Omega-3s show cognitive decline benefit in review

Omega-3s supplementation is emerging as a valuable tool in managing age-related cognitive decline, according to a new review. The benefits are mild, but are clearly statistically significant, and are remarkably consistent across recent systematic reviews, the authors concluded.

The new research was the work of a team of researchers associated with hospitals and universities in Portugal. It was published recently in the journal Nutrients.

The authors noted that omega-3s are a very well-researched ingredient — and with that long history and many studies of different duration, statistical power and methodologies — a wider than ideal range of outcomes has been achieved. This is especially true in the arena of omega-3s and their relationship to cognitive health.

Taking the 30,000-foot view

In an attempt to clarify that somewhat muddy picture, the authors decided to look at the systematic reviews that have been published over the past decade to get a picture of where the overall research trend is headed.

To that end, they conducted searches in MEDLINE, the Cochrane Database of Systematic Reviews, Scopus, and the PROSPERO International prospective register of systematic reviews between January 2014 and December 2024.

The authors were looking for systematic reviews that evaluated studies in adults or older adults, who were healthy, had mild cognitive decline or had Alzheimer’s disease. In addition, they were looking for research done with supplementation only, instead of omega-3s that were paired with other interventions.

They also wanted reviews that focused on randomized controlled trials in human populations only. The authors restricted their search to research that had been published in English, Spanish or Portuguese. They ended up with nine systematic reviews to include in their meta review. In total, they evaluated systematic reviews that included 26,881 participants aged 40 years or older.

Scope limited to studies that used validated measurement tool

They limited their scope to studies that used the Mini Mental State Examination (MMSE) as an evaluation tool of cognitive impairment. The MMSE was first developed in 1975 and consists of 11 standard questions. Since the late 1990s its verified validity and quick reproducibility has made it one of the standard ways to gauge cognitive performance and the risk of developing dementia.

One interesting thing that emerged from the authors’ evaluation is that the benefits of omega-3s might involve building up a certain level within the body, rather than the dose-dependent effects seen in some other nutrients.

“These findings suggest that the therapeutic mechanism may involve threshold effects rather than linear dose–response relationships, with benefits achieved once minimum effective levels are reached,” they said.

“The observed positive (albeit small) effect of omega3 supplementation on reduction in cognitive decline, independent of time or dose, suggests that clinicians can consider using this intervention paired with other recommended interventions to prevent cognitive impairment,” the authors concluded.

Welcome addition to body of evidence

William Harris, Ph.D., head of the Fatty Acid Research Institute (FARI), said this new research is a welcome addition to the growing body of omega-3s evidence.

“This updated review of the effects of omega-3 fatty acids on cognitive decline points to small but significant benefits of these important nutrients in mental health. Larger and definitive randomized trials are needed to determine the proper doses and time to intervene to slow the loss of mental capacity,” Harris told SupplySide Supplement Journal.