Leucine is an essential amino acid. It’s designation as essential means that is it an amino acid that cannot be made by humans and so is essential to the human diet. But according to a growing body of scientific research, leucine may be essential to preventing age related muscle loss.
Age Related Muscle Loss
Muscle in adults is constantly being built and broken down. When we are young, our bodies keep these two processes in balance. But as we age, the balance starts to shift towards the breakdown side of the equation. This process is similar to the situation that many women face with osteoporosis. However, numerous studies are showing that the addition of the amino acid leucine to the diet of aging individuals can reverse this condition.
According to the research:
- Leucine stimulates new muscle growth
- Leucine is the major amino acid responsible for the muscle producing capability of food
- Adding leucine to a meal increases muscle growth by 50 to 70 percent
- Leucine works best when taken with a mixed carb / protein meal. This is due to:
- The insulin surge that comes from the carbohydrates in the meal, and…
- The other essential amino acids are present.
- Leucine does not work as well with carb-only or protein-only meals
- The change in leucine levels in the blood seems to be more important than the overall amount. Therefore, it is better to take a small serving of leucine with a meal (level of leucine increases), wait a few hours (let the leucine levels drop), and then take another serving with some food (levels increase again).
Leucine supplementation has also shown to be effective as a supplement for athletes interested in adding functional muscle mass.
I am usually very hesitant to recommend any form of supplements. In most cases, I feel that our nutritional needs can be met with whole foods.
However, in this case, the upside of leucine supplementation is very strong and, to this point, there doesn’t seem to be any downside. I will be “guinea-pigging” this supplement on myself and a few of my clients. I will report back with the results..
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- Stipanuk, Martha H. Leucine and protein synthesis: mTOR and beyond. Nutrition Reviews. 2007;Mar;Vol. 65, No. 3:122-9.
- Paddon-Jones D, et al. Amino acid ingestion improves muscle protein synthesis in the young and elderly. Am J Physiol Endocrinol Metab. 2004 Mar;286(3):E321-8.
- Tipton, KD, et al. Postexercise net protein synthesis in human muscle from orally administered amino acids. Am J Physiol. 1999 Apr;276(4 Pt 1):E628-34.
- Rasmussen BB, Phillips SM. Contractile and nutritional regulation of human muscle growth. Exerc Sport Sci Rev. 2003 Jul;31(3):127-31.
- Rieu, Isabelle. Leucine supplementation improves muscle protein synthesis in elderly men independently of hyperaminoacidaemia. J. Physiol. 2006;575;305-15.
- Blackwell Publishing Ltd.. “Feeling Old? Supplement Diet With Leucine Prevents Muscle Loss Linked To Aging.” ScienceDaily 4 December 2005. 3 October 2008
- University Of Illinois At Urbana-Champaign. “Eating Proper Foods At Right Time After Exercise Can Speed Recovery.” ScienceDaily 13 July 1999. 3 October 2008