There have been many studies advocating how omega-3 fatty acids can benefit our health. But a new study suggests that high levels of omega-3 are of no benefit to cognitive decline in older women.
Omega-3 polyunsaturated fatty acids (PUFAs) are types of fats commonly found in plant and marine life.
Of particular interest to nutritionists and health care professionals are two types of omega-3 acids - DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid) - due to their rumored health benefits.
The acids are thought to play an important role in reducing inflammation throughout the body.
And studies have shown numerous other health benefits, including the potential to prevent or delay cognitive decline. But researchers from the University of Iowa suggest otherwise.
Their study, published in the journal Neurology, involved 2,157 women aged between 65 and 80, who were enrolled in the Women's Health Initiative clinical trials of hormone therapy.
The research team took blood tests from all women before the beginning of the study, in order to measure the amount of omega-3 present in their blood.
The study showed that women who ate omega-3s did not perform better on memory tests, compared with women who had low levels of the fatty acids in their blood.
The women were required to complete thinking and memory skills tests annually over an average of 6 years.
The study revealed that there was no difference in results between women who had high levels of omega-3 in their blood at the time the first memory tests were completed and women who had low levels of omega-3 in their blood.
Additionally, the results showed that there was no difference in how fast thinking skills declined over time between women who had high or low levels of omega-3 in their blood.
Despite findings, change of diet 'not recommended'
These results are contrary to earlier studies. Last year, Medical News Today reported on a study suggesting that increasing consumption of omega-3 may improve the memory of young adults.
More recently, researchers from Loyola University Stritch School of Medicine suggested that omega-3 may help prevent alcohol-related dementia.
Eric Ammann, of the University of Iowa and study author, told Medical News Today:
"We found that omega-3 levels were not associated with cognitive change over the course of the study, or with cognitive function at baseline.
Identifying interventions that might delay cognitive decline is an important goal, so a finding of no association is somewhat of a disappointment. But it's important that people have a clear idea of what works and what doesn't."
However, Ammann adds that the researchers do not recommend people change their diet based on these results:
"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."
Ammann told Medical News Today that it is likely more randomized trials of omega-3 supplements will be done, which will provide more definitive information on the relationship between omega-3s and cognitive function in older adults.
"In addition," he notes, "longitudinal studies that track people's dietary practices in middle age and later years may provide richer data on the effects of diet on long-term health outcomes."
Doug Brown, director of research at the Alzheimer's Society, notes this is not the first study to suggest that omega-3 does not protect against cognitive decline, but he says the results of this study are inconclusive.
"It's important to note that the study looked at cognitive decline due to aging and not specifically at dementia, which is caused by diseases of the brain," he adds.
"Don't avoid your favorite fish supper or a handful of cashews on account of this research. The best thing people can do to try and reduce their risk of developing dementia is to eat a healthy, varied diet and take regular exercise."