Nutrition
Omega-3 fatty acids have a minor impact on brain development
Opinions differ as to the benefits of omega-3 fatty acids. A systematic analysis of 29 studies has shown that they have a positive, though very minor, impact on the brains of young people.
Fat-rich cold-water fish such as salmon may contain particularly high levels of eicosapentaenoic acid, but eating more to boost your brains is not recommended. | Image: wikipedia/LFL16
Researchers are divided about whether or not omega-3 fatty acids can influence the development of the brain and our cognitive abilities. A meta-analysis carried out by the universities of Zurich, Bern and Basel has investigated 29 studies of over 4,000 test subjects, and has shown that eicosapentaenoic acid (EPA) has a limited but positive impact on young people.
Earlier studies had suggested that EPA and docosahexaenoic acid (DHA), another omega-3 fatty acid, are important for the normal development of the brain. DHA is found most often in the brain, but EPA seems to be important for certain functional aspects. However, no one knows how much DHA and EPA has to be ingested with food, and what deficiency might mean for the development of certain areas of the brain.
“There are a lot of studies about this”, says Sophie Emery of the Psychiatric Clinic of the University of Zurich and the lead author of the study. “We used 29 out of a total of 1,126 studies for our meta-analysis. There were only 79 studies that measured cognitive abilities, and the statistical aspects and study design of many did not meet our own strict criteria”. One fundamental problem with nutrition studies is that it is usually impossible to identify a single substance as the cause of any small effect. This is because people ingest thousands of chemical substances with their food every day.
But the results did show that EPA had a small, positive impact on the working memory and long-term memory of young people, and also on their ability to solve problems. DHA, however, proved to have no impact at all. “This surprising result is something we can’t explain”, says Emery. Nor is it clear just what proportion of substances in the blood can actually penetrate the blood-brain barrier, nor what influence our genes and individual intestinal flora have on our metabolic processes. Given these uncertainties and the minimal impact of omega-3 fatty acids, the researchers cannot expressly recommend an additional intake by young people in hopes of treating cognitive deficits.
