BCAA - Branched Chain Amino Acids

BCAAs can active glutamate dehydrogenase—an enzyme that is deficient in amyotrophic lateral sclerosis (ALS), also called Lou Gehrig’s disease. In one double blind trial, 26 grams per day of BCAA supplements helped those with ALS maintain muscle strength.¹⁵ However, a larger study was ended early when people using BCAA not only failed to improve, but experienced higher death rates than the placebo group.¹⁶ Other studies have shown no benefit of BCAA supplementation for ALS or other neuromuscular diseases.^17 18

One study investigating the advantages of BCAA supplementation for diabetics undergoing an intense exercise program found no additional benefit of BCAA on reducing abdominal fat or improving glucose metabolism.¹⁹

Patients with liver diseases that lead to coma—called hepatic encephalopathy—have low concentrations of BCAAs and excess levels of certain other amino acids. Preliminary research suggested that individuals with this condition might be helped by BCAAs. Double blind studies have produced somewhat inconsistent results,^20 21 22 but a reanalysis of these studies found an overall benefit for the symptoms of encephalopathy.²³ Therapeutic effects of BCAAs have also been shown in children with liver failure²⁴and adults with cirrhosis of the liver.²⁵ Any treatment of people with liver failure requires the direction of a physician.People with chronic renal failure may also benefit from BCAA supplementation.

A preliminary study found improved breathing and sleep quality in people given intravenous BCAAs during kidney dialysis.²⁶

Phenylketonuria (PKU) is a genetic disease that allows abnormally high amounts of phenylalanine and its end products to accumulate in the blood, causing damage to the nervous system. A controlled trial demonstrated that regular use of BCAAs by adolescents and young adults with PKU improved performance on some tests of mental functioning.²⁷

Where are they found? Dairy products and red meat contain the greatest amounts of BCAAs, although they are present in all protein-containing foods. Whey protein and egg protein supplements are other sources of BCAAs. BCAA supplements provide the amino acids leucine, isoleucine, and valine.

Who is likely to be deficient? Only an individual deficient in protein would become deficient in BCAAs, because most food sources of protein supply BCAAs. Few people in Western societies are protein deficient.

How much is usually taken? Most diets provide an adequate amount of BCAA for most people, which is about 25–65 mg per pound of body weight.^28 29 Athletes involved in intense training often take 5 grams of leucine, 4 grams of valine, and 2 grams of isoleucine per day to prevent muscle loss and increase muscle gain, though most research does not support this use of BCAAs.

Are there any side effects or interactions? Side effects have not been reported with the use of BCAAs, except in the one study of ALS described above. At high intakes, of BCAAs are simply converted into other amino acids, used as energy, or converted to fat for storage. However, individuals with kidney or liver disease should not consume high intakes of amino acids without consulting their doctor.

At the time of writing, there were no well-known drug interactions with branched-chain amino acids.
Do branched-chain amino acids really work to increase muscle gain? A 1997 study published in the Italian journal Medicina Dello Sport investigated the effect of taking supplemental branched-chain amino acids (leucine, isoleucine, and valine) on bodybuilding progress. The study involved 31 male bodybuilders between ages 18 and 34, all of whom were drug-free. All these athletes had at least two years of training experience, and were divided into two groups: 16 subjects ingested a placebo and 15 others ingested 0.2g per kilogram (2.2 pounds) of a branched-chain amino acid supplement 30 minutes before training and 30 minutes after the workout.

The results showed that while body weight increased in both groups, those taking the BCAA supplement showed greater weight gains. Analysis of the composition of this weight increase in the BCAA group showed an increase in muscle mass in both the legs and arms, with no changes in the trunk area of the body. In contrast, those taking the placebo showed no muscle mass gains in these areas. The BCAA group also showed strength gains in both the squat and bench press, while those ingesting the placebo got stronger only in the squat exercise.

Dosage Guidelines: The authors of the study to suggest that BCAAs are best taken in two doses of 0.2 g/kilogram of body weight , prior to and after training.