*Note: The opinions expressed by the key opinion leaders in this article are their own and should not be construed as being those of their university.
Multiple sclerosis (MS) is a chronic inflammatory disorder of the central nervous system that affects approximately 400,000 Americans. Despite the existence of many FDA-approved disease-modifying therapies, most patients with MS still experience disability and persistent symptoms. As a result, many MS patients will use adjunctive therapies, such as vitamins and dietary supplements. Recent surveys suggest that most patients with MS are interested in using vitamins and dietary supplements, and more than half are already doing so.
“Considering the widespread use of supplements by patients with MS, it’s important to critically review the evidence behind such use,” explains Emily Evans, MD. For an article published in JAMA Neurology, Dr. Evans teamed with Anne H. Cross, MD, and Laura Piccio, MD, PhD, to develop a review that informs clinicians on the current evidence regarding common vitamins and dietary supplements that may be used by patients with MS. “This information can augment care and assist clinicians in their counseling of MS patients on the efficacy and safety of these agents,” Dr. Evans says.
The research team examined biological plausibility, preclinical animal studies data, human studies data, and safety issues for 24 vitamins or supplements in their review. Specifically, they reviewed vitamins A, C, D, E, K, and the various B vitamins as well as caffeine, carnitine, coenzyme Q, creatine, curcumin, ginkgo biloba, green tea extract, lipoic acid, polyunsaturated fatty acids, probiotics, and resveratrol.
Benefits With Vitamin D
According to the review, vitamin D was the only supplement or extract with strong scientific evidence from clinical studies as an effective adjunctive therapy among patients with MS (Table). “Evidence shows that inadequate vitamin D could be harmful and vitamin D supplementation may decrease MRI lesions in patients with MS,” says Dr. Cross. “Several studies support the routine use of vitamin D supplements for MS patients, and larger-scale, more definitive clinical trials are ongoing. Hopefully, results from these studies will shed more light on this important issue.”
The authors also found promising results from small clinical trials using several other compounds, including biotin and lipoic acid, which are summarized in their review. “Ongoing clinical trials are investigating some compounds—including biotin, lipoic acid, and probiotics—in people with MS,” adds Dr. Evans.
More safety and efficacy data on vitamins and dietary supplements in MS are needed because there is currently not enough supportive evidence for many of these agents. “We found several examples of vitamins and supplements that appeared promising in animal models of MS, but they have only been tested in small numbers of people with MS or not at all in MS,” says Dr. Evans. “Some agents, such as riboflavin and niacin, may be good candidates for further research.”
Dr. Cross says physicians should recognize that many vitamins and supplements have side effects or potential toxicities. “For example,” she says, “some compounds can have toxic effects, especially vitamins A, B6, and E and green tea extract. Taking high doses of vitamin B6 can cause peripheral neuropathy. Vitamin E, polyunsaturated fatty acids, and resveratrol may increase bleeding risks. High doses of biotin (vitamin B7) can alter laboratory results. Carnitine, lipoic acid, and some other compounds can interact with certain medications. Considering these potential risks, physicians should specifically ask their patients with MS about vitamins and supplements they take and at what dose. Some patients may not feel the need to disclose over-the-counter medications unless they’re directly asked about them.”
“One surprising finding of our study was that the tolerable upper limit of intake is unknown for biotin and most dietary supplements reviewed,” adds Dr. Evans. “It is critical that future investigations provide information on potential toxicities and drug interactions for these substances.”