Dietary intake of vitamin B₆and concentration of vitamin B₆in blood samples of German vegans

Abstract

Objective: The study aimed to evaluate the dietary vitamin B 6 intake and determine the vitamin B 6 concentration in blood samples of German vegans. Design and setting: Cross-sectional study with 33 examination sites all over Germany. Subjects: Ninety-three vegans (50 females) with a mean (^standard deviation (SD)) age of 43.7^15.7 years who took no vitamin supplements. Methods: Dietary intake was assed using a semi-quantitative food-frequency questionnaire. Erythrocyte aspartate aminotransferase activity coefficient (EAST-AC) was calculated as the ratio of stimulated (pyridoxal 5 0 -phosphate added) to unstimulated activity in blood samples that were provided after an overnight fast. Results: Mean^SD vitamin B 6 intake was 2.83^0.98 mg day 21 and mean^SD protein intake was 56.6^21.7 g day 21 . Of the participants 4% showed vitamin B 6 intakes lower than daily recommended intakes for Germany, 16% showed EAST-AC . 1.85, and a further 58% showed EAST-AC of 1.5-1-85. Moderate vegans were affected to a lesser extent than strict vegans. None of the established confounders was a significant predictor of EAST-AC. In logistic regression analyses the contribution of nutriments and cereals to pyridoxine intake was the only predictor of EAST-AC classified as # 1.85 and . 1.85, respectively. Conclusions: In spite of the high total intake of vitamin B 6 , an adequate concentration in blood samples could not be realised for a majority of the participants. Due to the health implications of a marginal pyridoxine status, vegans should be encouraged to include foods with a high bioavailability of pyridoxine, such as beans, lentils and bananas, in the daily diet.EAST-AC Dietary intakeThe vitamin B 6 content of foods consists of several pyridoxine derivatives (pyridoxine, pyridoxal, pyridoxamine and their phosphorylated forms) 1 . Foods of animal origin contain mainly pyridoxamine and pyridoxal 2 , resulting in a bioavailability of approximately 75% 3 , which approaches 100% in some foods 2 . Vitamin B 6 in foods of plant origin consists mainly of pyridoxine and the phosphorylated form -derivatives that have reduced bioavailability. Furthermore, a large proportion of the vitamin B 6 content in foods of plant origin is glucosylated, which reduces the bioavailability further 2,4 . For example, the bioavailability of pyridoxine glycosides (pyridoxine-5 0 -b-D-glycosides) is approximately 50 -58% that of free pyridoxine applied orally 5,6 . Furthermore, pyridoxine glycosides show an antagonistic effect on the metabolism of pyridoxine 4,5 . Therefore it can be assumed that persons with a dietary regimen that consists mainly (vegetarian diet) or exclusively (vegan diet) of plant foods are at risk of inadequate blood vitamin B 6 concentrations. Some studies indicate that vegetarians have comparable vitamin B 6 status to omnivorous study populations 7,8 , while other studies have found contradictory results 9 . The health implications associated with marginal pyridoxine status are increased risk for coronary diseases -independently...

Direct and Functional Biomarkers of Vitamin B6 Status

“…An investigation of vegans showed a high percentage of marginal to low vitamin B6 status (EAST-AC) despite high vitamin B6 intakes (approx. 2.8 mg/day), and strict vegans were more affected than moderate vegans (242). …”

Intake and adequacy of the vegan diet. A systematic review of the evidence

“…Total protein intake in vegan groups was the lowest compared to other diet groups (Table 3) [5,12,57]. TEI from protein was approximately 13e15% [5,26,27,31,48,53,57,59,62,63]. WHO recommends protein intake 15% of TEI, dependent on factors such as sex, age, activity, health condition etc.…”

“…Low alcohol consumption is recorded frequently in vegan diets (Table 6) [5,6,10,25,27,28,32,39,44,46e48,53,54,57e59]. However, in some studies, differences in alcohol consumption between diet groups were not observed [12,31,50,63]. Alcohol intake among vegans ranged from 0.25 g/d to 12.6 g/ d [5,6,25,26,32,39,44,46,47,53,54,59,63,68], and in one study [27] as high as 20 g/d for a minority of mainly male vegans.…”

Diet-Dependent Net Endogenous Acid Load of Vegan Diets in Relation to Food Groups and Bone Health-Related Nutrients: Results from the German Vegan Study

“…Although a large number of studies on vegetarian [24,25,26,27,28,29,30,31,32,33,34,35] and vegan nutrition [20,21,36,37,38,39,40,41] have been published during the last years, only one small study has examined the effect of vegan diets on acid-base homeostasis [42]. Whereas the effect of diets on human acid-base status has significant implications on skeletal health [7,8,9,10,43,44], the primary aim of this cross-sectional study was to investigate how vegan diets affect acid-base balance.…”