Sports nutrition supplements : untangling the science and the hype
For as long as competitive cycling has been around, riders have been looking for ways to improve their performance, to gain an edge over their competitors. One popular method is the use of sports nutrition supplements. In this first part of a two-part series, sports nutritionist Alan McCubbin takes us through the life-cycle of sports nutrition supplements, from initial research to marketing and explains the role that science does and doesn’t play in the process.
A couple of weeks ago Wade asked if I could write a piece on the scientific merits of beetroot juice, to see if the research matches up to the hype. Beetroot juice has been around for a little while now, but the research is continuing to evolve such that what I can write about it now is quite different to even 12 months ago.
But before we look at the evidence that supports or rejects any particular supplement, I thought it’d be good to start with an overview of how a supplement comes to exist, from concept to commercial product, with the science, marketing and ultimately profits that accompany it.
I’ve worked as a sports dietitian for several years now, and it’s quickly become obvious that there’s a typical pattern with which the latest supplement emerges on the scene. Many supplements don’t actually get conceived by the marketing gurus at first – rather there’s a scientific theory or proposed mechanism by which the supplement works, which has been discovered by the academic community. This usually involves a bright spark that’s thought laterally about the limits of exercise performance, and then tried to find a potential angle of attack.
The earliest studies of sports nutrition supplements often slip under the radar for most people — they’re basic science studies (often in petri dishes or with rats) that examine the safety of a supplement and how it works in the body. The point at which people start to sit up and take notice tends to be in the next phase.
In this part of the cycle, the actual mechanism by which the supplement is proposed to benefit athletes is first tested in humans — often non-athletic uni students because they’re young, free of major health problems and easy to recruit as participants.
These early studies often provide the first bit of excitement about a supplement, and it’s here that manufacturers start jumping on the bandwagon and promoting the evidence that these supplements work.
It’s important to realise, though, that at this stage no-one has shown that these supplements actually improve performance, because performance has not even been tested. But as mentioned in a previous article, a supplement manufacturer won’t wait for the performance studies to be done to start producing and promoting a supplement.
This is probably in part because they’re trying to beat their competitors to market which is fair enough. It may also be because they can convince people to buy a product simply based on studies that show changes in metabolism — and therefore imply a performance benefit to their potential customers — without having to wait another 2-5 years for studies to be conducted and published showing whether this is actually the case or not.
Cynics might argue that manufacturers do this deliberately, because they know that, historically, about 95% of supplements that show promise in these early studies fail to enhance performance when meaningful studies are conducted down the track. But my experience suggests that it’s usually because metabolic changes are enough to get the marketing team excited, and enough to get customers excited.
The next group of studies typically involves recreational athletes, often performing a very basic physical task which may or may not have any relevance to real-world sporting performance. For example, it could simply be a one-legged performance test in the lab, or a cycling or treadmill test at a constant speed until fatigue.
This is when the hype really kicks into over-drive, with claims of improved performance because participants could ride for longer after taking a particular supplement, or recovered one-legged strength better, or whatever the test may be. This is where it takes someone with specific scientific training in exercise, sports science and nutrition to sift through the research and pick out what’s relevant to the real world and what’s not.
Interestingly it’s often in the early stages that elite sporting teams and institutes will often get involved with using supplements, and often before the public have even heard of them. This is not because they get sucked in by manufacturers, but because of the need for elite sporting teams to get any edge possible over their competitors.
If an organisation like the AIS waited for conclusive evidence on a supplement, they’d potentially be conceding a couple of years to their rivals, and that could cost people results and ultimately their livelihood. It’s often the sports institutes who then work together with universities to design and conduct the more useful and relevant studies which actually tell us about the worth of the supplement.
The final phase of research on a product is where the supplement either becomes a staple part of an athlete’s routine, or the hype fades away and the supplement is never to be heard of again (or in some cases to make a comeback as an “all new breakthrough” several years later when everyone’s forgotten about it).
This is where real athletes (often high-level club athletes or occasionally elite athletes) are properly tested using a methodology that actually resembles the real world of competition. In cycling this usually means a time trial effort, often following a two-hour steady state (constant, moderate intensity) to simulate the pattern of effort in a road race. It is here that we finally know the answer to the question – does this supplement work for a particular type of athlete in a particular sporting situation?
If not, the product often slips quietly off the radar, surviving in only a small number of products. The manufacturers have made their money during the period of hype – it’s then on to the next big thing.
Some of the supplements you may have seen come and go in recent years are ribose, HMB, bovine colostrum and quercetin. Occasionally, though, supplements do prove their worth and continue to be recommended to athletes on an ongoing basis -– these include creatine monohydrate in team sports and strength sports (creatine has been around since the early 1990s), sodium bicarbonate for track cyclists and rowers, and, of course, caffeine.
Beetroot juice is in the midst of this cycle, so we don’t really know yet which way it’ll go. But next time we’ll take a look where the evidence is at to date, and you can decide for yourself.