A study by US scientists found that elderly people who eat fish at least once a week are three to five times less likely to develop the conditions than people who did not.But it is essential that the fish is cooked in a manner that preserves the vital Omega-3 fatty acids which help protect the brain, researchers said.
Grilling or baking the meat provides the maximum levels of Omega-3, which increase blood flow to the brain, reduce inflammation and limit the build-up of harmful plaques which precedes Alzheimer's. In contrast fried fish has very low amounts of Omega-3 and consequently offers no protection whatsoever against dementia and age-related memory loss, known as Mild Cognitive Impairment (MCI).
Researchers from the University of Pittsburgh studied a group of 260 healthy volunteers with an average age of 76. In a study to be presented at the Radiological Society of North America annual meeting tomorrow (WED), they questioned the participants about how regularly they ate fish. Brain scans carried out ten years later showed that those who did not eat fish regularly had suffered much more shrinkage in key areas of the brain linked to working memory. A further five years on, they found that 31 per cent of non-regular fish eaters had gone on to develop Alzheimer's or MCI, compared with between three and eight per cent of those who ate fish at least once a week.
Dr Cyrus A. Raji, who led the study, said further studies could help identify whether Omega-3 supplements yielded similar effects, and whether some types of fish offered better protection than others.
He said: "We know from other studies that salmon gives the maximum amount of Omega-3 fatty acids so it is very possible, but we did not look at which fish people were eating in the study. "Studies like this definitely justify trials that will look at Omega-3 fatty acid supplements. Having said that, I would speculate that taking supplements is no substitute for a lifetime of eating fish."
Dr Simon Ridley, head of research at Alzheimer’s Research UK, said: "This study suggests that eating fish on a weekly basis may reduce the risk of cognitive decline, but it is not clear whether other underlying factors may have contributed to the lower risk in people who eat fish."As a number of controlled studies using fatty acids from oily fish have failed to show benefits for dementia, there is a clear need for more conclusive research into the effects of dietary fish on our cognitive health."
Dr Anne Corbett, research manager of the Alzheimer's Society, added: "This moderately sized study adds weight to existing evidence suggesting that eating fish reduces your risk of developing cognitive decline."However, this research did not account for lifestyle factors such as other foods or exercise which could also have had an effect. The best way to lessen your chance of developing dementia is to eat a healthy diet including fruit and vegetables along with taking regular exercise and giving up smoking."
2011-12-03 18:16 编辑：kuaileyingyu