Taking vitamin B supplements may modestly reduce the risk of stroke, according to a meta-analysis of previous studies.
Study author Xu Yuming, MD, of Zhengzhou University in China, noted past studies have produced conflicting findings regarding the effect of vitamin B supplementation on risk of stroke and cardiac arrest. Some studies have even suggested that the supplements may increase the risk of these events, Xu said in a news release.
For a study published Sept. 18 on the website of the journal Neurology, scientists analyzed 14 randomized clinical trials with a total of 54,913 participants. All studies compared B vitamin use with a placebo or a very low-dose B vitamin. Participants then were followed for a minimum of six months.
There were 2,471 strokes throughout the studies, all of which showed some benefit of taking vitamin B. Vitamin B lowered the risk of stroke in the studies overall by 7%.
However, taking supplements did not appear to affect the severity of strokes or risk of death from stroke.
Folic acid, a supplemental form of folate (vitamin B9), which often is found in fortified cereals, appeared to reduce the effect of vitamin B. The researchers did not find a reduction in stroke risk for vitamin B12.
Based on our results, the ability of vitamin B to reduce stroke risk may be influenced by a number of other factors such as the bodys absorption rate, the amount of folic acid or vitamin B12 concentration in the blood, and whether a person has kidney disease or high blood pressure, Xu said.
Neurology is the medical journal of the American Academy of Neurology. Study abstract: www.neurology.org/content/early/2013/09/18/WNL.0b013e3182a823cc.abstract.