Omega-3 intake linked to better cognitive health in older adults, study finds

New research published in The International Journal of Psychiatry in Medicine has found a link between higher omega-3 fatty acid intake and improved cognitive abilities in older adults. Analyzing data from a nationally representative health survey, researchers discovered that participants who consumed more omega-3 fats scored higher on cognitive tests. The findings suggest that incorporating omega-3-rich foods like fish and certain plant oils into the diet could support cognitive health as people age.

The global rise in the number of older adults has brought cognitive decline into the spotlight, as it affects memory, learning, and the ability to carry out daily tasks. Researchers have long been interested in dietary factors that might influence cognitive health. Omega-3 fatty acids, found in fatty fish, flaxseeds, and walnuts, are known to benefit cardiovascular and brain health, and some studies have suggested a protective role against dementia.

However, solid evidence of the effects of omega-3 on cognitive function in older adults has been limited. The current study aimed to fill this gap by examining the relationship between omega-3 intake and cognitive performance in a large sample of older adults, paving the way for dietary recommendations that may protect against cognitive decline.

The study used data from the National Health and Nutrition Examination Survey (NHANES), a comprehensive survey conducted annually to assess the health and nutritional status of people in the United States. The researchers analyzed data from 2,430 individuals aged 60 and older who participated between 2011 and 2014.

To gather information on participants’ diets, trained professionals conducted two structured interviews with each participant, focusing on their food intake over the previous 24 hours. The first interview was conducted face-to-face, and a follow-up was done by phone a few days later. These interviews provided detailed dietary data, from which the researchers calculated each person’s daily omega-3 intake by assessing the combined intake of specific omega-3 fatty acids.

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Cognitive function was assessed through three tests:

1. CERAD Word List Test: A word recall test measuring memory retention.
2. Animal Fluency Test: A test where participants named as many animals as they could within a minute, assessing executive function and mental flexibility.
3. Digit Symbol Substitution Test (DSST): A test that evaluates processing speed and working memory by having participants match symbols to numbers under time constraints.

In addition to analyzing dietary and cognitive data, researchers considered factors like age, gender, education, body mass index, and lifestyle habits (such as smoking and alcohol use), as well as medical histories of diabetes, cardiovascular disease, and stroke, which could influence cognitive function. They then used a statistical model to analyze the relationships between omega-3 intake and scores on each of the cognitive tests.

Key Findings of the Study

The study found a positive relationship between omega-3 intake and cognitive performance. Higher omega-3 consumption was associated with better scores on all three cognitive tests, even after accounting for various demographic and lifestyle factors. Specifically:

• Each unit increase in omega-3 intake was linked to a 0.53-point improvement in the CERAD Word List Test, a 0.29-point improvement in the Animal Fluency Test, and a 0.61-point improvement in the DSST.
• Participants with the highest omega-3 intake consistently scored better across all cognitive tests than those with the lowest intake, underscoring a pattern that omega-3 may support cognitive health in aging.

Interestingly, the analysis also suggested that this relationship was nonlinear. For example, cognitive scores improved most rapidly with omega-3 intake levels up to a certain point, beyond which the improvement leveled off. This pattern suggests that while moderate omega-3 consumption is beneficial, consuming very high amounts may not lead to further cognitive gains.

The researchers conducted additional subgroup analyses to assess if these findings varied across different groups. They found that individuals with a higher level of education and those who had a history of stroke appeared to benefit most from increased omega-3 intake. These insights highlight the potential for omega-3 to serve as a particularly useful dietary factor for those at higher risk of cognitive decline.

Despite its promising results, the study has limitations to note. For one, the study relied on self-reported dietary information, which can be prone to inaccuracy. Since it was a cross-sectional study, which examines data at one point in time, it cannot establish a cause-and-effect relationship between omega-3 intake and cognitive function. This means that while a link was found, it remains unclear whether omega-3 intake directly improves cognitive abilities or if healthier individuals are simply more likely to consume omega-3-rich diets.

Further research is needed to explore the direct impact of omega-3 on cognitive health. Prospective studies, which follow participants over time, could better establish causation and provide insight into how long-term omega-3 consumption affects cognitive decline. Additionally, investigating whether omega-3 supplementation, as opposed to dietary intake alone, offers cognitive benefits could help develop targeted nutritional guidelines for older adults.

The study, “Dietary omega-3 intake and cognitive function in older adults,” was authored by Bingdian Wang, Deqin Li, Cuicui Peng, Jingfang Hong, and Yonggui Wu.