Batya Swift Yasgur MA, LSW
October 29, 2018
Higher serum levels of serum omega-3 polyunsaturated fatty acids (n-3 PUFAs) are associated with healthy aging in adults, defined as survival without chronic disease, such as cardiovascular disease, cancer, lung disease, or severe chronic kidney disease, a new study suggests.
Researchers measured cumulative levels of plasma phospholipid n-3 PUFAs in 2600 older adults at three time points over a 13-year period and found that higher levels of long-chain n-3 PUFAs were associated with an 18% lower chance of unhealthy aging.
In particular, n-3 PUFAs from seafood, eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA) were associated with healthier aging.
"We found that higher blood levels of omega-3s from seafood were associated with a higher likelihood of healthy aging and also saw that people with the highest blood levels of omega-3s self-reported fish intake of about two servings per week," lead author Heidi Lai, PhD, postdoctoral fellow, Friedman School of Nutrition Science and Policy, Tufts University, Boston, told theheart.org | Medscape Cardiology.
"This study supports current national guidelines to consume more seafood," she said.
The study was published online October 17 in BMJ.
"We're living longer but are not necessarily in good health, and the quality of life in old age is deteriorating," Lai said.
"In addition to quality-of-life concerns, longevity without good health increases healthcare costs, so as researchers, we want to start to focus on quality of life rather than longevity — a concept we call healthy aging, which means survival until death free of chronic disease and cognitive and physical dysfunction," she continued.
"We know that omega-3 PUFAs, mostly found in seafood, are beneficial for heart health, but we know less of their influence on other chronic diseases and healthy aging," she said.
Most previous studies have relied on self-reported dietary questionnaires, with few using biomarkers to provide "a complementary measurement to self report, with less recall bias and estimation errors," the authors write.
Moreover, biomarkers "greatly facilitate" investigation of the effects of individual n-3 PUFAs, which include long-chain EPA and DHA from seafood, and DPA that has been endogenously metabolized (to a lesser extent, also sourced from seafood). They also include α-linolenic acid from plants.
Additionally, all previous biomarker studies have used only one measure of n-3 PUFA at baseline, and did not account for trends or changes over time.
The researchers therefore used serial measures of n-3 PUFA biomarkers in the Cardiovascular Health Study, a multicenter prospective cohort of older adults in the United States recruited from a random sample of Medicare eligibility rolls, to investigate the association between circulating phospholipid n-3 PUFA levels and the likelihood of healthy aging.
The Cardiovascular Health Study began with 5888 ambulatory adults who were recruited in 1992 and 1993.
For this study, after the exclusion of participants who had died, did not have complete data, or were unavailable for follow-up, 2522 participants (mean [SD] age, 74.4 [4.8] years; 63.4% white; 10.8% nonwhite) were eligible for analysis.
The researchers analyzed cumulative levels of plasma phospholipid n-3 PUFAs using gas chromatography in 1992/93, 1998/99, and 2005/06, expressed as a percentage of total fatty acids, including a-linolenic acid from plants and EPA, DPA, and DHA from seafood.
Sociodemographic information included age, sex, ethnicity, enrollment site, education, and income.
Additional factors included body mass index, physical activity (excluding chores), blood pressure, lipids, smoking status, self-perceived general health, family history of myocardial infarction or stroke, hypertension, lipid-lowering drugs, depression, osteoporosis, alcohol use, and dietary habits.
Participants with higher long-chain n-3 PUFAs levels were more likely to be female, white, have higher income and education levels, and lead a healthier lifestyle, they found.
Those in the highest group consumed about one additional daily serving of fish, compared with the lowest group.
At baseline, n-3 PUFA levels were similar between healthy agers and unhealthy agers excluded at baseline.
During the 21,803 person-years of follow-up, 89% of participants experienced unhealthy aging, with 11% showing healthy aging — a "positive deviance," the authors point out.
After multivariable adjustment for demographic, lifestyle, cardiovascular risks, dietary habits, and other phospholipid fatty acids, higher long-chain n-3 PUFA levels were associated with a lower likelihood of unhealthy aging, although a-linolenic acid was not.
Overall, participants in the highest group of total long-chain n-3 PUFAs had an 18% (95% CI, 3% - 30%; P =.001) lower risk of unhealthy aging, compared with individuals with lower long-chain n-3 PUFAs.
When the researchers analyzed individual n-3 PUFAs separately, they found that participants in the highest EPA or DPA groups — but not α-linolenic acid or DHA — had a 24% (95% CI, 11% - 35%; P < .001) and 18% (95% CI, 6% - 29%; P = .003) lower risk of unhealthy aging, respectively, compared with the lowest group.
Linear models revealed that higher levels of long-chain n-3 PUFAs, although not α-linolenic acid, were consistently associated with a lower likelihood of unhealthy aging, with the risk of unhealthy aging for each interquintile range lower by 15% (95% CI, 6% - 23%) for EPA, 16% (95% CI, 5% - 24%) for DPA, and 18% (95% CI, 7% - 28%) for total long-chain n-3 PUFA.
After further adjustments for potential mediators, DHA was found to be associated with a 12% (95% CI, 0% - 23%) lower risk of unhealthy aging, whereas results for the remaining long-chain n-3 PUFAs were not appreciably altered.
"There have been studies that looked at the relationship between omega-3 and the individual components of healthy aging, but not in combination," Lai explained.
"Our study adds to the current pool of evidence, advancing research in the field of aging," she said.
"The second novelty [of our study] is the use of repeated blood measures at three different time points, which capture change over time, in comparison to studies that have only one single measure at baseline," she added.
No Conclusions Regarding Supplementation
Commenting on the study for Medscape Medical News, Yeyi Zhu, PhD, MS, research scientist, Division of Research, Kaiser Permanente Northern California, and assistant adjunct professor, Department of Epidemiology & Biostatistics, University of California, San Francisco, who was not involved with the study, said it "provides a clue that omega-3 fatty acids from seafood may be related to a higher likelihood of healthier aging."
He had one caveat. "Notably, the study focused on circulating levels of plasma phospholipid omega-3 fatty acids; no direct implications regarding the amount of food or even supplements can be made," said Zhu, who is the coauthor of an accompanying editorial.
Lai noted that some previous research suggested that omega-3 supplements do not reduce the risk for cardiovascular disease.
However, she noted, "our study did not study supplements, instead we looked at blood levels of omega-3s from seafood and found that higher levels were linked with a higher chance of living healthy long lives."
This research was supported by the National Heart, Lung, and Blood Institute (NHLBI). The Cardiovascular Health Study was also supported by the National Institute of Neurological Disorders and Stroke, with additional support provided by the National Institute on Ageing (NIA). Lai and Zhu report no conflicts of interests. The other authors' disclosures are listed on the original paper.