According to a new study, fish oil supplements that have high content of omega-3 fatty acids are not capable of protecting against mental decline in the face of what is thought generally. The study looked at 4,000 older people.

Elizabeth Chew, deputy clinical director at the National Eye Institute, related to the National Institutes of Health said that "The supplements just don't cut it. If people are thinking [taking them] is going to help cognitive function, it's not going to do so among the older age group”.

According to the US National Institutes of Health that sponsored the research, the clinical trial that have been conducted for a period of five years is "one of the largest and longest of its kind". The study has been published in the Journal of the American Medical Association.

As per study author Emily Chew, deputy clinical director at the National Eye Institute, which is related to the NIH, they didn't observe any benefit of omega-3 supplements for dealing with cognitive decline.

Fish oils consist of omega-3 fatty acids and people who consume fish like tuna, salmon and halibut on regular basis have better heart, eye and brain health than those who do not consume these fish.

However, as per experts, consumption of the oils in pill form is not the same thing. It has been shown in a 2011 study that omega-3 supplements that are sold over the counter did not help improve the brain health of older people that have pre-existing heart disease.