Regular supplementation with vitamin B12 may improve arterial function and reduce atherosclerosis risk for vegetarians, suggests a new Chinese study.
To test a potential effect of vitamin B12 on vascular health, the randomized controlled trial measured blood homocysteine concentrations and flow-mediated blood vessel dilation (FMD) of 43 healthy vegetarians (average age 45 years) who received 12 weeks of supplementation with 500 micrograms of vitamin B12 per day or placebo (1). The study results showed a significant increase in blood levels of vitamin B12 in the supplemented group, as well as a lowering of homocysteine concentrations, which at high levels is linked to heart disease. In addition, the supplementation increased FMD from 6.3% to 6.9% and significantly reduced the average thickness of the carotid artery walls from 0.69 to 0.67mm, with no such improvements observed in the placebo group.
The researchers concluded that vitamin B12 supplementation in asymptomatic vegetarians with compromised vitamin B12 status may lead to a significant improvement in arterial endothelial function and carotid intima-media thickness, with potential benefit on cardiovascular health. As the participants in the current trial had low levels of vitamin B12 at the start of the study, it remains uncertain as to whether vitamin B12 supplementation would have the same effects in vegetarians with better vitamin B12 status.
It is commonly believed that vegetarians have a lower risk of cardiovascular disease, but some data has indica-ted that vegetarian diets are deficient in vitamin B12, and relatively high in salt, both of which may increase the risk of atherosclerosis. For vegetarians, apart from direct vitamin B12 supplementation, vitamin B12 deficiency is also preventable by higher and adequate intakes of dairy products, eggs and fortified cereals.