I’m taking a break from my trendy food investigations to investigate a trendy supplement. It claims a wide range of benefits for both endurance and weight lifting athletes. While it’s naturally found in food, it’s often added to gels, protein powders and even drinks. This week, I’m exploring branched chain amino acids (BCAA).
I will start with a brief nutritional science lesson. Protein is made up of different combinations of amino acids. There are 20 different amino acids. Nine of these amino acids are essential. Essential amino acids must be eaten in food because our body can’t make them. BCAA are a group of three amino acids: isoleucine, leucine and valine. BCAA are essential amino acids, so, like mentioned above, we must eat them to meet our body’s needs. BCAA are found naturally in foods that contain protein, like eggs or meat.
Each BCAA plays differing key roles in the body. While the specific role of valine is unclear, leucine plays an important role in muscle synthesis. Isoleucine plays a role in helping glucose go into the cell, so that our bodies can use the glucose for energy. There are many health and sports performance claims with BCAA consumption because unlike the other amino acids, muscle cells can use BCAA for energy. Fatigue prevention, muscle growth promotion and enhanced recovery are all benefits promised with BCAA consumption. However, does research actually support these claims or is it another marketing gimmick?
The claim that BCAA can help prevent fatigue during exercise is made because BCAA in the blood fall during exercise. When BCAA levels fall, it causes tryptophan to influx into the brain, followed by serotonin production. The end result of this is fatigue. The hypothesis is that by taking BCAA during or before exercise, it can prevent the tryptophan influx into the brain and subsequent fatigue. However, studies have only found this benefit for untrained or lightly training athletes during aerobic exercise. The reduced fatigue was not found in advanced athletes. My conclusion: If you’ve never run over a kilometer before and you plan on running a half marathon next weekend, consider taking GU Roctane Energy Gel with added BCAA. However, if you’ve been training all winter and are well prepared, the added BCAA in the sport gels are unlikely to help you. On the other hand, they won’t harm you either.
As mentioned, leucine is the key amino acid that plays a role in making muscle. The threshold for the amount of leucine that builds muscle is about 2-3 grams. Consuming more than 2-3 grams of leucine at once has no additional benefits for muscle growth. To put this into context, ¾ cup of cottage cheese contains 2.3 grams, 100 grams of chicken has 2.4 grams and 1/3 cup of soy nuts contains 1.6 grams. Leucine has also been shown to be as effective as a high dose of protein to promote muscle growth. If you don’t have access to a food source containing about 20-30 grams of protein after exercise, a BCAA supplement containing 2-3 grams of leucine could be used instead to stimulate muscle growth.
The role of BCAA in reducing muscle soreness after exercise is not as promising. Most studies showed no significant influence on muscle soreness 2-3 days afterwards when BCAA supplements were taken before exercise. Unfortunately, recovery tactics such as ice baths and rest are still the best bets for post-exercise soreness rather than taking a BCAA supplement.
BCAA supplementation is unnecessary for people with a high protein intake (1-1.5 g/kg/day) because they are likely getting enough BCAA through diet. If you do choose to take a BCAA supplement, here are the general dosing guidelines:
· Isoleucine: 48-72 mg/kg of body weight
· Leucine: 2-3 grams
More research is needed regarding proper dosage for valine and possible reasons for supplementation. The supplement will probably come in a combination dose of all three BCAA. Look for a ratio of leucine: isoleucine: valine of 2-3:1:1.
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