Many people are now self-declaring they are vegetarians and say they eat no meat of any kind. Are these types of diets always healthy? A recent review of studies shows that some vegans’ deficiencies of omega-3 fats and vitamin B12 may raise heart disease risks. Vegetarians who do not supplement their diet with vitamin B12 tend to have elevated homocysteine (an amino acid) levels. Elevated homocysteine is associated with early mortality, heart disease, stroke, dementia, and birth defects, although results of previous studies have been mixed. There is evidence that lowering homocysteine levels in otherwise healthy people can prevent death from stroke.
Vitamin B12: Animal foods are the only natural food source of B12. Look for fortified cereals, and soymilk or a supplement to meet daily needs. Vegetarians who get 3 to 100 µg of B12 per day through fortified foods or supplements will minimize any elevated homocysteine problems due to a low B12 intake.
Omega-3 fatty acids: Three types of omega-3 fats predominate in the diet, alpha linolenic acid (ALA), EPA and DHA. ALA is provided by flaxseed, flaxseed oil, soybean, canola oils and walnuts. However, the conversion of ALA in the body to the heart healthier fats, EPA and DHA, is often reduced due to many factors. Lower proportions of omega-3 fatty acids are found in the blood of vegetarians compared to omnivores (meat and vegetable eaters), note researchers from the Department of Food Science, RMIT University, Melbourne, Victoria, Australia.
In another study by scientists from the Research Institute of Nutrition, Bratislava, Slovakia, the fatty acids in the blood were measured in a group of children consisting of 7 vegans (strict vegetarians), 15 lactoovovegetarians (include dairy and eggs) and 10 semivegetarians (people who eat flesh foods periodically). The children ranged in age from 11-15 years and were followed for 3.4 years. The results were compared with a group of 19 omnivores. Values of omega-3 fatty acids in lactoovovegetarians were identical to those of omnivores whereas they were significantly increased in semivegetarians consuming fish twice a week. Due to the total exclusion of animal fats from the diet, vegans had significantly reduced values of omega-3 fatty acids.
A recent report in the American Journal of Clinical Nutrition found that male vegetarians actually had platelets that clumped together more readily than male omnivores. In other words, vegetarians’ red blood cells were more likely to form clots that could lead to heart disease or stroke.
Vegetarian diets have been shown to confer many health benefits to those who follow them correctly. But be careful before declaring yourself a vegetarian. You may be inadvertently increasing your cardiovascular disease risks if these types of diets are not planned carefully. Do some homework first.
American Chemical Society. “Vegans’ elevated heart risk requires omega-3s and B12, study suggests.” ScienceDaily, 15 Feb. 2011. Web. 21 Sep. 2011
- Vegan Foods That Are High in Vitamin B12 (fitsugar.com)