Article

The journal of nutrition, health & aging

, Volume 16, Issue 6, pp 569-573

First online:

Vitamin B-12 supplementation improves arterial function in vegetarians with subnormal vitamin B-12 status

  • T. KwokAffiliated withDepartment of Medicine and Therapeutics, The Chinese University of Hong Kong
  • , P. ChookAffiliated withDepartment of Medicine and Therapeutics, The Chinese University of Hong KongSchool of Life Sciences, The Chinese University of Hong Kong
  • , M. QiaoAffiliated withDepartment of Medicine and Therapeutics, The Chinese University of Hong Kong
  • , L. TamAffiliated withDepartment of Medicine and Therapeutics, The Chinese University of Hong Kong
  • , Y. K. P. PoonAffiliated withDepartment of Medicine and Therapeutics, The Chinese University of Hong Kong
  • , A. T. AhujaAffiliated withDepartment of Diagnostic Radiology and Organ Imaging, The Chinese University of Hong Kong
  • , J. WooAffiliated withDepartment of Medicine and Therapeutics, The Chinese University of Hong Kong
  • , D. S. CelermajerAffiliated withDepartment of Cardiology, The University of Sydney
  • , K. S. WooAffiliated withDepartment of Medicine and Therapeutics, The Chinese University of Hong KongSchool of Life Sciences, The Chinese University of Hong KongRoom 191, Science Centre South Block, Biochemistry Programme, School of Life Sciences, The Chinese University of Hong Kong Email author 

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access

Abstract

Objective

Vegetarians are more vascular-healthy but those with subnormal vitamin B-12 status have impaired arterial endothelial function and increased intima-media thickness. We aimed to study the impact of vitamin B-12 supplementation on these markers, in the vegetarians.

Design

Double-blind, placebo controlled, randomised crossover study.

Setting

Community dwelling vegetarians.

Participants

Fifty healthy vegetarians (vegetarian diet for at least 6 years) were recruited. Intervention: Vitamin B-12 (500µg/day) or identical placebo were given for 12 weeks with 10 weeks of placebo-washout before crossover (n=43), and then open label vitamin B-12 for additional 24 weeks (n=41).

Measurement

How-mediated dilation of brachial artery (FMD) and intima-media thickness (IMT) of carotid artery were measured by ultrasound.

Results

The mean age of the subjects was 45+9 years and 22 (44%) were male. Thirty-five subjects (70%) had serum B-12 levels <150pmol/l. Vitamin B-12 supplementation significantly increased serum vitamin B-12 levels (p<0.0001) and lowered plasma homocysteine (p<0.05). After vitamin B-12 supplementation but not placebo, significant improvement of brachial FMD (6.3±1.8% to 6.9±1.9%; p<0.0001) and in carotid IMT (0.69±0.09mm to 0.67±0.09 mm, p<0.05) were found, with further improvement in FMD (to 7.4±1.7%; p<0.0001) and IMT (to 0.65±0.09mm; p<0.001) after 24 weeks open label vitamin B-12. There were no significant changes in blood pressures or lipid profiles. On multivariate analysis, changes in B-12 (β=0.25; p=0.02) but not homocysteine were related to changes in FMD, (R=0.32; F value=3.19; p=0.028).

Conclusions

Vitamin B-12 supplementation improved arterial function in vegetarians with subnormal vitamin B-12 levels, proposing a novel strategy for atherosclerosis prevention.

Key words

Vegetarians vitamin B-12 endothelial function intima-media thickening