^Craig, Winston J (May 2009). "Health effects of vegan diets". The American Journal of Clinical Nutrition. 89 (5): 1627S–1633S. doi:10.3945/ajcn.2009.26736N. PMID19279075. Vegan diets are usually higher in dietary fiber, magnesium, folic acid, vitamins C and E, iron, and phytochemicals, and they tend to be lower in calories, saturated fat and cholesterol, long-chain n–3 (omega-3) fatty acids, vitamin D, calcium, zinc, and vitamin B-12. ... A vegan diet appears to be useful for increasing the intake of protective nutrients and phytochemicals and for minimizing the intake of dietary factors implicated in several chronic diseases.
^Mangels, Reed; Messina, Virginia; and Messina, Mark. "Vitamin B12 (Cobalamin)," The Dietitian's Guide to Vegetarian Diets. Jones & Bartlett Learning, 2011, pp. 181–192.
Mangels, Reed. "Vitamin B12 in the Vegan Diet", Vegetarian Resource Group, accessed December 17, 2012: "Vitamin B12 is needed for cell division and blood formation. Neither plants nor animals make vitamin B12. Bacteria are responsible for producing vitamin B12. Animals get their vitamin B12 from eating foods contaminated with vitamin B12 and then the animal becomes a source of vitamin B12. Plant foods do not contain vitamin B12 except when they are contaminated by microorganisms or have vitamin B12 added to them. Thus, vegans need to look to fortified foods or supplements to get vitamin B12 in their diet."
"Vitamin B12", Office of Dietary Supplements, National Institutes of Health, accessed December 17, 2012.
Norris, Jack. "Vitamin B12: Are you getting it?", Vegan Outreach, July 26, 2006: "Contrary to the many rumors, there are no reliable, unfortified plant sources of vitamin B12 ... [There is an] overwhelming consensus in the mainstream nutrition community, as well as among vegan health professionals, that vitamin B12 fortified foods or supplements are necessary for the optimal health of vegans, and even vegetarians in many cases. Luckily, vitamin B12 is made by bacteria such that it does not need to be obtained from animal products."