BCAAs are also known as Branched Chain Amino Acids.
Leucine, Isoleucine and Valine are three of the twenty amino acids constituting proteins in our body. In particular, BCAAs are among the eight essential amino acids, the ones our body cannot synthesize and therefore must necessarily be taken through the diet.
They have unique physiological characteristics:
- They comprise approximately 1/3 of the amino acids in muscle protein;
- They are strictly linked to each other. If the quantity of one of these three amino acids is higher, it affects the catabolism of the others;
- Enzymes that catabolize (degrade) BCAAs are present in many tissues, not only in the liver, as is common for most amino acids;
- They can serve as fuel for the muscles and brain;
- Transamination is one of the most important chemical reactions of BCAAs, which is useful for their recirculation, and depends directly on the presence of vitamin B6. The presence of this vitamin is therefore advisable.
- Alanine and Glycine in the liver, Glutamine and GABA in the brain act as nitrogen donors. Therefore, they are used by our body to form other non-essential amino acids that are very important especially for sports people.
Using the mTOR pathway, Leucine is able to trigger protein synthesis directly and without being influenced by other aspects (growth factors and/or insulin). The estimated quantity necessary to trigger this mechanism is equal to 2-2.5 g. KIC (Ketoisocaproic acid) and HMB (hydroxymethylbutyrate) are two very important Leucine metabolites, which often act in reducing the use of Leucine. Leucine is considered a ketogenic amino acid, and may be used by the brain as an energy substrate in glucose deprivation, such as when fasting.
Isoleucine activity may be considered either glucogenic, since it can be transformed into glucose, or ketogenic, just like Leucine. It is an important amino acid for the uptake of glucose into the muscles, helping recovery after physical activity that uses glycogen. Thanks to this feature, it is thought that it may regulate blood sugar. One of its metabolites is alpha-keto-beta-methylvaleric (KMV).
Valine is largely metabolised in the brain, where it is the main competitor of tryptophan. It has a glucogenic effect, just like Isoleucine, and therefore it is mainly used for recovery after a workout. One of its metabolites is ketoisovaleric acid.
• Reduction in fatigue. Sharing the same tryptophan carrier, BCAAs are able to inhibit its action and, consequently, that of serotonin, which signals fatigue at a central level.
• It aids the recovery and mitigation of DOMS (Delayed Onset Of Muscle Soreness), thanks to the Leucine action on protein synthesis. DOMS are the characteristic aches that occur 24-36 hours after physical activity, especially following resistance exercises using an opposing force.
• Glycogen-saving, because BCAAs can be used as an energy substrate.
• Anticatabolic properties. The body detects their presence in the blood and does not activate the catabolism of muscle proteins.
Although BCAAs are known primarily for their direct function, i.e. providing energy, they also have more properties.
In fact, they also act as indicators for the body. If their presence in the blood decreases, the body perceives it as a deficiency and reacts by blocking protein synthesis and triggering muscle catabolism.
This effect shows up mainly during a sports activity or when following a severe calorie restriction. BCAAs are therefore essential in various situations that require different amounts and timings to achieve intended goals.
Here are some tips:
Prolonged activities – marathons, long-distance cycling, triathlon –
We recommend using soluble BCAAs, starting the intake before the sports activity and carrying on drinking them, if possible, during the entire activity.
The dosage should be at least 1-1.5 g per 10 kg of body weight, considering whether to increase the dose depending on the duration and the effort required by the exercise.
Endurance training – strength training, body building –
We recommended taking soluble BCAAs before training. You could keep a dose to take immediately after the workout to try to reactivate protein synthesis. To achieve this result, Leucine alone would be more effective.
The dosages of BCAAs to be taken are 1 g per 10 kg of body weight. According to some studies, effective results can be seen in Leucine dosages of 44.5 mg/kg/day and Isoleucine and Valine dosages of 22.25 mg/kg/day.
Hit, Circuit Training, Military
In these physical activities, with explosive gestures repeated over time, BCAAs are particularly effective. To support both the physical and mental efforts required, we recommend higher doses of 1.5 g per kg of body weight.
Prolonged outdoor activities – alpine skiing, cross-country skiing, sailing, hiking –
These activities are carried out over long periods of time, even entire days, during which it is difficult to eat. In order to maintain performance and concentration, a continuous BCAA supply becomes essential, preferably when the Leucine level is high (4:1:1, 8:1:1).
The ideal dosage would be 5 g per hour/hour and a half, when no other protein source is taken.
Fasted training can be planned with the aim of forcing the body to burn fats, or it may take place due to organisational issues. In both cases we recommend taking 1 g of BCAAs per 10 kg of body weight before and during training, especially if it exceeds 60min.
Caloric restrictions are used to reduce fat mass. Taking fewer calories, our body tends to derive the energy and proteins necessary for its functions from the muscles, causing their catabolism. To prevent this from happening and therefore to preserve lean mass, it is essential to take BCAAs, and particularly Leucine. The recommended dosage is 2 g every 3 hours or so.
I principi di biochimica – Lehninger
Fisologia dell’uomo – Conti
ISSN – position stand
ACSM – position stand
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Dr R. Cannataro