Tuesday, 17 July 2012

Vitamin D Deficiency and Asthma Management

Scientists have discovered that children who regularly take inhaled corticosteroids to manage their asthma have worse lung function if they are deficient in vitamin D. Along with all its other benefits vitamin D is known to reduce inflammation, and corticosteroids do the same thing. Together they seem to be very beneficial in calming the inflamed airways that are present in asthma.

Another interesting piece of research showed the effect of vitamin D deficiency in STRA children. These children have severe therapy-resistant asthma and form 5 to 10% of the childhood asthma population. A study performed with STRA children found that they had a lower vitamin D level in their blood than children who were responding to therapy. In addition, the muscles surrounding the airways in the non-responsive children showed structural changes, including an increase in mass. The vitamin D deficiency may have been responsible for the muscle changes, although more research is needed to confirm this.

An inhaled corticosteroid: photo by author
Asthma is a very unpleasant - and sometimes very dangerous - disorder. During an asthma attack the linings of the airways leading to the lungs become inflamed and swollen, and there is an increase in mucus production. The flow of air into the lungs is reduced. In addition, in a severe attack the muscles around the airways tighten, causing the airways to narrow and making it very hard for the affected person to inhale air. Asthma attacks range for mild to life-threatening. Symptoms include wheezing, coughing, shortening of breath and a tight feeling in the chest.

People with asthma have some degree of inflammation in their airways even when they’re not having an asthma attack. Taking inhaled corticosteroids reduces and controls this inflammation, and vitamin D may enhance the effect of the corticosteroids.

Our bodies make vitamin D when ultraviolet radiation from sunlight hits our skin. However, this same radiation can cause sunburns, skin aging and skin cancer. Health experts tell us we should all be wearing protective sunscreen when we go outside. The sunscreen interferes with vitamin D manufacture, however, so for many of use the regular use of a vitamin D supplement is necessary. This is especially important for people who live in areas with short summers or who cover their skin for religious reasons. It’s also important for people who have dark skin, which contain lots of melanin, the pigment that blocks some - but not all - of the light hitting the skin.

For people who have asthma or another inflammatory condition it’s worth taking a vitamin D supplement (in the locally recommended dose) to see if this helps the condition. There are blood tests that can determine whether the level of vitamin D in the blood is acceptable.