There’s no shortage of supplements offering the promise of improved performance in sport and exercise. But do they really work? Sports dietitian Dr Trent Watson of the Dietitians Association of Australia gives his advice on what’s worth trying — and what’s not.
Sports supplements are mainly for people who spend more than 15 hours a week training or who exercise vigorously for more than 60 minutes four to five times a week — such as an elite athlete or an endurance-based amateur athlete.
Supplements are especially useful for people who want to maintain their weight or gain weight, rather than lose it. However, they’re not a replacement for regular meals based on quality carbohydrates (such as whole grains, vegetables and fruit) and lean protein (like lean meat, poultry and fish, legumes, nuts and low-fat dairy foods), says Watson. These foods provide round-the-clock fuel for muscles as well as the building blocks for their growth and repair.
These are useful for those who either put in a lot of hours of exercise or training or who want to put on weight.
Protein shakes high in quality carbohydrates, protein and other nutrients can help people recover after training and build and repair muscle, says Trent Watson. They also help people maintain their weight — people who train at a very high intensity often struggle to sustain their weight, he adds.
However, for people who are training less or at a lower intensity, protein shakes aren’t necessary — especially for someone who’s trying to lose weight and doesn’t need the extra kilojoules. Regular meals and snacks based on healthy carbohydrate foods and lean protein should be enough to meet your needs, says Watson.
Before you invest in a protein supplement, it’s also important to understand exactly what your body needs for muscle growth — it’s not just about protein.
There are two components to building muscle — one is that you need to stress the muscle to the point of exhaustion to make it adapt and grow, the other is that you need protein to act as a building block to help it grow and repair too, explains Watson. But many people don’t realise that without sufficient carbohydrates, your muscles will use protein for fuel — and you won’t have enough protein left to help the muscle grow.
“Anyone who’s strength training and not consuming enough fuel will still see an improvement in strength and get leaner — but if you want to add bulk, you need to ensure you have enough fuel for your muscles, which includes both carbohydrates and protein,” he adds.
These are a concentrated carbohydrate in an easily-digestible gel form that’s easy to consume while you’re exercising. When you’re exercising at high intensity for more than an hour, you can run out of glycogen — the form of carbohydrate that fuels your muscles. Depending on the intensity of exercise, muscles may only store enough glycogen for approximately 90 minutes, explains Watson. Carbohydrate gels can provide a useful portable top up of fuel for anyone taking part in endurance events or training or for team sport players during breaks in play.
Creatine is a substance found in muscle that helps to fuel muscle for short spurts of high-intensity exercise such as sprinting or lifting weights. There’s good evidence that creatine supplements can improve performance with these activities, says Watson. If you’re lifting weights for example, creatine supplements can help you lift a heavier weight for more repetitions. This will help the muscle get stronger — or larger — in a shorter period of time.
Creatine supplements are useful for anyone who’s taking their athletic performance seriously and whose activity includes sprints or strength training or team sports such as rugby league or rugby union which require repeated spurts of explosive power, says Watson.
Research suggests that 70–200mg of caffeine before, during or toward the end of exercise can improve performance in exercise sessions lasting more than 60 minutes. However we’re all different when it comes to caffeine — although some of us will benefit from it, others won’t.
One side effect of vigorous exercise is that it causes the body to produce free radicals — harmful molecules that damage cells and the immune system. Antioxidants protect the body from free radicals and help reduce their damage. As a result, there’s been debate about whether or not keen exercisers or athletes need extra antioxidants such as vitamin C and E. However, Trent Watson’s own research and that of other researchers suggests that a diet high in vegetables and fruit — natural sources of antioxidants — provide enough protection against free radicals without the need for extra supplements.
In fact, Watson’s research found that when athletes did take antioxidant supplements, it increased free radical damage.
“Supplements often take the focus off getting the diet right — the biggest mistake I see many athletes make is not making diet a part of their training program. Healthy food is the foundation of our diet — supplements are just the tip of the iceberg” says Watson.
Sports drinks containing carbohydrates are a useful option for high-intensity exercise sessions of 60 minutes or more. Besides helping to keep you hydrated they help top up carbohydrate stores to fuel muscles as well.
Dietitians Association of Australia www.daa.asn.au/
Australian Institute of Sport www.ausport.gov.au/ais
Australian Institute of Sport. AIS Sports Supplement Program. [online] Bruce, ACT: Australian Sports Commission. 2009 [accessed 26 Aug 2010] Available from: http://www.ausport.gov.au/
Australian Institute of Sport. Recovery nutrition. [online] Bruce, ACT: Australian Sports Commission. c2010 [last updated July 2009, accessed 26 Aug 2010] Available from: http://www.ausport.gov.au/
Watson TA. The science of antioxidants and exercise performance. In: Burke L Deakin V, editors. Clinical Sports Nutrition. 3rd edition. Sydney, NSW: McGraw Hill. 2006.
Watson TA Callister R Taylor RD et al. Antioxidant restriction and oxidative stress in short-duration exhaustive exercise. Medicine and Science in Sports and Exercise. 2005; 37(1): 63–71.
Watson TA MacDonald-Wicks LK Garg ML. Oxidative stress and antioxidants in athletes undertaking regular exercise training. International Journal of Sport Nutrition and Exercise Metabolism. 2005; 15(2): 131–146.
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Last published 31 October 2010