A review of current evidence has concluded that omega-3 fish oil supplements are unlikely to prevent cognitive decline. The new Cochrane systematic review will be published online on 13 June.
While there has been some evidence from population studies that people who eat oily fish or other foods rich in omega-3 could be protected against cognitive decline and dementia, there have been few high quality clinical trials to back up these observations.
The systematic review aimed to look at all of the evidence from randomised clinical control trials of omega-3 fish oil supplements for the prevention of cognitive decline or dementia. After excluding research studies which did not meet their strict criteria, the team led by scientists from the London School of Hygiene & Tropical Medicine, were left with three high quality trials.
Together these trials followed 3536 healthy adults over the age of 60 for up to three and a half years. None of the studies measured whether these volunteers went onto develop dementia, but volunteers were given memory and thinking tests to monitor any cognitive decline.
The review reports that none of the trials showed any benefit of omega-3 supplements on cognitive decline, although longer trials would be needed to assess potential long term benefits.
Dr Marie Janson of Alzheimer’s Research UK said:
“Cochrane reviews are an excellent way of pulling together high quality scientific evidence. This summary has reviewed data from three clinical trials of people taking omega-3 fish oil supplements and concluded that they do not have likely benefits in preventing cognitive decline. As these trials had relatively short follow-up periods, there may be longer-term benefits, but further research would be needed to investigate this.
“While taking omega-3 supplements may not be the key to staving off cognitive problems, eating a healthy balanced diet, including fish and other natural sources of omega-3, is important for maintaining good health. We know that what is good for the heart can be good for the head so maintaining a healthy weight, eating a balanced diet, exercising and keeping our blood pressure in check are all ways that we could reduce our risk of cognitive decline and dementia later in life.”