Higher blood levels of omega 3 fatty acids found in seafood are associated with a higher likelihood of healthy aging among older adults, finds a US study published by The BMJ today.

With populations across the world living longer, there is a growing focus on healthy aging, a meaningful lifespan without major chronic diseases and with good physical and mental function.

Previous studies suggest that omega-3 polyunsaturated fatty acids(n-3 PUFAs) derived from seafood and plants may have beneficial effects on the body that could promote healthy aging, but results are inconsistent.

So a team of US researchers, led by Heidi Lai at the Friedman School of Nutrition Science and Policy at Tufts University in Boston, set out to investigate the association between circulating blood levels of n-3 PUFAs and healthy aging among older adults.

The study involved 2,622 adults who were taking part in the US Cardiovascular Health study from 1992 to 2015. The average age of participants at the start of the study (baseline) was 74 years, 63% were women, and 11% were from non-white groups.

Blood levels of n3-PUFAs

Blood levels of n3-PUFAs were measured at baseline, 6, and 13 years. These included eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), docosapentaenoic acid (DPA), and alpha-linolenic acid (ALA).

The main dietary sources of EPA, DHA, and DPA come from seafood, while ALA is found mainly in plants (nuts, seeds, and leafy green vegetables). Based on these measurements, participants were split into five groups (quintiles) of circulating blood n-3 PUFA levels, from lowest to highest.

Through a review of medical records and diagnostic tests, the researchers found that 89% of the participants experienced unhealthy aging over the study period, while 11% experienced healthy ageing—defined as survival free of major chronic diseases and without mental or physical dysfunction.

After taking account of a range of other social, economic, and lifestyle factors, the researchers found that levels of seafood-derived EPA in the highest quintile were associated with a 24% lower risk of unhealthy aging than levels in the lowest quintile.

For DPA levels, the top three quintiles were associated with an 18-21% reduction in the risk of unhealthy aging. However, seafood-derived DHA and plant-derived ALA were not associated with healthy aging.

A possible explanation for this effect is that n-3 PUFAs help to regulate blood pressure, heart rate and inflammation, explain the authors. They point out that this was an observational study so that no firm conclusions can be drawn about cause and effect, and they cannot rule out the possibility that some of the observed risks may be due to other unmeasured factors.

We live in challenging times when lifespans are increasing, but healthy lifespans are not, they write. "Following the World Health Organization's policy framework for healthy aging, any evidence-based clues to improve health in later life are welcome, but additional efforts to accelerate this area of research are essential," they conclude.