Importance of Medical Foods and the Alphabet Soup of Inborn Errors of Metabolism

By Joshua Baker, DO, Katherine Kim, MS and Vera Shively, MS, Lurie Children's Division of Genetics, Birth Defects and Metabolism

For people with inborn errors of metabolism (IEMs) medical foods are a necessity, much more than a recommendation for good health. They are often a critical part of a treatment plan.

What are Inborn Errors of Metabolism?

Inborn errors of metabolism are genetic conditions in which an error in the DNA ultimately interferes with normal metabolism. A change in the DNA instructions for one of the enzymes needed for metabolism leads to little or no enzyme being made. This then leads to a buildup of toxins or lack of energy. Although any given IEM is rare, taken as a group of disorders, they occur in about 1 in 2500 births.

There are many different types of IEMs. Their symptoms vary, even within the same condition. This variability depends on the enzyme affected and the degree to which it works. The conditions typically have long names, so abbreviations are common. Examples of this alphabet soup include the following disorders:

  • CPT II (carnitine palmitoyl-transferase II deficiency)
  • MSUD (maple syrup urine disease)
  • OTC (ornithine transcarbamylase deficiency)
  • PKU (phenylketonuria)
  • VLCADD (very-long chain acyl-CoA dehydrogenase deficiency)

Medical Foods Are Treatment (and Costly!)

Medical foods are a form of treatment that is consumed by mouth or given through a feeding tube. They are specially formulated and intended for specific dietary management of conditions like IEMs. The treatment is supervised by healthcare professionals. Treatment plans may also include foods modified to be low in protein, and/or supplements with specific formulations and large doses of vitamins.

To remain healthy, we eat every day, usually three meals per day. The same is true for people with IEMs. Typically, they consume their prescribed medical food every day. There are no cures for IEMs, so treatment plans are lifelong. Medical foods, however, are much more expensive than foods we buy at the grocery store. It is estimated that out-of-pocket costs for medical nutrition products can be up to eight times the cost of normal groceries.

For example, a person with PKU cannot properly process the amino acid phenylalanine (Phe) as needed. Proteins are made of strings of amino acids, including Phe. Foods that are rich in protein like nuts, meat, soy and dairy products have high levels of Phe, and are often eliminated from the diet of a person with PKU. To satisfy their nutritional needs, someone with PKU drinks a special formula (medical food) that contains a blend of nutrients and other amino acids, minus the Phe. The National PKU Alliance estimates the average annual costs to be $10,000 for medical foods for one person with PKU.

Support the Medical Nutrition Equity Act

Unfortunately, many health insurance plans in the United States do not provide reimbursement for the cost of medical foods. For many patients with IEMs, the medical foods that are so important for their health and well-being are not affordable.

The Medical Nutrition Equity Act (H.R. 2501/S. 3657) would mandate private and Federal health programs to cover medical formula and low-protein modified foods for adults and children with inherited metabolic disorders and certain digestive conditions. This bi-partisan bill was reintroduced in the United States Congress in early June 2021 and is currently in Committee. Click here to see if your representative and senators were co-sponsors of the Medical Nutrition Equity Act and learn what you can do to support this important bill.

Additional Information

Learn more about the Division of Genetics, Birth Defects and Metabolism

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