In recent years there's been a growing awareness of the role of protein in the diet, especially for weight loss, but also for increasing or maintaining muscle mass. No longer reserved solely for body builders, commercial protein supplement powders and bars are filling shelves in supermarkets, pharmacies and health food stores. But do you really need a special supplement, or would a healthy diet suffice?
We look at the protein needs of the three main groups targeted by protein supplement marketing, and weigh up whether they're necessary, helpful or a waste of money. These groups are:
- athletes who want to build muscle and recover quickly from exercise,
- weight-loss dieters looking for appetite suppression and preserved muscle mass, and
- elderly people who need to retain muscle mass.
Protein for athletes
Protein supplements are often targeted at active people – everyone from your average gym junkie to elite athletes. While it's true that athletes have higher protein needs than less active people, it's debatable whether they really need a supplement. Protein is said to have several key benefits for athletes: building strength and muscle mass, improving performance relating to speed and stamina, and aiding recovery.
Athletes attempting to increase muscle size and power need more protein at the beginning of an intensive strength-training program, but the muscles soon adapt to the new regime and don't require as much. So athletes only need slightly more protein than a typical active person, and because people who exercise heavily tend to have a greater appetite, their protein requirements are generally met without the need for a special high-protein diet or supplements – even body builders.
Some pre-workout protein supplements claim to help increase speed and stamina, but is there any evidence for this? A 2010 review of studies found that consuming protein before or during exercise doesn't help people go faster, but it does help with endurance. However, in studies that found this, the protein drink contained more kilojoules than the drinks it was compared with, so it could have been the extra energy rather than the protein that made the difference. More studies comparing preparations with similar energy value are needed.
After training or competing, athletes need to refuel, rehydrate and repair muscle. This is particularly important for athletes who need to perform again soon after, but it also helps alleviate muscle soreness after a hard workout. Sweetened liquid protein drinks are ideal because the carbohydrate helps restore glycogen to muscles, the liquid helps rehydrate and the protein helps prevent muscle tissue breakdown and stimulates muscle tissue synthesis, which is further assisted by the insulin resulting from the simple carbohydrate (generally sugar).
Timing and amount
The optimal amount of protein for a post-workout snack is thought to be about 20 grams of high-quality protein (from meat, eggs and dairy) – any more than this probably won't be used by the body. Protein supplements marketed for post-exercise recovery may contain the required elements, but there's a growing body of evidence in favour of flavoured low-fat milk, which has protein, fluid, electrolytes and carbohydrate, and is cheap, effective and readily available.
Whey protein found in milk is considered an ideal choice because it's high in an important muscle-building amino acid called leucine, and is digested quickly, so it's available when muscle tissue synthesis is at its peak. Flavoured yoghurt, smoothies and breakfast cereal with milk are also recommended. However, protein supplement drinks and bars may be a convenient alternative for some people – they can be kept in a gym bag, or taken when travelling without needing to be refrigerated.
There's a large body of evidence showing that consuming protein immediately after training (within an hour) enhances muscles' uptake of amino acids from the protein, and therefore gives the maximum benefit. But muscle repair continues for 24 hours, so regular consumption of protein thereafter is also important.
Commercial protein supplements (drink powders and bars) may be a convenient source of protein to have on hand post-workout for serious athletes, but aren't necessary for recreational athletes who are likely to get plenty of protein from their normal diet. They may also be more expensive per gram of protein than other sources such as milk, eggs or meat, and – depending on how they're used – may provide more protein than can be used by the body.
Protein for weight loss
Another major target market for protein supplements is people trying to lose weight. Visit a pharmacy, health food store or supermarket and you'll find a huge range of protein powders, bars and snacks claiming to help with weight loss. And it's true – protein can help. Increasing the amount of protein in the diet can keep you with feeling fuller for longer, and kilojoule for kilojoule it requires more energy than fat or carbohydrate to process and store in the body. Having adequate protein when reducing kilojoule intake also helps reduce the loss of muscle mass, especially when combined with resistance training, and this also contributes to weight control because muscle tissue consumes energy.
But do you need special supplements?
According to Dr Rosemary Stanton, when it comes to weight loss the evidence is really only that kilojoules count. However, she acknowledges, "Some people have found it easier to reduce their kilojoule intake by omitting foods high in carbohydrate or fat – and that leaves protein." With concerns raised by some studies about the long-term effects of a diet high in red meat, alternatives like protein shakes, snacks and supplements have been marketed as a better source of protein. Stanton argues, though, "that this is an expensive way to get extra protein and with no evidence that such diets are of any special benefit for long-term weight loss, it seems a fairly useless exercise."
Most Australians get plenty of protein in their diet and don't need protein supplements to achieve weight loss. A diet featuring vegetables, fruit, wholegrains, low-fat dairy and lean protein is consistently linked with successful weight control. For snacking, try replacing high-sugar or high-fat manufactured snack foods with whole foods such as low-fat plain yoghurt, a handful of nuts and seeds or a hard-boiled egg.
Protein for elderly people
In recent years it's been acknowledged that nutrient needs in adults change with age, and it's increasingly recognised that elderly people need more protein than younger adults. As we age, we metabolise amino acids differently, and need higher doses to stimulate muscle protein synthesis. Inadequate protein causes bone (osteopaenia and osteoporosis) and muscle (sarcopaenia) wastage, and also affects immunity and wound healing.
The most recent Nutrient Reference Values for Australia and New Zealand (2006) recommend an increase in the daily protein intake from the age of 70. For men, this is an increase from 0.86 to 1.07 grams of protein per kilogram of body weight, and for women from 0.75 to 0.94g/kg. The most recent National Nutrition Survey (which is unfortunately from 1995) found adults aged 65+ consumed an average of 73g of protein per day, which is likely to be in line with the NRV recommendations (81g and 57g for the average-weight male and female in this age group respectively).
But it's likely the optimal protein intake for adults over 50 may be higher than this, with recent research suggesting that the recommended intake may not be adequate to preserve muscle, and that levels of 1 to 1.3g/kg would meet the protein needs of older adults while avoiding issues of too much protein.
So, while the protein needs of older adults increase, decreased physical activity and a change in perceptions of taste and smell may mean a decrease in appetite and food intake. Food preferences and cooking habits may also change, and unless a conscious effort's made to ensure there's adequate protein, people may not get enough to meet their needs. Marketers have cottoned on to this, and are promoting protein powders as a way for older people to ensure they're getting enough.
But do you really need to take a protein supplement when you hit 50? Probably not, says Milena Katz, spokesperson for the Dietitians Association of Australia, as most people get plenty of protein in their diet. However, she recommends people review their diet when they retire, with the help of a dietitian. "People change their eating habits as they get older, and particularly when they retire and radically change their lifestyle."
Bottom line for 50-plus
Taking protein supplements isn't as effective (or as affordable) as eating whole foods high in protein, because there are other nutritional benefits in whole foods that you don't get from protein alone. Most people can get enough protein from a balanced diet, however, for some people – especially frail elderly people who have little interest in eating – supplements are the best option. Your doctor can give you a referral to a dietitian, and you may be eligible for a Medicare rebate.
Healthy ageing and sarcopaenia
Sarcopaenia is the loss of skeletal muscle mass and strength that occurs with advancing age. It affects 5-50% of people aged 60 and older, varying according to age and how sarcopaenia is defined. Loss of muscle strength can impact heavily on quality of life, affecting mobility, increasing the risk of falls and fractures, making it difficult to perform daily activities and ultimately resulting in a loss of independence and increased likelihood of early death. Thankfully, sarcopaenia isn't inevitable and is reversible – a program of strength training combined with protein consumption can be used to successfully maintain and rebuild muscle mass.
The Centre for Strong Medicine provides exercise-based medicine programs for older adults at Balmain Hospital in Sydney. The exercise programs, which are done either at home or at the centre, are targeted at people with various conditions, including arthritis, diabetes, heart disease and osteoporosis, as well as frailty, functional impairment and walking difficulties, which are often related to sarcopaenia.
The centre's dietitians advocate eating a high-protein meal or snack containing 20 grams of protein within 30 minutes of finishing training, to maximise the benefits of training on muscle growth. This can be achieved with conventional foods, such as lean meats, poultry and fish, dairy products or eggs. However, people who exercise at the centre are offered protein supplements for a quick and convenient protein hit.
- The Australian Institute of Sport (AIS) has a fact sheet on the protein needs of athletes at varying levels and how to meet these needs.
- The AIS also has information on protein and recovery nutrition.
- While aimed at health practitioners, this summary of recent research in sarcopaenia, with links to full articles, provides a good grounding on the condition.