L-Leucine

 

Leucine is an essential amino acid, which cannot be manufactured in the body and is part of the three branched-chain-amino-acids. Supplements and protein powders that contain leucine are used extensively by bodybuilders and other athletes to promote muscle recovery.

Among the most beneficial and effective supplements in any sports nutrition program are the branched chain amino acids which includes the essential amino acids leucine, isoleucine, and valine.

Deficiency of this nutrient is rare, since all protein foods contains it, but vegans and vegetarians without adequate protein sources may suffer from a deficiency. Hypoglycemia symptoms may appear if the diet is deficient and may include dizziness, fatigue, headaches, irritability etc.

Dosage:  The daily dosage of leucine is about 16 mg per kilogram of body weight per day - which would translate to about 1120 mg for a 70 kg male. The dosage listed is the Recommended Daily Allowance (RDA), but be aware that this dosage is the minimum that you require per day, to ward off serious deficiency of this particular nutrient. In the therapeutic use of this nutrient, the dosage is usually increased considerably, but the toxicity level must be kept in mind.

If you are taking a supplement of leucine, keep it in balance with the other two branched-chain-amino-acids isoleucine and valine in the formula of 2 mg of leucine and valine for each 1 mg of isoleucine. Leucine is found in protein foods, as well as brown rice, beans, nuts and whole wheat.

Research:

Leucine may benefit body composition. Researchers from the University of Illinois Urbana-Champaign noted in a review that part of the benefit of a higher protein diet for weight loss may be due in part to increased intake of the branched chain amino acid (BCAA), leucine.1 They noted leucine and the BCAAs aid in regulating both muscle protein synthesis and glycemic control.

In a rat study conducted in Sao Paulo, Brazil, rats recovering from protein malnutrition that received a leucine-rich diet had better body weight recovery than control rats, including collagen recovery.2 And a small study of five lean women compared to five women with abdominal obesity found lower rates of leucine release in obese women following a 22-hour fast, indicating preservation of body protein during weight loss.3

1. Layman DK, Baum JI. "Dietary protein impact on glycemic control during weight loss." J Nutr. 134, 4:968S-73S, 2004.

2. Ventrucci G et al. "Effects of a leucine-rich diet on body composition during nutritional recovery in rats." Nutrition. 20, 2:213-7, 2004.

3. Patterson BW et al. "Regional muscle and adipose tissue amino acid metabolism in lean and obese women." Am J Physiol Endocrinol Metab. 282, 4:E931-6, 2002.