Eating fish, nuts and related foods may protect parts of the brain linked to Alzheimer’s disease and memory problems by influencing an important brain protein.
The link between foods such as fish oils which are rich in omega 3 oils and blood levels of a protein called beta-amyloid was measured by Dr Nikolaos Scarmeas and his team at Columbia University Medical Centre, New York, USA.
The team looked at the diets of 1,219 people above the age 65 who were free of dementia. Intake of various nutrients over an average of just over a year was measured, then their blood was tested for beta-amyloid.
The nutrients were saturated fatty acids, omega-3 and omega-6 polyunsaturated fatty acids, mono-unsaturated fatty acid, vitamin E, vitamin C, beta-carotene, vitamin B12, folate and vitamin D. Of these, only omega-3 fatty acids appeared to be linked to blood beta-amyloid levels, say the researchers.
They calculate that consuming one gram of omega-3 per day (about half a fillet of salmon per week) more than the average amount eaten by study participants was associated with 20 to 30 per cent lower blood beta-amyloid levels.
Omega-3 fatty acids are found in other oily fish, chicken, some oils, eggs and nuts. The authors report on their findings in yesterday’s (May 2) online issue of the journal Neurology.
Dr Scarmeas says: "While it’s not easy to measure the level of beta-amyloid deposits in the brain in this type of study, it is relatively easy to measure the levels of beta-amyloid in the blood, which, to a certain degree, relates to the level in the brain."
He calls for further research to confirm whether omega-3 fatty acids relate to levels of beta-amyloid in the spinal fluid and brain. This "can strengthen our confidence on beneficial effects of parts of our diet in preventing dementia," he says.
Scarmeas, N. et al. Neurology May 2 2012
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