leucine reduces muscle wastageAmino acids are not only useful for bodybuilders who want to increase their muscle size; they have specific medical benefits. A study, which is currently continuing, has proved that muscular atrophy is reduced by low doses of Leucine. A total of twenty-three amino acids play different roles in the formation of proteins in the body and are called proteinogenic amino acids.

They are not synthesised in the body but need to be ingested in order to be utilised in the liver and the muscles. There are three branched-chain amino acids, or BCAA. Leucine is one, together with Isoleucine and Valine. They play a central role in muscle building and energy supply, and are often used by athletes and others who want to increase physical strength.

All three BCAA should be taken in an appropriate ratio in order to maximise protein synthesis.

Lack of Exercise and Muscle Atrophy

effect of weightlessness on astronautsA NASA-funded study from the University of Texas examined the success rates of one of the BCCAs, Leucine, in preventing muscular atrophy

1. Astronauts working for the US Space Agency often spend months in orbit and are unable to perform effective exercise routines. The study is continuing and is assessing different groups of subjects. The most recently published report from the University of Texas research unit focused on middle-aged and older patients who were bed-bound for some periods of time.

Previous Experience with a High-Dose Mix of Amino Acids and Carbohydrates

Previous studies have found that good results can be achieved with a cocktail of amino acids and carbohydrates. Thirteen healthy adults were given bed rest for twenty-eight days. This led to significant muscle wasting in the subjects, but those taking the amino acid and carbohydrate combination lost only half as much muscle mass as participants who were given a placebo.

The director of this series of large-scale studies, Dr Douglas Paddon-Jones, had some reservations about the practicalities of applying the results. While the substances administered were effective, their unpleasant taste made them unpalatable to bedridden patients, who are usually, in his experience, unable and unwilling to eat sufficient quantities of any food.

Dr Paddon-Jones also raised a cost argument about the considerable expenditure required.

Sole Ingestion of Leucine less Effective, but More Practical

Nuts are rich in BCAAs and leucineIn the most recent investigation, the amino acid and carbohydrate mix was substituted with small doses of Leucine on its own2. This was given to patients of over 45 years old, who were given ten days of bed rest.

Three grams of Leucine was given at breakfast, lunch and dinner contained in 115 grams of lean beef. This was found to be palatable to those with reduced appetite and also cost effective. Dr Paddon-Jones and his team have opted for this Leucine-only method because the amino acid is not only a protein, but has a unique function as a trigger for the activation of protein synthesis pathways to initiate the process of muscle building.

While addressing the loss of muscle with an amino acid only is slightly less effective than the high-dose combination of amino acids and carbohydrates, it offers several advantages. Administration is easier and more easily maintained, with less bloating and discomfort experienced by patients. The final results of this study are currently being prepared for publication and should soon be available.

Related studies:

  1. “Paddon-Jones, Douglas, et al., “dietary protein recommendations and the prevention of sarcopenia – protein, amino acid metabolism and therapy”, Curr Opin Clin Nutr Metab care. 2009 January, 12(1), 86-90″
  2. “Paddon-Jones, Douglas, et al., “Leucine supplementation chronically improves muscle protein synthesis in older adults consuming the RDA for protein”, clinical nutrition, 2012 Aug, 31(4), 512-9″