Omega-3 and longevity: a link confirmed by years of research
Combining the results of 17 different studies revealed that, in people with the highest blood levels of omega-3 fatty acids, the risk of death was significantly lower
Omega-3 and lifespan — but also quality of life: this is the connection that emerges from a study published in Nature Communications by an international research group, including scholars from Harvard and Cambridge universities. To definitively answer the question about the relationship between polyunsaturated fatty acids (PUFA) and longevity, the researchers analyzed, using accurate statistical methods, data from 42,500 people included in several clinical studies.
Years of research on omega-3s
The omega-3 family has been the subject of many investigations since their associations with a reduced risk of heart attack were reported among Greenland Eskimos in the 1970s. Although many studies have been conducted since then, these results have often been debated. This frequently occurs in nutrition studies due to sample heterogeneity, difficulties in analyzing long-term outcomes, measurement uncertainties, and effects that are hard to monitor over extended periods.
To evaluate lifespan, it is necessary to follow participants, their diets, and lifestyles for decades, as well as to have a very large and as homogeneous as possible sample. For these reasons, meta-analysis is widely used in nutrition studies: this research tool summarizes data from several primary studies, allowing a broader view of the phenomenon and greater statistical power.
Regarding omega-3 studies, the only meta-analyses reporting a beneficial association with mortality were based on self-reported nutrient intake, which for various reasons results in a very rough estimate of the actual fatty acid levels consumed: fish contains many nutrients beyond omega-3s alone, self-reported food intake depends on memory, and food databases can be outdated.
Omega-3 in the blood
A more reliable and objective measure of omega-3 consumption is their blood level, which is primarily determined by dietary intake of these fatty acids. The researchers of the Nature Communications study conducted a pooled analysis, gathering 17 cohort studies that explored associations between circulating omega-3 levels and all-cause mortality. In total, data from 42,500 people followed for an average of 16 years were analyzed.
The average age at which subjects started the study was 65 years, and the age range across cohorts was between 50 and 81 years. Thirty-seven percent of the sample died during follow-up; approximately 30% of deaths were attributed to cardiovascular diseases, 30% to cancer, and the remaining 39% to all other causes.
Those who live longer have higher circulating omega-3 levels
Analyzing all the data collected in the study, and after adjusting for other major risk factors, the result is that long-chain n-3 PUFAs are associated with a lower mortality risk. Specifically, the 20% of people with the highest omega-3 levels had about a 15-18% lower mortality risk compared to the 20% with the lowest levels. These relationships were generally linear for DPA, DHA, and EPA + DHA fatty acids. Therefore, chronically higher tissue levels of these fatty acids, acting through a variety of mechanisms, may slow the aging process. The mechanisms underlying the beneficial effects of long-chain n-3 PUFAs on human biology include:
- Reduction of blood triglycerides
- Antihypertensive effect
- Prevention of platelet aggregation and reduced risk of thrombus formation
- Positive effects on adipocyte biology (fat tissue cells)
Although many mechanisms remain a mystery to biologists, “Regardless of their specific actions,” the study states, “higher cellular omega-3 levels generally appear to slow the aging process.”
