Why do the majority of people who go to the gym to build muscle know so little of amino acids and protein, and their importance in achieving our goal of muscle building? Amino acids; everyone has heard of them, protein powders list them. So what is the importance of them? Do we really need them?
Amino acids are the building blocks of protein and also muscle tissue. And they also play a major part in physiological processes relating to our energy, recovery, mood, brain function, muscle and strength gains, and also in our quest for fat loss.
There are 23 amino acids and 9 of these are classed as essential or indispensable amino acids (IAA) that must be obtained from our nutritional intake. The others are termed dispensable amino acids (DAA) or non-essential due to the body being able to synthesise them from other amino acids.
When we eat a meal we don't pay much attention to the content and balance of amino acids but the content of the meal determines the body and health building value of the protein food or supplement. In addition the importance of the amino acids content of our meal is important to support maximum growth we also have to take another factor into account which is to what extent these amino acids are actually delivered to the tissues when they are needed which takes us to the issues of digestion, absorption and also the bioavailability.
What is Bioavailability?
Eating our protein foods such as lean meats and non-fat dairy products, or having our protein drinks are the most common ways that we get our amino acids, we also can obtain amino acids from vegetables, and legumes also have levels of most amino acids. We can also use protein drinks and amino acid supplements as a convenient means to supplement our dietary needs.
The reason we use these supplements is the bioavailability of the amino acids. Bioavailability is a measure of the efficiency of delivery and how much of what is ingested is used for its intended use by the body. There are factors which determine the amino acid bioavailability. One is how much fat is contained in the protein source and the length of time it takes for the amino acids to be available for use by the body.
Cooking also can affect the amino acids; some are more or less sensitive to heat and cooking may cause decomposition of some amino acids. The physical nature of the particular food is also a factor, whether it is solid, liquid, powder, or even tablet, and to what extent it is chemically pre-digested as some amino acid supplements are, fillers and binders also can have an affect on the digestion of the amino acid. The condition of our digestive system can also have an affect on amino acid digestion, genetics, age, health, specific diseases and illnesses all have an affect on our digestion.
Amino acids and Bodybuilding.
Exercise, hormones and nutrients will all cause muscle growth. As will supplementation of free form amino acids high in the branch chain amino acids (BCAA's) Leucine, Isoleucine and Valine. The best time for us to get our amino acids is immediately after our training when the muscle is especially receptive to nutrients and also blood flow to the exercised muscles which still remains high. The solution to optimising our recovery and growth after training is a s meal composed of protein with both simple and some complex carbohydrates. This is the time when ideally we require a fast digesting protein such as whey protein.
Amino Acid Supplementation.
The popularity of amino acid supplements has increased dramatically. Packaged workout and recovery drinks that contain hydrolysed (pre-digested) proteins and often some free-form amino acids can be found in most gyms. Also tubs of powdered or capsulated amino acids are being used by an increasing number of weight trainers. The good thing about these supplements is that they don't require digestion like food does. The term free-form means that they are free of chemical bonds to other molecules and as such move quickly through the stomach, into the small intestines where they are very rapidly absorbed into the blood stream. When absorbed, amino acids are processed by the liver. The liver can only process so many at one time, so by taking a dose of 3-4g of amino acids these will be rapidly absorbed and would exceed the liver's capacity which would result in the amino acids being directed to the tissues that would require them such as muscle that is recovering from your training.
Amino acids and Energy.
A lot of misconceptions exist about the muscle contraction and the use of energy substrates during heavy high intensity weight training. When performing your training using repetitive power workouts a substantial portion of your energy comes from non-carbohydrate sources. When your muscles contract they use stores of adenosine triphosphate (ATP, a substance vital to the energy processes of all our living cells) for the first few seconds. The compound used to immediately replenish these stores is creatine phosphate (CP). This is how the supplement creatine, became so popular to bodybuilders and strength trained athletes. Creatine is made from three amino acids: arginine, methionine and glycine. To keep our CP and ATP levels high, these amino acids must be kept elevated in our blood stream. The amino acids in creatine supplements can be supplied by foods in our diet but the process of elevating these amino acids takes a great deal of time in digestion, and also would be accompanied by fats and carbohydrates which may or may not be desired. So the use of free form amino acids, either alone or in combination with creatine supplements can provide direct source of energy for power and strength.
Amino acids & Fat loss.
In fat loss two major processes must occur (1) the mobilisation and circulation of stored fats in the body must be increased; and (2) Fats must be transported and converted to energy at the mitochondria (the powerhouse site of cells). Several nutrients can assist in the conversion of fat to energy including the amino acid methionine, which in sufficient amounts can help improve the transport and metabolism of fat. When attempting to keep our total calories down during dieting, amino acid supplements including BCAA's and glutamine can also help to keep our food volume down but still provide support directly to the muscles, liver and our immune systems which are critical to optimising our body composition.
Amino acids & Muscle catabolism.
Our body has the ability to breakdown our muscle tissue for use as an energy source during heavy exercise. This is part of a bodily process called gluconeogenesis which means producing or generating glucose from non-carbohydrate sources. The part of this reaction that is important to us as bodybuilders is known as the glucose – alanine cycle, in which the BCAA's are stripped from the muscle tissue and parts of them being converted to the amino acid alanine, which is then transported to the liver and converted into glucose. If we consume supplemental BCAA's the body does not have to breakdown our muscle tissue to gain extra energy. Studies have concluded that the use of BCAA's (up to 4g) during and after training can result in a significant reduction of muscle breakdown during training. Catabolism of muscle can cause shrinkage of our muscles and muscle soreness and may also lead us to injury.
Amino acids and the anabolic effect.
Resistance training generally stimulates both protein synthesis and protein degradation in exercised muscle fibres. Muscle hypertrophy (growth) occurs when an increase in protein synthesis results in the body's normal state of protein synthesis and degradation. The normal hormonal environment (e.g, insulin and growth hormone levels) in the period following resistance training stimulates the muscle fibres anabolic processes while blunting muscle protein degradation. Dietary modifications that increase amino acid transport into muscles raise energy availability or increase anabolic hormones should augment the training effects by increasing the rate of muscle anabolism and/or decreasing muscle catabolism. Either effect should create a positive body protein balance for improved muscular growth and strength.
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Amino acids. Barry Finnin, PHD. and Samual Peters .
Exercise physiology. 5th Edition, William D, McArdle. Frank I Katch, Victor L Katch.