Inhaled corticosteroids are the most common medications for asthma, but their long-term use is associated with considerable side effects: cataracts, bone loss and immune system suppression. The results of the new study suggest that vitamin C supplementation may reduce the amount of steroid drugs used to keep asthma symptoms under control.
The first thing that was determined was whether vitamin C (1 gram daily for 16 weeks) or magnesium (450 mg daily for 16 weeks) could better control asthma symptoms than a placebo in 92 adults with asthma. Vitamin C and magnesium failed to improve symptom control significantly. As previous research had suggested that these nutrients could offer benefits, the authors designed a second part of the study to find out if any of the positive effects of the supplements could have been masked by the drugs, which were not discontinued during the study. To explore this, people continued their supplement (vitamin C, magnesium or placebo) for a period of 10 weeks during which their corticosteroid medication was reduced.
People who took vitamin C were able to reduce the intake of inhaled corticosteroids without losing control of their symptoms. This is important because the side effects of corticosteroids increase the higher the dose. Reducing daily intake, even in small amounts, can prevent some adverse effects. Magnesium was not effective.
The adrenal glands are responsible for the production of corticosteroid hormones in the body. Research suggests that the adrenal glands need vitamin C to make them. Thus, it makes sense that taking a vitamin C supplement can help the body to produce its own adrenal corticosteroids, making it possible to reduce the amount of hormone needed as a drug.