Study Roundup: Could Omega-3 Supplements Slow the Effects of Aging?

- by Meera Lee Sethi

The Gist

In the past few years, omega-3 fatty acids have been all the rage among those who track health trends. These "health" fats (commonly found in fish and plant oils) are the latest cure-all, supposedly lowering risk for heart disease, inflammatory diseases, and developmental disorders.

Now, new research by Ohio State University scientists has shown that taking a nutritional supplement containing omega-3 fatty acid can effectively alter the ratio of dietary oil consumption in the body in a way that protects immune cell telomeres in older adults.

Telomeres are repeating sequences of DNA found at the ends of chromosomes. Although they themselves do not encode essential information, they function as a kind of protective buffer for the genetic code contained in the rest of the chromosome. Each time a cell divides, these buffer zones shrink. When they become too short, the cell loses its ability to regenerate. Telomere shortening is believed to play a key role in the process of biological aging.

The Expert Take

In this study, researchers compared telomere length between a control group and two groups taking either a high or a low dose of an omega-3 supplement: omega-3 is a polyunsaturated fatty acid known to be beneficial to heart health.

Lead author Janice Kiecolt-Glaser explains that the researchers saw no significant differences in telomere length between the control group and the groups taking the tested supplements. However, “as we looked across the subjects as a whole, we saw significantly increased telomere length in those who showed decreases in the ratio of omega-6 to omega-3.” Omega-3 fatty acids occur naturally in fish oils, while omega-6 fatty acids are derived from vegetable oils. Although there is evidence that consuming omega-6 fatty acids—like the fatty acids that come from fish oils—has positive health effects, the typical American consumes too few omega-3 fatty acids in relation to omega-6 fatty acids.

In other words, implementing a change in diet to include more omega-3 fatty acids seems to be an effective way of increasing telomere length. This simple step, the study suggests, may act as a defense against many afflictions common amongst middle-aged and older adults: things like diabetes, coronary heart disease, and arthritis.

In addition, the researchers found that taking either a high or a low dose of an omega-3 supplement reduced subjects’ level of oxidative stress by an average of 15 percent. Oxidative stress is a type of cell damage that is believed to underlie a wide variety of disorders, particularly neurodegenerative conditions like Parkinson’s and Alzheimer’s disease.

Earlier this year, Kiecolt-Glaser’s team reported that those who received a placebo in the same study group experienced a 36 percent increase in interleukin-6, a pro-inflammatory protein found in the blood, over the course of the study. In contrast, the groups that received the omega-3 supplements saw their interleukin-6 levels drop by up to 12 percent. According to Kiecolt-Glaser, this is probably the mechanism by which omega-3 supplements actually restore telomere length. “Inflammation,” she explains, “triggers the replication of certain immune cells, and this replication is one known cause of telomere shortening in those cells.”

The Take-Away

Since age-related diseases and earlier mortality seem to be associated with higher inflammation and telomere shortening, notes Kiecolt-Glaser, “the finding that a simple dietary intervention makes a difference is noteworthy.” The takeaway message for consumers, she says, is that “having sufficient omega-3 as part of a healthy diet is important.”

Source and Method

The study recruited 106 subjects, each sedentary, overweight, otherwise healthy, and at least 50 years of age. The subjects were randomly assigned into three treatment groups. The control group received a placebo consisting of a combination of palm, olive, soy, canola, and cocoa butter oils matching the daily diet of the typical American adult. The two test groups received a supplement containing either 2.5g or 1.25g of omega-3 polyunsaturated fatty acids.

Blood samples were collected before and after each participant completed a four-month course of their assigned supplement. Peripheral blood lymphocytes, a type of immune system cell, were extracted from the samples; it was these cells whose telomere lengths were measured. In addition, the researchers examined how the supplements affected subjects’ levels of F2-isoprostanes: compounds found in blood plasma. These were used as a marker for oxidative stress.

The researchers also examined the effects of the supplement regimen on mental health. A comparison of clinical interviews conducted before and after the treatment showed no significant changes in participants’ depressive symptoms; however, there were few signs of depression among the study group to begin with.

The study appeared online on September 23^rd, 2012, and will be published in an upcoming print issue of the journal Brain, Behavior, and Immunity.

Other Studies

Several previous studies have investigated the relationship between telomere length and polyunsaturated fatty acids like omega-3. For example, a 2010 Journal of the American Medical Association paper by a University of California, San Francisco team found that in patients with coronary artery disease, those with higher blood levels of omega-3 fatty acids had a slower rate of telomere shortening.

But, says Kiecolt-Glaser, prior work has largely relied on observational studies that failed to establish a direct causal link between a change in diet and telomere activity. “This study,” she explains, “was a randomized controlled trial, the gold standard for assessing causality. We were able to look at changes over time in telomeres related to dietary variation.”