Doubt cast on the benefits of omega-3 for the brain Research on the benefits of omega-3 fatty acids is inconclusive Omega-3 fatty acids are found in nuts as well as oily fish "The great superfood U-turn," claims the Mail Online, suggesting that scientists have shown that "feasting on salmon and nuts may not preserve brainpower after all". The news is based on a study of more than 2,000 older women. The researchers looked at the relationship between their blood levels of two omega-3 fatty acids and their performance in tests of thinking and memory skills. These tests were repeated every year for several years. The study found no difference in cognitive skills at the start of the study between women with high and low levels of these fats in their blood, and no difference between the two groups in how quickly their thinking skills changed over time. There are quite a few problems with this study, not least, that it measured blood levels of omega-3 fats only once, at the start of the study. It is possible that blood levels changed over the years if women changed their diets or started or stopped taking fish oil supplements. There is little hard evidence that foods high in omega-3 fatty acids boost cognitive function or protect against conditions such as dementia. The best evidence about the health benefits of omega-3 fats suggests that they protect the heart rather than the brain. Some research shows that eating oily fish, which is a rich source of omega-3 fats, may help prevent heart disease. HOWEVER.............: This study investigated the possible benefits of a diet high in omega-3 fatty acids on the brain. It has several limitations: •One problem is that it only measured blood levels of omega-3 fatty acids at the start of the study. These might have changed over time if the women changed their diets or started – or stopped – taking omega-3 supplements. Also, the first cognitive tests were administered on average three years after the blood samples were taken. •It’s important to note that the researchers did not measure women’s dietary intake of omega-3 fats, only blood levels, although the authors say these have been found to correlate with dietary habits. •Finally, the fact that this was retrospective, secondary analysis of previous research means the results should be viewed with caution. The research on omega-3 fatty acids remains inconclusive, as is the case with many so-called superfoods. While it remains unclear whether a diet rich in omega-3 fats may help protect against dementia or related conditions, some research has found omega-3 fats may help protect against heart disease. A healthy diet should include at least two portions of fish a week, including one of oily fish. It is interesting to note that this study is a relatively rare example of a study published in a high profile journal that has produced a negative finding. This should help combat the problem of publication bias.
Posted on: Fri, 27 Sep 2013 16:34:43 +0000
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