I am always amazed by the wide range of sports nutrition products on sale in gyms and sports centres. No matter the time of day, it seems gym goers are always drinking nutrient shakes. The sports nutrition market has grown rapidly in the UK in the last few years. In 2012 for example, it was worth around £260m.
There are health benefit claims all over these products, such as enhanced recovery, increased muscle mass, fat burning, improved muscle definition and improved “well-being”.
With so many of these messages out there, people are obviously keen to separate the good products from the bad. As a sports scientist I am often asked which ones people should consume when training. My general opinion is that supplements are unnecessary as you should be able to satisfy all your nutritional requirements with an appropriate diet.
But since this answer never seems to satisfy, what follows will look at some of the most common supplements and the data on their importance for those taking exercise. It is aimed not at professional body builders but at the sort of people who work out a few times a week.
The main reason for taking protein is to increase muscle mass, since it stimulates the body to produce muscle protein. This is well established, but what is often debated is how much protein is sufficient, what type to take and the best time to take it.
The best type appears to be whey protein. It is absorbed into the gut more than 70% faster than other options such as casein or soy protein supplements. This means it gets to the muscles quicker, which increases the rate the body builds muscle protein by more than 20% compared to the other options.
On the timing issue many gym goers will swear by something called the “anabolic window”. This claims that the protein needs to be taken within minutes of stopping exercise for any gains to be realised. Put simply, this is pretty much hype. The window is likely to last closer to 24 hours to 48 hours rather than a few minutes.
As for how much protein to take, a recent study found that in young men of between 80kg and 85kg (12st 8lb and 13st 4lb) who weight-train regularly, it took 20g of whey protein to achieve the best possible result – what we in the trade call “maximal stimulation”.
Taking any more than 20g protein appears unnecessary, in this population anyway. It just leads to a lot of extra protein being excreted in the urine.
Creatine has been a popular supplement for many years, though it also occurs naturally in red meat, eggs and fish. Quite a large body of scientific evidence supports its use to gain muscle mass and enhance recovery.
The science says that when creatine is taken up into the muscle, it helps to generate energy. This allows the muscle to contract and exercise to continue. This can help enhance gains in muscle mass and strength in response to weight training.
But creatine’s effects on sport performance are less convincing. It increases body water storage, which increases body mass. In sports where body weight is important, this counteracts the muscle benefits and means there are unlikely to be benefits overall.
It is often assumed that vitamins are good for health. While that is true, when taken in excess the opposite can be true for both health and exercise.
In particular vitamin C and E, which act as antioxidants, have actually been shown to hamper the body’s adaptation to exercise training. Two recent studies found that people who took large amounts of the two vitamins (1000mg/day of vitamin C and 267mg/day of vitamin E) showed no improvement in aerobic fitness or exercise performance.
This level of consumption was 250 times the recommended dietary allowance for vitamin C and 80 times that for vitamin E – though well within the range of commercially available supplements.
The study produced another important finding. Two benefits of taking regular exercise are that human bodies become more sensitive to insulin, meaning the person is less likely to get diabetes; and they can produce more energy, through creating more of the “work horse” units in cells that are known as mitochondria.
The people in the study who took the vitamins found that these benefits were attenuated to some extent. This suggests that these supplements may do more harm than good, certainly if you take them in large quantities.
People don’t take caffeine to help adapt their bodies to training but rather for improved performance during a single exercise bout, such as on a competition day.
Taking caffeine supplements will indeed prolong your endurance during exercise. Coffee lovers will be happy to know that you can get the same benefits from coffee consumption, though I’m not sure if I can see folk slurping the stuff on the treadmill.
Carbohydrate-based drinks have been around for a long time, having long been seen as worthwhile because of the way they increase the delivery of energy to the body and give it better hydration. But in recent years the evidence supporting their ability to improve acute exercise performance has been called into question.
While I am confident these drinks will be of use during prolonged intense exercise for durations of around two hours, they are often consumed during shorter duration exercise when they are likely to have little benefit.
There has also been a lot of concern in recent years about young children consuming these drinks, while performing little exercise, and unwittingly increasing their sugar and calorie consumption and possibly contributing to the obesity crisis. These drinks also often contain caffeine, which is not recommended for children either.
There are several other supplements available which claim to be of benefit to exercisers. These may include things like beta-alanine, fish oil, conjugated linoleic acid, L-carnitine, L-arginine, nitrate and vitamin D. Current evidence would suggest there is no apparent benefit in taking such supplements.
In a recent study 10% of supplements tested contained banned products, such as steroids. Clearly this is not only a concern for potentially failing a drugs test if exercising competitively but also it is extremely concerning to me that these substances could be in health products that can be picked up from your local supermarket.
In short, this takes us close to where we started. Nutrition products can benefit people that work out, but there’s so much misinformation that you may well be wasting money or even undermining your body’s performance.
If the question is, “what supplements should I take to enhance my exercise training?”, the simple answer is: Nothing. Exercise, have a balanced diet and enjoy it!