完全菜食とビタミンB_12欠乏 : 完全菜食において海苔はビタミンB_12の供給源として有効である Vegans (pure vegetarians) and vitamin B_12 deficiency
Vegetarians are divided into three categories; Vegans, or pure vegetarians who abstain from all foods of animal origin; lacto-vegetarians who include milk and dairy products in their diets; and lacto-ovo-vegetarians who consume egg products as well as milk and dairy products. Vitamin B_12 deficiency has been reported in strict vegans. A nutritional analysis was conducted on the dietary intake of a group of 19 vegans aged 7 to 72 years who had been living on a vegan diet for from 7 to 50 years, and on that of age-matched control group. In addition, their serum vitamin B_12 levels were determined. In vegans' diets, 2-4g of nori (dried laver), which contained B_12, were consumed daily. Not a single case of symptoms due to B_12 deficiency was found. There were no stastistically significant differences between the two groups with respect to vitamin B_12 levels. Therefore, consumption of nori may keep vegans from suffering B_12 deficiency.