A Scientific Basis for Vegetarianism
Deep Roots of Vegetarianism
Many people possess the misconception that man’s early ancestors were mighty hunters. Indeed, fossil records clearly show that humans and their ancestors ate meat throughout the process of evolution. The amount of meat consumed by developing humans, however, varied considerably. During the Ice Age, vegetation was scarce and diets relied more heavily on meat. At other times, especially after the development of agriculture, plants were the major source of nourishment (Messina 9). Even before agriculture, diets centered on vegetables, fruits, nuts, seeds, and meat. The heavy skeletal structure of Neanderthals and Cro-Magnons suggests that they were receiving large amounts of calcium, which was abundant in the wild vegetation that existed at the time (10).
The earliest human ancestors scavenged, eating what was left after a predator had abandoned his kill. Some anthropologists point out that cuts in animal bones made by prehumans are often found in places where there was likely to have been very little meat. Perhaps human ancestors ate only the nutrient rich marrow left in these bones (Messina 9).
Through much of human history, even before the dawn of agriculture, plant foods were the staples of the diet. With the advent of farming, ten to twelve thousand years ago, the diet became almost ninety percent plant-based (10).
The ancient Greeks developed vegetarianism. Pythagoras and Porphyry were the best known, although Diogenes, Plato, Epicurus, and Plutarch also supported the cause (Amato and Partridge 2). Pythagoras thought vegetarianism was the most natural and healthy way of eating. To attain spiritual and physical health, he prescribed a lifestyle that included an ordered daily regimen, simple clothing, and vegetarian diet of fresh foods (Messina 10). In The Republic, Plato describes the vegetarian diet as being the best suited for his ideal society because it promotes health and requires less land to support. Other Greek thinkers often rejected meat on aesthetic grounds. Vegetarianism was carried over into Roman culture and furthered by the poet Ovid and the philosopher Seneca (Amato and Partridge 2).
At the fall of Rome and the spread of Christianity, vegetarianism lost popularity. Saint Augustine, Saint Thomas Aquinas, and other Christian thinkers provided intellectual grounds for the eating of animals by humans. Animals, they argued, did not have souls, free will, or rationality and were placed on earth for human benefit. Monks of the Benedictine, Trappist, and Cistercian orders of Christianity, however, all practiced vegetarianism for some length of time (Amato and Partridge 3).
If that era were to be considered the "Dark Ages" of vegetarianism, its "Renaissance" can be said to have occurred during the late eighteenth and nineteenth centuries (3). Justification for the eating of animals grew harder to find with the acceptance of Darwin’s theory of evolution. People now felt a certain connection to what had previously been just their food, and with this altered attitude appeared the first written European works on vegetarianism. Writers, Leo Tolstoy and Percy Bysshe Shelley advocated the "Pythagorean diet" (4).
The Bible Christian Church, founded by William Cowherd in 1809 in Manchester, England, proclaimed that Christ’s teachings of mercy extended to animals and that vegetarianism was a healthier lifestyle. Members of this church eventually formed the Vegetarian Society in 1847, the first secular vegetarian organization in the West. It still exists today as the Vegetarian Society of the United Kingdom (Amato and Partridge 4).
Other religious groups, such as the Seventh-Day Adventists, also carried the movement into the twentieth century. Local groups and organizations forming in most Western countries furthered vegetarianism. It was supported by public figures such as George Bernard Shaw and Mohandas Gandhi. The International Vegetarian Union, which is still active today, entered the scene in 1908, calling conferences for vegetarians from around the globe (4, 5).
Social activism of the 1960s and 1970s boosted vegetarianism’s popularity. People found new interests in the effect of diet on health and grew fascinated with Eastern philosophy and religion. They developed the desire to preserve the environment and support the rights of the oppressed. The peace movement grew, along with the utopian belief in a perfectible society (5).
Health and Disease
Some researchers consider the desire for meat an innate and permanent biological impulse. Less than one percent of the world’s population practices vegetarianism voluntarily. In underdeveloped countries, meat is simply unavailable to a large section of the population. In addition, those who can afford to purchase meat will seldom abstain from flesh foods, and meat consumption climbs rapidly with a country’s economic prosperity. Are humans simply natural carnivores (Ballentine 71)?
Humans do have four canines for the shredding of meat, and they do lack the extra stomachs of grazing animals. Human canines, however, are short and blunt. The mouth contains twenty molars, for crushing and grinding plant foods, and eight incisors, for biting into fruits and vegetables. While a carnivore’s jaw only swings vertically, to tear food, the human jaw swings vertically and laterally, to crush food (Murray and Pizzorno 44).
The saliva of humans, unlike that of carnivores and omnivores, contains enzymes designed to break down carbohydrates. The length of the small intestine in carnivores and omnivores is less than six times the length of the body. In humans, as in herbivores, the small intestine exceeds ten body lengths (Messina 16).
Like humans, other primates, such as monkeys, gorillas, and chimpanzees, are omnivores. Researchers often call them "herbivores and opportunistic carnivores" (Murray and Pizzorno 45). Their diets consist mainly of fruits and vegetables but sometimes include small animals and eggs.
The amount of animal food a particular primate consumes is generally inversely related to its body weight. The gorilla obtains only one percent of its total calories from animal foods, while the smaller orangutan consumes two percent. Humans are between the weight of these primates, and some researchers thereby conclude that the human body is best suited to derive approximately one-and-one-half percent of its calories from animal foods (45).
The acceptance of vegetarianism as a natural diet has been hindered by several misconceptions about the body’s needs that a society raised on meat is bound to have. Those claiming that vegetarianism is an unhealthy diet often believe that it is unable to provide an individual with some nutrients, primarily protein, iron, and calcium.
Protein deficiency is so rare in America that many nutritionists and doctors would be unable to identify the symptoms (Vegetarian Times 20). Most vegetarians, in fact, exceed the recommended dietary allowance of protein by fifteen grams (Turner). In her 1971 edition of Diet for a Small Planet, Lappé suggested that vegetarians needed to combine protein sources from plants in order to make them available to the body, a myth that still exists today. In the 1991 edition of her book, however, Lappé concedes that this is not the case (Lappé 162). Even vegans appear to have no difficulty meeting protein requirements. As long as the diet contains variety of plant foods and enough whole plant foods to meet calorie needs, protein intake will be adequate (Stepaniak 212).
In the past, researchers linked iron deficiency to plant-based diets because it was prevalent in third-world countries, where meat-consumption was low. The true cause of the deficiency, it appears today, was a lack of vitamin C, which is necessary for iron absorption (Vegetarian Times 26).
Lacto ovo vegetarians, those who occasionally eat dairy or eggs, have calcium intakes as high or higher than those of meat-eaters (Turner). Nutritionists believed, for a long time, that calcium was not absorbed well from plant foods. Recent studies show that this is not the case. Calcium is better absorbed from some plant foods than it is from milk (Stepaniak 215).
"Research clearly indicates that vegetarians tend to be healthier and live longer than do omnivores" (Parachin 10). A twenty-one year study comparing the health of vegetarians and meat-eaters in a group of 27,529 Californians determined that the greater the meat consumption, the greater the death rate from all causes combined (10). The practice of vegetarianism is not only natural for the human body, but it is also linked to a lower incidence of many diseases.
Atherosclerosis, the hardening of arteries caused by a buildup of a fatty substance on the linings of the blood vessels, is a primary cause of many vascular diseases. The atherosclerotic diseases are the cause of over half of all deaths in America (Ballentine 49, 50)!
One atherosclerotic disease, heart disease, kills 550,000 people every year in the United States (8). The average American takes in forty to forty-five percent of his calories from fats and oils (45). In Japan, at a time when, in some regions, people received less than ten percent of their calories from fat, heart disease was virtually unknown (Ballentine 50).
"Research suggests that development of atherosclerosis could be significantly retarded or even totally prevented by a marked reduction in dietary fats and oils" (50). According to the American Heart Association, the greatest risk factors in heart disease are high cholesterol, high blood pressure, and smoking, followed by diabetes, lack of exercise, obesity, and a family history of the disease (Amato and Partridge 11).
In plants, cholesterol is completely absent, and saturated fat, which boosts cholesterol levels, is scarce. Vegetarians have lower blood pressure and weigh less than do meat-eaters. According to a review by the Physicians Committee for Responsible Medicine, of more than one hundred research studies from around the world, vegetarians have fifty-six percent fewer cases of heart disease than have meat-eaters ("In Posthumous Book…").
Atherosclerosis also causes high blood pressure, or hypertension. This condition affects more than sixty million Americans and over half of all Americans ages sixty-five to seventy-four (Murray and Pizzorno 524). According to the Physicians Committee for Responsible Medicine, vegetarians have fifty percent fewer cases of hypertension ("In Posthumous Book…"). This low level of occurrences may be attributable to a diet high in potassium, complex carbohydrates, essential fatty acids, fiber, calcium, magnesium, and vitamin C, and low in cholesterol and saturated fat (Murray and Pizzorno 526).
An estimated sixty percent of U.S. cancer cases in women and forty percent in men are significantly related to diet (Ballentine 11). According to the FDA, diets low in fats and high in whole grains, fruits and vegetables, and other rich sources of fiber are associated with a reduced risk of some types of cancer (Farley). Fats and oils are thought to interact with radiation and environmental chemicals, such as tars and certain drugs, to produce cancer (Ballentine 47).
Breast cancer does not occur frequently in populations around the world that eat plant-based diets. Vegetarians generally have lower levels of blood estrogens, which raise the risk of breast cancer. The length of time between periods in vegetarian women is longer, which means less overall exposure to estrogen over the course of a lifetime. They begin menstruation later than average, a change that also reduces risk. Soy and soy products consumed by many vegetarians contain isoflavons, which can block the activity of estrogen (Messina 38).
The type of cancer with which diet is most strongly connected is colon cancer, and vegetarians are much less likely to develop this disease. There is less cell proliferation, growth and division, in the colons of vegetarians. This reduces the number of cells that are likely to turn cancerous. In the colon, primary bile acids are turned into their carcinogenic counterpart, secondary bile acids. People consuming plant-based diets have fewer of these carcinogenic bile acids, an effect partly produced by a lower level of the types of bacteria that convert primary acids to secondary ones. In addition, vegetarians have lower levels of fecal enzymes that enhance the absorption of carcinogens and lower levels of mutagens, which promote cancer cell formation (Messina 38, 39).
Other diseases often can be traced back to a few primary causes, some of which have already been mentioned. Diabetes, for example, is more common in people who eat more sugar, fat, and protein (especially animal fat and animal protein) and who have higher cholesterol levels. It is less common in people with high carbohydrate and high vegetable fat intakes (Messina 43).
Kidney disease can be caused by the high rate of filtration brought on by excess protein in the diet. The filtration rate of vegetarians is approximately half that of meat eaters. In addition, animal proteins increase the rate more than do plant proteins (Messina 45).
High filtration rates increase the excretion of calcium into the urine, which causes kidney stone formation, a separate disease. Once again, more protein equates to greater risk. In a study of 50,000 men, animal protein increased risk by thirty percent (46).
The best diet concerning the prevention of obesity, which afflicts about one-fourth of all adults below age seventy-four, is low in fat and high in carbohydrates and fiber (44). Low fiber is connected to the development of gallstones. In addition, animal proteins increase gallstone formation, whereas vegetable proteins lower rates (Murray and Pizzorno 480).
The excretion of calcium caused by excess protein is not only associated with kidney stone formation, but it can also lead to osteoporosis. Raising the daily protein intake from forty-seven to one hundred forty-two grams per day, a level not uncommon in the U.S., doubles excretion of calcium (713).
Meat-based diets sometimes cause damage more directly. After the 1993 outbreak of E. coli, the United States Department of Agriculture hired two hundred new meat inspectors, at a cost of over five hundred million dollars. However, outbreaks of poisoning from E. coli, Salmonella, and other food-borne illnesses continue today. The USDA estimates that fifteen percent of meat and poultry carcasses are contaminated with disease-causing bacteria (Parachin 64).
Ethical Considerations
It is not hard to illustrate the economic inefficiency that accompanies the typical American diet. "Even driving many gas-guzzling luxury cars can conserve energy over walking—that is, when the calories you burn walking come from the standard American diet!" (Robbins 375). Two calories of fossil fuel are expended to produce one calorie from soy protein, whereas seventy-eight calories of fossil fuel must be expended to obtain one calorie from beef protein (Vegetarian Times 7).
The production of animal foods requires more than one-third of all the raw materials used in America, including fossil fuels like petroleum. It takes forty-eight gallons of gasoline to produce the amount of poultry and red meat consumed by the typical American each year (Messina 53). The production of meat, egg, and dairy protein requires more than eight times as much fossil fuel energy than that needed to produce an equivalent amount of plant protein (Stepaniak 68). In fact, the value of resources used to produce food from livestock is greater than the value of all oil, gas, and coal consumed in the U.S. Growing grains, vegetables, and fruits uses less than five percent of the raw materials consumed by meat production (Robins 374).
Seventy-two percent of the cereals produced in the U.S. is devoted to meat production, and only eleven percent is fed directly to humans (Stepaniak 59). The production of one pound of beef requires sixteen pounds of grain and soybeans and 2,500 gallons of water. In fact, fifty percent of the water consumed in America is used to produce beef alone (Clarke and Riedlinger). At least eighty percent of America’s water is used on feed-crops. Non-industrial domestic consumption accounts for only five percent (Stepaniak 59).
The excessive number of feed-crops the U.S. must grow in order to maintain its meat habit are taxing the soil, increasing the need for fertilizers, and leading to an import dependency. Corn alone uses forty percent of Americas major fertilizers. Twenty percent of ammonia fertilizer and sixty-five percent of potash fertilizer is currently imported from other countries (Lappé 10).
The inefficiency of supporting meat-diets is evident across the globe. Industrialized countries, which contain twenty-four percent of the world’s population, consume forty-eight percent of the world’s grain and sixty-one percent of its meat. These figures should come as no surprise, considering that nearly half of the world’s cereal production is used to feed animals (Clarke and Riedlinger).
It is hard to estimate the amount of money that could be saved by reduction of illnesses were the world to make a transition to vegetarianism. Though only five percent of the population actually has a hereditary tendency toward heart disease, forty-four billion dollars are spent annually in the U.S. just for angioplasty and bypass surgeries (Vegetarian Times 119, 120). Together, coronary heart disease, cancer, stroke, diabetes, obesity, hypertension, and osteoporosis cost the U.S. approximately two hundred fifty billion dollars every year in medical costs and lost productivity (Frazao).
National, state, and local governments spend billions of dollars every year subsidizing animal agriculture. There are government funded programs to kill pests and provide water, drainage, fencing, and topsoil conservation for ranchers. Governments sometimes buy unneeded dairy products in order to artificially boost prices (Reinhardt 214).
If the cost of water to the meat industry were not subsidized by local and federal governments, the entire industry would be unprofitable. "[T]he cheapest hamburger meat would cost more than thirty-five dollars a pound" (Robins 367). Every dollar in irrigation subsidies given to livestock producers costs tax payers over seven dollars in lost wages, higher living costs, and reduced business income (368).
World hunger is "equally complicated in terms of ethics, politics, and economics" (Havala 21). It is obvious, however, that eating high on the food chain is not an efficient way to utilize resources. By using grain to produce livestock, ninety percent of its protein, ninety-six percent of its calories, and all of its fiber and carbohydrates are lost (Robins 352). It is also clear that if people ate low on the food chain, there would be more than enough food available—enough to supply every human being with 3,600 calories every day (Clarke and Riedlinger).
There is an economic connection between meat consumption and world hunger. The market for animal feed and livestock is strong in poor countries, just as it is in affluent ones. The small percentage of people that have economic power in developing nations are interested in profit, so they choose to grow cash crops or to raise animals for exportation (Havala 22). Millions of peasants are forced off of family farms by the pressure to grow animal feed (Stone). Land and other resources that might have otherwise been used to produce food for the local population is thus depleted (Havala 22).
Guatemala provides a perfect example. It exports forty million pounds of meat to America every year, while seventy-five percent of Guatemalan children younger than five years old are undernourished (Robins 352).
The meat industry is also, to a certain extent, responsible for poverty in America. Jobs in the meat-processing and slaughter industries are considered to be among the most dangerous ones in North America. Work injuries include carpal tunnel syndrome, cumulative trauma disorder, ammonia exposure, tuberculosis, infections from toxins, puncture wounds and gashes, and crippling disabilities (Stepaniak 52) For this reason, these industries are "virtually dependent on a steady flow of legal and illegal immigrant labor" (Stepaniak 52). Eighty percent of slaughterhouse jobs are held by people of color, immigrants, and women between the age of eighteen and twenty-five making five to six dollars and hour.
Before animal agribusinesses opted for ruralization in the 1980s, the unionized white majority of the workforce earned nineteen dollars an hour, benefits included. Today, health care coverage and other benefits are rare. Where they are offered, many workers are fired before they would go into effect (Stepaniak 53).
Packing and processing plants often release wastewater that contaminates drinking water and groundwater. Some emit ammonia gas, which is linked to acid rain. Impoverished communities have neither the political nor economic means to challenge these practices or move to other areas (54). Beef industry workers have illiteracy rates among the highest in the nation (Stone).
"[T]he process of livestock rearing is the most ecologically damaging segment of the entire U.S. agribusiness industry, and perhaps all other industries as well" (Stepaniak 60). This damage is caused by irrigation, feedlot waste runoff, fertilization, chemical spraying of animal feed-crops, meat processing and packing, and refrigerated transport of meat to the grocery shelf (60).
Agriculture accounts for sixty-four percent of all river pollution and fifty-seven percent of all lake pollution. Animal excrement is one of the biggest sources of agricultural pollution (Messina 54). U.S. livestock produces twenty times as much excrement as the entire human population of the country, at a rate of about two hundred fifty thousand pounds per second (Robbins 372).
The water that has not yet been polluted is being consumed rapidly. It is being depleted from groundwater stocks at a rate twenty-five percent higher than the rate at which it is replaced. The Colorado River is so depleted by irrigation for California, Colorado, and Arizona’s feed-crops that it no longer flows into Mexico. The Ogallala aquifer, the main source of water for the plains states, is being consumed sixty percent faster than nature can replenish it; at this rate, it will be nonproductive within forty years (Stepaniak 63).
The manure that contaminates rivers causes rapid growth of algae, which depletes water of oxygen and triggers a process called eutrophication. The U.S. Senate Agricultural Committee linked animal waste to a "dead zone" in the Gulf of Mexico. This seven thousand square mile area is now incapable of supporting life because of low enough oxygen levels (65).
Animal agriculture contributes to global warming. The two primary sources of methane, a greenhouse gas, are rice paddies and cattle. The sheep, goats, and cattle on the planet produce seventy to eighty million tons of this gas every year, as much as thirty percent of the total amount released into the atmosphere.
The destruction of the rainforest, as a means of producing land for grazing, also contributes to the greenhouse effect. The burning of the trees produces large amounts of carbon dioxide (Messina 54). Since 1960, more than one-third of the tropical rainforest in Central America has been destroyed to create land for cattle grazing (53).
The current rate of soil erosion in the U.S. is significantly higher than it was during the 1930s dust-bowl era. Nature creates topsoil in America at a rate of about one-inch every hundred years. Ninety percent of American cropland is loosing soil at thirteen times this rate. In most western rangeland, it could take several hundred years to replace one inch of soil (Stepaniak 61). Erosion causes eutrophication, drainage disruption, sewer siltation, flooding, loss of wildlife habitat, disruption of stream ecology, and a reduction in the ability of soil to filter carbon dioxide (62).
Animal agriculture is accountable for at least eighty-five percent of this topsoil loss (Reinhardt 83). Soil compaction, feed-crop production, and overgrazing are the major contributors to the problem. The erosion caused by overgrazing has killed off more plant species in America than any other cause.
Elk and many other native species cannot compete with cattle for the little food that is left. Even animals in national parks and grasslands, wildlife refuges, and other sensitive areas are no longer safe. The government allows cattle grazing in half of all the designated wilderness areas in the West (Stepaniak 62).
The Vegetarian Future
People are becoming increasingly aware of the force with which diet affects life, on both the individual and global levels. When people set aside their preconceptions and examine the empirical evidence, it is obvious that vegetarianism is healthful and natural for the human body. People are also beginning to understand the intricate connection between our eating habits, poverty, global economics, and the environment. Knowledge of these relationships gives us an opportunity to improve our lives as individuals and promote balance in the world we share.
Works Cited
Amato, Paul R., and Sonia A. Partridge. The New Vegetarians. New York City: Plenum Press, 1989.
Ballentine, Rudolf. Transition to Vegetarianism. Honesdale, PA: The Himalayan Institute Press, 1999.
Clarke, Beth and Dyanna Riedlinger. "The Politics of Vegetarianism." Briarpatch Feb. 1997: 18-19. [SIRS].
Farley, Dixie. "Vegetarian Diets." FDA Consumer Magazine May 1995: 1-4. [SIRS].
Frazao, Elizabeth. "The American Diet: a Costly Health Problem." FoodReview Jan.-April 1996: 2-6. [SIRS].
Havala, Suzanne. The Complete Idiot’s Guide to Being Vegetarian. New York City: Alpha Books, 1999.
Lappé, Frances Moore. Diet for a Small Planet. New York: Ballantine Books, 1991.
Messina, Virginia, and Mark Messina. The Vegetarian Way. New York City: Crown Trade Paperbacks, 1996.
Murray, Michael and Joseph Pizzorno. Encyclopedia of Natural Medicine. Rocklin, CA: Prima Publishing, 1998.
Parachin, Victor. 365 Good Reasons to be a Vegetarian. Garden City Park, NY: Avery Publishing Group, 1998.
"In Posthumous Book, Noted Child Doctor Advocates Vegan Diets for Kids." Environmental News Network April 22, 2001. [EBSCO].
Reinhardt, Mark Warren. The Perfectly Contented Meat-Eater’s Guide to Vegetarianism. New York: Continuum Publishing, 1998.
Robins, John. Diet for a New America. Walpole, NH: Stillpoint Publishing, 1987.
Stepaniak, Joanne. The Vegan Sourcebook. Los Angeles: Lowell House, 1998.
Stone, Eden. "Good-bye to Beef." New Age Journal March-April 1992: 43-9. [SIRS].
Turner, Lisa. "Vegetarian Options." Better Nutrition Oct. 2000: 68-6. [EBSCO].
Vegetarian Times Vegetarian Beginner’s Guide. New York City: Macmillan, 1996.
