Can vitamin B reduce the risk of stroke?

This study investigated whether taking vitamin B supplements to reduce homocysteine levels in the blood, reduces the risk of cerebrovascular disease. 

Homocysteine is an amino acid, which is a building block that makes up proteins, found in the blood. High levels of homocysteine are associated with damage to arteries and blood vessel disease. Damage to blood vessels that supply the brain is called cerebrovascular disease. Cerebrovascular disease can result in events such as stroke, which is where blood supply to a part of brain is disrupted and can cause cell death.

Vitamin B decreases homocysteine levels in the blood and therefore may reduce the risk of cerebrovascular disease and stroke.

This study carried out a review of clinical trials that investigated whether reducing homocysteine levels using vitamin B supplements reduces the risk of cerebrovascular disease and stroke. A total of 14 trials were reviewed involving 54,913 participants, where patients either received vitamin B supplements or placebo (substance with no therapeutic effect).

This review found that there was a 7% reduced risk of overall stroke in patients that took vitamin B supplements compared to placebo.

When the investigators compared vitamin B supplementation and placebo between subgroups of stroke (e.g. comparing those with or without a history of stroke), vitamin B supplementation did not reduce the risk of stroke in any one group more than another. However, the researchers did find an increased benefit of vitamin B in subgroups of stroke in patients who were followed up for >3 years and who did not have a history of kidney problems. 

The study concluded that vitamin B supplementation for homocysteine reduction significantly reduced stroke events.

This review only gives a general overview of the effect of vitamin B supplementation on stroke reduction and does not provide enough information to determine what group of patients benefits most vitamin B supplementation and what form it should be taken in. 

If you, or someone you know is at risk of developing blood vessel disease, talk to a doctor or dietician about increasing vitamin B in your diet in order to help keep your blood vessels healthy.