A Randomized Pilot Trial to Evaluate the Bioavailability of Natural versus Synthetic Vitamin B Complexes in Healthy Humans and Their Effects on Homocysteine, Oxidative Stress, and Antioxidant Levels

Meinrad Lindschinger,Olaf Stanger,Gerhard Cvirn,Barbara Lindschinger,Irene Schmid,Franz Tatzber,Wolfgang Schimetta,Willibald Wonisch,Eugenia Lamont

doi:10.1155/2019/6082613

Abstract

The vitamin B complex comprises 8 different water-soluble constituents that humans must sequester from the diet. This pilot study compared natural versus synthetic vitamin B complexes for their bioavailability, accumulation, and their impact on antioxidants, homocysteine levels, and oxidative stress. We conducted a double-blind randomized clinical trial with thirty healthy participants. They were randomly assigned to group N (natural) and group S (synthetic). Vitamin B was ingested daily for 6 weeks in the range of about 2.5 times above the recommended daily allowance. Blood samples were taken at baseline, 1.5 h, 4 h, 7 h (diurnal), 6 w (discontinuation of supplements), and 8 w (washout). Blood levels of thiamine (B1), riboflavin (B2), pyridoxine (B6), folic acid (B9), cobalamin (B12), homocysteine, total antioxidants, peroxidase activity, polyphenols, and total peroxides were determined. Compared to initial values, serum levels of each B vitamin increased at the end of the supplementation period: i.e., B1 (+23% N; +27% S), B2 (+14% N; +13% S), B6 (+101% N; +101% S), B9 (+86% N; +153% S), and B12 (+16% N) (p < 0.05). Homocysteine (-13% N) decreased, while peroxidase activity (+41% S) and antioxidant capacity increased (+26% N). Short-term effects were already observed after 1.5 h for B9 (+238% N; +246% S) and after 4 h for vitamin B2 (+7% N; +8% S), B6 (+59% N; +51% S), and peroxidase activity (+58% N; +58% S). During the washout period, serum levels of B vitamins decreased except for thiamine and peroxidase activity, which increased further. This clinical pilot study revealed comparable bioavailability for both natural and synthetic B vitamins but did not show statistically noticeable differences between groups despite some favourable tendencies within the natural vitamin group, i.e., sustained effects for cobalamin and endogenous peroxidase activity and a decrease in homocysteine and oxidative stress levels.

Highlights

The vitamin B complex comprises eight water-soluble constituents: thiamine (B1), riboflavin (B2), niacin (B3), pantothenic acid (B5), pyridoxine (B6), biotin (B7), folic acid (B9), and cobalamin (B12)
In group N, supplied with the natural source of vitamin B complex, and in group S, supplied with the synthetic vitamin B complex, both bioavailability and storage capacity were very similar with respect to vitamin B1 serum levels
Since by definition a pilot study has a limited number of cases, this might account for the failure of some trends between the groups to achieve significance. These trends would warrant a suitably powered clinical trial. This clinical double-blind pilot study focused on systemic alterations of serum vitamin B levels in healthy subjects in response to a vitamin B supplementation, in the range of about 2.5 times above the recommended daily allowance for six weeks, and a washout period for another two weeks

Summary

Introduction

The vitamin B complex comprises eight water-soluble constituents: thiamine (B1), riboflavin (B2), niacin (B3), pantothenic acid (B5), pyridoxine (B6), biotin (B7), folic acid (B9), and cobalamin (B12). They are functionally related and cooperate in protein, lipid, and nucleic acid synthesis, energy production, and immune defence; they exert numerous effects on brain function. These essential nutrients are sequestered from the diet and act as coenzymes in various processes. The bioavailability of synthetic vitamin C was comparable to vitamin C derived from kiwifruit [8]

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