Effect of oral zinc supplementation on agents of oropharyngeal infection in patients receiving radiotherapy for head and neck cancer

We aimed to investigate the effect of zinc supplementation on oropharyngeal infections in immunocompromised patients. Thirty patients receiving radiotherapy for head and neck cancer received 150 mg/day zinc or placebo, orally, during radiotherapy and for a further 6 weeks. None received antibiotics during this period. Oropharyngeal samples were collected I day before the first course and 1 day after the last course of radiotherapy, and 1 week and 6 weeks after radiotherapy. Samples were cultured and pathogens identified using microbial diagnostic and gas chromatography methods. Coagulase-positive and -negative staphylococci, group A beta-haemolytic streptococci, Streptococcus pneumoniae, and Candida species were detected in both groups, but some infections, especially with Candida species and staphylococci, were prevented by zinc supplementation. We therefore suggest use of low-dose antibiotics and oral zinc supplementation in patients with these infections. No effects of zinc supplementation were observed on group A beta-haemolytic streptococci and Streptococcus pneumoniae, making it essential to start antimicrobial chemotherapy before radiotherapy.