Omega-3 fatty acids do not necessarily help to reduce the risk of developing dementia in older people, new research suggests. A Cochrane Review of data collected during studies over the last three and a half years indicates that supplements offer no benefits over placebos. While a number of studies have suggested omega-3 could be beneficial for keeping nerve cells in the brain healthy, there is little evidence these fats prevent cognitive decline and dementia. Participants who had been given omega-3 in one trial scored no better in standard mental state examinations than those who had been given a placebo. Lead researcher Emma Sydenham, of the London School of Hygiene and tropical medicine, said: "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." Omega-3 fats make up part of most people's daily diet and are found in nuts, seeds and oily fish such as mackerel and salmon. Read more about Barchester's dementia care homes.