Does fish oil reduce Alzheimer’s risk? What a new US study says

Under the two-year, placebo-controlled test, researchers studied 365 adults aged between 55 and 80 at risk for Alzheimer’s.

A pile of gelatin capsules containing fish oil high in omega-3 | Wikimedia Commons

New Delhi: Fish oil supplements have been linked to a reduced risk of Alzheimer’s and brain decline among older adults. They contain omega-3 fatty acids, which are key nutrients that help form brain cell connections needed for cognition. However, a recent study shows that the supplements have little effect on brain health even after they reach the brain.

Conducted by the Keck School of Medicine, University of Southern California (USC), the study was published on 18 June in eBioMedicine. Hussein N Yassine, a neurology professor at USC, led the two-year, placebo-controlled, double-blinded study.

The analysis showed that high doses of omega-3s did not improve memory, cognitive function, or brain cell loss in areas of the brain related to Alzheimer’s.

“We’re focused on better understanding how the brain processes omega-3s and whether factors, such as poor health, dietary pattern, genetic risk and age, may change the brain’s ability to effectively absorb and use omega-3s,” said Yassine.

The omega-3 supplements market in India is booming. According to one study, it will reach $879.1 million by 2030.

What the study found

Researchers recruited 365 adults aged between 55 and 80 who they considered at risk for Alzheimer’s. They didn’t eat fish, an important source of omega-3s. About 47 per cent carried an APOE4 gene, the strongest genetic risk factor for late-onset Alzheimer’s.

After six months, the DHA (docosahexaenoic acid, a vital omega-3 fatty acid) levels in participants’ cerebrospinal fluid increased by an average of 17 per cent. This helped the researchers confirm that the omega-3 reached the brain.

But participants who took the supplements did no better on tests for memory and cognitive abilities than those who took a placebo. Brain scans showed that the omega-3 supplements did not prevent shrinkage of the hippocampus. The hippocampus is a region of the brain linked to memory and is often used as a marker of brain ageing and Alzheimer’s risk.

“We are working to develop medications that may help the brain better utilize these nutrients to preserve cognitive function,” Yassine said.