According to the review article which appeared in the Journal of Agricultural and Food Chemistry, meat eaters typically have a higher cardiovascular risk than most vegetarians but vegans are at an increased risk. Vegan diets are generally rich in fiber, magnesium, folic acid, and vitamins C and E, but the vegan diet can lack some important nutrients like iron, omega-3 fatty acids, vitamin B12 and zinc. It is possible for vegans to consume healthy levels of protein, but they may not be getting enough healthy fats in the diet.
Compared to meat-eaters, vegetarians and vegans have lower levels of vitamin B12 and omega-3 polyunsaturated fatty acids (PUFAs) in the blood. Very low blood levels of vitamin B12 have been significantly linked to increased homocysteine.
High levels of homocysteine are believed to cause atherosclerosis and an excess of blood clots which can lead to heart attacks. Elevated homocysteine has also been associated with the development of blood clots in the veins or deep vein thrombosis.
The review article suggests that there is a scientific basis for vegans to increase amounts of omega-3 fatty acids and vitamin B12 in the diet. It is possible that additional amounts of these important nutrients can diminish the risk for heart problems and stroke among this group of people. Omega-3 fatty acids can be found in salmon, scallops, halibut, shrimp, cod, walnuts and flax seed. Rich sources of vitamin B12 include red snapper, calves liver, salmon, shrimp, kelp and tofu.
The review article author, Duo Li from Zhejiang University in China states, “On the basis of the present data, it is suggested that vegetarians, especially vegans, could benefit from increased dietary intake of omega-3 PUFA and vitamin B12… which may reduce any thrombotic tendency that might increase their generally low risk of cardiovascular disease.”
While it is important to consume a healthy diet chock full of nutrients, dietary supplements are a quick and easy way to guarantee adequate levels of Omega-3 fatty acids and vitamin B12. These natural supplements can be found at your local whole foods store or through nutritional supplement websites.
Duo Li, Chemistry behind Vegetarianism, J. Agric. Food Chem., 2011, 59 (3), pp 777–784, Publication Date (Web): January 4, 2011