Fish oil pills 'offer no protection against dementia' They found older people taking omega-3 fish oil capsules performed no better in mental tests than those who took dummy pills. Several studies have suggested that omega-3 fatty acids - particularly those found in oily fish - are essential for keeping nerve cells in the brain healthy. Others have found those who eat oily fish regularly have a lower chance of developing memory loss or full-blown Alzheimer's. However, researchers from the London School of Hygiene and Tropical medicine found no evidence of benefit. They looked at results from 3,500 people over 60, who took part in three trials, which lasted between six months and three-and-a-half years. Alan Dangour, a nutritionist at the school, and co-author of the report, said: "From these studies, there doesn't appear to be any benefit for cognitive health for older people of taking omega-3 supplements. 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. It may take much longer to see any effect of these supplements. The research is published in the Cochrane Database of Systematic Reviews. There is stronger evidence that oily fish has other health benefits. For example, it is known to help maintain a healthy heart. Dangour said: "Fish is an important part of a healthy diet and we would still support the recommendation to eat two portions a week, including one portion of oily fish."