Many adults fear a decline in their cognitive function later in life and, as a result, adopt diets that include foods rich in omega-3 fatty acids, such as salmon and walnuts. Despite this belief, new data shows that the consumption of these foods may not be the best way to strengthen the brain.

Recently, Emma Sydenham of the London School of Hygiene and Tropical Medicine and fellow researchers reviewed evidence from three trials involving omega-3 fatty acids. None of the 3,536 individuals who participated in the trials showed any signs of poor cognitive health at the onset of the research.

After taking in omega-3 fatty acids through three different methods, including digestible capsules, for a period of six to forty months, the researchers found there was no change in these individuals’ cognitive abilities. In fact, they scored no better on a standard mental state examination than those who had been given a placebo.

"From these studies, there doesn't appear to be any benefit for cognitive health for older people of taking omega-3 supplements," said Alan Dangour, the report’s co-author. "However, these were relatively short-term studies, so we saw very little deterioration in cognitive function in either the intervention groups or the control groups."

If older adults have a diet rich in omega-3 fatty acids, one of the best ways to see how effective they actually are is to take an IQ test.