Fish oil supplementation appears to offer some protection against cardiovascular disease, but whether this effect is due to a weakening of the stress-responsive system is unclear.
In a large, prospective study of nearly half a million people, higher fish intake was linked to lower all-cause mortality. One factor linked to biological aging is the length of telomeres, which are strands of DNA at the ends of chromosomes, and there is good evidence that telomeres shortening is associated with increased mortality and as is the case with individuals who consume higher amounts of omega-3 fatty acids There is a reduced risk of telomere shortening. In addition, increased physiological stress is a risk factor for many physical and mental illnesses, and again there is evidence that the pro-inflammatory response to mental stress is weakened to some extent by omega-3 fatty acids. Taken together, these results suggest that omega-3 fatty acid supplementation can positively influence markers of stress reactivity. This was the hypothesis of a team at the Institute for Behavior Medicine Research at Ohio State University College of Medicine, Ohio, USA, who studied the response of a group of individuals to a social stress test. The team randomized participants into three groups, who received either 2.5 g / day, 1.25 g / day omega-3, or placebo for 4 months. At the beginning, all participants had to undergo the stress test, in which a 5-minute speech was given without the use of tools or notes. Both saliva and blood samples were taken before the stress test and 0.75, 1.25, 1.75 and 2 hours after, and the test was repeated at the end of the study. Parameters evaluated included cortisol, telomerase (an enzyme that maintains and restores telomeres), and several inflammatory markers, interleukins 6, 10, and 12, and tumor necrosis factor (TNF). Participants also had to rate their anxiety levels before and after the test.
A total of 138 people (63% female) with an average age of 51.1 years and 72% white descent were recruited. Among those who took 2.5 g of omega-3 per day, their salvia cortisol levels were 19% lower during the last stress test than those who received placebo (p = 0.01), although this difference was for the 1.25 g / day group was not significant. Similarly, the high-dose supplement group had 33% lower interleukin-6 levels compared to placebo (p = 0.007). However, there were no differences to the other interleukin levels or to TNF. While the telomerase values remained unchanged in both supplement groups, the values decreased by 24% between 45 and 120 minutes after the stress test.
The authors commented on how supplementing with 2.5 g of omega-3 fatty acids per day blocked the stress-related decline in telomerase levels and lowered levels of both cortisol and pro-inflammatory interleukin-6 in a dose-dependent manner. They suggested that omega-3 supplements have a unique stress-buffering effect on cellular aging biomarkers, and concluded that their data, while preliminary, could, if replicated, limit the effects of repeated stress.
Madison AA et al. Omega-3 supplementation and stress reactivity of biomarkers for cell aging: a supplementary sub-study of a randomized, controlled study in middle-aged adults. Mol Psychiatry 2021.