New research suggests that the omega-3 fatty acids found in fish and nuts may not have brain-saving powers for seniors.

Omega-3 fatty acids are said to have numerous health benefits, but new research casts doubt on one of them.

According to a study released Wednesday in the journal Neurology, omega-3 fatty acids may not have the brain-boosting benefits prior research suggested, at least not in healthy postmenopausal women.

Eric Ammann, a Ph.D. student in epidemiology at the University of Iowa College of Public Health, studied 2,157 women ages 65 to 80 who were part of the Women’s Health Initiative clinical trials of hormone therapy. As part of the study, the women had blood tests done to measure their levels of omega-3 fatty acids, as well as annual tests of their thinking and memory skills.

After an average of six years, the women with high levels of omega-3 fatty acids in their blood showed no difference in mental decline, compared with the women with low omega-3 levels.

Prior research showed that omega-3s have a protective effect on thinking skills, but Ammann’s research shows otherwise. He told Healthline that despite his findings, the matter is anything but settled.

“Our study was observational and should not be viewed as a definitive answer on the relationship between omega-3s and cognitive function. In making health-related decisions about diet and supplements, we would advise people to consider the total body of evidence and to consult with their healthcare providers,” he said.

And the new findings don’t necessarily mean omega-3 fatty acids are useless in other respects, namely strengthening the heart, blood vessels, and brain.

“Based on proposed biological mechanisms, it is reasonable to hypothesize that omega-3s could be good for the brain,” Ammann added. “Omega-3 fatty acids are a major constituent of neurons, and omega-3s may reduce the arterial hardening and inflammation that contribute to strokes.”

Warding off mental decline in our golden years is a serious concern for medical professionals. Earlier this month, a study in the Canadian Medical Association Journal showed that even the best dementia drugs are ineffective at slowing the progression of mild cognitive impairment in seniors.

Dementia Drugs Ineffective at Slowing Mental Decline

“As with omega-3s, research on other interventions to delay cognitive decline isn’t settled science. Generally speaking, cardiovascular risk factors are somewhat predictive of dementia and cognitive decline,” Aamann said. “Regular exercise, healthy eating, maintaining a healthy body weight, and blood pressure and cholesterol control could help. It is also possible that regular use of one’s cognitive skills and having a supportive social network could delay cognitive decline.”

There is, however, plenty of other research that shows the health benefits of omega-3s, which are often taken in the form of fish oil supplements.

Earlier this year, researchers at the Harvard School of Public Health found that fish oil supplements rich in omega 3 fatty acids lower a person’s risk of type 2 diabetes and coronary heart disease. The research, published in The Journal of Clinical Endocrinology & Metabolism, found that the supplement helps increase levels of the hormone adiponectin, which helps the body regulate glucose levels and inflammation.

Despite its potential benefits, fish oil may not be for everyone, especially men at a high risk for prostate cancer.

Research from the National Cancer Institute shows that men with high concentrations of omega-3 fatty acids in their blood have a 43 percent greater risk of developing prostate cancer, the most common cancer affecting men.

Researchers discovered this after studying 834 men with prostate cancer. Of them, 156 had high-grade cancer.

They found that men with higher concentrations of omega-3 fatty acids were more likely to develop cancer, while men with high concentrations of linoleic acid—an omega-6 fatty acid—had lower incidences of prostate cancer. Linoleic acid is found in high concentrations in salicornia, safflower, sunflower, poppy seed, grape seed, and evening primrose oils.

Omega-3 fatty acids are a type of “good” fat that’s been shown to lower LDL, or “bad,” cholesterol levels, reduce inflammation throughout the body, improve skin appearance, and help a person’s heart.

Omega-3s are common in many types of freshwater fish, flaxseed oil, nuts, and certain spices. Fish oil supplements high in omega-3 fatty acids have become one of the most common supplement types on the market.

Where You Can Find Omega-3 Fatty Acids