Waterer and colleagues considered that nutrition may affect the severity of community-acquired pneumonia, and suggested that further studies are needed to find out which patients with pneumonia are at highest risk of delayed mortality (1). I would like to point out that the possible role of vitamin C on pneumonia should be studied.
Several studies have documented reduced levels of vitamin C in patients with pneumonia (2, 3). Dozens of animal studies found that vitamin C protected against bacterial and viral infections, including pneumonia, indicating that the physiological effects of this vitamin are not limited to preventing overt deficiency (2). Therefore, we performed a systematic review on the effect of vitamin C in the prevention and treatment of pneumonia (4) and found three prophylactic trials and two treatment trials, reporting significant benefit of vitamin C against pneumonia. The randomized double-blind, placebo-controlled treatment trial by Hunt and coworkers (3) is particularly interesting.
Hunt and colleagues studied the effect of 0.2 g/day vitamin C on 66- to 94-year-old patients who were taken into the hospital because of pneumonia or acute exacerbation of chronic bronchitis (3). Vitamin C or placebo was administered in addition to the normal medication. Vitamin C significantly improved the “total respiratory score” in the most severely ill patients, but had no effect on the less ill patients (3). Moreover, there were six deaths during the trial—all among the most severely ill patients. Five of the deaths occurred in the placebo group, but only one in the vitamin C group.
In a study using a combination of vitamins C and E, Nathens and coworkers (5) found no effect on the incidence of nosocomial pneumonia in critically ill surgical patients, but days of mechanical ventilation (−0.9; −0.6 to −1.2) were significantly reduced in the antioxidant group. Although this study is not specific to vitamin C, it suggests that antioxidants may affect pulmonary morbidity. More research on vitamin C and other antioxidants seems to be warranted.
|1.||Waterer GW, Rello J, Wunderink RG. Management of community-acquired pneumonia in adults. Am J Respir Crit Care Med 2011;183:157–164.|
|2.||Hemilä H. Do vitamins C and E affect respiratory infections? [Dissertation] Helsinki, Finland: University of Helsinki; 2006. pp. 5–9, 105–121.|
|3.||Hunt C, Chakravorty NK, Annan G, Habibzadeh N, Schorah CJ. The clinical effects of vitamin C supplementation in elderly hospitalised patients with acute respiratory infections. Int J Vitam Nutr Res 1994;64:212–219.|
|4.||Hemilä H, Louhiala P. Vitamin C for preventing and treating pneumonia. Cochrane Database Syst Rev 2007;1:CD005532.|
|5.||Nathens AB, Neff MJ, Jurkovich GJ, Klotz P, Farver K, Ruzinski JT, Radella F, Garcia I, Maier RV. Randomized, prospective trial of antioxidant supplementation in critically ill surgical patients. Ann Surg 2002;236:814–822.|