Contrary to earlier studies, new research led by University of Iowa investigators suggests that omega-3 fatty acids may not benefit thinking skills. The study is published in the Sept. 25 online issue of Neurology, the medical journal of the American Academy of Neurology. Omega-3s are found in fatty fish such as salmon and in nuts.

“There has been a lot of interest in omega-3s as a way to prevent or delay cognitive decline, but unfortunately our study did not find a protective effect in older women. In addition, most randomized trials of omega-3 supplements have not found an effect,” says study author Eric Ammann, a doctoral student in the UI College of Public Health Department of Epidemiology.

“However, we do not recommend that people change their diet based on these results,” Ammann says. “Researchers continue to study the relationship between omega-3s and the health of the heart, blood vessels, and brain. We know that fish and nuts can be healthy alternatives to red meat and full-fat dairy products, which are high in saturated fats.”

The study involved 2,157 women age 65 to 80 who were enrolled in the Women’s Health Initiative clinical trials of hormone therapy. The women were given annual tests of thinking and memory skills for an average of six years. Blood tests were taken to measure the amount of omega-3s in the participants’ blood before the start of the study.

The researchers found no difference between the women with high and low levels of omega-3s in the blood at the time of the first memory tests. There was also no difference between the two groups in how fast their thinking skills declined over time.

In addition to Ammann, the researchers included Robert Wallace, Ryan Carnahan, and Jennifer Robinson from the UI College of Public Health; Natalie Denburg from the UI Carver College of Medicine; James Pottala from OmegaQuant Analytics; William Harris from OmegaQuant Analytics and the University of South Dakota Sanford School of Medicine; and Mark Espeland from the Wake Forest School of Medicine.

This release contains information from the American Academy of Neurology.

The study was supported by the National Heart, Lung, and Blood Institute, National Institutes of Health, and U.S. Department of Health and Human Services.