Severe asthma: increased dietary intake of vitamin C may be beneficial

Increased dietary intake of vitamin C may be useful for patients with severe asthma often deficient, suggest the results of an Australian study published in the "European Respiratory Journal" (ERJ).

Several population studies have suggested that the increasing prevalence of asthma in industrialized countries may be associated with changes in supply leading to a decrease in consumption of antioxidants mode, such as vitamin C. Low levels of antioxidants and oxidative stress due to airway inflammation could then represent important determinants of asthma severity.

Dr Neil Misso, the Asthma & Allergy Research Institute, Nedlands (Australia) and colleagues looked to see if a low consumption of antioxidants and low plasma levels of antioxidants were associated with more severe asthma with 53 patients with mild to moderate asthma, 28 patients with severe asthma and 43 non-asthmatic people.

Among all participants, the consumption of vitamin C and carotene antioxidants, mainly from fruits and vegetables proved lower in men than in women, and has been particularly important in some men suffering a severe asthma.

Plasma concentrations of vitamin C appeared much lower in case of severe asthma, and that in both men and women to 31.9 micromolar (microM), against 52.3 in the case of mild to moderate asthma and 52.7 persons control.

The authors also found that, compared to other participants, patients with severe asthma were more often overweight, had a higher consumption of fat and a higher cholesterol.

In addition, lung function appeared to be better in those with higher plasma concentrations of vitamin C and lower cholesterol.

"These results suggest that patients, especially men, with severe asthma may benefit from a change in their diet to ensure a more adequate intake of antioxidants such as vitamin C," the authors write.

Further studies are needed to confirm whether this strategy would be easy to implement, could help reduce the morbidity and socioeconomic burden associated with severe asthma, they add.