Branched-Chain Amino Acids (BCAA)

One 2013 study in Japan has suggested that high dietary intake of BCAAs could decrease the risk of diabetes 2 ^[9].

BCAAs Supplements

BCAAs supplements are available as tablets, capsules, powder, drink and a solution for intravenous injection. They can be included in “protein powder” products or combined with creatine, glutamine or other amino acids.

BCAAs in supplements are in the free-form, which means they are not linked with each other like in proteins, so they do not need to be digested and can appear in the blood ad muscles much quicker than BCAAs from foods ^[12].

There is INSUFFICIENT EVIDENCE about the effectiveness of BCAAs supplements in reducing fatigue, improving concentration, in the treatment of diabetes 2 and spinocerebellar degeneration ^[1], promoting weight loss or fat loss ^[6,7] or treatment of hepatic encephalopathy (brain disorder in individuals with severe liver disease, mainly in alcoholics) ^[8] .

BCAAs supplements are POSSIBLY INEFFECTIVE in enhancing athletic performance ^[11], treatment of amyotrophic lateral sclerosis (ALS) [1] or treatment of muscle recovery after prolonged bed rest ^[5].

Dosage

• For chronic hepatic encephalopathy, tablets up to 25 grams per day, or intravenous injection of a BCAA solution, 80-120 g/day
• For mania, a drink with a BCAA mixture, 60 grams for 7 days
• For anorexia during hemodialysis, BCAA granules, 3 x 4 g/day
• Reference ^[1]

Uses

Bodybuilders and runners often use BCAAs. Sport doctors often recommend taking BCAAs pre- and post- workout to enable optimal muscle regeneration ^[11]. Again, several reviews have shown that BCAAs do not increase athletic performance ^[1,11].

BCAAs Safety: Side Effects, Toxicity

BCAAs supplements appear to be safe to use in children and adults according to studies lasting for up to 6 months. Side effects may include fatigue, nausea and muscle incoordination ^[1].

Allergic reactions to BCAAs supplements are possible but would be much more likely caused by added substances than BCAAs themselves.

Safety During Pregnancy and Breastfeeding

Pregnant and breastfeeding women should avoid BCAAs supplements since their safety during these periods has not been studied well ^[1].

Who else should avoid BCAAs supplements?

• Anyone drinking a lot of alcohol; BCAAs triggered hepatic encephalopathy in one case ^[1]
• Individuals with amyotrophic lateral sclerosis (ALS, Lou Gehrig’s disease)
• Individuals with  branched-chain keto aciduria, also known as maple syrup urine disease (MSUD); they should also have a low-BCAAs diet ^[2]
• Infants with idiopathic hypoglycemia
• Individuals scheduled for surgery in the next two weeks
• Main reference: ^[1]

BCAAs-Drugs Interactions

BCAAs supplements may ^[1]:

• Decrease absorption of levodopa
• Increase the glucose-lowering effect of anti-diabetic drugs, such as glipizide and insulin.

Maple Syrup Urine Disease (MSUD)

Maple syrup urine disease (MSUD) is a rare genetic disease with an inability to break down branched-chain amino acids (BCAAs) leucine, isoleucine and valine due to a lack of appropriate enzymes, so they accumulate in the blood and may affect the brain and other organs ^[14].

Symptoms, which develop from the 4th day to the second week after birth, include maple syrup smelling urine, poor appetite, vomiting and lethargy ^[14]. Mild and severe forms of the disease exist. If untreated, seizures, coma or death may occur. Brain damage can result in mental retardation. Blood tests show increased levels of leucine, isoleucine and valine, and the presence of alloisoleucine. There is no treatment; symptoms can be prevented by a life-long diet low in leucine, isoleucine and valine. With a strict diet, children may survive until adulthood.