(dailyRx News) High levels of an amino acid in the blood may slow down the mind. Vitamin B, however, has been shown to decrease this amino acid and improve brain function.

While some studies have shown that vitamin B may fight the mind-fogging effects of the amino acid homocysteine, scientists have recently discovered that the vitamin may not bolster the brains of stroke patients.

Graeme Hankey, MD, in the Stroke Unit, Department of Neurology, of Royal Perth Hospital, Australia, led research examining whether B vitamin treatment would reduce the risk of brain impairment (or cognitive decline) among individuals who had recently had a stroke.

Investigators observed 2,214 patients with recent stroke or a transient ischemic attack (when blood flow to a part of the brain stops for a brief period of time).

The patients, who were not mentally impaired, were randomly given one tablet daily of placebo (fake vitamins) or B vitamins (folic acid, vitamin B6 and vitamin B12). Doctors followed the patients for an average of 3.4 years.

At least every six months, individuals were given a brief questionnaire used to evaluate cognitive impairment. Based on results of this survey, doctors found no difference in cognitive impairment among the participants assigned to vitamin B versus those who took the placebo.  

Dr. Hankey told dailyRx News, “Our research adds to a growing body of evidence from clinical trials which suggests that B-vitamin supplementation is not helpful in slowing the rate of cognitive decline or the incidence of cognitive impairment in both cognitively unimpaired and impaired individuals.”

A 2010 study of more than 8,000 patients who had serious heart or vascular problems found that vitamin B did not help prevent repeat occurrence of strokes or heart attacks. A report in The American Journal of Clinical Nutrition stated that “randomized trials with folic acid, vitamin B-12, and vitamin B-6 provide no evidence of any improvement of cognition or dementia.”

The National Institutes of Health’s MedlinePlus health information website also says that vitamin B-12 is “possibly ineffective for preventing another stroke.”

Other studies have shown that the brain benefits from vitamin B. Another report in The American Journal of Clinical Nutrition concluded that older people could prevent cognitive decline by taking B-12 and folic acid supplements. Research in PLOS Clinical Trials found that homocysteine could be lowered by B vitamins and slow the rate of brain atrophy in older patients.

The study was presented in February at the American Stroke Association’s International Stroke Conference 2013. Findings are considered preliminary until published in a peer-reviewed journal.