YOUR mother was right: eating up your fish really is good for the brain. Scottish scientists have discovered that fish oil helps to keep dementia at bay and slows the brain’s ageing process.

People who eat oily fish or take fish oil supplements score 13% higher in IQ tests and are less likely to show early signs of Alzheimer’s disease. Researchers say that their brains appear to be have aged up to two years less than those of people who do not consume fish oil.

Although it has long been established that the omega-3 fatty acids found in fish reduce the risk of heart disease and arthritis, their effect on the brain has been less clear.

Scientists at Aberdeen and Edinburgh universities contacted more than 300 people who had taken part in a national IQ survey in 1947, when they were aged 11, and tested them again in 2000-01 when they were aged 64.

Volunteers completed a questionnaire on their diet and the amount of omega-3 in their blood was tested.

The study, published in The American Journal of Clinical Nutrition, shows that the scores for fish oil users were 13% higher. In other tests to identify signs of dementia, the fish oil users did 6% better.

Lawrence Whalley, a professor of mental health at Aberdeen University and head of the research team, said there was evidence that fish oils slow the ageing of the brain by reducing inflammation. This reduces damage to the blood vessels that supply the brain.

“The big difference we found was not in memory but in mental speed,” he said. “The brains of fish oil users seemed to be faster. There was a strong relationship between mental test scores and the omega-3 content in the blood.

“The results suggest to me that they have younger brains than the non-users. The ageing of their brain is being slowed down by a year or two.

“Although their memory may not be different they think faster on their feet. Virtually all the advantages we are seeing are in the efficiency of connections between the different parts of the brain.”

Whalley said that doctors already knew that giving fish oil to people who had just had a heart attack improved their chances of survival by about 40%. Now it may also play a part in reducing the likelihood of developing dementia, which affects 750,000 people in Britain. One person in 20 over the age of 65 suffers from dementia and one in five over the age of 80 is affected. oThe diet of many Britons — particularly among the middle classes — has got worse despite the millions of pounds spent on healthy eating campaigns, a study has revealed.

The research shows that up to a third of Britons — equivalent to 20m of the population — have increased their consumption of fried food and a similar proportion takes less exercise.

According to the study, which tracked more than 11,000 “baby-boomers” for almost a decade, the middle classes are eating more chips and the working classes are eating more fried food.

Many have spurned wholemeal bread in favour of processed white varieties, while consumption of fruit and vegetables may have fallen despite promotional campaigns.

Scientists say that the findings illustrate the failure of successive governments to convey effective health messages to a population that is increasingly beset by lifestyle diseases, despite campaigns that cost about £130m a year.

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