There is much evidence that vegetarian diets (and even more so vegan diets) have many health benefits and can reduce and in some cases reverse several life-threatening diseases.
The Academy of Nutrition and Dietetics, formerly known as the American Dietetic Association, a valuable, respected source for health and nutrition information, states that, “well-planned vegetarian diets are appropriate for individuals during all stages of the life cycle, … are associated with a lower risk of death from heart disease, … [result in] lower low-density lipoprotein cholesterol levels, lower blood pressure, and lower rates of hypertension and type 2 diabetes, … [and in] lower body mass index and lower overall cancer rates.”
Their conclusions are reinforced by many types of scientific studies:
Migration studies: When Japanese people migrate to the United States and shift to the standard American diet, their rates of chronic, degenerative diseases increase sharply.
Wartime studies: When the meat supply was sharply reduced for Denmark during World War 1 and Norway during World War 2, the death rates due to diseases sharply decreased only to return to pre-war levels after the wars ended.
Epidemiological studies: The China-Cornell-Oxford study, the largest epidemiological study in history, dubbed by the New York Times as ‘the grande prix of epidemiology, investigated the health and mortality conditions for 6,500 people in 65 Chinese communities, in each of which the diet conditions were relatively uniform. The researchers concluded that the more animal protein and fat in the diet the greater the risk for serious diseases. Other epidemiological studies reached similar conclusions.
Time-trend studies: Countries like China and Japan that have shifted toward animal-based dies in recent years have seen a sharp increase in life-threatening diseases. By contrast, Finland has sharply reduced its meat consumption and made other positive lifestyle changes, resulting in an 80% decrease in heart disease.
Controlled studies: Dr. Dean Ornish, an American doctor from California, worked with patients with severe heart problems, 28 of whom went on a mainly vegan diet and 20 of whom served as a control group adopting the diet recommended by the U.S. medical establishment, up to 30% fat and permitting chicken without the skin and fish, with both groups randomly chosen. After one year, almost everyone on the vegan diet saw sharp decreases in coronary blockages and a complete or nearly complete disappearance of chest pains, while none of the people in the control group saw an improvement and some experienced increased heart problems. More recently, other doctors found comparable results from similar studies. Initially insurance companies would not reimburse people who were treated with the Dr. Ornish approach but later they recognised that it is far less expensive and more permanent and now do reimburse for it.
Based on a comprehensive review of such studies, Robert M. Kradjian, a breast cancer surgeon for thirty years, concluded that the main cause of breast cancer is animal-based diets. He argues that prevention, not early detection, is the best defense against the disease. His conclusions are in his potentially groundbreaking book, “Save Yourself from Breast Cancer: Life Choices That Can Help You Reduce the Odds.”
Despite the very strong evidence from the studies mentioned above, very few people in the western world have vegetarian or vegan diets. A major reason involves the belief that major amounts of protein and calcium are needed for proper nutrition. Probably the most common question that vegetarians and vegans get is, ‘how do you get enough protein?” Yet, well-balanced, nutritious vegan diets easily provide enough protein. The incorrect thought that humans need a lot of protein is because much of the initial protein research was based on experiments with rats. While a rat’s mother’s milk has almost 50% of its calories in protein, a human mother’s milk, ideal for an infant who will double his or her birth weight in about six months, has only six percent of its calories in protein. Many plant foods, including nuts, seeds, legumes, beans, and even some fruits, including melons, and vegetables, including spinach, have far more than that six percent and have positive health effects. But excessive animal protein in the diet has negative health effects.
It is commonly believed that consuming large amounts of calcium, especially in the form of dairy products, is the best way to avoid getting osteoporosis. However, the countries that consume the most dairy products, including the United States, Israel, and Scandinavian countries, have the highest percentages of people with osteoporosis. Most Chinese people are lactose intolerant and thus consume far less dairy products, resulting in far less calcium in their diets. Yet they get far less osteoporosis. One theory is that the high amounts of protein in dairy products and other animal-based foods acidify the blood and calcium is needed to buffer or neutralise the excess acidity. If there is not enough calcium in the blood it is drawn from the bones. Since the human body can absorb only a limited amount of protein, unlike the case for fat and carbohydrates, the excess protein is excreted along with calcium, leading to a negative calcium balance, even when large amounts of calcium have been consumed, increasing the risk of getting osteoporosis. Since the excreted protein and calcium passes through and strains the kidneys, kidney problems also often result from high animal-based diets. Fortunately, several plant-foods, including green, leafy vegetables and soybeans, are good sources of calcium.
In summary, one can be properly nourished and very healthy on a vegetarian or vegan diet. However, to be extra safe, it is important to, as with other kinds of diets, have periodic medical checkups, including blood tests, to assure that all necessary nutrients are being obtained.