Diet principles - IVA

The main goals of nutritional management in IVA are to prevent metabolic decompensation during metabolic stress, such as illness and fasting, and stabilize and restore metabolic homeostasis by rapidly reducing toxic metabolite leucine to prevent the production of isovaleric acid by achieving or maintaining anabolismRestriction of natural protein, will limit the intake of leucine.

Since leucine does not accumulate in plasma, it is not a marker for the level of restriction on natural protein/leucine intake.

Diet principles^1,2

Limit the intake of dietary of leucine by restricting the natural protein intake to prevent production of isovaleric acid,
- usually a modest protein restriction in infants and young children around 2g protein/kg bodyweight
- and 1 g protein/kg bodyweight in older patients.
In some patients adequate L-amino acid supplementation by a leucine free, L-amino acid supplement is appropriate; including micronutrients, essential fatty acids (EFA) up to a level recommended in the age range, in order to maintain adequate protein status for IVA patients.
Adequate energy intake to promote appropriate growth and weight maintenance and prevent catabolism.
Provision of an emergency regimen during illness, fasting and infections, surgery or increased activity, consisting of high energy diet.
Monitor nutritional status and adjust diet as needed.
Provision of a palatable, varied and ‘easy to maintain’ diet.

IVA Management³
IVA Severe forms	All age groups	Low leucine intake trough low protein diet	Target plasma level: Leucine 50-180 µM or normal range for labatory
IVA Mild forms	All age groups	Reduced natural protein intake Multi vitamins and minerals

References

Dixon MD, MacDonald A, White F, Stafford J. In: Clinical Paediatric Dietetics. 4^th ed: West Sussex: John Wiley & Sons Limited, 2014:381-525.
E-IMD – isovaleric Aciduria: http://www.e-imd.org/en/healthcare-professionals/individual-conditions/organic-acidurias/iva/index.phtml