Vitamin B-12 status of long-term adherents of a strict uncooked vegan diet ("living food diet") is compromised.

The present study examined the vitamin B-12 status in long-term adherents of a strict uncooked vegan diet called the "living food diet." The study was comprised of two parts. In the cross-sectional part, the data on serum vitamin B-12 concentrations and dietary intakes in 21 (1 male, 20 females) long-term adherents (mean 5.2 y, range 0.7-14) of the "living food diet" were compared with those of 21 omnivorous controls matched for sex, age, social status and residence. In the longitudinal part of the study, food consumption data were collected and blood samples were taken from nine "living food eaters" (1 male, 8 females) on two occasions 2 y apart. The cross-sectional study revealed significantly (P < 0.001, paired t test) lower serum vitamin B-12 concentrations in the vegans (mean 193 pmol/L, range 35-408) compared with their matched omnivorous controls (311, 131-482). In the vegan group, total vitamin B-12 intake correlated significantly (r = 0.63, P < 0.01) with serum vitamin B-12 concentration. The vegans consuming Nori and/or Chlorella seaweeds (n = 16) had serum vitamin B-12 concentrations twice as high as those not using these seaweeds (n = 5) (mean 221 pmol/L, range 75-408, vs. 105, 35-252, P = 0.025). In the longitudinal study, six of nine vegans showed slow, but consistent deterioration of vitamin B-12 status over a 2-y observation period. On the basis of these results we conclude that some seaweeds consumed in large amounts can supply adequate amounts of bioavailable vitamin B-12.(ABSTRACT TRUNCATED AT 250 WORDS)