More People Trying Vegetarian Diets

Article

By: Dixie Farley

Date: October 1995

Source: FDA Consumer, (October 1995): 52-55.

About the Author: This article was written by a staff member of FDA Consumer, the official magazine of the U.S. Food and Drug Administration (FDA). Now part of the Department of Health and Human Services, the FDA began in 1862 as a single chemist working for the Department of Agriculture. Today, the agency regulates the production, sale, delivery, and storage of medicine and medical devices, and evaluates applications for new drugs, medical products, and food additives.

INTRODUCTION

In 1971 Frances Moore Lappé's Diet for a Small Planet reinvigorated the American vegetarian movement. A researcher into world poverty, Lappé showed that raising animal protein for food required wasteful amounts of energy, land, grain, water, and other natural resources. It would be kinder to the planet and its people, she said, to eat lower down the food chain. Though not a vegetarian herself, Lappé's words struck a chord; the book became a commercial success and the popularity of vegetarianism soared.

The term "vegetarian" was coined by the British Vegetarian Society in the mid-1800s. Around this time in Britain, many people were practically vegetarian by default as beef and pork were very expensive. Only with the introduction of effective refrigeration and freight transport in the early twentieth century did meat became a staple of Western diets.

Diet for a Small Planet was followed four years later by another influential work, Animal Liberation: A New Ethics for Our Treatment of Animals, by Australian philosopher Peter Singer. This book spurred the development of the U.S. animal rights movement and the group People for the Ethical Treatment of Animals (PETA), both of which strongly promote vegetarian eating as part of their campaign for animal rights.

The health effects of eating meat were analyzed by Dr. John McDougall in The McDougall Plan for Super Health and Life-Long Weight Loss in 1983. He advocated a vegan diet in which no animal products are consumed, a term and concept first espoused by British teacher Donald Watson in the mid-1940s.

In 1987 John Robbins combined the ethical and health arguments for vegetarianism in Diet for a New America, which fueled yet another resurgence of interest in vegetarianism. Recognizing the benefits of less meat consumption, the U.S. government revamped its "food pyramid" in the 1990s to emphasize the consumption of grains, vegetables, and fruits. The article below discusses the health benefits of the vegetarian diet.

PRIMARY SOURCE

MORE PEOPLE TRYING VEGETARIAN DIETS

Perceiving plant foods as beneficial because they are high in dietary fiber and, generally, lower in saturated fat than animal foods, many people turn to vegetarian diets.

Grain products, for instance, form the base of the U.S. Department of Agriculture and Department of Health and Human Services' Food Guide Pyramid, which recommends 6 to 11 daily servings of bread, cereal, rice, and pasta. Daily intakes advised for other foods are: 3 to 5 servings of vegetables; 2 to 4 servings of fruits; 2 to 3 servings of milk, yogurt, and cheese; and 2 to 3 servings of meat, poultry, fish, dry beans, eggs, and nuts. The guide advises using fats, oils, and sweets sparingly.

And, who hasn't seen signs in their grocer's produce section urging consumers to eat "5 a day for better health"? This slogan reflects a major government-industry campaign to help people eat more fruits and vegetables as part of a high-fiber, low-fat diet that emphasizes variety.

The campaign is consistent with the USDA-DHHS Dietary Guidelines for Americans (〈www.cfsan.fda.gov/∼lrd/nutguide.txt〉), which states, "Most Americans of all ages eat fewer than the recommended number of servings of grain products, vegetables, and fruits, even though consumption of these foods is associated with a substantially lower risk for many chronic diseases, including certain types of cancer" Also noted: "Most vegetarians eat milk products and eggs, and as a group, these lacto-ovo-vegetarians enjoy excellent health."

But health benefits are not the only reason vegetarian diets attract followers.

Certain people, such as Seventh-day Adventists, choose a vegetarian diet because of religious beliefs. Others give up meat because they feel eating animals is unethical. Some believe it's a better use of the earth's resources to eat low on the food chain—that is, to eat plant foods, rather than the animals that eat the plant foods. And many people eat plant foods simply because they are less expensive than animal foods.

It's wise to take precautions, however, when adopting a diet that entirely excludes animal flesh and dairy products, called a vegan diet.

"The more you restrict your diet, the more difficult it is to get the nutrients you need," says John Vanderveen, Ph.D., director of the Food and Drug Administration's Office of Plant and Dairy Foods and Beverages. "To be healthful, vegetarian diets require very careful, proper planning. Nutrition counseling can help you get started on a diet that is nutritionally adequate."

If appropriately planned, vegan diets, though restrictive, can provide adequate nutrition even for children, according to the American Dietetic Association and the Institute of Food Technologists.

Plant Food Benefits Registered dietitian Johanna Dwyer, of Tufts University Medical School and the New England Medical Center Hospital, Boston, summarizes these plant food benefits:

"Data are strong that vegetarians are at lesser risk for obesity, atonic [reduced muscle tone] constipation, lung cancer, and alcoholism. Evidence is good that risks for hypertension, coronary artery disease, type II diabetes, and gallstones are lower. Data are only fair to poor that risks of breast cancer, diverticular disease of the colon, colonic cancer, calcium kidney stones, osteoporosis, dental erosion, and dental caries are lower among vegetarians."

According to Dwyer, vegetarians' longevity is similar to or greater than that of non-vegetarians, but is influenced in Western countries by vegetarians' "adoption of many healthy lifestyle habits in addition to diet, such as not smoking, abstinence or moderation in the use of alcohol, being physically active, resting adequately, seeking ongoing health surveillance, and seeking guidance when health problems arise."

Can Veggies Prevent Cancer? The National Cancer Institute 〈www.cancer.gov〉 in its booklet "Diet, Nutrition, & Cancer Prevention: A Guide to Food Choices," states that 35 percent of cancer deaths may be related to diet. The booklet states:

• Diets rich in beta-carotene (the plant form of vitamin A) and vitamin C may reduce the risk of certain cancers.
• Reducing fat in the diet may reduce cancer risk and, in helping weight control, may reduce the risk of heart attacks and strokes.
• Diets high in fiber-rich foods may reduce the risk of cancers of the colon and rectum.
• Vegetables from the cabbage family (cruciferous vegetables) may reduce the risk of colon cancer.

FDA, in fact, authorized several health claims on food labels relating low-fat diets high in some plant-derived foods with a possibly reduced risk of cancer.

While FDA acknowledges that high intakes of fruits and vegetables rich in beta-carotene or vitamin C have been associated with reduced cancer risk, it believes the data are not sufficiently convincing that either nutrient by itself is responsible for the association. Nevertheless, since most fruits and vegetables are low-fat foods and may contain vitamin A (as beta-carotene) and vitamin C, the agency authorized a health claim relating diets low in fat and rich in these foods to a possibly reduced risk of some cancers.

Another claim may relate low-fat diets high in fiber-containing vegetables, fruits and grains to a possible reduction in cancer risk. (The National Cancer Institute recommends 20 to 30 grams of fiber a day.) Although the exact role of total dietary fiber, fiber components, and other nutrients and substances in these foods is not fully understood, many studies have shown such diets to be associated with reduced risk of some cancers.

Lowering Heart Disease Risk FDA also notes that diets high in saturated fats and cholesterol increase blood levels of total cholesterol and LDL cholesterol, and thus the risk for coronary heart disease. (The National Cholesterol Education Program recommends a diet with no more than 30 percent fat, of which no more than 10 percent comes from saturated fat.) For this reason, the agency authorized a health claim relating diets low in saturated fat and cholesterol to a possibly reduced risk of coronary heart disease.

Another claim may relate diets low in fat and high in fruits, vegetables, and grain products that contain fiber, particularly soluble fiber, to a possibly reduced risk of coronary heart disease. However, the agency recognizes that it is impossible to adequately distinguish the effects of fiber, including soluble fiber, from those of other food components.

With respect to increasing fiber in the diet, Joanne Slavin, Ph.D., R.D., of the University of Minnesota, in 1990 in Nutrition Today, gives this advice: "The current interest in dietary fiber has allowed recommendations for fiber supplementation to outdistance the scientific research base. Until we have a better understanding of how fiber works its magic, we should recommend to American consumers only a gradual increase in dietary fiber from a variety of sources."

Precautions The American Dietetic Association's position paper on vegetarian diets states, "Because vegan diets tend to be high in bulk, care should be taken to ensure that caloric intakes are sufficient to meet energy needs, particularly in infancy and during weaning." Dwyer and Suzanne Havala, also a registered dietitian, updated the paper in the 1993 issue of the association's journal.

It's generally agreed that to avoid intestinal discomfort from increased bulk, a person shouldn't switch to foods with large amounts of fiber all at once. A sensible approach is to slowly increase consumption of grains, legumes, seeds, and nuts. "Some may choose to eliminate red meat but continue to eat fish and poultry occasionally, and such a diet is also to be encouraged," said Jack Zeev Yetiv, M.D., Ph.D., in his book Popular Nutritional Practices: A Scientific Appraisal.

As with any diet, it's important for the vegetarian diet to include many different foods, since no one food contains all the nutrients required for good health. "The wider the variety, the greater the chance of getting the nutrients you need," says FDA's Vanderveen.

In its position paper on vegetarian diets, the American Dietetic Association states that, with a plant-based daily diet, eating a variety of foods and sufficient calories for energy needs will help ensure adequate intakes of calcium, iron and zinc.

The mixture of proteins from grains, legumes, seeds, nuts, and vegetables provides a complement of amino acids so that deficits in one food are made up by another. Not all types of plant foods need to be eaten at the same meal, since the amino acids are combined in the body's protein pool.

"Soy protein," the paper states, "has been shown to be nutritionally equivalent in protein value to proteins of animal origin and, thus, can serve as the sole source of protein intake if desired."

The Institute of Food Technologists also recommends careful diet planning for vegetarians. This is especially important when the diet excludes dairy foods, to ensure adequate intake of calcium, iron, riboflavin, and vitamin D. For these vegetarians, the institute recommends calcium supplements during pregnancy, when breast-feeding, and for infants and children.

The institute and the American Dietetic Association say a vitamin D supplement may be needed if sunlight exposure is limited. (Sunlight activates a substance in the skin and converts it into vitamin D.)

They also point out that vegan diets should include a reliable source of vitamin B12, because this nutrient occurs only in animal foods. Vitamin B12 deficiency can result in irreversible nerve deterioration.

The need for vitamin B12 increases during pregnancy, breast-feeding, and periods of growth, Dwyer says. In a recent issue of Annual Review of Public Health, she writes that elderly people also should be especially cautious about adopting vegetarian diets because their bodies may absorb vitamin B12 poorly.

Unless advised otherwise by a doctor, those taking dietary supplements should limit the dose to 100 percent of the U.S. Recommended Daily Allowances.

With the array of fruits, vegetables, grains, and spices available in U.S. grocery stores and the availability of vegetarian cookbooks, it's easy to devise tasty vegetarian dishes that even non-vegetarians can enjoy.

However, the key to any healthful diet—vegetarian or non-vegetarian—is adherence to sound nutrition principles.

SIGNIFICANCE

In the ten or so years that have elapsed since the above article appeared, the food and health debate has narrowed to focus on the optimal balance of fat, protein, and carbohydrate in the diet.

The vegan diet is the most restrictive form of vegetarianism, for it excludes any kind of animalbased food. Lacto-vegetarians eat dairy products such as milk and cheese, but not eggs. Lacto-ovo-vegetarians include both dairy and eggs. There are even more "liberal" vegetarians who eat fish and chicken but avoid all red meat. These varied diets will, inevitably, have very different amounts of fat, protein, and carbohydrate.

When Diet for a Small Planet was published, some nutritionists were concerned that a meatless diet would not contain sufficient protein and could have an adverse effect on health. Lappé herself believed, at the time, that plant protein was not as complete, in terms of its amino acid content, as animal protein. To compensate, she advocated "protein complementarity"—in which plant foods are eaten in prescribed combinations (rice and beans, for instance) to get the proper balance of amino acids. This made the vegetarian diet a complicated prospect for many. However, the theory was later discredited and she retracted it in the 1981 edition of the book.

When considering protein content, foods must be evaluated in their own right, rather than as plant or animal derived. Experts disagree on how much protein is necessary to maintain health—estimates vary between 2 and 10 percent of daily dietary intake. Meat contains, on average, 50 percent protein, although bacon has only 5. Beans contain on average 28 percent protein, nuts 10, and fruit about 5. In general, a varied diet—vegetarian or not—provides a sufficient amount of protein. Strict vegetarians and vegans, however, must guard against vitamin B12 deficiency, since animal foods are the main source of this vitamin.

In 1999, the FDA highlighted the benefits of soy protein, which for many vegetarians many is a diet staple. Products with more than 6.25 grams of soy protein per serving were labeled "heart healthy," since many studies indicated that soy protein could lower the cholesterol profile which, in turn, lowers the risk of heart disease. Obtaining these health benefits, however, was thought to require a daily intake of at least 25 grams of soy protein. This can come from tofu or tempeh, both made from cooked soybeans; miso, a paste made from fermented soybeans; or soy milk. Many vegetarian versions of meat products like hamburgers and sausages also contain high amounts of soy protein. In January 2005, however, the American Heart Association backed away from its strong endorsement of soy protein as beneficial in reducing risk factors for cardiovascular disease. Based on data from twenty-two randomized clinical trials, the American Heart Association stated it found no measured benefit from soy protein in lowering LDL cholesterol, improving HDL cholesterol, or lowering blood pressure. Although there is still much to learn about what makes a nutritionally complete, healthy diet, the vegetarian trend is now considered a growing mainstream nutritional option.

FURTHER RESOURCES

Books

Lappé, Frances Moore. Diet for a Small Planet. Twentieth Anniversary Edition. New York: Ballantine, 1991.

Web sites

FDA Consumer Magazine. "Soy: Health Claims for Soy Protein, Questions About Other Components." 〈http://www.fda.gov/fdac/features/2000/300_soy.html〉 (accessed March 20, 2006).

Vegetarian Guide. "A History of Vegetarianism" 〈http://michaelbluejay.com/veg/history.html〉 (accessed January 8, 2006).