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Branched chain amino acids

(Known as BCAA, Leucine, Valine, Isoleucine, Branched chain amino acids)

The branched-chain amino acids (BCAAs) are leucine, isoleucine, and valine. BCAAs are considered essential amino acids, because human beings cannot survive unless these amino acids are present in the diet. BCAAs are vital for the maintenance of muscle tissue and preserve muscle stores of glycogen (a storage form of carbohydrate that can be converted into energy) [1]. BCAAs also help prevent muscle protein breakdown during exercise [2]. Many endurance athletes (such as long-distance runners and cyclists) also use BCAA during exercise to strengthen their immune system and delay fatigue.

BCAAs help to delay fatigue during exercise, making them suitable for people taking part in sports such as distance running or cycling. Those involved in team sports, such as rugby, football or hockey will also benefit. The beneficial effect of BCAAs on muscle preservation and growth also makes them suitable for anyone wanting to lose fat without losing muscle.During exercise, BCAAs are used up by your body as a fuel source. This leads to an increase in the levels of an amino acid called tryptophan. When tryptophan enters your brain, it leads to feelings of tiredness. Some experts believe that by supplementing with BCAAs during exercise, you can keep exercising at a higher pace for longer. Indeed, several studies show that BCAAs consumed during exercise has a beneficial effect on performance, reducing fatigue and raising energy levels [5, 6, 7]. There is also research showing that BCAAs improve recovery rates between exercise sessions. In one such study, 26 subjects took part in a 30-kilometer cross country race and another 32 subjects ran a full length marathon. In both races, the participants found that BCAAs improved physical performance and helped them recover more quickly.

A Brazilian research team has also shown that BCAAs can strengthen the immune system of elite triathletes [9]. Thirty days of supplementation was enough to reduce symptoms of infection by an impressive 34%. The group was given either six grams of BCAAs or a 'dummy' supplement thirty days before taking part in an Olympic triathlon. Endurance events typically require a high volume of training, and often involve multiple daily workouts, which can weaken the immune system. As such, any supplement offering protection against the ravages of training is something most athletes would find invaluable. The main finding of the study was that the reduced incidence of infection was linked to higher levels of glutamine in the triathletes supplementing with the BCAAs.

BCAA supplementation are also useful in special situations, such as preventing muscle loss at high altitudes and prolonging endurance performance in the heat [3, 4]. In one study, a group of 16 subjects participating in a 21-day trek at high altitude were divided in two groups. One group took BCAAs (5.76, 2.88 and 2.88 grams per day of leucine, isoleucine and valine, respectively) or a placebo. The BCAA group lost significantly less muscle than those using a placebo. Subjects using BCAA lost about 10% more fat compared to the group using the placebo. Arm muscle size tended to increase in the BCAA group, whereas there was a significant decrease of 6.8% in the placebo group. The same tendency was observed for the thigh muscles [3].

Dairy products and red meat contain the greatest amounts of BCAAs, although they are present in all protein-containing foods. Whey protein (particularly whey protein isolates rather than the cheaper concentrates) is especially rich in BCAAs, and has become a staple part of the diet for anyone wanting to build muscle. Because it helps to prevent the loss of muscle, whey protein is also used extensively during weight loss programmes.

Evidence for this comes from research carried in the International Journal of Sports Medicine [8]. Twenty-five competitive wrestlers were assigned to one of several groups. Each group followed a slightly different diet. One of the groups, however, consumed a diet that was high in BCAAs. After 19 days of low-calorie dieting, subjects using BCAAs lost the most weight and body fat.
Approximately 3-5 grams of BCAAs can be taken during exercise (preferably with 30-50 grams of carbohydrate) to delay fatigue and improve exercise performance. Because of the high doses of BCAAs needed to preserve muscle, most experts recommend the use of several servings of whey protein per day instead of consuming BCAA capsules, as whey is very high in BCAAs.Most users report an immediate improvement in performance during extended periods of exercise. Consumed for several months, a diet high in BCAA will reduce the incidence of infection. You can also expect faster muscle growth during periods of intense training, and less muscle loss when attempting to lose weight. To date, no side effects have been reported with the use of BCAAs.BCAAs work especially well at delaying fatigue when combined with carbohydrate and water, and consumed during exercise. Athletes involved in intense training often use several servings of whey protein each day (whey is high in BCAAs) day to prevent muscle loss and increase muscle gain.

1. Blomstrand E, Ek S, Newsholme EA. Influence of ingesting a solution of branched-chain amino acids on plasma and muscle concentrations of amino acids during prolonged submaximal exercise. Nutrition 1996;12:485-90
2. MacLean DA, Graham TE, Saltin B. (1994). Branched-chain amino acids augment ammonia metabolism while attenuating protein breakdown during exercise. American Journal of Physiology, 267, E1010-1022
3. Schena F, Guerrini F, Tregnaghi P. (1992). Branched-chain amino acid supplementation during trekking at high altitude. The effects on loss of body mass, body composition, and muscle power. European Journal of Applied Physiology, 65, 394-398
4. Mittleman KD, Ricci MR, Bailey SP. (1998). Branched-chain amino acids prolong exercise during heat stress in men and women. Medicine and Science in Sports and Exercise, 30, 83-91
5. Hassmén P, Blomstrand E, Ekblom B, Newshomle EA. (1994). Branched-chain amino acid supplementation during 30-km competitive run: mood and cognitive performance. Nutrition, 10, 405-410
6. Blomstrand E, Hassmen P, Ek S. (1997). Influence of ingesting a solution of branched-chain amino acids on perceived exertion during exercise. Acta Physiologica Scandinavica, 159, 41-49
7. Blomstrand E, Hassmen P, Ekblom B. (1991). Administration of branched-chain amino acids during sustained exercise-effects on performance and on plasma concentration of some amino acids. European Journal of Applied Physiology, 63, 83-88
8. Mourier A, Bigard AX, de Kerviler E, Roger B, Legrand H, Guezennec CY. (1997). Combined effects of caloric restriction and branched-chain amino acid supplementation on body composition and exercise performance in elite wrestlers. International Journal of Sports Medicine, 18, 47-55
9. Bassit, R.A., Sawada, L.A., Bacurau, R.F.P., Navarro, F., & Costa Rosa, L.F.B.P. (2000). The effect of BCAA supplementation upon the immune system of triathletes. Medicine and Science in Sports and Exercise, 32, 1214-1219

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