A study from Harvard University shows that omega-3 fats may help prevent cognitive decline in older people.
Omega-3 fatty acids (also called omega-3 fats and n-3 fats) are essential fats—the body can’t make them from scratch but must get them from food.
Foods high in omega-3 include fish, vegetable oils, nuts (especially walnuts), flax seeds, flaxseed oil, and leafy vegetables.
Omega-3 fats are a key family of polyunsaturated fats. There are three main omega-3s:
Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) come mainly from fish, so they are sometimes called marine omega-3s.
Alpha-linolenic acid (ALA), the most common omega-3 fatty acid in most Western diets, is found in vegetable oils and nuts (especially walnuts), flax seeds and flaxseed oil, leafy vegetables, and some animal fat, especially in grass-fed animals.
In the current review study, researchers aimed to provide an update on omega-3 fatty acids in preventing cognitive decline and dementia.
Previous studies and three new meta-analyses suggest that fish or omega-3 fat intake is linked to a reduction in the development of mild cognitive decline and Alzheimer’s disease.
Supplementation with DHA in clinical trials in people with mild cognitive impairment showed benefit on cognitive decline, whereas there was no benefit in Alzheimer’s disease.
In cognitively healthy people with coronary artery disease, researchers found 3.36 g EPA and DHA daily slowed cognitive aging by 2.5 years.
Among 15 clinical studies in cognitively healthy older people age more than 55 years, seven reported benefits whereas eight did not.
The team says the possible mechanisms for differences in outcomes include supplementation dose, study duration, apolipoprotein E genotype, gender, levels of cognitive decline, and cognitive tests used in the studies.
The apolipoprotein E (APOE) genotype is a genetic risk factor for dementia, Alzheimer’s disease, and coronary artery disease.
They suggest that the downstream product of DHA, neuroprotectin D1, may be involved in the brain’s beneficial effects.
The researchers conclude that people with early memory complaints or a family history of dementia and those with coronary artery disease should consider the potential benefits of fish intake and supplementation with omega-3 fats.
ApolipoproteinE4 carriers may especially benefit from DHA supplementation before the development of cognitive decline.
The research was published in Current Opinion in Lipidology and conducted by Francine K Welty.
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