juice, there's very little loss of the vitamin. So, it depends upon the nutrient and the food matrix in question.
Q: Do you see any chance for substantive changes in the 1994 food legislation?
A: Frankly, I don't see any likelihood of change in the immediate future, i.e., the next two years. I think the legislation is far too new and it may take a few marketplace disasters before there is any compelling reason to change.
Q: Are there examples of collaborative research across the industry?
A: I can think of very few. Most of the collaborative research efforts across the food industry are of a defensive nature. If there is a problem common to the industry, such as the E. coli issue, then the industry will come together and provide the resources necessary to do the research and solve the problem. Generally, those problems are of such significance that they threaten the industry as a whole. This is not likely to happen in the case of strategic research that deals with future opportunities. Because the food industry cannotgrow larger in terms of collective food volume, companies can grow significantly only at the expense of each other, leading to a very competitive situation. Therefore, I think it important for government to take away disincentives for individual companies to invest in research.
Q: Is the problem with the regulatory agencies?
A: In many cases it's simply the slowness of the system. Regulatory agencies obtain no advantage by working quickly because once a decision is made there's only two things that can happen: the decision was right or it was wrong. Being right yields the regulator no particular benefits; but being wrong leads to undesirable consequences. Thus, the whole system is geared to move very slowly. This is not all negative because it probably ensures that fewer wrong decisions are made. It is negative, however, when the regulatory environment controls and limits technical developments in the industry.
Q: Are there mechanisms or incentives to produce agricultural products with specific health benefits?
A: ConAgra's Healthy Choice® brand is a good example. A brand that connotes to consumers certain attributes. In this case the brand connotes low in fat, healthy and good for you. It has nothing to do, necessarily, with the raw agricultural ingredients that go into the product; it has to do with the composition of a final product. This has been a very successful strategy for ConAgra. I'd say that at least half of the products with the Healthy Choice® label are not manufactured by ConAgra; companies license the brand from ConAgra with very tight requirements that the final food product must meet. The approach has worked very effectively for them.
Improving the healthfullness of raw agricultural products is more difficult. In the case of the major commodities, such as soybeans, it might be possible to develop varieties with better fatty acid profiles or higher sulfur-containing amino acid contents. But unless the entire industry could be transformed to use the new variety, there would be serious problems involving the need to isolate the new variety, i.e., to keep the beans segregated throughout distribution and processing channels. Thus, the new variety would constitute a separate, distinct commodity to be handled and processed differently. That can be done, but it has some very high costs associated with it.
Q: What would it take to get breeders to improve the micronutrient contents of food plant?
A: It would take some sort of economic incentive to do it or disincentive not do it. Unfortunately neither has been there for individual nutrients because it's a lot easier to add them during post-harvest processing. For example, most minerals in cereal grains are found in the outer coatings of the grains and are lost in milling. So, it would be unexpected that the mineral contents of the edible portion, the seed endosperm, can be increased so that the mineral ends up in the milled flour. It is usually easier to add minerals directly to the flour. The same is true for vitamins, which can be added to flour very easily and cheaply at the mill to guarantee that the nutrient will be present in the food product. To add a nutrient has to be considered with all of the impacts that it has on productivity, cost and complexity throughout the food chain. There are undoubtedly some components of food for which this will not be true; an example is the case of edible oils. Historically, we've produced mostly soybean oil because that was the cheapest to produce, and we have hydrogenated it to get the degree of hardness that was desired for various manufacturing ends. With increasing negative publicity about trans-fatty acids generated in the hydrogenation process, there is an increasing desire for fats with desired hardnesses without having to use hydrogenation. Should the research on trans-fatty acids support all of the presumed negatives, then this will be an instance in which a component of processing will have created a demand for a totally different type of oil. This may quickly change the whole of the soybean industry to a different oil, rather than trying to keep different streams segregated.
Q: What is the value of blue-green algae, which I have heard touted as health-promoting?
A: I think that product is touted because of it's high levels of carotenoids. To my knowledge, there isn't any real evidence of its benefits. In the early stages of the US space program, bluegreen algae became a very critical component of closed ecological systems, as it could both trap CO2 and also serve as food. I conducted some of the first experiments involving feeding bluegreen algae in significant quantities to human subjects. On the basis of that experience, I would have some serious concerns about the consumption ofsignificant quantities of algae. In small amounts as a supplement this problem is probably not significant. But, as I mentioned before, I think it very important to examine the evidence supporting health claims made for such products. If carotenoids are a concern, there are some tastier, easier, cheaper ways to get carotenoids than bluegreen algae.
"Creating a Healthful Food System: Linking Agriculture to
Human Needs"
AAAS Symposium, Seattle, WA, Feb. 1997
The American food systems is safest food system in the world and is getting
even safer. Nevertheless, there have been serious breakdowns in the food
system, such as recent problems with unpasteurized fruit drinks and recurring
problems with E. coli in beef and Salmonella sp. in poultry.
Better inspection and detection systems are being developed, and there is
a continuing need for consumer education about the handling and cooking
of raw meats. The United States Department of Agriculture (USDA) now requires
instructional cooking and handling labels on raw meat and poultry products.
Through efforts led by the Food and Drug Administration (FDA), there also
have been substantial improvements in the labeling of food to enable consumers
to determine what is 
actually in the product by providing
information on the contents of fats, cholesterol, sodium, carbohydrates,
protein, vitamins and minerals. The USDA and the Department of Health and
Human Services (DHHS) have developed nutritional guidelines to help consumers
make healthy choices about their diet. The Food Guide Pyramid makes it possible
for even school children to know what are the proper choices. Therefore,
while we have a healthful food system, we can improve it further.
MAKING FURTHER IMPROVEMENTS IN FOOD SAFETY
First on the agenda for a more healthful food system is continued improvement in food safety. The President has proposed a $22.2 million increase in the Food Safety and Inspection Service budget to continue the implementation of a modernized inspection that is science based and founded on Hazard Analysis and Critical Control Point (HACCP) systems with an emphasis on process control and testing for bacteria in facilities that slaughter and process meat and poultry. HACCP systems will replace a sight and smell-based system of inspection that had not changed significantly over the last 100 years. The President's budget also recommends a $8.0 million allocation of Research, Education, and Economics funds to the Agricultural Research Service, USDA's in-house research unit, to conduct a competitive research program on the chemical, biological and physical factors that can lead to an improved inspection program. Improved analytical methods can be used quickly and inexpensively to identify and trace the source of micro-organisms and contaminants in the food supply. DNA probe and immunoassay technologies are being developed to detect viral or pathogenic micro-organisms or their toxic constituents or by-products. Similarly, specific and highly sensitive analytical techniques and tools are needed to determine more precisely the presence and fate of chemical contaminants and toxicants in raw materials and processed foods. Although not on the agenda, additional research and education on food irradiation could essentially eliminate the risk of bacterial contamination, such as Salmonella sp. in chicken; unfortunately, technology languishes on the shelf.
IDENTIFYING THE HEALTH-PROMOTING COMPONENTS OF FOODS
Secondly, we must look more closely at the components in the food that makes up our diet. The Surgeon General's 1988 Report "Nutrition and Health" (U.S. Department of Health and Human Services, 1988) stated "good health does not always come easy" and the National Research Council's report "Diet and Health" (National Research Council, 1989) stressed the importance of changing food consumption patterns both by altering the compositions of available diets and by increasing health-promoting behaviors in food choice and consumption. Although the interactions between the US diets and chronic disease risks are still incompletely understood, both reports deemed the scientific evidence sufficiently strong to recommend reductions in total and saturated fats, to increase consumption of complex carbohydrates as well as fruits and vegetables, and to increase the consumption of foods containing calcium and iron. About two years after the release of these reports, the Food Guide Pyramid was released by the USDA and the DHHS.
There is growing interest in food components that may prevent disease. This includes several antioxidant nutrients such as vitamin E, vitamin C and selenium, which have been associated with protection against cancer, heart disease and, perhaps, rheumatoid arthritis. Antioxidants are known to inactivate free radicals; by blocking free radical-mediated DNA damage, it is thought that antioxidants reduce the risk to cancer. Evidence suggests that flavonoid phenolic compounds may be responsible for the reduced risk of coronary heart disease associated with the consumption of red wine. One of these compounds, resveratrol, is also found in the Chinese medicinal herb Polygonum cuspidatum used to treat atherosclerosis. Terms such as phytopharmacetuticals or nutriceuticals are being used to describe these and other specific food components which have the disease protecting effects.
Through improved technology it is easier to detect, isolate and identify food components with specific health benefits. It is also easier to introduce and/or modify plant and animal constituents with the tools of molecular biology or biotechnology. However, the complexity of interrelationships of the components of the food system multidisciplinary, systems approaches. It is clear that chronic diseases such as obesity, diabetes, cardiovascular disease and cancer are influenced by diet, heredity and lifestyle in ways that are affected by many socio-economic, cultural and environmental factors. Interactions among food components also have to be taken into consideration. For example, a high fiber diet can reduce the bioavailabilty of vitamin A, and phytates and tannins can reduce the bioavailability of iron and zinc by forming non-digestible complexes with those minerals. In case of iron, strategies to increase bioavailability include development of low-phytate grains and beans through plant breeding and genetic engineering, the addition to the foods or diets fungal phytase, a phytate-degrading enzyme, the inclusion in diets food rich in vitamin C which enhances iron bioavailability, and the use of meats which have factors that enhance the absorption of iron and zinc (Welch, Combs and Duxbury, 1997).
NEEDS FOR INTERVENTIONS
In the 1995 international workshop organized the Cornell University Food Systems for Improved Health Program, "Food-Based Approaches to Preventing Micronutrient Malnutrition: An International Research Agenda" (Combs et al, 1996), it was pointed out that malnutrition affects nearly half the world's population. More than 840 million people are estimated not to have access to enough food to meet their basic daily needs, and more than one-third of the worlds' children are stunted due to diets inadequate in quantity and quality. An estimated 2 billion people live at risk to diseases resulting from deficiencies of vitamin A, iodine and iron most of them women and children living in less developed countries. If a child does not receive required micronutrients within the first 18 months of life, his/her cognitive potential is lowered and set for life. Even in the US and other economically developed countries, iron-deficiency is estimated to affect as much as 20% of women.
Although tremendous gains in agricultural production have been achieved as the result of research in universities, national agricultural research services and international agricultural research centers, the focus of most of those efforts has been on increasing the production of carbohydrates and protein. That goal is essential but not sufficient. In fact, in some regions that narrow focus may have exacerbated problems of micronutrient deficienciess, also referred to as "hidden hunger", as the "green revolution" led to reductions in the diversity of crops and cropping systems. Last year's report "Lost Crops of Africa" by the Board on Science and Technology for International Development (BOSTID) of the National Research Council (National Research Council, 1996), found that there are more than 2,000 native grains, roots, fruits and other food plants which have been feeding people for thousands of years, but which have been given little or no attention by recent agricultural development efforts. While not necessarily truly lost, most of these indigenous species are not in the mainstream of international science and, thus, are lost to people outside of their indigenous regions. The BOSTID has called for the inclusion of anthropological studies in the global food systems research agenda.
Nutritional intervention by providing the limiting nutrients have been successful in the short term to prevent the most serious manifestations of micronutrient deficiencies, such as blindness and mental retardation. Periodic administration of large doses of vitamin A and iodine to children is clearly effective in preventing and correcting these serious deficiency signs. Provision of iron tablets, particularly to pregnant women, is an accepted public health practice. The downside is that these remedies require regular follow-up by health workers and consistent monitoring of the population to assure program coverage. When claims on a national budget exceed available funds, such programs are not sustained.
Fortification of foods with specific nutrients is another strategy to address micronutrient deficiency. Iodization of salt has been a clear success in many but not all countries. Calloway (1995) found that only a quarter of Kenyan households used fortified salt part of the time and that the use of iodized salt was positively correlated with economic status and "modernity" of the adults. Cost was cited as the manin reason cited for non-useage of iodized salt. If a fortified product is priced beyond the means of its target population, the product will not be effective. Effective fortification requires a developed food processing industry and marketing system and adds to product cost. It requires a surveillance system to assure efficacy and compliance.
THE NUTRITION RESEARCH INITIATIVE
The logical solution to diet-related health problems is to assure intake of enough food of the right kind. The challenges are how to do this, where and how to intervene in complex, multi-factorial, domestic and international food systems. One approach is a USDA/ARS Nutrition Research Initiative which has been included in the President's budget. The $12 million initiative has the following goals:
The goals of the initiative are meritorious. The challenge will be to convince the US Congress to fund the initiative, as human nutrition research has not been a high priority for the House and Senate Agricultural Appropriations Committees. It will be necessary to covinvce the members that this is a good investment, that it will begood for their constituents because staying healthy in this era of trying to manage health care costs is the most positive way to improve the quality of life while also saving money. From the domestic agricultural and food industry perspective, adding value to our commodities can greatly enhance their competitive advantages in the world marketplace. Fruits, vegetable, grains and meats that contain better nutrition and help prevent disease would serve the customer better and would be met with enhanced demand.
To acheive these sorts of goals, the USDA/ARS has decided move the Western Human Nutrition Research Center from its present location at the Presidio of San Francisco to the University of California, Davis campus on a site adjacent to the School of Medicine. The combined vision of these institutions is to create a center devoted to designing foods for health. This will be focused on health-promoting components in fruits, nuts and vegetables produced in California, which supplies 60% of this nation's fruits and vegetables. Once beneficial compounds have been identified, plant and animal breeders and molecular biologists can study how to enhance their amounts in current foods or how to introduce them into other food crops. Food scientists can ensure that such beneficial components are not modified in food processing and they can develop appropriae methods of food fortification.
Education must remain an essential component of the national agenda for improving the healthfulness of food systems. It is important to develop objective, science-based information on diet, nutrition and health, because there are as many myths about nutrition and health as there are exciting new breakthroughs - the world wide webs has nearly forty thousand citations related to nutrition and health. We must provide consumers with solid information on which they can make informed choices about the foods and supplements they have available in the marketplace.
FINAL REMARKS
In summary, an agenda for a heathy food system must include further improvements in food safety; the exploitation of positive, health-protecting components of foods and the elimination or reduction of food components that contribute to chronic disease or compromise immunity; increased nutrition research and education as investments to reduce health care costs, improve the quality of American life, and increase the international competitiveness of American agricultural products.
Q: Could you explain more about the move of the Western Human Research Center to the University of California, Davis, campus?
A: The President's budget includes a health initiative that would provide $12 million in increased funding for the USDA Human Nutrition Centers located throughout the US. The USDA has decided to move the center presently located at the Presidio. From our persective at the University of California, Davis, and, I think, that of the USDA, important synergisms might be realized by locating that center nearer to our medical school and nutrition department. Therefore, our university and the USDA have formed a working team that is planning the move. It will be probably about three years before such a move is actually made; but we are already developing collaborative research programs.
Q: Why is gamma-irradiation of foods not used more widely in the United States?
A: There is a very dedicated group of people who oppose radiation because they believe there are hazards; they have been very effective. Whenever an industry has tried to start up a food irradiation process, even though it's now been approved by the FDA and by USDA for poultry, the anti-foor irradiation lobby has been to peruade major retailers such as McDonald's, Inc. to refuse to announced that they would not use irradiated food, thus, finding in the issue a marketing advantage. In my judgment, the safety of food irradiatoin has been research looked at very thoroughly with clearly positive results and we have a tremendous public relations job to do. Particularly for horticultural crops, if the preservation of quality can be greatly enhanced by low levels of irradiation, shelf-life is extended enormously. That would mean that asparagus can be shipped from California to the Pacific Rim on a boat. Most consumers do not realize that the seafood that we receive from overseas is irradiated, and that spices are already irradiated in the US. I am hopeful that we can help recover this useful technology; but it will take a lot of effort.
The United States has what is arguably the world's most sophisticated food and health systems; yet is also has public health problems associated with the food habits of its people - problems that erode the quality of life and impose huge costs on the society. Each year, the US has a million new cases of cancer, 1.5 million heart attacks, a half-million people affected by stroke, 13 million people with diabetes, a third of the population overweight, 50 million people with hypertension, and half of the women over fifty showing signs of osteoporosis. Collectively, these chronic diseases cost the US economy an estimated $250 billion, not to mention the many important personal impacts.
Several trends provide the context in which we must seek ways to improve
the ability of the American food system to support improved health and well-being:
The global population is expanding rapidly.
The world is adding some 90 million people a year. This means that, for the first time ever, people are living in a world that will double it's population within their own lifetimes. Within the next two decades there will be 12 billion more people; this is going to present huge demands on food production systems.
Nearly 13% of Americans are over 65 years of age; it is expected that, by the year 2020, that figure will be 25%. This shift in the age structure of the population is going to have huge impacts on health; it will mean a progressive increase in the prevalences of chronic diseases.
No other set of environmental factors have comparably relentless effects on phenotypic expression than does diet. Every stage of the life cycle can be affected by nutritional status and, therefore, by diet quality.
Rapid progress is being made in the ability to characterize individual genotypes if rapidly developing, which will make it possible to individualize nutritional guidance along with other health care services. For example, the ability to identify sodium-sensitive hypertensive individuals will allow recommendations for reduced salt intakes to be targeted to persons at risk, thus, making obsolete the use of a population-based recommendation as is now necessary. The ability to characterize genotypes will also make it more important to be able to characterize phenotypes, which will call for metabolically sophisticated approaches.
As the result of liberalized trade and improved technology, foreign markets are available to producers more than ever before. This means, for example, that an apple producer in Washington or New York states competes with producers in Chile and elsewhere as well as her/his neighbors down the road.
All of these developments are occurring in an environment of shrinking public sector support for research, training and extension.
In this context, efforts must address several issues if they are going to be successful in exploiting the potentials of various components of food systems for the improvement of health and well-being.
ISSUE: FOOD NEEDS OF EXPANDING POPULATIONS
The global food system has been able to make impressive gains in the production of food: it now produces a per capita excess as great as 16-18% of food energy (calories) (Uvin, 1994). This is not to say that global food resources are distributed with equity; but at least the productive capacity of the system appears great enough to satisfy the needs of the world population at its current size. This situation has been achieved by increasing the outputs from global agricultural systems, e.g., per capita grain production has increased by nearly 20% over the last two decades during which time the world has added a billion people. This is no mean feat. However, it is not clear whether and how this trend can be continued into the future, and whether agricultural production can be developed in ways that also address the need for balanced nutritional output to prevent micronutrient malnutrition and associated poor health.
Expanding global food demand will present unavoidable pressures on the American food system that may directly affect food security and health in this region. Economic development, as pointed out Brown (1996), is also allowing many people, particularly those in Asia, to "move up the food chain" and, thus become pullers on the world market to an unprecedented extent. This is already being manifest as increasing world demands for grains, which come at a time when world grain production seems to be stagnating. Complicating this picture is the fact that much of the world's productive acreage is under unsustainable irrigation. According to the Economic Research Service, USDA, some 21% of US agricultural lands are presently irrigated by drawing down aquifers. There are serious issues about how long some crop lands will be able to be maintained in intensive production.
ISSUE: ADEQUACY OF FOOD GUIDELINES
The paradigm of nutrition is changing from one focused on preventing specific nutrient deficiencies (e.g., scurvy due to vitamin C deficiency) to one based on promoting health in its fullest sense, i.e., not only freedom from disease but social, psychological and physical well-being.
This new paradigm has informed dietary guidelines and is reflected in such instruments as the Food Guide Pyramid (Welsh et al, 1993). That instrument has had remarkable impact: few Americans are not aware of it; but few Americans follow it.
Despite notable increases in the consumption of vegetables (by about 10% in the last decade), and non-citrus fruits, the reality is that most Americans consume diets that are substantially lower than the current food guidelines recommend. For example, a state-wide survey of New Yorkers (New York State Nutrition Surveillance Program, 1992) showed that very few people ate the recommended numbers of servings of fruits and vegetables. This pattern is not limited to that state, USDA data indicate that substantial numbers of children across the country are eating in such ways as not to be meeting the guidelines to reduce fat or to obtain required amounts of calcium, iron and zinc. In general, Americans are not eating the amounts of many types of foods, particularly vegetables and fruits, that our food guidelines would suggest that are needed. This is particularly true for the deep-green and deep-yellow vegetables, i.e., those that are likely to have pro-vitamin A carotenoids in substantial amounts. For most Americans, half of the vegetables consumed is comprised of a short list of 4-5 foods (fresh and frozen potatoes, onions, processed tomatoes, lettuce) the greenest of which is head lettuce (Putnam, 1994).
These discrepancies between dietary guidelines and practice are so widespread that one must ask serious questions about the ways food guidelines are communicated, perceived and used. Are they understood as relating only to the choices available to primary food preparers, a role that has been moving increasingly outside the home in today's society? How useful is the "serving" concept? With Americans spending almost half their food dollars outside of the home, where are the loci of control over the numbers of servings that people eat? How does one interpret the numbers of servings of foods in the partially prepared meals that constitute an expanding portion of the market?
ISSUE: ADEQUACY OF THE FOOD PRODUCTION SYSTEMS
Productive though it may be, the American food system was not designed explicitly to optimize health. In fact, the nature of its output shows little alignment with contemporary understanding of healthful dietary needs, under-producing vegetables and fruits and overproducing fats, oils and sugars. Kantor (1996) estimated that the American food system supplies a daily per capita average of just over 3 servings of fresh, frozen or canned vegetables and 1.5 servings of fresh and processed fruits and fruit juices. These levels fall substantially short of the recommendations (4 servings of vegetables and 3 servings of fruits for a 2200 cal diet) of the Food Guide Pyramid. On the other hand, the food system now supplies some 55 g/person/day of fats and oils in addition to those fats that occur naturally in foods; this is at least a third more than recommendations would allow. The food system produces even more sugars: 32 tsp/person/day - nearly three times the recommended 12 tsp/day level of consumption. Only for grains and meats does the food system show reasonable correspondence with food consumption guidelines.
O'Brien (1995) has pointed out that bringing food production in alignment with healthful patterns of food consumption will call for strengthening and integrating farm, food and health policies with close cooperation between the public and private sectors. Among other things, this will call for efforts that increase consumer "pulls" on the marketing of healthful foods. An example of such an effort is the program in British Columbia to characterize food choices in terms related to regional agricultural production. This has been done by developing a pictorial rainbow of meat and milk products, vegetables and fruits, grain products, all of which are produced in that province. Wilkins and Bokaer-Smith (1996) have extended this approach in developing the Northeast Regional Food Guide, an interpretation of the Food Guide Pyramid that emphasizes foods grown in each season in the Northeastern US. This instrument contains such traditional foods as rutabagas and turnips, which have dwindled in popularity, taking with them significant opportunities for agricultural production in that region. Such approaches relate to the growing consumer demand for "local" foods, "local" having the connotation of quality and healthfulness (Lockeretz, 1986). These kinds of strategies could be used to link healthful diets and food production in the minds of consumers and, perhaps, provide a pull on agricultural systems towards both healthier diets and more local agricultural diversification.
ISSUE: TRENDS IN FOOD MARKETING
In order to improve the healthfulness of diets it will be necessary for individuals to change their food habits. The question emerges as to how to assist such consumer changes by generating demand and, thus, adding market value for healthful foods, i.e., how to create consumer "pulls" for health-promoting foods on the marketing channels that deliver them. This goal must be considered in the context of the major trends in the food industry (Senaur, 1990).
Throughout the country the scale of retail food marketing is increasing. The typical supermarket now carries some 40,000 products on its shelves; this is growing with the emergence of the "hypermarket" that offers the consumer an even greater array of options. Out-of-home prepared meals is expected to be the big growth area for the 1990's in retail marketing. Vertical integration is increasing in the food industry, with food retailers and food collectors in many cases bing the same. The largest producers of poultry and eggs, are now retail food stores chains. With this development has been the simultaneous proliferation of small, convenience stores. This polarization is most visible in metropolitan areas where the supermarket is located in suburban areas where traffic flow permits it to be successful and where urban areas are left with smaller stores able to offer less variety usually at higher prices to the disadvantage of the urban poor. The HANESII data show that 3.9% of Americans are "food-insufficient", that is, with significant frequency have concerns about whether they can eat or where their next meal will come from (Interagency Board of Nutrition Monitoring and Related Research. 1995.). Food insecurity clusters among low income Americans, affecting some 3 million children and 2.5 million older adults. Of concern must be how these trends in our marketing channels, which further disconnect food from agriculture, will affect the prevalence of food insecurity.
ISSUE: USE OF EMERGING KNOWLEDGE ABOUT DIET AND HEALTH
Knowledge about the interrelationships of diet, nutrition and health is still developing; important discoveries continue to be made. The food system must be able to capitalize on this emerging knowledge, the alternatives being that benefits to society are not realized or, in many cases, that such information is consigned to the pharmaceutical industry for implementation. A case in point is the recent finding by our group (Clark et al, 1996) that a nutritional dose of the essential nutrient selenium can reduce cancer risks. In a decade-long, blinded, placebo-controlled trial, we found selenium-supplementation to be associated with a 39% reduction in the risk of total cancers, and specifically, with reductions in risks to colorectal and prostate cancers of 61% and 65%, respectively. Assuming that these findings, which have substantial support in the experimental tumorigenesis literature, can be replicated, the issue will be how they can be used. In this case, can ways be found to enhance the amounts of selenium compounds in foods or shall this be left to the area of prophylactic drug development? A healthful food system should be able to exploit emerging knowledge about diet and health.
FINAL REMARK
The American food system is the most complex and sophisticated in the world, providing the world's safest and most diverse food supply and comprising nearly a quarter of the US economy. Nevertheless, diet-related chronic diseases persist, imposing enormous societal costs which can be expected to increase as the age structure of the society continues to shift. Given the magnitude of these drains on the economy, it is appropriate, indeed good business sense, to consider costs of food system-based research, training and extension as investments in the society that will yield returns not only in the form of improvements in the quality of American life, but also in reduced health care costs and increased competitiveness of American products in the international marketplace.
