Seafood contains fatty acids that may help people age healthily.
A new study, led by Heidi Lai from the Friedman School of Nutrition Science and Policy at Tufts University in Boston, MA, investigates the link between high consumption of omega-3-rich seafood and healthy aging.
Lai and colleagues define "healthy aging" as "meaningful lifespan without chronic diseases and with intact physical and mental function."
As the researchers explain in their paper, the problem of healthy aging is increasingly important. Populations are aging rapidly across the globe and the rates of chronic disease along with them.
So, more and more research is looking into what constitutes healthy aging and what we can do to achieve it. In this regard, the studies on the link between omega-3 fatty acids and age-related chronic disease have been somewhat inconsistent.
For instance, some studies referenced by Lai and colleagues have found an inverse relation between omega-3 consumption and cardiovascular disease. However, others have found that omega-3 intake correlates with a higher incidence of prostate cancer.
So, the researchers set out to clarify this potentially significant role that dietary omega-3 fatty acids play in the aging process. The scientists published their findings in the journal The BMJ.
Studying omega-3s and healthy aging
The team examined the circulating blood levels of omega-3 fatty acids of 2,622 adults who were enrolled in the United States Cardiovascular Health Study.
At the beginning of this study in 1992, the participants were 74 years old, on average. Their blood levels of omega-3s were measured then, 6 years later, and 13 years later.
The types of omega-3s considered in the study were eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), docosapentaenoic acid (DPA), and alpha-linolenic acid (ALA).
The primary food source for the first three types of omega-3s is fish — such as salmon, mackerel, tuna, herring, and sardines — and other seafood, while nuts, seeds, and plant oils contain ALA.
Lai and colleagues divided the participants into fifths, or quintiles, based on their blood levels of omega-3s.
Risk of unhealthy aging 24 percent lower
Overall, by the end of the study period in 2015, 89 percent of the participants had experienced age-related chronic diseases or mental or physical dysfunction, whereas 11 percent aged healthily.
The analysis revealed that people in the highest seafood-derived DPA consumption quintile were 24 percent less likely to age unhealthily than those who consumed the least.
Moreover, participants in the top three DPA-consuming quintiles were 18-21 percent less likely to experience unhealthy aging.
Finally, seafood-derived DHA and ALA obtained from plants did not correlate with healthy aging. Lai and colleagues point out that the study is observational and cannot explain the mechanisms responsible for these associations.
"These findings encourage the need for further investigations into plausible biological mechanisms and interventions related to [omega-3 fatty acids] for maintenance of healthy aging, and support guidelines for increased dietary consumption of fish among older adults."
In an editorial that accompanies the article, professor Yeyi Zhu of the Kaiser Permanente Northern California Division of Research in Oakland, CA, and her colleagues say that the new research makes "a valuable contribution" in the study of omega-3 fatty acids and aging.
However, they warn, "Epidemiologic associations cannot infer causality." Therefore, write Prof. Zhu and her colleagues, "we caution against using these findings to inform public health policy or nutritional guidelines."