Omega-3 fish oil supplements do not slow cognitive decline in older people

Many older people take omega-3 fish oil supplements in the belief it boosts their brain power. However a large clinical trial has now found they are wasting their money as it found no evidence that omega-3 supplements slow cognitive decline in older people.

The research by the National Institutes of Health (NIH) followed 4,000 patients over a five-year period and is the largest and longest of its kind.

“Contrary to popular belief, we didn’t see any benefit of omega-3 supplements for stopping cognitive decline,” said Emily Chew, deputy clinical director at the National Eye Institute (NEI), part of NIH.

Dr Chew leads the Age-Related Eye Disease Study (AREDS), which was designed to investigate a combination of nutritional supplements for slowing age-related macular degeneration (AMD), a major cause of vision loss among older Americans. That study established that daily high doses of certain antioxidants and minerals—called the AREDS formulation—can help slow the progression to advanced AMD.

A later study, called AREDS2, tested the addition of omega-3 fatty acids to the AREDS formula, but the omega-3’s made no difference.

Omega-3 fatty acids are made by marine algae and are concentrated in fish oils; they are believed to be responsible for the health benefits associated with regularly eating fish, such as salmon, tuna, and halibut. Previous studies on people’s dietary habits and health have found that regular consumption of fish is associated with lower rates of AMD, cardiovascular disease, and possibly dementia.

Dr Simon Ridley, head of Research at Alzheimer’s Research UK, said: “Dementia is a huge global challenge and while the search for effective therapies intensifies, it is also important to look at more readily available tools that may stave off the onset of memory and thinking difficulties.

“Oily fish, which contains omega-3 fatty acids, is thought to be an important part of a healthy diet. Some studies have linked higher omega-3 intake with a lower risk of dementia, but current evidence does not suggest any benefit of taking omega-3 supplements on cognition.”

He added: “Similarly, this clinical trial suggests there is no benefit to taking omega-3 in later life when it comes to memory and thinking skills, although this study didn’t go on to look at a dementia diagnosis. As volunteers in this study had age-related macular degeneration and were being treated for this condition, it is difficult to know how these results apply to the wider population.”

“The best current evidence suggests that what’s good for your heart is good for your head and that keeping weight and blood pressure in check, quitting smoking and eating a healthy balanced diet can help reduce dementia risk.”

The study was published in the Journal of the American Medical Association.