Vegetarians refrain from eating animal flesh of any kind. Lacto vegetarians accept dairy foods, and lacto ovo vegetarians both dairy and eggs. Vegans are vegetarians who refrain from dairy, eggs, and often honey. Ethical concern for animals and the environment motivate most people who adopt such vegetarian diets. However, growing scientific evidence reveals that vegetarianism can also have substantial health benefits for its practitioners as well. The American Heart Association cautions that a vegetarian diet "can be unhealthy if it contains too many calories and/or saturated fat." It must be "carefully planned" to yield its health benefits.
Lower Rates of Some Cancers
Compared to the general population, vegetarians have lower rates of some cancers, especially prostate, colorectal, and possibly other malignancies of the gastrointestinal tract. Non-vegetarians may have an 88 percent higher rate of colorectal cancer and a 54 percent higher rate of prostate cancer than vegetarians. The exact reasons for such differences in cancer rates are as yet unknown but likely complex. One possibility is that vegetarians probably take in more phytochemicals, plant compounds with many known antioxidant and other cancer-reducing properties.
Better Cardiovascular Health
Ischemic heart disease involves reduced oxygen supply to heart muscle. Lifelong vegans may have as much as 57 percent less ischemic heart disease and lifelong vegetarians 24 percent less than meat eaters, perhaps because vegetarianism often results in reduced total and low density lipoprotein or LDL cholesterol. Vegetarianism and especially veganism also protect against hypertension, or high blood pressure, perhaps because vegetarians have lower rates of overweight and obesity and likely consume more beneficial plant compounds.
Reduced Vulnerability to Type 2 Diabetes
In type 2 diabetes, the body produces insulin but has difficulty using it to metabolize food. Even when their overall lower rates of obesity and overweight are factored out, vegetarians are at reduced risk for type 2 diabetes. Higher consumption of whole grains, legumes, and nuts appears to make the body more sensitive to the insulin it produces.
Protection Against Kidney Disease
Vegetarian diets appear connected to lower rates of kidney disease as well as slower progression when it already exists. This could be because vegetarians tend to have lower cholesterol levels and appear to consume less protein. In addition plant-derived proteins may stress the kidneys less than animal-derived.
Less Risk of Dementia
As long as their vitamin B12 intake is adequate, vegetarians appear less vulnerable to dementia than meat eaters. egetarians' lower blood pressure readings and cholesterol levels seem to result in less vascular, or blood vessel, disease in the brain.
Other Possible Benefits
Although the evidence is more limited than for other health benefits, vegetarianism may help protect against gallstones and diverticulitis, a chronic inflammatory disease of the intestines. Studies of vegetarianism and rheumatoid arthritis, also a chronic inflammatory disease, are inconclusive but intriguing. Vegetarians with adequate calcium intake--for example from dairy, fortified nondairy milks or leafy greens---appear to enjoy at least the same bone health as meat eaters.
References
- American Dietetic Association: Vegetarian Diets
- American Heart Association: Vegetarian Diets
- Dietitians of Canada: Position of the American Dietetic Association and Dietitians of Canada: Vegetarian Diets
- Vegetarian Nutrition: Vegetarian Diets and Cancer Prevention
- Vegetarian Nutrition: Vegetarian Diets in the Treatment of Rheumatoid Arthritis
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