If you are what you eat, then you would expect vegetarians and meat-eaters to vary in overall health. Both vegetarian and meat-based diets can have health benefits and drawbacks. Strict vegans, who consume no animal products but who are considered a type of vegetarian, have different health issues than vegetarians who include poultry, eggs or fish in their diets. The amount and type of meat you eat can affect the health of meat-eaters. For both vegetarians and meat-eaters, many factors can affect health, but some generalizations apply.
Body Mass Index
The rise in the average American body mass index causes grave concern among health practitioners. Extra weight increases the risk of cardiovascular disease, diabetes and arthritis. In a University of Oxford EPIC study reported in the June 2003 "International Journal of Obesity and Related Metabolic Disorders," researchers compared body mass index, or BMI, between four dietary groups. The study, which included 37,875 individuals, divided subjects into meat-eaters, fish eaters, vegetarians, who eat eggs, and strict vegans. All three of the vegetarian groups had a lower body mass index on average than the meat-eater group. High-protein and low-fiber intake correlated with the highest BMI levels; vegans had the lowest BMI.
Vegetarians have a higher risk of developing nutritional deficiencies caused by lack of animal protein in their diet than meat-eaters. The more restrictive the diet, the higher potential for vitamin B-12, protein, calcium and iron deficiencies. Food from animals supplies all the essential amino acids, the building blocks for protein, while most plant proteins, with the exception of soy and the grain quinoa, do not contain all the essential amino acids. Vegetarians must consume foods that contain different amino acids over the course of the day to ensure that they get all the amino acids they need. While plants contain iron, your body absorbs the iron they supply, called nonheme iron, less efficiently than heme iron from meat. Consuming foods high in vitamin C along with plants high in iron increases iron absorption. Many vegetables contain substances that reduce calcium absorption, increasing the risk of calcium deficiency and bone loss in vegetarians who don't consume dairy products. Beans, lentils and vegetables such as spinach contain iron.
Heart Disease Risks
Vegetarians tend to have lower cholesterol levels than meat-eaters. High cholesterol is a risk factor for heart disease. A Brazilian study published in the January 2007 issue of "Arquivos Brasileiros de Cardiologia" compared cholesterol and triglyceride levels in different types of vegetarians and meat-eaters. Vegans had the lowest total cholesterol, low-density lipoprotein, the so-called "bad" cholesterol and triglyceride levels, while meat-eaters had the highest levels. However, vegetarians also have some increased risks for heart disease, according to a Chinese study published in the February 2011 "Journal of Agriculture and Food Chemistry." Risks include lower high-density lipoprotein levels -- the "good" cholesterol -- as well as lower omage-3 fatty acid levels and higher homocysteine levels, all associated with a higher risk of heart disease.
Studies on cancer in vegetarians compared to meat-eaters have shown mixed results. Some studies have shown a mildly protective benefit against cancer in those who follow a vegetarian diet. A University of North Carolina Asheville article published in the December 2010 issue of "Cancer Management and Research" suggested a 10 to 12 percent reduction in cancers in vegetarians compared to meat-eaters. A study published in the May 2009 "American Journal of Clinical Nutrition," which used data derived from the University of Oxford EPIC study, found a lower risk of most cancer in vegetarians compared to meat-eaters but a higher risk of colorectal cancer.
- Journal of Agriculture and Food Chemistry: Chemistry Behind Vegetarianism
- International Journal of Obesity and Related Metabolic Disorders: Diet and body mass index in 38000 EPIC-Oxford Meat-eaters, Fish-eaters, Vegetarians and Vegans
- University of California, Davis: Vegetarian Diets
- Arquivos Brasileiros de Cardiologia: Vegetarian Diet and Cholesterol and Triglycerides Levels
- Cancer Management and Research: Reduced Cancer Risk in Vegetarians: An Analysis of Recent Reports
- American Journal of Clinical Nutrition: Cancer Incidence in Vegetarians: Results from the European Prospective Investigation into Cancer and Nutrition (EPIC-Oxford)
- Columbia University Health Services: Complete and Incomplete Proteins in Grains and Vegetables?
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