Vegetarianism and Human Health
Vegetarianism and Human Health
Usha R. Palaniswamy
SUMMARY. Vegetarianism dates back to a time before recorded history and, as many anthropolo- gists believe, most early humans ate primarily plant foods, being more gatherers than hunters. Human diets may be adopted for a variety of reasons, including political, esthetic, moral, environmental and economic concerns, religious beliefs, and a desire to consume a more healthy diet. A major factor influencing the vegetarianism movement in the present time is primarily associated with better health. Epidemiologic data support the association between high intake of vegetables and fruit and low risk of chronic diseases and provide evidence to the profound and long-term health benefits of a primarily vegetarian diet. Vegetables and fruit are rich sources of nutrients, vitamins, minerals, and dietary fiber as well as biologically active nonnutrient compounds that have a complementary and often multiple mechanisms of actions, including antioxidant, anti-inflammatory, hypoglycemic, hypocholesterolemic, and hypolipidemic properties, and mechanisms that stimulate the human immune system. Because of the critical link established between diet and health, consumers have begun to view food as a means of self-care for health promotion and disease prevention. Functional foods are targeted to address specific health concerns, such as high cholesterol or high blood sugar levels, to obtain a desired health benefit. Functional properties identified in a number of plant species have led to a modern day renaissance for the vegetarian movement.
t is often asserted that humans are naturally vegetarian because the human body resembles plant eaters, not carnivores. However, Ihumans are omnivores, capable of eating either meat or plant foods, or general feeders, with more generalized anatomical and physi- ological traits. Human beings have developed feeding habits that is individualized, and acquired through a number of factors including religious and philosophical beliefs, habitat, availability, taste prefer- ences, socioeconomic status, and specific health requirements. Recently, a number of epidemiological and clinical trials have estab- lished a strong link between the intake of fruit and vegetables and a lower risk of several chronic diseases and conditions including cancer and heart disease (Hankey and Leslie, 2001; Key et al., 2002, Lampe, 1999). Additionally, scientific advances have aided in a greater under- standing of the potential advantages of a vegetarian diet and the role of fruit and vegetables in human health promotion and disease preven- tion. The suggested benefits of a predominantly vegetarian diet are so many that Americans, who were meat and potato dieters and finding self-definition in steaks, pot-roasts, hot dogs, and hamburgers just a decade ago, have paused to reconsider their food choices. In the United States until recently, vegetarians were scarce and considered as being odd, intimidating, cranky, fussy, and moralistic. Today, the vegetarian choices have become mainstream and continue to grow in popularity. At present many mainstream restaurants now feature veg- etarian dishes regularly (Restaurants USA, 1999).
School of Allied Health-Asian American Studies Institute, U-2101 University of Connecticut, Storrs, CT 06269.
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Workshop1 243 2/27/03, 1:31 PM The term vegetarianism generally Porphyry and Plato in the West. In the Evangelicalism. Oswald published The refers to a diet that is free from meat on East, the antiquity of vegetarianism can Cry of Nature (1791) expressing his the basis of religious, spiritual, ethical, be traced back to Zoroaster [628–551 outrage against cruel killings of animals economic, hygiene, and environmental BCE (before current era)], the founder (Whorton, 2001). In 1822, a law was considerations or the simple desire for of Zoroastrianism or Parseeism in India, passed to protect work animals from better health, free from chronic diseases Buddha (566–486 BCE) the founder of abuse (Turner, 1980). and conditions. There exists varying Buddhism, Mahavira (599–527 BCE) In the West, the nutritional superi- degrees of vegetarianism, depending on the founder of Jainism, and Ashoka ority of vegetarianism over an omnivo- what a vegetarian includes in the diet (265–238 BCE) the great emperor of rous diet was first demonstrated by besides products of plant origin: the India (Spencer, 1995). Although George Cheyne, a physician and health vegans are pure vegetarians and do not Hindhuism does not require a strict writer who had personally benefited include any animal product in their diet; vegetarian diet, it encourages a satvic from turning a vegetarian. He was greatly the lacto-ovo vegetarians include dairy (one of the three characteristics of things convinced that flesh food “inflames the and eggs in their diet; the lacto-vegetar- in the universe, which is pure, creative, passions, and shortens life, begets ians consume dairy, but not eggs; the illuminating and healthy) vegetarian diet chronical distempers and a decrepid age” ovo-vegetarians consume eggs, but not for good health, as befitting for gods (Cheyne, 1813). He recommended veg- milk; the pesco vegetarians eat fish, but and sages, and strictly forbids killing of etarianism exclusively for the physical no other meat; the pollo vegetarians eat the cows. A vegetarian diet is advocated well-being based on his clinical cases poultry, but no other meat; the macro- in Indian traditional medicine, Ayurveda, and personal benefits. William Lambe, biotics eat relatively high amounts of which is often defined as a way of life another English physician who claimed brown rice, accompanied by smaller (rather than a medical system), for a benefits from turning to a vegetarian amounts of fruit, vegetables and pulses; healthy and long life. Vegetarianism is diet, insisted that a strict vegetarian diet the fruitarians eat only vegetables and encouraged in the ancient verses of the was an absolute necessity to manage- nuts; the raw-foodists and natural hy- Upanishads and also mentioned in Rig ment of chronic illnesses. He proposed gienists do not consume any processed Veda, the most sacred of ancient Hindu that meat was unnecessary and what is foods and adhere to a very strict vegetar- texts. Pivotal to such religions are doc- unnecessary cannot be natural and what ian diet; sproutarians who eat a diet trines of nonviolence and respect for all is not natural cannot be useful to the primarily around sprouted seeds such as life forms. Thus, vegetarianism in the human body (Lambe, 1815). Vegetari- bean sprouts (Vigna radiata), wheat East was tied to philosophical and reli- anism was brought to the United States sprouts (Triticum sp.) or broccoli sprouts gious beliefs and faiths as well as better by William Metcalfe, an envoy of Bible (Brassica oleraceae var. italica); and the health and longer life. Christian Church, founded by William term partial vegetarian (or part-time The Eastern philosophers had a Cowherd, the first organization in the vegetarian) can be applied to any of the considerable influence in the West when West requiring vegetarianism for mem- above definitions used for individuals Pythagoras (580–500 BCE) was influ- bership (Spencer, 1995). In 1830, who occasionally consume some type of enced by the teachings of Zoroaster, MetCalfe’s movement involved Sylvester meat product due to personal, cultural, Buddha, and Mahavira. Pythagoras was Graham, a Presbyterian minister who or traditional reasons. In an online sur- a prominent vegetarian and the initiated a health reform based on the vey by Time/CNN, consisting of 10,007 Pythogorean diet came to mean avoid- principle that “physiology must be con- adult Americans, 57% reported to be ance of the flesh of slaughtered animals gruent with morality”, and “any behav- semi-vegetarians, 36% ovo-lactoveg- (Spencer, 1995). Pythagorean philo- ior that tarnished the soul must also etarians, 5% vegans and 2% other types sophical morality was not to kill living injure the body.” He also advocated of vegetarians (HarrisInteractive, 2002). creatures, never to eat meat and to against alcohol, extramarital sex, late- Since the simple term vegetarian or abstain from animal sacrifice, because all night entertainments, and consump- vegetarian diet does not provide for all animate are akin. Plutarch [46–120 CE tion of meat. During that period, Will- these minor variations, several other (current era)] connected vegetarianism iam Beaumont, demonstrated that veg- terms including plant-based diet or liv- with preservation of health: “indiges- etarian diets needed more time and ing food have been suggested for use to tion is to be feared after flesh-eating for probably “greater powers of the gastric describe a diet that is predominantly it very soon clogs us and leaves ill conse- organs” than animal foods. Graham based on foods derived from plants quences behind it. It would be best to postulated, however that meat was more (Dwyer, 1999; Weinsier, 2000). More accustom oneself to eat no flesh at all. … pathologically stimulating than veg- recently, it has also been suggested that and from over-eating man derives most etables. The present day graham crack- children raised on hit movies like Babe of his diseases” (Plutarch, 1889). ers bear his name. and Chicken Run tend to nonviolent In the 17th century, medical as well Vegetarians were also described as diets as a way to save their movie heroes as moral constraints were central to a smelling better and of superior mental (Corliss, 2002). vegetarian philosophy. Meat was con- and physical strength and performance sidered a harmful food that could “breed compared with meat eaters (Alcott, History of vegetariansim great store of noxious humors,” and 1844). The first vegetarian society was Abstention from eating meat be- that “flesh eating produced much sick- formed in 1847, in England and the cause it is wrong to kill animals has been ness and a vice as well” (Ryder, 1979; term vegetarian was first coined from held by a number of ancient philoso- Tryon, 1683). In the 18th and 19th the Latin vegetus that means lively or phers, including Zoroaster, Buddha, century, the regard for animal life and vigorous. In 1888, W.O. Atwater, who Mahavira, and Emperor Ashoka in the welfare were intensified by the politi- was the first director of U.S. Depart- East, and Pythogoras, Plutarch, Plotinus, cally influential religious movement of ment of Agriculture (USDA) and the
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Workshop1 244 2/27/03, 1:31 PM father of modern American nutrition, restored by an ideal dietary regimen that pillars in the choice of carbohydrates: tabulated and published the fat, pro- comprised of 10 stages, the last stage of eating high-quality complex carbohy- tein, and carbohydrate contents of vari- which consisted of brown rice, salt and drates that are low in simple carbohy- ous foods. fluids that included mostly herbal teas. drates and high in the anti oxidants In early 1900s, John Harvey Kellog, Reports indicate that such extreme veg- [e.g., carrots (Daucus carota), beets a Seventh-Day Adventist who followed etarianism resulted in many nutritional (Beta vulgaris), peas (Pisum sativum), Graham’s rules of health supported the deficiencies and death in some cases and and green leafy vegetables such as spin- autointoxication theory that proposed caused the decline of this dietary regi- ach (Spinacea oleracea)]. Atkins pro- the intestinal autointoxication occurred men after Ohsawa’s death. Later in 1978, posed that by limiting carbohydrate in- through bacterial purification of undi- Michio Kushi, who was inspired by take the body burns stored fat. Since gested protein in the colon (Spencer, Ohsawa’s concept of integrating the high-protein, high-fat, low-carbohy- 1995). He believed in the significant Asian beliefs and Western medicine, drate diets force the body into a fasting contribution of fiber to the nutritional founded the Kushi Institute in Becket, state called ketosis, which may bring value of the vegetarian diet and pro- Mass. and developed several dietary regi- about quick weight loss. The Atkins diet posed that modern people consumed a mens for various diseases, which were has became very popular among people diet insufficient in roughage to stimu- predominantly vegetarian, but included who are obese because it guaranteed late the bowels to action. He claimed fish occasionally (Kushi and Kushi, significant weight loss. Numerous health that the vegetarian diet was high in 1992). agencies, however, including the Ameri- fiber, but low in protein and hence In the 1970s, Robert Atkins, a can Institute for Cancer Research caused low autointoxication of the in- medical doctor, proposed the Atkins (AICR), have expressed concern over testine and body. diet which advocates a high protein, the choice of this dietary regimen be- In 1911, Casimir Funk discovered high fat diet with a significant restriction cause ketosis can lead to muscle break-
vitamin B1 and coined the term vitamin of dietary carbohydrate (Atkins and Buff, down, dehydration, headaches, nausea, in 1916. The American Dietetic Asso- 2000). The Atkins diet comprises of 50 and kidney problems. ciation was founded in 1917 in Cleve- to 75% of proteins and fats (meat, poul- Since the 1940s, federal agencies land, Ohio to promote sound nutrition try, eggs, fish, seafood, cheese, nuts, began translating the new knowledge information for the public, promoting seeds, olive (Olea europaea), avocado gained from research into practical di- optimal nutrition and well being for all (Persea americana), fats and oils), 25 to etary guidelines for consumers. The people. In 1923, Elmer McCollum, a 50% of complex carbohydrates (veg- seven-group plan was developed by biochemist and nutritionist who discov- etables, grains, whole-grain flour prod- USDA in 1943, which was then revised ered vitamins A and B estimated that at ucts, and legumes), and less than 10% of to the basic four in 1958, and later the least 90% of the food eaten by most simple carbohydrates (fruit, fruit juice, six-food group pattern in 1989 (Table American families was restricted to white sweets, milk, yogurt). The Atkins diet 1). Beginning in 1980, there has been bread and butter, meat, potatoes, sugar advocates a crucial balance between two an overwhelming emphasis on diet and and coffee and expressed concern over Table 1. Historical overview of food guides and food choices for Americans: the the general health and well being of most up-to-date advice from nutrition scientists that formed the basis of Federal Americans. He called for a national nutrition policy in 1943, 1958, and 1989 for a healthful diet (U.S. Department reform to educate and convert the pub- of Agriculture, 1943, 1958, 1989). lic to replace the traditional diets to what he called the protective foods. The Food group pattern public attention was drawn to the in- creased intake of vitamins and fiber and Basic Seven (1943) resulted in the manufacture of breakfast 1. Green and yellow vegetables, cereal foods by Kelloggs and Charles W. 2. Citrus fruit, tomatoes, raw cabbage, Post. In the 1920s, the food processing 3. Potatoes, other vegetables, fruits industry became the largest manufac- 4. Milk and milk products turing industry and the large food manu- 5. Meat, poultry, fish, eggs, dried legumes facturers like General Mills and Sunkist 6. Bread, flour and cereals emerged and used the vitamin content 7. Butter and fortified margarine of their products as a strong selling point (Dyson, 2000). Basic Four (1958) The Zen macrobiotic diet was de- 1. Milk veloped in the 1930s by George Ohsawa, 2. Meat a Japanese philosopher who integrated 3. Vegetable and fruits traditional Asian medicine and belief 4. Bread and cereal with Western medicine and the Chris- tian teachings. The Zen macrobiotic Six-food groups (1989) diet, which is based on the concept of 1. Bread, cereal, other grains yin and yang, (the two opposite forces of 2. Fruits life), became popular in the 1960s. Ac- 3. Vegetables cording to the philosophy behind Zen 4. Meat, poultry, fish, macrobiotics, disease results from an 5. Milk, cheese, yogurt imbalance of yin and yang, which can be 6. Fats, sweets, alcoholic beverages
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Workshop1 245 2/27/03, 1:31 PM health both in the areas of nutrition other special groups (e.g., soul food etarian diets are also reported to reverse research and its applications to Ameri- pyramid, soy foods pyramid), written in coronary artery disease (Franklin et al., can food habits. The importance of diet native languages for the ethnic groups 1995; Gould et al., 1995); vascular for overall health promotion and disease and non-English speaking immigrants, dilatory responses of lacto-ovo-vegetar- prevention had been brought to the and the food items chosen to reflect ians were better and may help to ac- attention of the public by the govern- familiar ethnic foods and also modified count for the lower incidence of athero- ment, food industry, innumerable pro- as a pagoda for the Chinese (Chinese sclerosis and cardiovascular mortality fessional and consumer groups, and the Nutrition Society, 2000). A major con- (Lin et al., 2001). Vegetarians may be at mass media. In 1984, the food guide cern in establishing the actual number lower risk of dying from diabetes than was first presented as a wheel by the of servings is the differential nutritional nonvegetarians (Snowdon and Phillips, American Red Cross–USDA nutrition composition of fruit and vegetables due 1985), because the plant foods high in course, then as a table, and later in 1992, to the genetic variability and/or other fiber and low in glycemic index offer in the form of logos in a pyramid (Ameri- external and environmental conditions, benefits in prevention and in the clinical can Dietetic Association, 1992; Bonci, processing and handling (Davis et al., management of diabetes, reducing the 2001). The food pyramid is a graphic 2001). incidence of diabetes by 40% (Salmeron representation that demonstrates the et al., 1997). The high fiber content of relative importance of food groups pro- Health benefits of vegetarian legumes, fruit, and vegetables also in- viding minimal daily servings. The pyra- diets crease fecal bulk and decrease transit mid was established with three key A survey in the early 1990s (Veg- time, thus reducing the exposure of the themes: variety, proportionality, and etarian Times, 1992) reported that more intestinal epithelium to mutagens moderation. Variety is shown through people reported that their choice of a (McIntyre et al., 1993). the separate food group selection and vegetarian diet is for health reasons (46%) Several of the phytochemicals such food group names, proportionality by than for animal rights (15%), family or as flavonoids, isothiocyanates, and allyl the size of food group sections and friend influence (12%), ethics (5%), en- sulfides derived from fruit and vegetables numbers of servings for each group, and vironmental issues (4%), and other rea- are inhibitors of carcinogenesis, modu- moderation by the relative sizes of por- sons (18%). There is accumulating epi- lating the enzyme system responsible tions as parts of the pyramid, small size demiological, laboratory and clinical for metabolizing carcinogens, which can at the top and accompanying text (e.g., evidence that high consumption of fruit decrease the incidence of cancers use sparingly for fat and sugar group of and vegetables protects against degen- (Lampe, 1999; Messina, 1999). Veg- foods). Food pyramid for various groups erative diseases including cancers, is- etarians are also reported to have higher of vegetarians (Fig. 1) has been devel- chemic heart disease (Kwok et al., 2000; antioxidant vitamin levels in the blood oped (Haddad et al., 1999). Steinmetz and Potter, 1991), and that serum (Hanninen et al., 2000; Pronczuk Since its formulation, the pyramid vegetarians have a lower risk of morbid- et al., 1992). Vegetarian diets were ben- has been modified to suit many sub- ity and mortality form several degenera- eficial to bone health (Anderson, 1999) groups including the minority and eth- tive diseases than do nonvegetarians as well as in improving age-related neu- nic populations, infants, vegetarians, and (Key et al., 1996; Knutsen, 1994). Veg- rological dysfunctions and brain perfor- mance (Kuresh and Joseph, 2001). It has been proposed that since the veg- etarians consume many carbohydrate- rich plant foods such as fruit and veg- etables, cereals, pulses, and nuts, their diet contains more antioxidant vitamins (vitamin C, vitamin E, and beta-caro- tene), phytic acid, and polyphenols that inhibit formation of N-nitroso com- pounds (potential carcinogens) (Bartsch and Frank, 1996, Rauma and Mykkänen 2000). Lignins and phytoestrogens in soy have been shown to lower the risk of hormone-dependent cancers (Phipps, et al., 1993). Certain oligosaccharides have growth-promoting effects on bifidobacteria that are important for the health of the colon, maintaining a healthy colon and decreasing the risk of colon cancer (Mitsuoka, 1982). The early model on the adequacy of vegetarian diets and public health risks and benefits (Fig. 2), which pre- vailed for the first part of the 20th cen- tury, illustrated that if a population fol- Fig. 1. Vegetarian food guide pyramid. Design of the pyramid based on the lowed a vegetarian diet, that population suggested model, Haddad et al. (1999); 8 fl. oz = 237 mL. would be more prone to develop nutri-
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Workshop1 246 2/27/03, 1:31 PM meat-based dietary pattern versus the vegetarian dietary pattern, which can also be interpreted by the populations that no overall improvements in health and general well-being would be ac- complished by changing the proportion of animal and plant foods in the diet. This model does not appropriately state the evidence derived from numerous studies that have documented the quan- tifiable benefits of a vegetarian and other plant-based diets and the reduction in risk for many chronic degenerative dis- eases and total mortality (Messina and Burke, 1997). Since a major public health educa- tional objective is to bring about dietary changes to increase the plant based food in the American diet, a new model has been proposed (Fig.4) to indicate the public health risks and benefits of a plant-based and meat-based diet based Fig. 2. Early model on the adequacy of vegetarian diets. The area under the on the epidemiological, clinical and ba- curve public health represents the proportion of individuals in a population for sic science research on the potential whom a given diet may be adequate or deficient (Sabaté, 2001). health benefits of numerous plant foods ent deficiency diseases than those that disease with either a deficiency or an and phytochemicals (Sabaté, 2001). This followed a diet based on animal foods excess of nutrients are shown at both proposed new model attempts to cap- (Sabaté, 2001). This model was rightly extremes and the area in the center ture the new understanding of the roles termed the model on the adequacy of represents the proportion of subjects for vegetarian and meat-based diets play in vegetarian diets because it was based on which the diet is optimal or most benefi- human health and disease. In this model, the available knowledge at a time of cial. As per this model, there is no overall the area under each curve is the same as numerous nutrient deficiencies being difference in the risk–benefit ratio (pro- the current model, but the shapes of the recorded in clinical trials on vegetarians. portion of subjects at risk divided by the two curves are different because of the This early model only considered the proportion of subjects benefiting) of a different distribution of individuals in health risks posed on the vegetarians and suggested that populations include meat and dairy products to decrease the nutrient deficiencies and did not take into account the potential benefits of vegetarian diets. This is largely because during that period of time, the focus of research in human nutrition was on identifying and proposing nutrient in- take for vegetarians and nonvegetarians who were mostly studied to determine if they met the recommended dietary allowances (RDA) for the various nutri- ents. The relationship between vegetar- ian diets and chronic illnesses and the long-term effect of diet on human health promotion and diseases were yet to be determined by nutritional epidemiol- ogy, which is a relatively new discipline. The current model (Fig. 3), termed the model on the public health risks and benefits of vegetarian and meat-based diets, indicates the health risks and ben- Fig. 3. Current model on the public health risks and benefits of vegetarian and efits of vegetarian and meat based diets meat-based diets. The area under each curve represents the proportion of (Sabaté, 2001). The area under each individuals in a population for whom a give diet pattern may be a health risk or curve represents the proportion of the benefit (optimal). At both extremes of the health continuum there is risk of population for which a given diet pat- disease through deficiency or excess of nutrients. The area in the center repre- tern may be risky or beneficial to opti- sents the proportion of individuals for whom the diet is optimal or most mal health. In this model, the risk of beneficial (Sabaté, 2001).
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Workshop1 247 2/27/03, 1:31 PM tioned because of the essential role played by the various groups of fats in human metabolism and membrane function (Lyon, 1977). It is also evident that humans require different types of fats for different purposes, both structural and functional (Abrams, 2001). The American Dietetic Association’s position on vegetarian di- ets is that when appropriately planned, “vegetarian diets are healthful, are nu- tritionally adequate, and provide health benefits in the prevention and treat- ment of certain diseases” (Messina and Burke, 1997). Some nutritional con- cerns expressed over a vegetarian diet include the inadequate intake and/or bioavailability of zinc and other trace elements (Rauma and Mykkänen 2000), calories, proteins, calcium, iron, ribofla- vin, and niacin as compared with the omnivores (Meirelles et al., 2001). It is Fig. 4. Proposed model on the public health risks and benefits of vegetarian generally believed that the vegetarian and meat-based diets. The area under each curve represents the proportion of individuals in a population for whom a give diet pattern may be a health risk or diets may provide less protein than an benefit (optimal). At both extremes of the health continuum there is risk of omnivorous diet. But it may be ad- disease through deficiency or excess of nutrients. The area in the center repre- equate because an omnivorous diet may sents the proportion of individuals for whom the diet is optimal or most really be providing more protein than is beneficial (Sabaté, 2001). really needed and perhaps more healthy because lower protein in the diet is the population by health status. In this men, because they need fewer calories associated with a lower risk of osteoporo- new model, the more favorable risk– and their need for specific nutrients such sis, since high protein intakes lead to benefit ratio for the vegetarian diet is as calcium, folic acid and iron are higher greater excretion of calcium (Leslie and clearly observed. The expanded area than men. Animal foods are high in St Pierre, 1999). under the risk of deficiency under the calories, saturated fats and sodium and The low calories and high fiber meat-based diet curve indicates the risk completely devoid of fiber and complex content of a vegetarian diet is also viewed of diseases due to phytochemical defi- carbohydrates, and phytochemicals and as an advantage. Although the iron con- ciency due to marginal intake of plant thus do not promote optimal health and tent of the vegetarian diets are low, foods. are harmful to health; however, animal research indicates bioavailability and foods are also good sources of protein, absorption of iron is higher in the veg- Vegetarian diets and human iron, calcium, iron, zinc, vitamin B , and etarians than in the omnivorous diet dietetics 6 unique sources of vitamin B12, preformed which contain a higher concentration of While research supports the huge vitamin A, and vitamin D. If a woman iron, but which is not as well absorbed. health benefits of largely plant-based eliminated animal foods completely, she Additionally, some studies report that diets, there are expressed concerns over must get these nutrients from other the ferritin level of vegetarians and om- the complete avoidance of animal meat sources or nutrient supplements to main- nivorous subjects were not significantly and dairy in the daily diet. There exists tain normal health. Infants and children different (Ball and Bartlett, 1999), and great controversy over the superiority of may suffer from extreme vegetarian di- an appropriately planned well-balanced predominantly vegetarian diets over ets resulting in poor growth and devel- vegetarian diet may be compatible with nonvegetarian meat based diets opment (Kerr, 1974). an adequate iron status (Craig, 1994). (Whorton, 2001). Total vegetarians are Vegetarian infants and children are In general, a well planned vegetar- likely to suffer from inadequate protein, smaller and grow at a slower rate as ian diet must consider the following: calories, calcium, riboflavin, and zinc compared with the general meat eating choose whole grains, legumes, veg- (Dwyer, 1991; Freeland-Graves, 1988). populations (Erhard, 1973) and are etables, soy products, seeds and nuts more susceptible to tooth decay (Navia, that are high in protein and good sources Vegetarian diets are deficient in B12 and hence vegetarians are also at risk of 1979). Although dietary fat taken in the of both essential and nonessential amino hyperhomocysteinemia, which can lead form of animal meat, eggs, and milk acids; include good sources of iron, such to vascular disease (Clarke et al., 1991). have been implicated in the develop- as dried beans (Phaseolus vulgaris), spin- Vegetarian dietary patterns present ment of chronic diseases, in many re- ach, green leafy vegetables; enriched particular challenges to women because search reports, there is inconclusive evi- products and whole grains; include vita-
of their varying nutrient needs due to dence on the harmful effect of saturated min B12 fortified breakfast cereals; forti- pregnancy and lactation across their life and monounsaturated fats (Taubes, fied soy beverages; and vitamin supple- cycle. Additionally, the nutrient density 2001). The benefits of polyunsaturated ments; ensure the intake of adequate in women’s diet has to be greater than fats consumed in large amounts is ques- vitamin D, by remaining in the sunlight,
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Workshop1 248 2/27/03, 1:31 PM using fortified milk, or vitamin supple- 2) cultivating an increased intake of a respond to the human nutrition re- ments; include vegetable greens such as variety of plant based foods and estab- quirements and increase the fruit and spinach, kale (Brassica oleracea var. lishing the number of servings and fre- vegetable production by 1) increasing acephala) and broccoli, legumes and quency, for disease prevention; 3) de- the area of production; 2) identifying or soybean (Glycine max) products as good sign of improved educational programs developing high yielding varieties; 3) sources of calcium from plants and grains, promoting the consumption of veg- exploring ways to reduce the prices of and nuts and legumes as sources of zinc etables and fruit by giving more specific vegetables and fruit; 4) diversifying the (McBride, 1998). directions (Williams, 1995); 4) study production of vegetables by growing the domain of phytochemicals suffi- newer crops that have found their way in Conclusions ciently to identify their essential role in to the American diets due to a number In the past decade, there has been disease prevention, functional benefits of reasons (Palaniswamy, 2001); 5) de- a steady increase in the number of people and establish a recommended intake velop suitable production strategies for choosing a vegetarian diet. In 1994, the levels for humans; and 5) address the the newly emerging food crops number of vegetarians in the US was inadequate supply of vegetables and (Palaniswamy and Palaniswamy, 2001); estimated as 12.4 million, twice the fruit with greater nutritional quality. 6) develop programs for promoting and number in 1986 (Rajaram and Sabaté, While the health claims associated marketing new crops and products, sug- 2000). The number of studies report- with a wide range of phytochemicals gesting methods of preparation and ing the benefits of vegetarian diets has and nutraceuticals are still tenuous and consumption (Miles and Allman, 2001); also increased tremendously. There has often described as needing more evi- 7) design crop improvement programs been an increase in publication in bio- dence, more research is needed in estab- that include the nutritional requirement medical journals of review articles and lishing specific roles of these individual as a guiding note and improve the original contributions in vegetarian nu- nutraceuticals and establishing a required nutraceutical and functional properties trition (Sabate et al., 1999). A recent daily dosage for human beings. One is of vegetables and fruit; 8) crop improve- survey (HarrisInteractive, 2002) of reminded of the 1920s, when vitamins ment by genetic modifications; 9) char- 10,007 adult Americans, reported that were discovered. Although scientists acterizing the environmental conditions more people attributed their choice of a knew that the vitamins were necessary and cultivation practices that would se- vegetarian diet for health reasons (32%), for good general health and vision, they lectively manipulate and maximize the than for chemicals and hormones in did not know the specific role of vita- phytochemical concentrations in the meat products (15%), not liking the mins in good health nor what quantity produce (Palaniswamy et al., 2000a, taste of meat (13%), love of animals was needed for effective protection of 2000b, 2001a, 2001b, Rosenfeld et al., (11%), animal rights (10%) and reli- health and prevention of diseases. This 1997); 10) achieve regional self-suffi- gious reasons (6%). The choice of the is the case now with phytochemicals. ciency by encouraging local production public to adopt a more healthful diet With more focused and extensive re- of vegetables and fruit; and 11) encour- and life style based on published scien- search including human clinical trials age organic crop cultivation to increase tific evidence is also closely related to the the specific role of the individual quality and a higher content of nutri- steadily increasing health care costs. phytochemicals and the mechanism of tionally significant minerals, vitamin C, An ideal diet is one that can pro- action may be identified to establish a iron, magnesium, and phosphorus and mote optimal health and longevity. daily dosage for daily intake. lower amounts of nitrates and some Throughout history, human societies Recognizing their importance, fruit heavy metals (Worthington, 2001); and have developed varieties of dietary pat- and vegetables have been given a central 12) design of appropriate nutritional terns based on available food plants and position in the food pyramid, constitut- information and educational programs animals. As the primitive agricultural ing the second in quantity after grains as to increase healthful choices. economies changed with advances in well as frequency of intake. Current scientific knowledge, industry and tech- agricultural production of dietary com- Literature cited nology, food scarcity turned to abun- ponents identified in the food pyramid dance, and principal diet-related dis- is in substantial surplus for all groups Abrams, Jr., H.L. 2001. Vegetarianism: Another view, p. 1564–1571. In: K.F. Kiple eases have shifted from nutrient defi- except the vegetable and fruit group and K.C. Ornelas (eds.). The Cambridge ciencies to chronic diseases related to (Duxbury and Welch, 1999). Accord- world history of food. Cambridge Univ. dietary excesses. This shift has led to ing to the USDA dietary guidelines, the Press, Cambridge, U.K. increasing scientific consensus that eat- deficit in vegetable production is about ing more plant foods but fewer animal 30% of current production (Duxbury Alcott, W.A. 1844. Vegetable diet defended. foods would best promote health. This and Welch, 1999). If all Americans con- J. Chapman Publ., London. consensus is based on research relating sumed the recommended amount of American Dietetic Association. 1992. Pyra- dietary factors to chronic disease risks, fruit and vegetables as per the ADA mid power is here to stay: Behind the new and to observations of exceptionally low guidelines, the supply of fruit and veg- food guide. J. Amer. Dietetic Assn. chronic disease rates among people con- etables appear to be inadequate to meet 92(8):925. suming vegetarian. the needs of all Americans, and if one Anderson, J.J.B. 1999. Plant-based diets Current issues that need to be re- considered the average per capita in- and bone health: Nutritional implications. solved include 1) the definition of an come of an American, the prices are also Amer. J. Clinical Nutr. 70 (suppl):539S– optimal vegetarian diet, not only in the higher than what an average American 542S. context of human health but also in an can afford to spend (Kinsey and Atkins, R.C. and S. Buff. 2000. Dr. Atkins’ ecological context meeting the nutri- Bowland, 1999). age-defying diet revolution. St. Martin’s tional needs of all groups of vegetarians; It is important that horticulture Press, New York.
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Workshop1 249 2/27/03, 1:32 PM Ball, M.J. and M.A. Bartlett. 1999. Dietary fication. J. Amer. Medical Assn. 274:894– Lin, C., T. Fang, and M. Gueng. 2001. intake and iron status of Australian vegetar- 901. Vascular dilatory functions of ovo- ian women. Amer. J. Clinical Nutr. 70:353– lactovegetarians compared with omnivores. 358. Haddad, E.H., J. Sabaté, and C.G. Whitten. Atherosclerosis 158:247–251. 1999. Vegetarian food guide pyramid: A Bartsch, H. and N. Frank. 1996. Blocking conceptual framework. Amer. J. Clinical Lyon, N. 1977. Cholesterol is just one heart the endogenous formation of N-nitroso Nutr. 70(suppl):615S–619S. threat. Sci. Dig. 81: 28–31. compounds and related carcinogens. Intl. Agency for Res. Cancer Sci. Publ. 139:189– Hankey C.R. and W.S. Leslie. 2001. Nutri- McBride, J. 1998. Vegetarians can get 201 tion and coronary heart disease. Coronary enough zinc and other minerals from food Health Care 5:194–201. alone. 9 Oct. 2001.
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Workshop1 250 2/27/03, 1:32 PM Agr. Food Chem. 49:3490 –3493. Spencer, C. 1995. The heretic’s feast: A history of vegetarianism, Univ. Press New Phipps, W.R., M.C. Martini, J.W. Lampe, England, Hanover, N.H. J.L. Slavin, and M.S. Kurzer, 1993. Effect of flax seed ingestion on the menstrual cycle. J. Steinmetz, K.A. and J.D. Potter. 1991. Clinical Endocrinol. Metab. 77:1215. Vegetables, fruit and cancer. II. Mecha- nisms. Cancer Causes Control 1:427–442. Plutarch, 1889. Of eating flesh, p. 3–16. vol. 5: In: W.W. Goodwin (ed.). Plutarch’s mis- Taubes, G. 2001. The soft science of dietary cellanies and essays, Little Brown, Boston, fat. Science 291:2536–2545. Mass. Tryon, T. 1683. The way to health, long life Pronczuk, A. , Y. Kipervarg, and K.C. Hayes. and happiness. E. Richardson, London. 1992. Vegetarians have higher plasma al- pha-tocopherol relative to cholesterol than Turner, J. 1980. Reckoning with the beast: do non-vegetarians. J. Amer. College Nutr. animals, pain, and humanity in the victorian 11:50–55. mind. Johns Hopkins Univ. Press, Balti- more, Md. Rajaram, S. and J. Sabaté. 2000. Health benefits of a vegetarian diet. Nutrition. U.S. Department of Agriculture, 1943. Ba- 16:531–533 Rauma, A.L. and H. Mykkänen. sic 7 food guide (1943–1955). 14 Oct. 2000. Antioxidant status in vegetarians ver- 2002.
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