Supplementing Attempts to Avoid Stroke

Vitamin B helped lower stroke risks in analysis of many studies

(RxWiki News) Whether vitamins and other supplements promote cardiovascular health is not a new question. Previous studies have offered conflicting evidence about whether vitamin B lessens the chances that a person at risk for stroke will suffer such a trauma.

But a new study has found that taking vitamin B supplements may actually reduce stroke risks.

"Always inform your doctor if you are taking supplements."

The lead author of this study was Xu Yuming, MD, PhD, a neurologist with First Affiliated Hospital of Zhengzhou University in Zhengzhou, China.

Dr. Yuming and his team of researchers analyzed 14 previous clinical trials involving a total of 54,913 participants. Those 14 previous studies aimed to determine whether taking vitamin B supplements reduced the levels of homocysteine, an amino acid commonly found in red meats, seafood and dairy products, in people's blood streams.

High homocysteine levels have been linked to diseases of the heart and blood vessels. During a stroke, blood vessels burst or are blocked, keeping oxygen from properly flowing to the brain. Homocysteine levels also rise as individuals age.

Of the 54,913 total participants, roughly half were assigned to take vitamin B supplements. The other half were assigned a placebo pill containing no vitamin supplements.

Based on their analyses of the 14 older studies, all of which were conducted before August 2012, the authors of the current study concluded that the risk for stroke fell 7 percent among study participants who took a daily dose of vitamin B. The dose ranged from less than 0.5 milligrams daily to 2 milligrams or more.

Sarah Samaan, MD, FACC, a Plano, Texas cardiologist and author on heart health, told dailyRx News that health consumers shouldn't rely too heavily on study findings or, in general, supplements.

"Although when the combined studies are taken as a whole there does appear to be a small benefit, it's hard to draw strong conclusions about supplements," Dr. Samaan said. "It's always best to get our nutrition from food, rather than from a pill. In nature, foods rich in B vitamins, such as fish, green leafy vegetables and dairy products, also are full of important antioxidants and other nutrients that support brain and heart health."

Despite the benefits researchers cited, the researchers also said the supplements were particularly less effective for certain groups. For example, elderly persons with stomach and intestinal problems may have a harder time absorbing supplements taken by mouth. For them, vitamin B injections may be a better option, the researchers wrote.

Others for whom vitamin B may not be as beneficial include people with kidney disease and high blood pressure, the researchers concluded.

"Although we found beneficial results of B vitamin supplementation in reducing stroke events, several strictly designed trials reported increased stroke events, even with B vitamin supplementation," the researchers wrote.

There were 2,471 strokes recorded in the 14 studies. In those cases, "...taking supplements did not appear to affect the severity of strokes or risk of death from stroke," the researchers concluded.

The researchers also wrote that folic acid, which fortified breakfast cereals sometimes include, appeared to limit the potential beneficial effect of vitamin B.

The researchers did not disclose funding sources for this study.

The study was published online September 18 in Neurology.

Review Date: 
September 15, 2013