In recent years there has been a growing number of companies offering DNA tests to consumers, some specifically focusing on the fitness impact of certain genes. The marketing hyperbole suggests that the purchaser will, with the results of their swab test, be able to tailor their workout routine specifically to their DNA for superior physical results.
Frankly, I was ready to start writing this article completely dismissing the value of direct to consumer DNA testing for fitness and exercise prescription as it stands today. Researching the article got to me though. It is an intellectually exciting topic and too intriguing to dismiss out of hand.
Is there any tangible benefit to purchasing a DNA test, one that claims to give you information on which to practically base your training routine? Read on to find out.
Our understanding of genetics and the role that genes play in physical abilities and performance is increasing all the time. Examples of genetic mutations are being discovered frequently, some of obvious benefit to their carriers, others to their detriment. It is because of their genes that Tibetan Sherpas can cope with high altitude exercise far better than visitors to the Himalayas. One gene of note here is the hypoxia pathway gene EPAS1, which keeps haemoglobin levels low: meaning Sherpa blood is thinner, better for high altitude living and working.
There are also exceptionally rare genetic mutations that cause even more unusual traits in their carriers. One such example is a mutation in the ZFHX2 gene known as Marsili syndrome, named after a family who carry it. Marsili syndrome results in the individual experiencing far less physical pain than normal. They can fracture bones, immerse limbs in ice, and burn themselves without even being aware of it! Whilst this may sound like a heroic super-power, it unfortunately leads to significant long-term health issues.
Great athletes are made up of mutations
Great athletes, to date at least, are examples of natural (parentally given) but relatively rare combinations of beneficial genetic mutations that enable them to excel in their given sport. Some, if not most of these advantaged individuals, under the pressure of competition, will look to improve their hand further still, when the possibility to do so exists.
In the past, this has meant via the use of stimulants and steroids. In the future, it will more likely be through gene manipulation. More on athletes in a few paragraphs.
A brave new world
We live in a brave new world indeed, one in which our understanding of human DNA is just starting to shape the future of health care. This, for example includes the possible ability to correct pathogenic gene mutations in human embryos and gene-based therapy for cancer.
These developments are borne out of the medical/scientific establishment, but DNA treatment is also being explored by small companies and visionary/desperate, brave/foolish (delete as you see fit) biohacking individuals. One such individual is Tristan Roberts, who is attempting to cure his own HIV infection with an unproven and unregulated form of gene therapy. Another is Brian Hanley, who is self-experimenting with gene therapy in an attempt to stave off the aging process.
Bodybuilders and muscle enthusiasts note that Josiah Zayner has been attempting to induce muscular gain by injecting a plasmid into his forearm with the goal of knocking out the muscle restricting myostatin gene locally… it hasn’t worked so far folks!
Before you go reaching for the needle and CRISPR (a segment of DNA containing short repetitions of base sequences), high on thoughts of age-reversal and myostatin suppression heaven, note there are risks to genetic self-experimentation. The least of which is it just not working, think: risk of infection, inflammatory response and possibly much worse.
When we are truly able to harness gene manipulation and tinker with our own DNA, one can only imagine the type of human experience possible: reduction or elimination of genetic diseases, the creation of hyper-elite athletes, and soldiers who can operate in extreme environments and feel no pain! I will leave you to have your own ethical debate about this, there is however no doubt that genetic medicine and manipulation is going to dramatically impact our world as we move toward tomorrow.
From stimulants and steroids to genetic manipulation
Most of you will have read about the notorious use of blood doping and more recently injections of EPO (erythropoietin, a hormone naturally produced by the kidneys) to increase red blood cell count in endurance athletes. In the future, exogenous EPO will likely be unnecessary old technology superseded by gene therapy that will enable the athlete to produce more EPO endogenously, without the need for continuous, short-term, short-acting injections. Gene therapy will be harder for doping agencies to detect, although athletes who competed in the Rio Olympics of 2016 are being retrospectively tested for EPO gene coding. After all this however, there is a possibility that EPO may not be the performance booster it has been believed to be.
Indeed this kind of confusion is part of the problem with our current level of knowledge of genes as they relate to exercise and sports performance. Our understanding of the impact and influence of genes as they relate to exercise is relatively poor. We just don’t know enough about individual genes nor the interactions between different genes and the overall global impact on the body.
Fitness focused DNA tests
This challenge brings us to the direct to consumer DNA fitness tests that have flooded the market in the past 5 years. These tests that often claim to be able to give you insight into your DNA that will enable you to structure workouts tailored to best develop your body and performance. The true picture given by these fitness focused tests however, is at best incomplete and perhaps at worst insignificant, at the current level of scientific understanding.
The worth and credibility of DNA testing when it comes to paternity, ancestry, certain genetic diseases and disease risk is solid: good, strong, proven science. This unfortunately is not so much the case when it comes to athletic performance prediction and exercise prescription where associations are much weaker. So weak in fact that leading scientists in the field have stated:
“The general consensus among sport and exercise genetics researchers is that genetic tests have no role to play in talent identification or the individualised prescription of training to maximise performance.” Webborn N, Williams A, McNamee M, et al Direct-to-consumer genetic testing for predicting sports performance and talent identification: Consensus statement Br J Sports Med 2015;49:1486-1491.
The consensus statement goes on:
“the current level of knowledge is being misrepresented for commercial purposes”.
One isolated gene vs. multiple genes
A big part of the problem is that even one of the most researched genes in the field of exercise, ACTN3, has at most a 2-3% impact on the talent it is most associated with: sprinting, and some say its practical impact is more likely less than 1%. This is obviously negligible, likely only to make a difference when all other genetic coding required to make a great sprinter is in place too.
Rather than looking at the influence of one isolated gene, what if we look at multiple genes associated with exercise performance together? Can that tell us anything of greater value? This is what companies such as the UK’s DNAfit are attempting to do. DNAfit is one of the leading providers of direct to consumer DNA testing that focuses on fitness and diet. They have recently funded research conducted at the University of Central Lancashire and published in the Journal of Biology in 2016.
For this research paper, 123 athletes had a combination of 15 genes tested and their individual results run through a DNAfit proprietary algorithm, that concluded whether the athlete was power or endurance dominant. Some athletes were then ascribed to a “DNA appropriate” routine whilst others were deliberately mismatched, this was done in a double-blind manner. The research showed that the DNA matched group bested the mismatched group in both tests measured by: 6.2% vs 2.3% (cycle test) and 7.4% vs 2.6% (countermovement jump). Perhaps there is a glimmer of hope, maybe there is something to be said for DNA fitness testing, especially when a combination of genes are assessed together. Perhaps DNAfit’s choice of genes to test and algorithm is robust?
Before we jump the gun, it is important to bear in mind this is just one study, and one with a few downsides worth noting. With only 67 of the original 123 subjects completing the study, there was a high drop out rate for some reason: why, and what impact did that have on the results? Also the study was funded by DNAfit a company with a commercial interest in the results of the study. I for one would love to see the results replicated in more research.
Today or tomorrow?
There is no doubt that we live in very exciting times, we are on the cusp of even greater, more wide reaching, impactful developments in the world of genetics research. Some of these developments will have significant practical impact on our understanding of the individual’s response to exercise and how to specifically program exercise tailored to the individual.
Are we there yet? My cautionary side says no, and my enthusiastic side says perhaps we can already glean something of value from the tests out there that attempt to look at 10-20 fitness related genes together. Even if my cautious optimism is well founded it is important to remember that currently DNA fitness tests can only show us a small hazy part of a much bigger, clearer picture.
The real question is when will a DNA test be able to tell you as much or more, more quickly, about appropriate exercise for you, than the eye and expertise of a seasoned coach or personal trainer?