Researchers in the US studied 1,219 people aged over 65 who did not have dementia. The participants were asked questions about their daily diet and had their blood tested for beta-amyloid levels.
Beta amyloid is the main component of amyloid plaques in the brains of Alzheimer’s disease (AD) patients. An accumulation of beta-amyloid in the brain is one of the key hallmarks of Alzheimer’s disease.
The results showed that those who consistently consume fish high in omega-3 fatty acids had lower beta-amyloid levels in their blood compared with those eating less fish. It was found that consuming one gram of omega-3 each day lowered the blood levels of beta-amyloids by between 20% and 30%.
Levels of the protein in the blood are believed to reflect those found in the brain, indicating a protective effect from consuming omega-3 rich foods.
“Although it is not easy to measure the levels of beta-amyloid deposits in the brain in this type of research, 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”, said lead researcher Dr Nikolaos Scarmeas from Columbia University Medical Center in New York, as reported on Dailymail.
“Determining through further research whether omega-3 fatty acids or other nutrients associate with spinal fluid or brain beta-amyloid levels, or levels of other Alzheimer’s disease-related proteins, can improve our confidence on beneficial effects of parts of our diet in preventing Alzheimer’s.”
The researchers, whose findings are reported in the journal Neurology, looked at 10 nutrients including vitamins C, D, E, and B12, omega-3, omega-6 fatty acids, saturated fatty acids, mono-unsaturated fatty acid, folate and beta-carotene. However, other nutrients besides omega-3 fatty acids were not associated with different blood levels of beta-amyloid.
The link between omega-3 and blood beta-amyloid remained the same after adjusting for a range of potential influences, including possession of a version of the apolipoprotein E (APOE) which is known to increase Alzheimer’s risk.
Fish that are high in Omega-3 fatty acids include salmon, tuna, sardines, mackerel, and herring. Other sources of Omega-3s include caviar, oysters, flaxseeds, chia seeds, vegetable oils, and some vegetables, such as Brussels sprouts, spinach and kale.