The possible influence of dietary antioxidants, especially vitamin C, on the in creasing prevalen ce of asthma is explored. Vitamin C intake in the general population appears to correlate with asthma, suggesting that a diet low in vitamin C is a risk fa ctor for asthma. Epidemiologi cal studies show asso ciations among oxidant exposure, respiratory infe ctions, and asthma in children of smokers. Symptoms of ongoing asthma in adults appear to be in creased by exposure to environmental oxidants and de creased by vitamin C supplementation. There is eviden ce that oxidants produ ced endogenously by overa ctive inflammatory cells contribute to ongoing asthma. Vitamin C is the major antioxidant substan ce present in the airway surfa ce liquid of the lung, where it could be important in prote cting against both endogenous and exogenous oxidants. Nitrogen oxides are exemplary of oxidants that could arise from both endogenous and environmental sour ces, whi ch are prote cted against by vitamin C, and that may be important in causation and propagation of asthma.

References:

Hat ch, GE. 1995. Asthma , inhaled oxidants, and dietary antioxidants. AJ CN , 61: 625S-630S .