New research suggests eating fish and taking fish oil supplements might actually not help improve one's memory and brain health, like previously believed, HealthDay reported.

The researchers did not find a difference in memory and thinking test scores, even with omega-3 fatty acids being present in the blood stream. The study was published online Wednesday in the journal Neurology.

"We looked at the association of blood biomarkers of [omega-3 fatty acids] and measure of cognitive [thinking] function and found no statistically significant association between baseline levels or over time," said lead author Eric Ammann, an epidemiology doctoral candidate at the University of Iowa.

A study published in the same journal in February suggested the exact opposite, that omega-3 fatty acids help brain health as it ages. The participants in that study, middle and older age people, scored higher on memory and thinking tests while regularly eating fish and taking fish oil supplements.

Docosahexaenoic acid (DHA) is present in omega-3 and is a structural component to brain tissue. DHA has components that may be able to slow brain deterioration.

Ammann theorized prior to the study that omega-3 would have a protective effect on thinking and memory in people aged 65 and older, as opposed to actively improving.

The researchers used data on 2,000 women aged 65 to 80, with normal memory and thinking, from the U.S. Women's Health Initiative. The participants took memory and thinking tests every year for an average of six years each.

The researchers found no difference in the women's thinking and memory at the end of the study.

"There were two marginally significant findings between high and low omega-3s, and to some extent those findings align with other studies, but we did look at about 14 different outcomes, so by chance, we would expect to find some on the cusp of statistical significance," said Ammann.

"This was a select group of women who were older and healthy at baseline. It's one piece of evidence on the effect of omega-3s and cognitive function," he said. "Our results are looking at the short-term effect of omega-3s. We don't know for someone [who has higher levels] for a longer time, if that would have a more gradual, cumulative effect over time."