Omega-3 and longevity: a link confirmed by years of research
Pooling the results of 17 different studies, it was found that in people with the highest blood levels of omega-3 fatty acids, the risk of death was significantly lower
Omega-3 and longevity - but also quality - of life: this is the combination resulting from the study published in Nature Communications by an international research team, in which scholars from Harvard and Cambridge universities also participated. To definitively answer the question of the relationship between polyunsaturated fatty acids (PUFAs) and longevity, the researchers analyzed, using careful statistical methods, data from 42,500 people included in several clinical trials.
Years of research on omega-3s
The omega-3 family has been the subject of much investigation since their associations with a lower risk of heart attack were reported in Greenland Eskimos in the 1970s. Although many studies have been done on the subject since then, they were always subject to debate. This is often the case with dietary studies because of the heterogeneity of the sample, the difficulty of analyzing the results years later, uncertainty in the measurements, and because of the effects, which, as they extend over a long period of time, are difficult to monitor.
In order to assess lifespan, in fact, it is necessary to follow participants, their diet and lifestyles for decades, as well as to have a very large sample that is as homogeneous as possible. For these reasons, in nutrition studies, meta-analysis is widely used, a research tool that, by summarizing data from several primary studies, provides a broader view of the phenomenon and greater statistical power.
Regarding omega-3 studies, the only meta-analyses done to report a beneficial association with mortality were based on self-reported nutrient intake, which for several reasons results in too rough an estimate of actual fatty acid intakes: fish contains many nutrients in addition to omega-3 alone, self-reported food intake depends on memory, and food databases may be out of date.
Omega-3 in the blood
A more reliable and objective measure of omega-3 consumption is their level in the blood, which is primarily determined by dietary consumption of these fatty acids. Researchers in the Nature Communications study conducted an aggregate analysis, bringing together 17 cohort studies that explored associations of circulating omega-3 levels and all-cause mortality. In total, data from 42,500 people followed for an average time of 16 years were analyzed.
The average age at which the subjects started the study was 65 years, and the age range between the different cohorts was 50 to 81 years. Thirty-seven percent of the sample died during follow-up; about 30 percent of the deaths were attributed to cardiovascular disease, 30 percent to cancer, and the remaining 39 percent to all other causes.
Those who live longer have more omega-3s in their system
Analyzing all the data collected in the study, and after controlling for other major risk factors, the result was that LC n-3 PUFAs were associated with a lower risk of mortality, i.e., the 20% of people with the highest omega-3s had an approximately 15-18% lower risk of mortality than the 20% of people with the lowest values. These relationships were generally linear for DPA, DHA and EPA + DHA fatty acids. Thus, chronically higher tissue levels of these fatty acids, working through a variety of mechanisms, may slow the aging process. The mechanisms underlying the beneficial effect of LC n-3 PUFAs on human biology are diverse, including:
- Lowering blood triglycerides
- Antihypertensive effect
- Prevention of platelet aggregation and reduction of the risk of thrombus formation
- Positive effects on the biology of adipocytes (the cells of fatty tissue)
Although many mechanisms still remain a mystery to biologists, "Regardless of their specific actions," the study says, "higher cellular levels of omega-3 appear, in general, to slow the aging process."
