Vegetarian diet and vitamin B12 deficiency:
In vegetarian women, supplementation of vitamin B12 is required due to the lack of this vitamin in vegetarian foods. (20)
Vegetarians, B12, and coronary artery disease (CAD): In a study involving 816 subjects (368 with coronary artery disease [CAD] and 448 controls) in India, levels of vitamin B12 were found to be significantly lower in patients with CAD, as compared to controls. In this study interestingly, vegetarians who were found to have lower levels of vitamin B12 were noted to have a higher incidence of coronary artery disease compared to non-vegetarians. (21)
Beta-carotene and cancer:
Cancer risk is lower in those who consume beta-carotene containing foods but not beta-carotene supplements according to the National Research Council, Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium, and Carotenoids. (22)