Respiratory researchers give vitamin C an A
March 22, 2004
OAKLAND, Calif. - Vitamin C plays an important role in normal airway function, may prevent symptoms associated with airway diseases such as cystic fibrosis and asthma, and may even help alleviate the dry cough suffered by smokers, according to researchers at Children's Hospital & Research Center.
The findings are a first step toward evaluation of vitamin C as a drug candidate and therapeutic agent in the complementary treatment of asthma, cystic fibrosis and chronic obstructive lung disease.
In the study, published in the first March issue of the Proceedings of the National Academy of Sciences, the Children's researchers found that low levels of vitamin C may play a role in the progression of common inflammatory airway diseases. Inflammatory airway diseases obstruct breathing and can literally leave patients gasping for breath.
Lead researcher Beate Illek, Ph.D. and her team Horst Fischer, Ph.D. and Christian Schwarzer, Ph.D. discovered that vitamin C supports the normal hydration of airway surfaces, while vitamin C deficiency may lead to dry, sticky mucus membranes lining the airway.
"When the airway is not sufficiently hydrated, it becomes susceptible to infections, which may eventually cause asthma attacks in asthmatics," said Illek. "Increased intake of vitamin C may loosen those sticky airway secretions and improve clearance in the respiratory tract. Vitamin C may prove to be an effective, safe and low-cost treatment to improve current therapies, including bronchodilators, anti-inflammatory medications and antibiotics."
In the two-year study, funded in part by The Cystic Fibrosis Foundation, vitamin C was tested on the function of a cell protein called the cystic fibrosis transmembrane conductance regulator (CFTR). A cystic fibrosis model also was used to examine the role of vitamin C on abnormal CFTR. The findings of cellular testing were confirmed by instilling vitamin C into the nasal passages of healthy human subjects. The results suggest that supplemental
Vitamin C may improve airway symptoms, pending further clinical trials.
A survey by the U.S. Department of Health and Human Services revealed a link between fruit consumption, vitamin C intake, and the risk of asthma.
Vitamin C is present in a healthy plant-based diet and is widely used as a dietary supplement. However, approximately 25 percent of the U.S. population fall below the recommended dietary intake level for vitamin C, and deficiencies of vitamin C have been reported in the airways of asthmatic patients. In California alone 1.8 million people suffer with asthma including a half a million children. Cystic fibrosis is a genetic disease affecting approximately 30,000 people in the United States. About 1,000 new cases of cystic fibrosis are diagnosed each year.