In recent years omega-3 fats (found, for instance in ‘oily’ fish such as salmon, trout, mackerel and herring) have become famous for supposed health-giving properties, particularly with regard to cardiovascular system and brain. This week saw the publication of a study which links omega-3 fats with a slowing of the ageing process [1].
The study, published in the Journal of the American Medical Association, assessed the relationship between omega-3 levels and ‘telomeric ageing’. Telomeres are to be found at the end of the chromosomes in the body’s cells. They can be thought of as ‘caps’ at the end of chromosomes, that are believed to protect the DNA within the chromosome from damage. Basically, the bigger the telomeres are, the better, as this will help protect DNA from damage. Shortening of telomeres is generally taken as not a good sign, and is used as a marker for ageing within cells.
In the study in question, levels of the omega-3 fats EPA and DHA were measured in more than 600 individuals with known heart disease. These levels were compared to telomere length over a period of about five years. The results of this study found that higher levels of omega-3 fats was associated with a reduced risk of telomere shortening. The suggestion here is therefore that omega-3 fats can retard the ageing process.
I generally enthusiastic about the idea that foodstuffs and specific elements within the diet may have benefits for health, and this does appear to be an example of this. However, I think it’s important to bear in mind that this study is epidemiological in nature, which essentially means that while omega-3 fats are associated with slower ageing in the cells, it cannot be used to conclude that the link is causal (i.e. that omega-3 fats cause slower ageing).
However, studies of this nature are very useful for identifying areas worthy of further study. The acid test would be to perform an intervention study in which individuals are randomised to take omega-3 fats or placebo, to see what effect this has on telomere length over time.
But then again, it’s also important to remember that telomere length is a ‘surrogate marker’ for health and longevity. In general terms, it’s more useful to perform studies that look at the relationship between whatever factor we’re interested in and things like disease risk and, if we have enough data, overall risk of death (overall mortality). With this in mind, I’d like to draw attention to previous meta-analysis (in this case, an amalgamation of 14 individual studies) which found that supplementation with omega-3 fats was associated with a 23 per cent reduction (statistically significant) in risk of death [2].
References:
1. Farzaneh-Far R, et al. Association of Marine Omega-3 Fatty Acid Levels With Telomeric Aging in Patients With Coronary Heart Disease. JAMA 2010;303(3):250-257
2. Studer M, et al. Effect of different antilipidemic agents and diets on mortality. Archives of Internal Medicine. 2005;165:725-730
