Your eXpert Guide to
Amino Acids

High protein diets for muscle growth and strength date back to Ancient Greece. Amino acid supplements hit the bodybuilding industry, to directly supply the important muscle building nutrients. Amino acids are considered an essential part of bodybuilders' nutrition, to support growth and recovery. Endurance athletes have also recognised amino acids' role in preventing muscle breakdown during heavy training.

Amino acids are the structural building blocks of protein. They are found in protein rich sources, such as meat and fish. Amino acids form the basic components of all living cells, found in virtually every part of the body. They are essential for the maintenance, growth and repair of muscle tissue.

Protein is broken down in digestion to its single amino acid component. Chemical bonds are formed between these single amino acids to make thousands of different proteins and enzymes. There are 20 amino acids that fall into 2 categories: essential and non-essential. Amino acids are listed in table 1.

Non-essential amino acids

12 amino acids are termed non-essential as they can be made from other amino acids as well as from carbohydrates and nitrogen.

Essential amino acids

8 amino acids are termed essential and must be supplied in the diet. They are essential as they can't be made in the body.

Branched chain amino acids (BCAA) are the 3 essential amino acids linked together:

• Valine
• Leucine
• Isoleucine

BCAA's are particularly important for weight training because they make up one third of muscle protein. BCAA's are essential for excessively stressed muscle to:

• Promote healing
• Supply energy
• Speed recovery
• Prevent muscle tissue breakdown
• Convert to other amino acids when a deficiency arises

Amino acid supplements

Amino acid supplements come in the form of tablets or capsules. They supply a high source of BCAAs and a balance of other amino acids, which are difficult to get from whole foods. On the other hand, protein powders must be broken down in digestion into amino acids. Amino acid supplements do not contain sweeteners, fillers, dyes or carbohydrates that are found in protein powders.

During exercise, muscles are broken down and need to be repaired and rebuilt for muscular growth. Combined with heavy training, amino acids create a muscle building environment to encourage growth and repair. By maximizing your training adaptations, performance can be improved¹.

Combined with heavy training, amino acids create a muscle building environment to encourage growth and repair

Amino acids have been shown to:

• Increase lifting capacity³
• Decrease muscle breakdown following exercise⁴
• Increase muscle mass⁵,¹⁰,¹⁵
• Decrease fatigue³,⁵,¹¹
• Increase immune function²
• Increase antioxidant capacity⁴
• Decrease protein breakdown during exercise⁵
• Supply energy⁶
• Increase growth hormones and Insulin-like growth factor IGF-17,¹⁰

Those who are involved in the following activities should benefit from amino acid supplementation:

• Strength and power training
• Long intense endurance training
• Athletes on a low carbohydrate diet
• New to strength training
• Weight loss program
• Vegetarian or vegans
• Returning to training following injury or illness
• Team sports that are long in duration and involve repetitive sprints ie football

Daily amino acid needs are higher if you train regularly. Your body needs more amino acids after exercise to repair the muscles. To increase muscle size and strength, higher protein content in the diet creates the ideal environment for adaptation and growth. Amino acids have several roles within the body to aid performance that are discussed below.

Build muscle strength and size

Your body must be in a state of positive nitrogen balance for muscle building. High intakes of amino acids increase nitrogen balance, providing the best environment for growth. Research shows muscle protein synthesis rates are higher when protein and amino acid intakes are high¹³,¹⁴. Furthermore, improvements in lean body mass during a weight training program were greater with amino acid supplementation¹⁵. Essential amino acids, including the BCAAs, are particularly known to aid muscle building¹⁷.

Reducing fatigue

The causes of fatigue are extremely complex, caused by both energy depletion and the central nervous system (CNS). Over the past 20 years research has supported the role of the brain and CNS in fatigue during exercise that doesn't deplete energy stores¹¹. Increased activity of the serotonergic system during exercise increases feeling of:

• fatigue
• tiredness
• perceptions of effort
• motivational loss

These factors limit physical and mental performance¹¹. During exercise involving physical and mental skills, such as football, fatigue can impact performance. BCAAs and tyrosine have been found to manipulate neurotransmitter precursors to delay the onset of fatigue. Studies have found that BCAAs taken before exercise improved mental and physical performance¹², although not all research agrees.

Increases anabolic hormones

Amino acid supplementation increases the amount found in the blood. Research shows increased concentrations of amino acids in the blood boosts the gene expression of IGF-1.

IGF-1 is a protein hormone that stimulates cell growth with muscle tissue being especially affected. Its production is stimulated by growth hormone, another hormone that encourages growth and cell reproduction. The release of IGF-1 stimulated from amino acid supplementation is unclear with some research supporting this view and others not⁹.

Prevent muscle tissue breakdown

BCAAs help prevent muscle tissue breakdown during exercise. BCAAs also have the ability to be used directly as an energy source by the muscles. Research demonstrated that 4g of BCAAs reduced muscle tissue breakdown during and after exercise⁵. Glutamine plays a major role in preventing tissue breakdown and boosts the immune system. This is detailed further in the SNC's Glutamine Buyers Guide.

Amino acid blends and BCAAs typically come in capsule form. Recommended uses vary slightly depending on the potency of the product, however the optimum time to supplement is both pre and post workout.

Glutamine is available in a tasteless white powder that dissolves in water. For more information please see SNC's Buyers guide to Glutamine.

Amino acids are considered an essential part of bodybuilders' nutrition, to support growth and recovery

As described in 'what are amino acids', they are the building blocks of protein. There are 20 different types and they form different combinations to create 1000's of different proteins. Amino acids can be divided into 2 categories which are the essential amino acids, including the branched chain amino acids, and non-essential amino acids.

Amino acids can be used in capsule form for high doses of specific amino acids. High quality protein and meal replacement shakes generally supply a good source.

When choosing an amino acid supplement look out for 2 things on the nutritional label:

1. A high supply of the BCAAs which are leucine, isoleucine and valine.
2. The amino acids should be L-form (e.g. L-arginine "L meaning Levo") denoting a naturally occurring amino acid. Other forms, such as d-forms are poorly absorbed and may be toxic.

Excessively high intakes of branched chain amino acids (BCAA) may reduce the absorption of other amino acids.

Will supplementing with BCAA be better than using a whey protein powder?

Protein powders and protein based meal replacement powders typically contain high amount of branched chain acids. Therefore using both may not be necessary.

Are amino acids better than whole food for achieving high protein intakes?

The sole use of supplements to supply nutrients should be discouraged. Supplements should be used to make up for short falls in your diet. Any use of supplements should be in conjunction with whole food. Although you can obtain protein solely from whole food, this can prove challenging for several reasons.

Many high protein foods have a high fat content and the financial and time expense involved in selecting, buying, preparing and eating high protein whole foods on regular intervals throughout the day can be overwhelming. Amino acids provide convenient, quick alternatives to supply your body with the best nutritional value amino acids without the hassle.

If I choose to reach my amino acids needs through whole food and protein powders, are there any tips to get the most from these food sources?

Absolutely. If you feel your protein intake from whole foods and/or protein based supplements is sufficient, amino acid supplements may not be necessary. If this is the case a good tip is to look out for vitamin B6 content. It plays an essential role in protein metabolism. Basically it helps improves the efficiency that protein is broken down into the amino acids.