More clinical studies are disproving the supposed health benefits found in fish oil supplements.

Rich in the beneficial fatty acid omega-3, fish oils are popularly believed to be effective for heart diseases. However, no hard evidence has been said to clinically prove this.

Another popularly believed health benefit found in fish oil supplements is their ability to slow down cognitive decline. Like the said benefits in heart disease, no hard evidence was found to clinically prove this. In fact, a new study showed that taking fish oil supplements does not help slow down mental decline at all.

Researchers from the National Institutes of Health conducted a study that lasted for five years, to test the efficacy of fish oils in slowing down the process of cognitive decline, and published their findings online in the Journal of the American Medical Association.

"Contrary to popular belief, we didn't see any benefit of omega-3 supplements for stopping cognitive decline," said NIH's deputy clinical director at the National Eye Institute (NEI) and deputy director of the Division of Epidemiology and Clinical Applications Emily Chew, M.D.

For their study, the researchers followed 4,000 older patients who had early or intermediate age-related macular degeneration (AMD). The average age of the participants was 72, with 58 percent being female.

At the beginning of the five-year-long study, the researchers gave cognitive function tests to the participants, to establish a baseline. Cognitive function tests were again given after two and four years. The same tests were also previously used in studies which looked at attention, processing speed, immediate and delayed recall and memory.

The participants were also randomly assigned to four groups - placebo, omega-3, Lutein and zeaxanthin omega-3 and Lutein/zeaxanthin

Because all participants were at risk for worsening of their AMD, they were also offered the original or a modified version of the AREDS formulation (without omega-3 or lutein/zeaxanthin).

As the study progressed its fifth year, the cognitive scores of the participants in each of the four subgroups decreased. The researchers found that no nutritional supplement, or a combination of them, made any difference in cognitive decline.

Chew's team conducted this five-year study, called Age-Related Eye Disease Study 2 (AREDS2), following the first AREDS which looked at a combination of other nutritional supplements for AMD. AREDS2 included omega-3 supplements to the previous combination, but still found no beneficial effects to the decline of cognitive function in older people.

"The AREDS2 data add to our efforts to understand the relationship between dietary components and Alzheimer's disease and cognitive decline," explained senior investigator Lenore Launer, Ph.D. from the National Institute on Aging's Laboratory of Epidemiology and Population Science. Launer pointed out that timing of nutrients or specific dietary patterns may have an impact to slowing down the decline of cognitive function.

Following the random AREDS2 clinical trial, the researchers said more research needs to be conducted to see if taking the supplement earlier will make a difference.

Photo: Health Gauge | Flickr

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