Sunday, October 19, 2008

Proteins in sports performance: More queries & few answers; part I

In ‘sports nutrition’ the first word that comes to mind is carbohydrates. That’s understandable. We all know how essential carbohydrate is to sports performance. But there’s another essential component of sports nutrition that’s equally important and that’s PROTEIN. Because protein is so much more than just an essential nutrient – it’s the largest component in the body after water, typically representing about 15% of body weight. What’s more, most of this protein mass is found in muscle, which explains the importance of protein to athletes.

However, while the basic biochemistry and functional roles of protein in the body have long been understood, there’s still a huge amount of mythology and confusion surrounding protein nutrition – especially where performance athletes are concerned. This is partly because of general misconceptions about basic protein metabolism, and partly because new research continues to throw up surprises about exactly what constitutes optimum protein nutrition! New research work in this area revealed by sports scientists is that protein is essential in conditioning, training, recovery, injury prevention etc.

Dietary Protein & role it plays in the human diet, further how protein metabolism works, and the particular importance and relevance of protein for sporting performance are the most important queries. Protein metabolism is in a constant state of flux i.e. although muscle and other tissues contain a large amount of stored protein, this protein is not ‘locked away’. So when dietary amino acids (the building blocks of protein) are insufficient, tissue protein can rapidly be broken down back to amino acid building blocks, which are then used to replenish the ‘amino acid pool’, a reservoir of amino acids that can be drawn upon to support such vital functions as energy production or immune function. This explains why muscle mass is often lost during times of stress, disease and heavy training loads, or poor nutrition. Conversely, when dietary amino acids are in plentiful supply and other demands for protein are low, tissue protein synthesis can become the dominant process. So it’s essential that we athletes maintain optimum protein status so we have the muscle mass we need to perform at our very best, regardless of our sport or event.

There’s more to protein nutrition than just eating the optimum amount; the timing of consumption and the type of protein selected can both impact on nitrogen balance; and there are a number of nutritional ‘co-factors’ that are either essential or useful in promoting optimum protein metabolism within the body. This is especially true where carbohydrate is concerned, because building or even maintaining lean tissue mass is an ‘energy-intensive’ process. Increasing protein intake at the expense of carbohydrate can be a bad strategy for athletes engaged in heavy training, because without sufficient carbohydrate the body simply switches to other fuels for energy, and amino acids from protein (particularly the so-called branched chain amino acids) provide a ready source of energy!

The Role of Protein in Recovery: How to maximise both the speed and extent of your recovery from strenuous exercise? One of the problems with making definitive recommendations about the timing of meals and drinks to enhance post-exercise recovery is the multifaceted nature of the components required for recovery. In broad-brush terms, there are four major nutritional requirements during post-exercise recovery:

Water – to replace fluid lost as sweat and to aid the process of ‘glycogen fixation’
Electrolytes – to replenish minerals lost in sweat (eg sodium, chloride, calcium, magnesium)
Carbohydrate – to replenish muscle glycogen, the body’s premium grade fuel for strenuous exercise, and also to top up liver glycogen stores, which serve as a reserve to maintain correct blood sugar levels
Protein – to repair and regenerate muscle fibres damaged during exercise, to promote muscle growth and adaptation, and to replenish the amino acid pool within the body.

To date, most research into performance nutrition has focused on the first three of these factors. But new research suggests a crucial role for protein.

A chemical imaging technique called radio labelling has enabled scientists to probe the uptake of ingested protein amino acids into muscle cells. The amino acid is ‘labelled’ by removing a normal hydrogen atom from the molecule and replacing it with radioactive hydrogen. This means you can see what happens to this molecule using scanners when a subject consumes a protein drink or food containing it. If you take a sample of muscle tissue and detect the presence of radioactive hydrogen, you know that the body has incorporated the amino acid into muscle tissues – that protein synthesis has taken place. These studies shed new light on various aspects of post-exercise recovery, with respect to protein’s particular role. When to take protein? What kinds of protein give optimal results and how to mix protein with other foodstuffs for best results?

A fascinating finding; ‘fast’ and ‘slow’ proteins.
This refer to the speed with which these substances are ingested and synthesized, ‘fast’ is not always necessarily better. Sometimes ‘slow’ proteins are needed.

The sports nutrition world is filled with high-tech products designed to make recovery as quick and as efficient as possible but we need to know something about the body’s principal nutritional requirements – particularly with respect to the role played by protein & how to go about restoring the body to a position of nutritional balance and using protein as a key part of that strategy.

Endurance Strength: how to optimise your protein intake and muscle mass for endurance. Endurance athletes face an interesting paradox when it comes to muscle mass. Bigger, stronger muscles generate more forceful contractions, resulting in higher power and greater speed. However, the weight of bulky muscles imposes greater demands on our limited energy stores, especially in weight-bearing sports. But as we all know, maintaining adequate sport-specific muscle mass is critical for optimal performance in endurance athletes. The question is: how to go about doing so to best effect? First we examine the issue of how much muscle an endurance athlete actually needs; various dietary strategies for building and maintaining muscle mass – from the perspective of an endurance athlete is mportant.

Using a protein-centred nutritional strategy to build optimal levels of muscle, reduce markers of post-exercise muscle damage and soreness in endurance athletes, and to improve performance in subsequent exercise is of prime focus now a days.

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