Management
Guidelines
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VLCAD Nutrition Management Guidelines
First Edition
February 2019, v.1.0
Current version: v.1.1
Updated: February 2019
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Nutrition Recommendations
Question
1.  For healthy individuals with VLCAD, what nutrient intake goals are associated with positive outcomes?
Conclusion Statement
Derived from evidence and consensus based clinical practice

Very-long chain acyl-coA dehydrogenase deficiency (VLCAD) presents in a continuum of phenotypes ranging from a "severe" neonatal presentation with cardiac complications to a "mild" late-onset presentation of exercise intolerance. Medical nutrition therapy for individuals with VLCAD depends on the severity of the enzyme deficiency, but typically includes restricting the intake of long-chain fatty acids by limiting the intake of dietary fat, supplementing with medium chain triglycerides (MCT) and avoiding excessive fasting. The goals of nutrition therapy are to reduce the production of abnormal fatty acid metabolites and provide a fat source as MCT to by-pass the enzymatic block in β-oxidation, thus preventing the reliance on glucose stores and production of ketones as a source of energy. Nutrition therapy can reduce clinical complications associated with untreated VLCAD, including hypoglycemia, cardiomyopathy and rhabdomyolysis.

Evidence for medical nutrition therapy for VLCAD is based primarily on expert opinion and limited case series, many of which report outcomes for individuals diagnosed prior to the availability of newborn screening (NBS) for this disorder. Newer reports suggest that dietary changes for well-appearing infants with a positive NBS for VLCAD may not be necessary; however, specifics and consensus are limited. For neonates who develop clinical symptoms prior to diagnosis, breastfeeding or regular infant formula should be discontinued and a source of MCT added, preferably from a low-long chain fat (LCF), high MCT medical formula. If confirmatory testing suggests a severe or moderate phenotype, but the infant remains asymptomatic, a combination of breastfeeding and a MCT-supplemented formula may be possible. Infants remaining asymptomatic with confirmatory testing suggesting a milder form of VLCAD may tolerate breastfeeding ad lib without supplemental MCT.

The suggested diet composition for the healthy individual varies with age and severity of VLCAD. Energy requirements are not typically higher than those recommended by the Institute of Medicine (EER/DRI) guidelines. However, lower energy intake may be necessary for those with reduced lean body mass. Most evidence does not suggest the need for restriction of total fat, but rather modification in fat composition is recommended. Limits for LCF sources are dictated by the severity of the disorder, and then sources of MCT are added to meet total fat needs. Those with a mild phenotype may not require any modification in dietary fat composition. Minimally, protein requirements need to meet the DRI for age. Some preliminary evidence suggests a higher protein and lower carbohydrate diet may increase lean body mass and reduce body lipid content in those with disorders of long-chain fatty acid oxidation (LC-FAOD); however, further study is needed before specific recommendations for higher protein can be established for those with VLCAD.

All healthy individuals with possible and confirmed VLCAD should avoid long periods of fasting, regardless of severity of disease. Recommended fasting times vary, but intervals ranging from 3 to 4 hours between feedings are suggested for asymptomatic infants during the neonatal period. At 9 to <12 months of age, recommended night-time fasting ranges from 8 to 10 hours and after 12 months of age, maximum fasting ranges from 10 to12 hours. For those with a severe phenotype, fasting limits should be set at the low end of the recommended range.

There is little evidence to support the routine use of uncooked cornstarch as a component of medical nutrition therapy for VLCAD. A snack containing complex carbohydrate is preferred if a bedtime feeding is necessary to prevent metabolic decompensation after an overnight fast. Those with VLCAD on a LCF-restricted diet are at risk for essential fatty acid and fat-soluble micronutrient deficiencies; however, supplementation is not necessary unless there is documented low intake or lab confirmation of a nutrient deficiency.

Recommendation 1.1

For neonates with suspected VLCAD, initiate fasting precautions while awaiting confirmation of the diagnosis. Asymptomatic neonates can continue to breast feed (or feed expressed breast milk) without MCT supplementation, if appropriate fasting precautions are followed (RECOMMENDATION TABLE #7, Recommendations for Fasting Intervals for Individuals with VLCAD when well).

Strength of Recommendation:
Insufficient EvidenceConsensusWeakFairStrong
Clinical Action:
ConditionalImperative
Recommendation 1.2

Consider age, disease severity and clinical history when establishing nutrition prescriptions for dietary fat composition (RECOMMENDATION TABLE #8, Recommended Fat (total, long chain and medium chain), Energy and Protein Intakes for Individuals with VLCAD when Well).  (For breastfeeding recommendations-see Recommendation 1.6)

  • When designing a diet for an individual with VLCAD, aim for, but do not exceed, the TOTAL fat intake recommended by the DRI for age. Total fat includes both LCF and MCT.
  • For individuals with a MILD form of VLCAD, it is not necessary to replace some of the LCF in the diet with MCT, as long as the individual remains asymptomatic and follows guidelines for fasting and illness management.
  • For individuals with a MODERATE form of VLCAD, restrict LCF to 15 to 30% of estimated energy needs considering age, disease severity and clinical history. 
  • For individuals with a SEVERE form of VLCAD, restrict LCF to 10 to 15% of estimated energy needs considering age, disease severity and clinical history.
  • Decreasing LCF below 10% of total energy intake may not provide additional clinical benefit, even for those with a SEVERE phenotype.
  • After LCF needs are determined, add a source of MCT to meet the individual's total fat needs.
Strength of Recommendation:
Insufficient EvidenceConsensusWeakFairStrong
Clinical Action:
ConditionalImperative
Recommendation 1.3

For infants and children with VLCAD who are healthy and gaining appropriate weight for age, use the Institute of Medicine Estimated Energy Requirement (EER) calculation for age and physical activity level (PAL) to estimate energy needs (RECOMMENDATION TABLE #8, Recommended Fat (total, long chain and medium chain), Energy and Protein Intakes for Individuals with VLCAD when Well).

Strength of Recommendation:
Insufficient EvidenceConsensusWeakFairStrong
Clinical Action:
ConditionalImperative
Recommendation 1.4
Strength of Recommendation:
Insufficient EvidenceConsensusWeakFairStrong
Clinical Action:
ConditionalImperative
Recommendation 1.5

Use standard equations to determine fluid requirements for an asymptomatic individual with VLCAD.

Strength of Recommendation:
Insufficient EvidenceConsensusWeakFairStrong
Clinical Action:
ConditionalImperative
Recommendation 1.6

Support breastfeeding of infants with VLCAD, taking into consideration the following:

  • For an asymptomatic infant with a MILD form of VLCAD, allow breastfeeding (or expressed breast milk) without MCT, as long as breast milk supply remains adequate, age appropriate weight gain is maintained, and fasting recommendations are followed.
  • For an asymptomatic infant with a MODERATE form of VLCAD, allow breastfeeding (or expressed breast milk) but consider supplementing breast milk with a low LCF, high MCT medical food. (RECOMMENDATION TABLE #5, Medical Foods for the Nutrition Management of VLCAD).
  • For an asymptomatic infant with a SEVERE form of VLCAD, the primary source of nutrition should be a low long-chain fat, high MCT medical food.
  • For a symptomatic infant, depending on the severity of symptoms and lab monitoring, consider allowing some breast milk while using a low LCF, high MCT medical food to meet energy needs.
  • If breastfeeding was discontinued during metabolic decompensation, consider reintroduction of partial breast feeding (or expressed breast milk) after the infant returns to an asymptomatic clinical state, if the mother's breast milk supply remains adequate to do so.
Strength of Recommendation:
Insufficient EvidenceConsensusWeakFairStrong
Clinical Action:
ConditionalImperative
Recommendation 1.7

Advise all individuals with VLCAD to avoid excessive fasting, taking into consideration the severity of disease (RECOMMENDATION TABLE #7, Recommendations for Fasting Intervals for Individuals with VLCAD when well).

Strength of Recommendation:
Insufficient EvidenceConsensusWeakFairStrong
Clinical Action:
ConditionalImperative
Recommendation 1.8

Consider an individual's age, dietary LCF restriction and plasma or red blood cell (RBC) fatty acid profiles to determine if additional sources of essential fatty acids are required:

Strength of Recommendation:
Insufficient EvidenceConsensusWeakFairStrong
Clinical Action:
ConditionalImperative
Recommendation 1.9

Supplementation with uncooked cornstarch (UCCS) at bedtime is not indicated in the treatment of VLCAD since hypoglycemia is not likely to develop when an individual is asymptomatic, if he/she avoids excessive periods of fasting and meets energy needs.

  • To meet fasting guidelines and prevent catabolism in children and adults, consider adding a bedtime snack emphasizing complex carbohydrates.
  • For those with a severe phenotype who do not tolerate extended fasting times, an overnight enteral feeding should be considered when a bedtime snack is not sufficient.
Strength of Recommendation:
Insufficient EvidenceConsensusWeakFairStrong
Clinical Action:
ConditionalImperative
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