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Branched-Chain Amino Acids

Branched-chain amino acids are essential nutrients. They are in proteins in food. Your muscles "burn" these amino acids for energy.

The specific amino acids that make up the branched-chain amino acids are leucine, isoleucine, and valine. The term branched-chain simply refers to their chemical structure.

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Why do people take branched-chain amino acids?

Athletes may take oral supplements of branched-chain amino acids (BCAAs). They take them to try to help with recovery from workouts and enhance athletic performance.

Studies suggest that BCAAs may prevent muscle breakdown during exercise. But they are not likely to help with athletic performance.

People also take BCAAs as medicine to try to treat problems such as:

  • Muscle wasting
  • Chronic loss of appetite
  • Certain brain disorders

In some cases, health care providers may deliver them intravenously (by IV).

Although more research is needed, BCAAs have been studied and may:

  • Improve appetite in people who are malnourished or have cancer.
  • Lessen episodes of mania in people with bipolar disorder.
  • Improve symptoms related to hepatic encephalopathy or tardive dyskinesia.

It is too early to prove whether BCAAs are helpful for diabetes or an inherited form of autism, two other reported uses.

Dosages of BCAAs vary, depending upon the reason for use. Quality and active ingredients in supplements may vary widely from maker to maker. This makes it hard to establish a standard dose.

Can you get branched-chain amino acids naturally from foods?

You can get branched-chain amino acids from these foods:

  • Whey, milk, and soy proteins
  • Beef, chicken, fish, and eggs
  • Baked beans and lima beans
  • Chickpeas
  • Lentils
  • Whole wheat
  • Brown rice
  • Almonds, Brazil nuts, and cashews
  • Pumpkin seeds

What are the risks of taking branched-chain amino acids?

Side effects. When taken up to six months, oral supplements of BCAAs have not often been linked with harmful side effects. However, side effects may include:

  • Fatigue
  • Loss of coordination
  • Nausea

Risks. BCAAs may interfere with blood glucose levels during and after surgery. You may also be at increased risk if you have chronic alcoholism or branched-chain ketoaciduria.

Also, avoid using BCAAs if you are pregnant or breastfeeding.

Interactions. Talk with your doctor first if you are taking:

Tell your doctor about any supplements you're taking, even if they're natural. That way, your doctor can check on any potential side effects or interactions with medications or foods. He or she can let you know if the supplement might increase your risk.

The FDA does not regulate supplements. However, it has approved an injectable branched-chain amino acid.

WebMD Medical Reference

Reviewed by David Kiefer, MD on December 01, 2012

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