VLCAD Nutrition Management Guidelines
First Edition
February 2019, v.1.4
Updated: November 2022
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Nutrition Recommendations
2. For the individual with VLCAD what nutrition interventions are associated with positive outcomes during illness (including cardiomyopathy and rhabdomyolysis), surgery or other stress?
Conclusion Statement
Derived from evidence and consensus based clinical practice

Illness in very-long chain acyl-coA dehydrogenase deficiency (VLCAD) covers a wide spectrum, ranging from minor decompensation in mild VLCAD to cardiomyopathy in severe VLCAD. This guideline includes recommendations for treating symptomatic individuals as well as prophylaxis to prevent illness and inpatient care for those with moderate or severe VLCAD who are prone to developing cardiomyopathy and/or rhabdomyolysis. Most of the evidence about illness management in VLCAD comes from case studies of individuals presenting with cardiomyopathy, rhabdomyolysis, and/or hypoglycemia. There is no published literature on managing illness in mild VLCAD.

For individuals with cardiomyopathy (with or without rhabdomyolysis or hypoglycemia), nutrition intervention often includes supplemental medium chain triglycerides (MCT-enriched formula in infancy or MCT-based supplements) and restricting intake of long-chain fat (LCF). Diet modification is almost always recommended with other interventions (fluids, glucose, L-carnitine, fasting restrictions), making it difficult to assess the impact of any single intervention. A low-fat diet with MCT supplementation or MCT-containing formula has been shown to reverse cardiomyopathy.

The effect of a MCT-supplemented, low fat diet to prevent or reduce episodes of rhabdomyolysis is inconclusive. In some reports of individuals presenting with both cardiomyopathy and rhabdomyolysis, the cardiomyopathy improved with diet modification, but rhabdomyolysis persisted. In other case reports of individuals with late-onset rhabdomyolysis, providing extra carbohydrate (without MCT) improved symptoms.

Home precautions to prevent symptoms in VLCAD include avoiding long periods of fasting through frequent and/or overnight feedings. Use of uncooked cornstarch (UCCS) has been reported in the literature, but is infrequently used among Delphi survey respondents. Avoidance of extreme and prolonged physical exercise appears to be helpful in preventing rhabdomyolysis. Clear guidelines regarding the recommended duration and intensity of exercise are lacking and the emphasis is on providing sufficient energy to support exercise, as tolerated.

In acute illness, fasting duration is reduced as compared to when well. Moreover, early institution of IV dextrose and adequate hydration helps to prevent a metabolic or myopathic crisis and may resolve or improve cardiomyopathy and rhabdomyolysis. Use of IV lipids is contraindicated during an acute illness.

Caregivers should be provided with, and utilize, an emergency protocol in times-of or leading-up-to a symptomatic presentation. Emergency intervention should not wait for detection of hypoglycemia, which is a late finding in VLCAD. For the same reason, home monitoring of blood glucose for presence of hypoglycemia is not recommended.

The use of carnitine and other medications/supplements during illness is discussed in Recommendation 3.

Recommendation 2.1

During illness, adjust the composition of the diet according to the severity of current symptoms:

  • For individuals with VLCAD who were previously asymptomatic but develop complications, restrict LCF according to the severity of the individual's current symptoms (Recommendation 1.2)
  • When treating individuals with acute rhabdomyolysis, emphasize carbohydrate (oral or IV) as an energy source
Strength of Recommendation:
Insufficient EvidenceConsensusWeakFairStrong
Clinical Action:
Recommendation 2.2

For all individuals with VLCAD, employ strategies to prevent conditions that may lead to metabolic decompensation:

  • Counsel individuals with VLCAD and/or their caretakers to space meals and snacks to avoid prolonged fasting and meet energy needs (see recommendation 1.7).
  • Encourage asymptomatic individuals with VLCAD to be physically active, as tolerated, and to increase energy intake prior to and during exercise.
  • Consider gastrostomy-tube placement for individuals with severe VLCAD who have feeding difficulties and are prone to frequent hospitalizations due to inadequate energy intake.
  • Discourage the use of home blood glucose meters to monitor the severity of clinical symptoms, as hypoglycemia is not likely to be the presenting symptom during illness.
  • Provide caregivers with an emergency letter to use when seeking urgent medical care.
Strength of Recommendation:
Insufficient EvidenceConsensusWeakFairStrong
Clinical Action:
Recommendation 2.3

For an individual with VLCAD who has mild illness managed at home (in consultation with medical team):

  • Counsel individuals and their caretakers to provide frequent, high carbohydrate feedings (glucose polymers, or simple or complex carbohydrates) and strive to achieve usual energy intake to prevent catabolism.
  • Decrease fasting duration as compared to when well.
Strength of Recommendation:
Insufficient EvidenceConsensusWeakFairStrong
Clinical Action:
Recommendation 2.4

For individuals with VLCAD who are hospitalized for illness (regardless of cause), in consultation with the medical team:

  • Provide a minimum of 10% IV dextrose with electrolytes at a rate of at least 1.5 times maintenance fluids if the individual is unable to consume adequate energy.
  • Avoid use of L-carnitine in acute illness. 
  • Consider central line placement for improved access in individuals with severe VLCAD/cardiomyopathy who require frequent hospitalizations.
  • Avoid the administration of IV lipids; however, after 7 days a source of essential fatty acids should be provided.
Strength of Recommendation:
Insufficient EvidenceConsensusWeakFairStrong
Clinical Action: