Clinical effects of apple polyphenols on persistent allergic rhinitis: A randomized double-blind placebo-controlled parallel arm study

Background: We often encounter persistent allergic rhinitis due to house dust mites in the practice of otolaryngology, and its prevalence in Japan is high (18.7%). Persistent allergic rhinitis is usually treated with antihistamines and local steroids, but they often cause adverse effects such as sedation and drowsiness. Polyphenols derived from apples have been reported to suppress histamine release from rat cells, reduce auricular swelling in allergic mice, and alleviate skin inflammation in atopic patients. These effects suggest that apple polyphenols are effective for the treatment of various allergic disorders, but the results of their clinical use have not been reported. Objective: To assess the effect of drinks containing apple polyphenols on clinical symptoms of persistent allergic rhinitis. Methods: Thirty-three patients aged 15 to 65 years with moderate or severe persistent allergic rhinitis in whom the symptoms persisted for 3 years or longer were treated without apple polyphenols (control group), with a low dose of apple polyphenols, or with a high dose of apple polyphenols, and changes in the clinical symptoms were examined. Results: Significant improvements were observed in sneezing attacks (P <.05) and nasal discharge (P <.01) in the high-dose group and in sneezing attacks (P <.05) in the low-dose group. Compared with the control group, an improvement was observed in sneezing attacks and nasal discharge in many patients of the polyphenol-treated groups. In terms of intranasal findings, a significant improvement was observed in swelling of the nasal turbinate in the low-dose group (P <.05). The percentage of patients who showed an improvement in swelling of the nasal turbinate was higher in the polyphenol-treated groups. Conclusions: We conclude that apple polyphenols are effective in alleviating symptoms of persistent allergic rhinitis.