Eating fish can help prevent dementia in elderly people, suggests a study in the Archives of Neurology. US researcher Martha Morris from Rush University Medical Center, Chicago, and colleagues found that elderly people who eat fish at least once a week have a 10 per cent slower rate of cognitive decline and memory loss.

The researchers reviewed a data from the residents of Chicago, who were 65 and above and were taking part in an ongoing study. They interviewed the people to assess their cognitive status, dietary practice, medical history, alcohol consumption, day-to-day activities and the level of exercise. “Dietary intake of fish was inversely associated with cognitive decline over six years in this older, biracial community study,” the researchers write.

According to Morris and his colleagues, data available in US and other countries have shown that dementia or cognitive decline in elderly population is a widespread and increasing public health problem. The researchers add, “Our data offer no insight as to whether this cognitive decline is pathological or the result of a normal aging process.”

The researchers believe that fish provides plenty of omega-3 fatty acids, which help protect brain functions and neuro-cognitive development, and thus fight cognitive decline.

Animal experiments have shown that among omega-3 fatty acids, docosahexaenoic acid is of particular importance in restoring memorising performance in old age.

3 links to mental decline in old age

1: Hormone treatment: A study published in the Journal of the American Medical Association suggests that hormone therapy could double the risk of dementia in elderly women. Researchers suggest that hormone therapy might injure brain cells by increasing clotting of blood and blocking of small blood vessels in the brain, thus contributing to occurrence of dementia.

2: HIV infection: Ageing HIV patients are more likely to suffer dementia, compared to the people who don’t have the infection, suggests a US study presented at the 9th International Conference on Alzheimer’s Disease in Philadelphia. A protein called (Tat) is responsible for the problem.

3: Diabetes: A study by US scientists suggests that poorly-managed diabetes increases the risk of dementia in the old. Researcher Yousef Mohammad of Ohio State University and colleagues have found that diabetes has a chemical effect which contributes to dementia.