What are branched chain amino acids (BCAA)?

Amino acids are a "building material" of proteins. Branched chain amino acids (BCAA) are called as follows because of their structure: they include a "chain side chain" containing one carbon and three hydrogen atoms. Three BCAA are distinguished: leucine, isoleucine and valine. Of these three amino acids, leucine is the most widely studied, besides, there is reason to believe that its use brings the greatest physiological benefit – more than in the sequel.

The BCAA is the very basis for protein synthesis and energy production. In fact, BCAA can contain up to one-third of muscle protein. And since they are so common and are also involved in protein synthesis and energy production, the BCAA plays an important role in many metabolic processes.

However, in order to ensure the involvement of the BCAA in these processes, they must be available in the body. This means that in order for these processes to take place, we need to take enough BCAA with our diet, and at the right moment.

Why is it so important to take enough BCAA?

BCAA are the only amino acids that are not degraded in the liver. All other amino acids are used in the gut and liver before entering elsewhere in the body, but BCAA enters the bloodstream directly. This means that the consumption of BCAA has a direct effect on plasma and muscle concentrations. Interestingly, during training, the BCAA is transformed into energy (oxidated), so these amino acids are also an important source of "fuel".

Taking BCAA shortly before exercise can help them get into muscle. It has many advantages:

  1. BCAA intake may reduce lactate concentrations after strength training and promote oxidation in skeletal muscles.
  2. BCAA may contribute to the circulation of growth hormone (GH), which has a strong association with anabolic mechanisms affecting muscle growth.
  3. BCAA intake may reduce serum concentrations of intramuscular enzymes creatine, kinase and lactate dehydrogenase after prolonged exercise. This process is likely to reduce muscle damage and improve their recovery.

Muscle is an important site for exposure to BCAA. It is in muscle that there is an increased concentration of BCAA and their degradation occurs.

BCAA is continuously excreted from the liver and other internal organs and enters the skeletal muscles, so that these amino acids can help maintain normal blood sugar levels.

What you need to know

Given that BCAA is so important for muscle people and that they help maintain normal blood sugar levels, it is essential for physically active people to ingest them in sufficient quantities. During or after training, it is possible to initiate an insulin reaction when ingesting carbohydrates, proteins and amino acids, which in turn helps to transfer BCAA to the body's cells. True, the availability of leucine plays a greater role than insulin. In muscle cells there is a special regulatory pathway for protein synthesis, stimulated by insulin, but which depends on leucine. In other words, the synthesis of proteins (and therefore the restoration of muscles after training) depends on the amount of leucine available. And as the BCAA runs out during exercise, the logical step would be to pick them up during or after training.

Since it is so important to ensure that leucine is available for protein synthesis by training on an empty stomach or skipping a meal after a workout, you risk losing more protein than the body is able to produce. It is true that during this period a sufficient amount of BCAA intake, in particular leucine, can contribute to protein synthesis processes.

Additional benefits

In order for the body to produce new proteins, it is necessary to take about 1 to 4 grams of leucine daily (FAO/WHO/UNU, 1985). This minimum amount should be ensured that leucine can affect the insulin signalling signal. However, this is only a guideline – the actual metabolic dose, especially for professional athletes and people engaged in intensive strength training, can be up to 12 grams per day.

It is believed that the BCAA is able to reduce central nervous system fatigue in endurance athletes, however, the data obtained so far do not support this theory.

BCAA content in food (grams of amino acids per 100 g of protein)

Whey protein isolate 26%
Milk proteins 21%
Muscle protein 18%
Soy protein isolate 18%
Wheat protein 15%

Summary and recommendations

The BCAA plays an important role in:

  • general protein synthesis;
  • glucose homeostasis (i.e. maintaining constant blood sugar levels);
  • direct regulation of muscle protein synthesis (insulin signalling).

The potential impact of the BCAA on the above processes depends on their availability and intake.

Adequate consumption of BCAA can help reduce body fat, protect muscles from breakdown, and regulate glucose/insulin balance.

How can you use this knowledge?

Try adding BCAA to your workout drink – 5 g BCAA for each hour of training.

In case of reduced caloric intake, BCAA supplements are taken every 2 to 4 hours throughout the day.


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