Telomeres are DNA fragments that act as “caps” for the pieces of coiled DNA called chromosomes.
They serve much like the protective plastic at the ends of shoelaces, to prevent degradation of DNA … but telomeres gradually shorten over time, leaving DNA vulnerable to decay.
Because telomere shortening is linked to age-related diseases and early death, scientists have been looking for ways to help preserve telomere length.
As professor Ron Glaser of Ohio State University puts it, “If that plastic comes off, the shoelace unravels … in the same way, every time a cell divides, it loses a little bit of its DNA at the ends, and over time, that can cause significant problems.” (OSU 2012)

Key Points
  • Omega-3 supplements raised people's omega-3/6 ratios.
  • This change was tied to a lengthening of DNA-protective telomeres.
  • The authors linked telomere degradation to inflammation.
  • Omega-3 supplements reduced key markers of oxidation and inflammation.

Dr. Glaser and colleagues from Ohio State University just reported exciting news from a controlled clinical trial.
These clinical findings lend strong support prior signs that omega-3s from fish fat help preserve telomeres.
Earlier study linked omega-3s to telomere protection
Two years ago, researchers based at the University of California compared the lengths of telomeres in blood cells from 608 heart patients at the beginning and end of a five-year period (see “Omega-3s' DNA-Telomere Effects vs. Heart Disease and Aging”).
They found that those with the lowest omega-3 levels experienced the speediest rate of telomere shortening, while those with the highest omega-3 levels showed the slowest rate of telomere shortening.
As the UC team wrote then, “These findings raise the possibility that omega-3 fatty acids may protect against cellular aging in patients with coronary heart disease” (Farzaneh-Far R et al. 2010).
Now, the results of a controlled clinical trial from OSU lend added weight to the idea that omega-3s help preserve telomeres and DNA … findings with positive implications for healthier aging.
Ohio State trial tests omega-3s as DNA-protectors
The OSU team conducted a placebo-controlled, double-blind trial among 106 healthy, sedentary overweight middle-aged and older adults (average age 51).
The researchers excluded people taking mood, cholesterol, or blood pressure drugs, vegetarians, diabetics, smokers, those routinely taking fish oil, people getting two hours of vigorous exercise weekly, and those whose body mass index was either below 22.5 or above 40.
The participants were divided into three groups, each assigned to a different regimen:
  • Pills providing 2.5 grams of omega-3 fatty acids (EPA + DHA)
  • Pills providing 1.25 grams of omega-3 fatty acids (EPA + DHA
  • Placebo pills providing the proportion of fatty acids in a typical American's diet.
The omega-3 supplements contained an unusually high a ratio of omega-3 EPA to omega-3 DHA … seven to one versus the average of two to one found in most fish.
The OSU team chose to test these unusual omega-3 pills because previous findings had suggested that EPA has greater anti-inflammatory powers than DHA … although that assumption has been challenged by newer research.
Higher omega-3/6 ratio extended telomeres
When the researchers analyzed the participants' blood cells, they found that having an increase in the omega-3 to omega-6 ratio was clearly associated with longer telomeres.
“The telomere finding is provocative in that it suggests the possibility that a single nutritional supplement might actually make a difference in aging,” said lead author Jan Kiecolt-Glaser, professor of psychiatry and psychology at Ohio State.
(While the length of telomeres increased in the volunteers who took omega-3 supplements, the relationship did not reach statistical significance, and could have been due to chance.)
Americans get a gross overload of omega-6 fatty acids from the cheapest, most commonly used vegetable oils (corn, soy, cottonseed, safflower, sunflower) and processed or prepared foods made with them.
But they get comparatively few omega-3s, whose best sources are cold-water fish such as salmon and tuna (and fish oil supplements).
While the ratio of omega-6 to omega-3 fatty acids in the standard American diet averages about 15-to-1, researchers agree that for maximum benefit, this ratio should be lowered to 4-to-1, or even 2-to-1.
To learn more, see “America's Sickening ‘Omega Imbalance'”.
Omega-3s also cut oxidation and inflammation
In addition to the telomere-preservation benefit seen in this trial, a key measure of oxidative stress (F2-isoprostanes) dropped by about 15 percent in the omega-3 group, compared to the placebo group.
Dr. Kiecolt-Glaser and her colleagues reported that omega-3 supplements also lowered inflammation in this same group of adults.
And the OSU team previously found that decreases in an inflammatory marker in the blood (IL-6) were associated with telomere lengthening  ... and that omega-3 supplements lowered IL-6 by 10 to 12 percent, depending on the dose.
Kiecolt-Glaser made a key point: “This finding strongly suggests that inflammation is what's driving the changes in the telomeres. Anything that reduces inflammation has a lot of potentially good spinoffs among older adults.” (OSU 2012) 
By comparison, those taking a placebo saw an overall 36 percent increase in IL-6 by the end of the study.
Kiecolt-Glaser also noted that because the participants were healthy – although overweight or obese and sedentary – other might gain even more benefit from omega-3s.
“People who are less healthy than this group, and especially those who experience chronic stress, may gain even more benefits from omega-3 supplementation,” she said. (OSU 2012)
The OSU researchers say the combination of effects they recorded suggests that omega-3 supplements could lower the risk for a host of diseases associated with aging, such as coronary heart disease, Type 2 diabetes, arthritis, and Alzheimer's disease.
Their clinical trial was supported in part by grants from the National Institutes of Health.

  • Kiecolt-Glaser JK, Belury MA, Andridge R, Malarkey WB, Glaser R. Omega-3 supplementation lowers inflammation and anxiety in medical students: a randomized controlled trial. Brain Behav Immun. 2011 Nov;25(8):1725-34. Epub 2011 Jul 19.
  • Kiecolt-Glaser JK, Epel ES, Belury MA, Andridge R, Lin J, Glaser R, Malarkey WB, Hwang BS, Blackburn E. Omega-3 fatty acids, oxidative stress, and leukocyte telomere length: A randomized controlled trial. Brain Behav Immun. 2012 Sep 23. pii: S0889-1591(12)00431-X. doi: 10.1016/j.bbi.2012.09.004. [Epub ahead of print]
  • Ohio State University (OSU). Omega-3 Supplements May Slow A Biological Effect of Aging. October1, 2012. Accessed at
  • Pot GK, Brouwer IA, Enneman A, Rijkers GT, Kampman E, Geelen A. No effect of fish oil supplementation on serum inflammatory markers and their interrelationships: a randomized controlled trial in healthy, middle-aged individuals. Eur J Clin Nutr. 2009 Nov;63(11):1353-9. Epub 2009 Jul 22.