Amino acids are the fundamental building blocks of all proteins in living organisms. Some of them must be supplied with food (essential amino acids), while others are produced by the body itself in the required quantities (endogenous amino acids). What roles do amino acids play in the body? What are the specific features of BCAA amino acids?
What are exogenous amino acids?
Amino acids are the basic building blocks of proteins. There are 20 different amino acids in animal bodies, both exogenous and endogenous. Amino acids are organic compounds that contain up to 6 carbon atoms per chain. Each amino acid has two functional groups - an amine (-NH2) and a carboxyl (-COOH). The amino acid molecules link together with a peptide bond to form large protein structures.
Amino acids are divided into exogenous and endogenous. Exogenous amino acids, or essential amino acids, are those, which the body is not able to produce on its own, and it is necessary to supply them with food. The exogenous amino acids include:
- Histidine - this amino acid is only required by children and young people during the growth period. At that time its production in the body is insufficient. For adults, histidine is a non-essential amino acid. Histidine participates in the synthesis of nucleic acids (DNA) and haemoglobin (red blood pigment). It is found in the highest amounts in meat, fish, nuts and seeds, e.g. pumpkin, sunflower and sesame.
- Lysine – is involved in cartilage synthesis, milk production, production of hormones, nucleic acids, antibodies, enzymes and tissue repair. It is very widely available in food. It is not present only in corn.
- Methionine – essential for growth, participates in creatine synthesis, takes part in fat metabolism. It is found in the greatest quantities in egg white, milk and cottage cheese.
- Phenylalanine – is involved in the production of the neurotransmitters – dopamine, epinephrine and norepinephrine. Phenylalanine deficiency may be associated with lowered mood, problems with concentration and depression. It is present in all foods in smaller amounts.
- Threonine – is a component of collagen and elastin - the building blocks of joints and skin. It is mainly found in gelatin, meat, fish, eggs and cottage cheese.
- Tryptophan – is necessary for the production of serotonin, protects us from states of depression. In the highest amount, it can be found in cereals.
- Valine, leucine, isoleucine - all three amino acids belong to the group of branched amino acids, they build muscle mass, prevent muscle protein breakdown during and after exercise. These essential amino acids are commonly found in animal products - meat, fish, dairy goods.
What are endogenous amino acids?
Endogenous amino acids (non-essential amino acids) are the ones that the body synthesises on its own. Endogenous amino acids are formed from the products of carbohydrate and fat metabolism, along with other compounds that must provide an amino group.
The nutritional classification of amino acids includes not only exogenous and endogenous ones but also conditionally essential amino acids. This group is formed from its precursors, which are other amino acids, mostly those that must be supplied with food (exogenous). If the amount of these precursors in the diet is insufficient, then the conditionally essential amino acids become essential ones and also need to be supplied with food. On the other hand, when the diet covers the demand for precursors, the conditionally essential amino acids are produced by the body just like the endogenous amino acids.
Endogenous amino acids include:
- Alanine – participates in nitrogen and glucose transport between muscles and liver.
- Aspartic acid - plays an important role in the immune system, has an anabolic effect.
- Asparagine – acts as a nitrogen store.
- Glutamic acid - supports the nervous system, reduces fatigue.
- Serine - participates in the production of nucleic acids.
Conditionally essential amino acids are:
- Arginine – is formed from glutamine, glutamic acid and aspartic acid. It is necessary for the production of nitric oxide, which supports the cardiovascular system. It strengthens the immune system, increases physical performance, and accelerates wound healing.
- Cysteine – formed from methionine and serine. It is a component of glutathione, key element in oxidation and reduction processes.
- Glutamine – formed from glutamic acid and ammonia. It is an energy source for the cells of the intestinal mucosa. Participates in the production of lymphocytes and macrophages.
- Glycine – formed from serine and choline. Participates in the synthesis of haemoglobin and nucleic acids.
- Proline –formed from glutamine. Found mainly in connective tissue.
- Tyrosine – formed from phenylalanine. It is necessary for the synthesis of thyroid hormones, adrenaline, noradrenaline and pigments produced in the body.
Exogenous and endogenous amino acids have numerous and diverse functions in the body. Those listed above are only examples showing how important it is to supply exogenous amino acids and precursors of conditionally essential ones with food.
BCAA amino acids
BCAA (branched-chain amino acids) are amino acids with branched side chains. What does this mean? Most amino acid molecules have a straight chain, shaped like a single line. BCAA amino acids, on the other hand, have arms that diverge from the main chain. It makes BCAA amino acids unique in comparison to other amino acids.
BCAA are 3 essential amino acids – valine, leucine and isoleucine. They represent around 25% of all muscle-building amino acids. BCAA amino acids are especially important for athletes, as they prevent muscle proteins from being used as an energy source during intensive workouts and support muscle mass gain. Opinions about BCAAs are consistent both among users and among scientists who study their effectiveness. Supplements with BCAA amino acids actually help.
What is the role of BCAA amino acids?
- Prevent catabolism and increase the anabolism of muscle proteins.
- Decrease the feeling of fatigue after exercise, which allows you to exercise longer and harder.
- Reduce pain during and after exercise.
- Increase muscle endurance.
Due to their obvious and very beneficial role during high physical activity, BCAA amino acids are a popular dietary supplement among athletes. They often wonder how to choose the best BCAAs? The ranking of BCAAs should take into account the amino acid content of the product, their ratio, water solubility and taste.
Classic products contain leucine, isoleucine and valine in a proportion of 2:1:1, which is the same ratio present in muscles. However, it is known that leucine is the key anabolic substance and has the biggest impact on the development of muscle mass. For this reason, the market offers a new generation of products with an increased proportion of leucine. Should the best BCAA contain amino acids in the proportion of 4:1:1, 8:1:1 or perhaps 20:1:1? There is still no clear answer based on scientific research, but the tendency among athletes is that the more training is focused on muscle mass gain, the more leucine in the supplement.
The dosage of BCAAs recommended by the scientific community is 1 g per 10 kg of body weight. However, most trainers suggest taking 10 g of BCAAs in two portions - 5 g before and 5 g after training. BCAA producers also recommend the dosage of their supplements on packages. The best way to choose the right dose of BCAAs is to observe your own body and adjust it individually.