Alpha-Lipoic Acid Useful in Treating Burning Mouth Syndrome

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Alpha-Lipoic Acid Useful in Treating Burning Mouth Syndrome
by: Dr. Richard L. Wynn is Professor of Pharmacology at the University of Maryland Dental School.

Alpha-lipoic acid, a nutritional supplement, appears to be effective in treating burning mouth syndrome. A dose of alpha-lipoic acid (600 mg per day for 30 days) resulted in various levels of improvement in patients with symptoms of burning mouth syndrome compared to similar individuals receiving a placebo. This is according to the Cochrane Database of Systematic Reviews.

In 2005, the Cochrane Database published a review on interventions for the treatment of burning mouth syndrome (Cochrane Database Systematic Review 2005; Jan 25 (1):CD002779). Among the interventions reviewed were the effects of alpha-lipoic acid. The Cochrane Database of Reviews, which searches various databases of published clinical trials, has concluded that this over-the-counter nutritional supplement may be beneficial as an intervention to reduce the burning and discomfort associated with burning mouth syndrome.

The Cochrane Database of Systematic Reviews is a product of the Cochrane Collaboration. The Cochrane Collaboration is a global network of volunteers who systematically review the effects of health care interventions published in the Cochrane Library. The library contains regularly updated, evidenced-based healthcare databases. The Database of Systematic Reviews brings together all the currently available Cochrane Reviews and is updated quarterly. Health care topics which have been reviewed in the past can be accessed at www.cochrane.org.

Burning mouth syndrome (BMS) is a burning sensation on the lips, tongue, or within the mouth when the cause is unknown and it is not a symptom of another disease. Additional symptoms include dryness and altered taste. The incidence of burning mouth syndrome in the general population varies between 0.7% and 15%. Postmenopausal women seem to be at the highest risk.

The Cochrane study reviewed the effectiveness of alpha-lipoic acid versus placebo for relief of symptoms and improvement in quality of life. Outcomes measured were the relief of burning or discomfort and changes in taste, and changes in feeling of dryness in the mouth.

A study of 42 patients with BMS compared alpha-lipoic acid 600 mg/day with a dummy pill in a 30-day trial designed as a randomized controlled trial, and was open label, in that the investigators knew the treatments used. A second trial compared alpha-lipoic acid 600 mg/day with a dummy pill over a 2-month period, and was also open label. A third trial was a double-blind protocol which compared alpha-lipoic acid with two active control interventions, lactoperoxidase mouthrinse and bethanecol, and a placebo group (xylitol in distilled water).

Results
In the 30-day trial, 21 patients were randomized to either the alpha-lipoic acid group or the dummy pill group. Outcomes were assessed according to changes in BMS symptoms (worsening, unchanged, slight improvement, decided improvement, resolution). After trial completion, 16/21 (76%) patients in the treatment group demonstrated some level of improvement; 7/21 slight improvement; 9/21 decided improvement; 5/21 remained unchanged. In the dummy pill group, only 3/21 patients demonstrated slight improvement; 14/21 remained unchanged; and 4/21 developed worse symptoms.

In the second trial, which compared alpha-lipoic acid 600 mg/day with a dummy pill over a 2-month period, 29/30 (97%) of those receiving alpha-lipoic acid showed some level of improvement at 2 months; 3/30 slight improvement; 22/30 decided improvement; 4/30 complete resolution. Only 12/30 (40%) of those receiving the dummy pill showed slight improvement.

The third trial was a 60-day trial of alpha-lipoic acid compared to the active control interventions lactoperoxidase, bethanecol, or a placebo. At trial completion, 18/20 (90%) of the patients receiving alpha-lipoic acid showed some level of improvement in symptoms; 2/20 slight improvement; 16/20 decided improvement. Four patients reported heartburn in this group. No improvements were seen in patients receiving lactoperoxidase or placebo. Two patients receiving bethanecol had sight improvement in symptoms.

The Cochrane Review concluded that all three trials showed a statistically significant improvement with alpha-lipoic acid. The Review cautioned, however, that the nature of the outcomes assessment (the relief of burning or discomfort and changes in taste, and changes in feeling of dryness in the mouth) was very subjective and the results should be interpreted with caution.

Since the early 1990s, alpha-lipoic acid has been used as a dietary supplement, typically at doses in the range of 100?200 mg/day. Alpha- lipoic acid is an essential cofactor for many enzyme complexes that regulate various cellular reactions. The molecule consists of a carboxylic acid and a cyclic disulfide structure. It is essential for aerobic life and is a common dietary supplement. Dihydrolipoic acid is the reduced form of alpha- lipoic acid, and is sometimes also called lipoic acid. One of the most visible roles of lipoic acid is as a cofactor in aerobic metabolic pathways, specifically the pyruvate dehydrogenase complex. This complex links the glycolysis metabolic pathway in the cell cytoplasm to the citric acid cycle in the cell mitochondria.