A new protein substitute for adolescents and adults with maple syrup urine disease (MSUD)

J Inherit Metab Dis. 2005;28(5):665-72. doi: 10.1007/s10545-005-0061-6.


Aim: The aim was to study the efficacy and acceptability of MSUD Express in adolescent and adult patients with maple syrup urine disease (MSUD).

Background: There are difficulties associated with current protein substitutes designed for adolescents and adults with MSUD. This can affect their metabolic control. MSUD Express is a new low-volume, nutritionally complete protein substitute, free from leucine, isoleucine and valine and designed specifically for older patients with MSUD.

Methods: Four patients with MSUD were included in the trial (aged 16-41 years). Product dosage was 4 x 25 g sachets per day, providing 1264 kJ and 72 g amino acids: more than adequately meeting requirements for all micronutrients.

Results: At the start of the study, the mean (range) of the previous eight leucine concentrations (on MSUD Aid III) was 564 micromol/L (430-817 micromol/L) and during the study (on MSUD Express) was 382 micromol/L (181-603 micromol/L). The average percentage fall in mean leucine concentrations was 32%. In patients 2, 3 and 4, low leucine levels resulted in an increase in the natural protein allowance per day. MSUD Express was rated as 'excellent' or 'good' by all patients on the basis of appearance, taste, smell and texture. All patients found the product 'very easy' to prepare and found it 'easy' or 'very easy' to take outside the home.

Conclusion: All patients thought the preparation of MSUD Express was 'very easy'. Metabolic control (mean leucine concentrations) improved in all of the patients. In three patients this meant that an increase in the amount of natural protein in the diet was possible. All patients elected to stay on MSUD Express after the trial period. MSUD Express appears to be an effective and acceptable product, offering an alternative to current protein substitutes available for older people with MSUD.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Amino Acids / chemistry
  • Body Weight
  • Diet
  • Diet, Protein-Restricted
  • Dietary Proteins
  • Female
  • Food, Formulated*
  • Humans
  • Isoleucine / chemistry
  • Leucine / chemistry
  • Male
  • Maple Syrup Urine Disease / diet therapy*
  • Maple Syrup Urine Disease / drug therapy
  • Valine / chemistry


  • Amino Acids
  • Dietary Proteins
  • Isoleucine
  • Leucine
  • Valine