Nutraceuticals to Supplement Duchenne MD Therapies: Fact or Fiction?

Researchers from Australia recently reviewed experimental and clinical data from multiple research projects and clinical trials in an attempt to determine whether nutraceutical supplements could benefit or prolong the health of Duchenne MD patients.

The findings suggest that some of these alternative products could be a valuable complementary therapy for DMD due to their anti-oxidant and anti-inflammatory properties.

Nutraceuticals are food, food groups, or parts of food that provide some health benefit and therefore may contribute to the treatment of diseases.

The review, “Nutraceuticals and Their Potential to Treat Duchenne Muscular Dystrophy: Separating the Credible from the Conjecture,”  was published in the journal Nutrients.

Muscle pathology goes hand-in-hand with increased inflammation and oxidative stress because of the immune system involvement. These conditions, when exacerbated, impact DMD onset and disease progression. As a result, substances with anti-inflammatory and anti-oxidative potential, whether real or speculative, are being studied for DMD patients.

The review focuses on a series of substances, particularly:

• Coenzyme Q10 (CoQ10­)
• Melatonin
• Traditional Chinese medicine
• Soybeans
• Curcumin
• Resveratrol
• Beetroot juice
• L-Arginine
• Vitamin D
• Green tea
• Taurine

Apart from DMD patients, most conclusions were derived from the use of the mdx mouse, which is the most widely used mouse model for DMD.

CoQ10, a natural antioxidant, was the focus of a double-blinded trial for patients and healthy individuals. The study concluded that CoQ10, in combination with corticosteroids, may contribute to muscle strength in DMD patients, though larger clinical trials are required. So far, the only side effect of this substance was moderate, occasional headaches when the CoQ10 dose was very high.

Although melatonin’s antioxidant effects have been known for a long time, its effects on muscle function have not been examined as well, but there is evidence to suggest it may be useful as a supplement for DMD patients.

Chinese herbal supplements – which are not subject to FDA regulation or approval – are sometimes consumed by DMD patients because they are thought to provide strong medicinal benefits. However, these herbs could interfere with DMD treatment therapies or cause adverse cumulative effects. Physicians recommend they should not be consumed by DMD patients, according to the review.

Green tea and green tea extract (GTE) are packed with high doses of polyphenols and have strong antioxidant capabilities. However, any green tea supplements should be monitored by doctors because the potential side effects of GTE could amount to liver toxicity. There is an ongoing clinical trial (NCT01183767) that aims to assess the effects of EGCG, the major polyphenol in green tea, in DMD patients. Another clinical trial (NCT01856868) using GTE in Becker muscular dystrophy patients is also ongoing.

Curcumin is derived from the roots of the turmeric plant and shows anti-inflammatory abilities. In the dmx mouse model, curcumin contributes to a healthier phenotype, but its effects have yet to be tested clinically on DMD patients. It is marketed as a supplement to some cancer patients, as it is considered to have anti-cancer properties.

Resveratrol, an antioxidant in grapes and coffee beans, is thought to increase lifespan. It seems to benefit muscle function in mdx mice, but its rapid metabolism by the liver or intestine limits its bioavailability (the proportion of the drug that actually goes into circulation). Research teams are currently working on improving this.

Unlike all the other substances in the review, beetroot juice and the sodium nitrate it contains have been the focus of only one study. The data suggests this vegetable juice may help decrease stress due to oxidation in DMD patient muscles.

When it comes to L-arginine, most results – albeit promising – are from the mdx mouse model and not from actual DMD patients. However, an open label, single center, proof-of-concept clinical trial with DMD patients concluded that L-arginine had a positive impact on motor function measures and mean 2 minute walking distance in most participating patients.

While the results of taurine supplementation in mdx mice are promising, with statistically significant improvements in grip strength and muscle function, the effects of taurine in DMD patients remain unstudied.

Vitamin D, found in fatty fish, juices and dairy, is important for overall bone  health. There is scientific literature to support the hypothesis that DMD patients may benefit from vitamin D supplements due to their restorative effect on calcium levels which contribute to bone and muscle health.

“While nutraceuticals will never cure DMD, they could have significant potential as complimentary therapies in counteracting the damaging effects of chronic inflammation or oxidative stress,” the review reads.

“A number of nutraceuticals have clinical merit and more research into their therapeutic potential to treat DMD is justified. Whilst corticosteroids are the current therapeutic standard for treating DMD and can prolong ambulation and muscle function, many patients experience serious adverse side effects,” the authors wrote.

“If a nutraceutical could produce similar therapeutic benefits to corticosteroids without adverse side effects, it could provide many DMD patients with an improved quality of life as well as reduce costs associated with recurrent hospital visits to monitor and treat corticosteroid-induced side effects. For this to occur, research needs to focus on performing good quality peer-reviewed research using compounds that have scientific merit and thus separate the credible from the anecdotal conjecture,” the authors wrote, emphasizing the need for future research.