Fatty Fish May Help Prevent Alzheimer's, but Other Fats Raise Risks
Jan. 26, 2004 -- Fish really may be brain food after all. A new study shows the omega-3 fatty acids found in fish can help fight the effects of aging on the brain and may reduce the risk of Alzheimer's disease.
But other types of saturated fats that raise cholesterol levels may actually increase the risk of age-related declines in mental performance.
The study showed that middle-aged men and women who ate a lot of fatty fish, such as tuna and salmon, were less likely to suffer from declines in mental performance. But those who had a high-fat diet had a higher risk of these declines.
Researchers say subtle declines in mental performance can be found at middle age, years before more serious symptoms of Alzheimer's develop.
Omega-3 Fatty Acids Protect the Brain
Researchers say few studies have looked at the relationship between eating fish and mental performance, especially in middle-aged people. The study, published in the January issue of Neurology, looks at the effects of fatty acid and fish consumption on mental performance in a group of 1,613 men and women aged 45 to 70.
The participants went through extensive mental performance testing, including tests that assessed their memory, thought processing speed, and mental flexibility, in order to pick up mild declines in brain function, and filled out questionnaires about their diet.
Researchers found that the participants' risk of mental decline was decreased for those who ate more fatty fish.
Specifically, the risk of impaired brain function and processing speed decreased by 19% and 28% for every increase in the amount of omega-3 polyunsaturated fatty acids they ate.
Cholesterol Raises Brain Risks
But when researchers looked at overall fat and saturated fat intake, they found a significant association between an increased risk of impairment and higher intakes of fat and cholesterol in the diet.
For example, the risk of impairment in memory, speed, and flexibility increased by 15% to 19% for each increase in saturated fat the participants ate.
The risk of impaired memory and flexibility also increased by 27% and 26%, respectively, for each increase in the amount of dietary cholesterol in the diet.
Researchers say eating more fish has already been shown to reduce the risk of heart disease, and the next step will be to determine if those dietary changes might actually help prevent age-related diseases of the brain, such as dementia and Alzheimer's disease.