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

Area of Science:

• Nutritional Science
• Cardiovascular Health
• Vascular Biology

Background:

• Vegetarians often exhibit vascular health benefits but can have subnormal vitamin B-12 status.
• Low vitamin B-12 is linked to impaired arterial endothelial function and increased intima-media thickness.

Purpose of the Study:

• To investigate the impact of vitamin B-12 supplementation on arterial endothelial function and intima-media thickness in vegetarians.
• To assess if vitamin B-12 supplementation can improve vascular markers in this population.

Main Methods:

• A double-blind, placebo-controlled, randomized crossover study involving 50 healthy vegetarians.
• Intervention included 12 weeks of vitamin B-12 (500 µg/day) or placebo, followed by a washout period and open-label vitamin B-12.
• Measurements included flow-mediated dilation (FMD) of the brachial artery and intima-media thickness (IMT) of the carotid artery via ultrasound.

Main Results:

• 70% of participants had serum vitamin B-12 levels below 150 pmol/l.
• Vitamin B-12 supplementation significantly increased serum B-12 levels and lowered plasma homocysteine.
• Supplementation led to significant improvements in brachial artery FMD and carotid artery IMT, with further gains after extended supplementation.

Conclusions:

• Vitamin B-12 supplementation effectively improved arterial function in vegetarians with subnormal vitamin B-12 levels.
• This intervention represents a potential novel strategy for the prevention of atherosclerosis in at-risk vegetarian populations.