Longevity Briefs: A Safe Supplement To Extend Telomeres?

Longevity briefs provides a short summary of novel research in biology, medicine, or biotechnology that caught the attention of our researchers in Oxford, due to its potential to improve our health, wellbeing, and longevity.

The problem:

Telomeres are the protective caps on the ends of our chromosomes. They are repetitive DNA sequences that don’t code for anything, and they play a sacrificial role. Cells cannot replicate the entire length of their chromosomes when they divide, so a bit of telomere is lost at each cell division. Once the telomeres grow too short, the cell has to stop dividing or it will start to lose important genetic information. This system protects us from cancer as it blocks runaway cell division, but it also contributes to ageing.

Telomerase is an enzyme that regrows telomeres, but is normally only active in a few types of cell. Mouse studies show that you can regrow telomeres by enhancing telomerase activity, and that this makes the mice live longer, though they may have a slightly higher chance of developing cancer. Some companies sell telomerase supplements for human consumption, but the safety and effectiveness of these products isn’t well established.

The discovery:

In this study, researchers found some evidence that Astragalus, a plant used in traditional Chinese medicine, might safely lengthen telomeres, at least in the short term. In the study, they randomly assigned 40 healthy people between the ages of 40 and 70 to receive either a placebo treatment or a supplement called ASTCOQ02. This was a blend with Astragalus extracts as its main ingredients, but also contained olive fruit extract, zinc oxide and grape seed extract. The trial was double-blind, so neither the researchers nor the participants knew who was getting the placebo until the end of the trial, which lasted 6 months.

The median (a form of average) telomere length derived from blood samples saw a statistically significant increase over the course of the study in the treatment group, but not in the placebo group. The placebo group did start the study with a longer median telomere length than the treatment group, but this difference was not statistically significant. In total, people taking ASTCOQ02 benefited from a median telomere lengthening of about 0.7 kilobases after 6 months. For reference, a person’s telomere length might be expected to decrease by about 20-40 bases during the same timeframe, though this varies according to age and lifestyle.

The implications:

This was a fairly small study, and the fact that telomere length didn’t significantly change in the placebo group suggests it probably needed to last longer. While telomere length does decrease over the course of a lifetime, it can remain stable or even increase over shorter timescales. However, safety needs to be established in shorter trials before longer ones should be attempted. Fortunately, there were no adverse effects reported, so hopefully larger, longer studies will follow, as the effects of astragalus on telomere length are worth exploring further.

Astragalus contains compounds called astragalosides which can be metabolised into another compound called cycloastragenol. Cycloastragenol enhances telomerase activity by acting on various signalling pathways and genes, and this is likely to be the main mechanism of telomere extension seen in this study. While telomere shortening is correlated with age-related disease, we still don’t know for sure whether telomere extension would slow ageing in humans because no study has lasted long enough. Still, it is probably worthwhile to explore different ways of extending telomeres.