Leucine

Leucine deficiency¹

Many disorders of protein metabolism are managed through the restriction of natural protein. Such restrictions can increase the risk of essential amino acid deficiency, particularly if one or more of the following factors apply:

• Tolerance for natural protein is low.
• Due to feeding difficulties, lack of appetite or aversion, the patient consumes even less natural protein than recommended.
• The biological value of the natural protein consumed is low.
• Limited or no use of protein substitutes (for example, in some patients with organic acidaemias) or essential amino acid supplements (for example, in some patients with UCD).

Ongoing monitoring of plasma amino acids is required in patients following low protein diets as part of their dietary management. L-leucine is an essential amino acid; it should be supplemented in the case of an L-leucine deficiency, where other methods of increasing L-leucine intake (e.g. increasing natural protein) are not feasible.