For years, many health experts have hailed foods rich in omega-3 fatty acids as being good for the lowering of stroke risk, as well as for the reduction of the risk of mild cognitive impairment. But other studies have suggested that omega-3 fatty acids - and fish oil supplements in particular - actually don't lower one's risk of stroke or heart attack.
With so many contrasting opinions, it's been difficult to determine what's true and what's not.
Now new research is clouding the picture even further by suggesting that omega-3 fatty acids - found in fatty fish such as salmon and in nuts - may not benefit thinking skills, as some earlier studies have indicated.
The study is published in the Sept. 25 online issue of Neurology, the medical journal of the American Academy of Neurology.
“There has been a lot of interest in omega-3s as a way to prevent or delay cognitive decline, but unfortunately our study did not find a protective effect in older women. In addition, most randomized trials of omega-3 supplements have not found an effect,” said study author Eric Ammann of the University of Iowa in Iowa City, in a press release. “However, we do not recommend that people change their diet based on these results. Researchers continue to study the relationship between omega-3s and the health of the heart, blood vessels, and brain. We know that fish and nuts can be healthy alternatives to red meat and full-fat dairy products, which are high in saturated fats.”
Researchers studied 2,157 women between the ages of 65 and 80 who were enrolled in the Women's Health Initiative clinical trials of hormone therapy. The women were given annual tests of thinking and memory skills for an average of six years. Blood tests were taken to measure the amount of omega-3s in the participants’ blood before the start of the study.
The researchers found no difference between the women with high and low levels of omega-3s in the blood at the time of the first memory tests. There was also no difference between the two groups in how quickly their thinking skills declined over time.
The study was supported by the National Heart, Lung, and Blood Institute, National Institutes of Health, and U.S. Department of Health and Human Services.
What does appear to be good for the brain is chocolate. In a small study conducted earlier this year, Harvard researchers found that drinking two cups of hot chocolate a day for 30 days was linked with improved blood flow to the brain and better scores on memory and thinking skill tests for elderly people.