Nasal Irrigation, Polyols, Nitrate Reducing Bacteria and Cardiovascular Disease

Nasal irrigation is a conventional but effective treatment modality against allergic rhinopathy. Its use started to expand during the early 1900s [1,2]. The technique involves rinsing the nasal cavity with saline solution (saltwater) delivered as liquid or spray. It can be performed with a squirt or spray bottle that creates low pressure saline flow or with a container that creates gravity-based pressure such as a device with a nasal spout (e.g., neti pot) [3]. Through removing contaminants, allergens (e.g., pollen) and excessive mucus that impedes ciliary function [4], nasal irrigation enhances mucociliary function [5,6] and improves coughing secondary to postnasal drip [7,8]. Reduced histamine and leukotriene C4 levels have also been observed in patients with allergic rhinitis who use sinus irrigation [4]. Regarding clinical outcomes, patients who were treated with sinus irrigation relied less on medication and made fewer doctor visits [4,7,9]. Studies performed by Chirico et al. [8] showed nasal irrigation improved symptoms, reduced the need for medications such as antihistamines, antibiotics, corticosteroids, and decongestants in pediatric patients suffering from acute sinusitis and allergic rhinitis. In patients with acute upper respiratory tract infection, a systematic review published in 2015 suggested that nasal saline irrigation has possible benefits for symptoms relief [10]. In terms of chronic rhinosinusitis (CRS), a systematic review published in Cochrane library included 2 randomized controlled trials (RCT) [11]. The article suggested there is some benefit in the use of daily large-volume (150 ml) saline irrigation with a hypertonic solution when compared with placebo, but the quality of the evidence is low for the three months as well as for the six months of treatment.