Consumption of omega-3 supplements for a four month period could help to shift the ratio of fatty acids in favour of the beneficial fatty acid, and therefore help to combat biological signs of ageing, say researchers from Ohio State University, USA.
Published in Brain, Behavior, and Immunity the study shows that the majority of overweight but healthy middle-aged and older participants who took omega-3 supplements altered the balance of dietary omega-3:omega-6 in a way that helped preserve the tiny segments of DNA in their white blood cells known as telomeres.
"The telomere finding is provocative in that it suggests the possibility that a nutritional supplement might actually make a difference in aging," said Professor Jan Kiecolt-Glaser of Ohio State, who led the study.
The team added that supplementation with omega-3 also reduced oxidative stress by around 15% compared to the placebo group.
Telomeres are known to shorten over time in many types of cells as a consequence of aging.
In the study, lengthening of telomeres in immune system cells was more prevalent in people who substantially improved the ratio of omega-3s to other fatty acids in their diet, revealed Kiecolt-Glaser and her team.
In the trial, participants took either 2.5 grams or 1.25 grams of active omega-3 polyunsaturated fatty acids or placebo pills containing a mix of oils representing a typical American's daily intake of dietary fats.
The omega-3 supplements were calibrated to contain a ratio 7:1 eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).
Participants receiving omega-3 supplements showed, on average, a non-significant lengthening of telomeres compared to overall telomere effects in the placebo group.
However, when the researchers then analysed the participants' omega-6:omega-3 ratio in relationship to telomere lengthening, lower ratios were clearly and significantly associated with lengthened telomeres, they said,
"The idea we were looking at with the ratio of omega-6 to omega-3 fatty acids was an increase in the denominator to make the ratio smaller. In the United States, we need to focus on the omega-3 part because we don't get enough of those," said Professor Martha Belury, who co-authored the study.
The team also measured levels of compounds called F2-isoprostanes in order to determine levels of oxidative stress – which is linked to a number of conditions that include heart disease and neurodegenerative disorders.
Both omega-3 groups together showed an average overall 15% reduction in oxidative stress compared to effects seen in the placebo group.
The researchers noted that in another recent publication based on the study data, Kiecolt-Glaser and her colleagues reported that omega-3 fatty acid supplements lowered inflammation in this same group of adults.
"Inflammation in particular is at the heart of so many health problems. Anything that reduces inflammation has a lot of potentially good spinoffs among older adults," she explained.
The researchers said this combination of effects suggests that omega-3 supplements could represent a rare single nutritional intervention that has potential to lower the risk for a host of diseases associated with aging, such as coronary heart disease, Type 2 diabetes, arthritis and Alzheimer's disease.
Source: Brain, Behavior, and Immunity
Published online ahead of print, doi: 10.1016/j.bbi.2012.09.004
“Omega-3 fatty acids, oxidative stress, and leukocyte telomere length: A randomized controlled trial”
Authors: Janice K. Kiecolt-Glaser, Elissa S. Epel, Martha A. Belury, Rebecca Andridge