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June 2013

Vitamin C Studied For Charcot-Marie-Tooth Disease

Ascorbic acid treatment has been evaluated for the improvement of nerve damage associated with Charcot-Marie-Tooth disease type 1A (CMT1A), according to a study.

Ascorbic acid, commonly known as vitamin C, is needed by the body to form collagen in bones, cartilage, muscle, and blood vessels, and to promote the absorption of iron. Dietary sources of vitamin C include fruits and vegetables, particularly citrus fruits such as oranges. Severe deficiency of vitamin C causes scurvy. Although rare, scurvy includes potentially severe consequences and can cause sudden death. Patients with scurvy are treated with vitamin C and should be under medical supervision. Many uses for vitamin C have been proposed, but few have been found to be beneficial in scientific studies. In particular, research on asthma, cancer, and diabetes remains inconclusive, and no benefits have been found for the prevention of cataracts or heart disease.

Charcot-Marie-Tooth disease (CMT) is an inherited disorder that causes nerve damage, or neuropathy, that worsens over time. The disease affects the myelin sheath, which is the fatty substance that insulates the nerves. Myelin is needed to transmit impulses along nerve cells. In CMT, genetic mutations cause the peripheral nerves to become damaged or the myelin to become dysfunctional, which makes the nerves vulnerable to damage. The disorder typically causes muscle weakness and sometimes numbness in the arms, legs, hands, and feet. Symptoms usually develop during adolescence or early adulthood, but they may occur at any time from early childhood into middle age. CMT is the most common hereditary form of peripheral neuropathy, affecting about one in 2,500 people worldwide. It is estimated that 150,000 people in the United States have CMT.

In the current study, researchers set out to compare ascorbic acid to placebo in the treatment of CMT1A. CMT Type 1 affects the myelin sheath, CMT Type 2 affects the nerve axon itself. There are many CMT types and sub-types. They recruited 110 people between the ages of 13-70 and randomly assigned them to receive either four grams of ascorbic acid daily or a matching placebo. The team wished to determine whether ascorbic acid treatment might reduce worsening on the CMT Neuropathy Score (CMTNS) by at least 50 percent over a period of two years, compared to a natural history control group who had neither treatment nor placebo.

The results suggested that the average two-year change in the CMTNS for both the ascorbic acid and placebo groups was better than natural history. The researchers reported that this change was well below the 50 percent reduction of CMTNS worsening from natural history.

The team concluded that subjects in both the treatment and placebo groups performed better than natural history. However, they stated that it seems unlikely that the findings support the need for a larger trial to further evaluate this dose of ascorbic acid in treating CMT1A.

Among the many integrative therapies that have been studied for neuropathy are alpha-lipoic acid, which is supported by strong scientific evidence, and gamma linolenic acid and magnet therapy, which are both supported by good evidence.

For more information about CMT, please visit Natural Standard's Medical Conditions database.

References

  1. Lewis RA, McDermott MP, Herrmann DN, et al. High-Dosage Ascorbic Acid Treatment in Charcot-Marie-Tooth Disease Type 1A: Results of a Randomized, Double-Masked, Controlled Trial. JAMA Neurol. 2013 Jun 24:1-7. doi: 10.1001/jamaneurol.2013.3178. [Epub ahead of print] 
  2. Natural Standard: The Authority on Integrative Medicine. 

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