Is it necessary to take a Protein Supplement?
It is recognised that physically active individuals have a higher protein requirement compared to sedentary individuals. This is because:
- Some protein will be used as a fuel source during prolonged exercise
- Extra protein may be required to repair muscle damage
- There may be an increase need for protein enzymes involved in oxidative metabolism during exercise
- Maintenance of an optimal environment for positive nitrogen balance so that the hypertrophic stimulus of resistance exercise is maximised
Although we know that physically active individuals have an increased requirement for protein, it is debatable whether protein supplements are necessary. Most Dietetians would agree that the increased protein requirements could be obtained from the diet.
However protein supplementation in the form of protein drinks/shakes may be beneficial because:
- They are a convenient, low fat, source of protein for individuals with busy lifestyles whose food preparation time may be limited
- They may provide a satiating snack for individuals who are trying to lose weight
- They can be consumed on the run by busy athletes to enhance post-exercise muscle recovery
Types of Protein Supplement
There is a huge array of protein supplements available on the market. The main forms of protein base are whey, casein, and soy.
Whey protein is one of the major proteins found in milk. The other major milk protein is casein. Whey protein has a higher biological value than casein. It is has a fast rate of digestion and absorption. Whey proteins consist of major whey proteins and so called "minor proteins" that have been found to be responsible for several observed bioactivities. These proteins may have properties which are linked to immune function
Casein is more slowly digested and absorbed compared with whey and so provides a slower, steadier release of amino acids into the blood stream. Caseins have been found to contain a number of encrypted bioactive peptides that have several multi-functional physiological activities.
The use of soy protein has the advantage of being dairy-free and is therefore an alternative for those who do not want to, or cannot consume significant amounts of dairy-based foods.
Some proponents of soy highlight the antioxidant properties of soy. Oxidant stress during exercise can contribute to fatigue and muscle damage, as well as delay recovery between exercise sessions. There is some research suggesting that soy could counteract such effects by elevating plasma antioxidant capacity. This issue needs further investigation.