Vitamin B-6 status and bioavailability in vegetarian women.

It has been hypothesized that the vitamin B-6 status of vegetarians and nonvegetarians may differ in relation to bioavailability of vitamin B-6. Fasting blood samples and 24-h urine collections were obtained from 13 Seventh-day Adventist (SDA) vegetarian and 16 non-SDA nonvegetarian women aged 50-83 y. The two groups were further subdivided into vitamin users and nonusers. Dietary intake was estimated from a 3-d diet record. Plasma pyridoxal 5'-phosphate (PLP) was measured by an enzymatic method. Vitamin B-6 intakes were similar and provided 85% of the RDA for both groups. The vegetarians consumed significantly more crude fiber than the nonvegetarians. No significant differences were found between the two groups for plasma PLP, urinary 4-pyridoxic acid, and urinary vitamin B-6 among vitamin nonusers or for age categories within groups. There appeared to be no adverse effect of fiber on the availability or metabolism of vitamin B-6 between these free-living groups.