Oxidation and free-radical damage are words to describe damage being done to cells by certain chemical constituents. A free radical is an electron that is easily given up by a molecule. It is “fired”, like a kind of chemical “bullet”. The words used to describe this action include oxidation, oxidative stress and free-radical damage. Certain nutrients, like vitamins C and E (among others) act like little “bullet-proof vests” that protect from this damage.
In asthma there are two things that contribute to the symptoms: irritation of the airways (from oxidative stress) and spasm of the airways. So it is reasonable to assume that a therapy that protects the lining of the airways, or relaxes them would be beneficial to patients with asthma. Research has shown an increased presence of free radical markers in asthma patients (“Evidence of Free Radical Activity in Asthma”, Owen, Stephen, M.D., et al, New England Journal of Medicine, August 22, 1991;325(8):586- 587).
Research does indeed show the benefits of antioxidants. In the American Journal of Clinical Nutrition (1995;61(Suppl.):625S-630S) found that a diet low in vitamin C is a risk factor for asthma. Exposure to oxidants also increases the symptoms of asthma. The article reviewed 11 research studies between 1973 and 1995 that looked at vitamin C supplementation for asthma patients. Seven of the studies showed improvement in pulmonary function tests with supplementation of 1 – 2 grams of vitamin C.
Low concentration of anti-oxidant nutrients in the plasma is associated with increased severity of asthma (“Plasma concentrations of dietary and nondietary antioxidants are low in severe asthma,” Misso NL, Ray S, et al, Eur Respir J., 2005; 26(2): 257-64). Also, low intake of foods containing vitamin C is low in asthmatics when compared to healthy subjects, according to research appearing in the journal Thorax (“Dietary anti-oxidants and symptomatic asthma in adults,” Patel BD, Welch AA, et al, Thorax, 2006 Feb).
Of course vegetables are an excellent source of antioxidants. Research supports the idea that eating more vegetables can reduce asthma symptoms (“Fruit and vegetable intakes and asthma in the E3N study,” Romieu I, Varraso R, et al, Thorax, 2006 Jan 5). In general, nutrition can be a valuable tool for bringing asthma under control. Nutrients other than antioxidants that have been shown by research to be useful for asthmatics include: omega-3 fatty acids, selenium, magnesium, CoQ10, and manganese.