Stuffy, runny nose? Watery, itchy eyes? Frequent sneezing?
These are all the signs of the start of spring/summer for some people as it brings with it the dreaded pollen. Allergic rhinitis, or hayfever as it is more commonly known, is caused when the body makes allergic antibodies (IgE) to a substance such as pollen and this exposure causes the release of chemicals from cells in the nasal pathways, eyes and airways. This results in inflammation and irritation to the lining of the eyes, nose and throat. Typical treatments include avoiding the specific allergen, and the use of antihistamines and nasal sprays which can help to suppress symptoms. However these don’t work for everyone and avoiding pollen in the summer months is not an easy thing to do.
Quercetin is categorized as a flavonol, one of the six subclasses of flavonoid compounds. It is found in foods such as apples, red grapes, citrus fruits, and tomatoes. It appears to have many potential beneficial effects on human health. Previous studies have suggested that in vitro, quercetin inhibits histamine release by mast cells and basophils, suggesting an anti-allergy effect1,2. In a Japanese study of mast cells from nasal mucosa of individuals with perennial allergic rhinitis, quercetin significantly inhibited antigen-stimulated histamine release3. Most recently, results of a 2013 study suggested that quercetin will be a good candidate in the management of eosinophil-mediated diseases, such as allergic rhinitis4. The results indicated that quercetin has a suppressive mode of action on eosinophil-mediated allergic immune responses. It has previously been reported that quercetin’s efficacy may be enhanced when bromelain is taken concomitantly5.
Bromelain, an enzyme from pineapple fruit, has been shown to relieve hay fever or sinusitis in a number of human clinical studies by working as a natural anti-histamine, anti-inflammatory and decongestant. A study from the 1960’s found that 85% of people taking bromelain had complete resolution of breathing difficulties and airway inflammation compared to just 53% and 40% in the placebo group respectively6. In addition, bromelain has demonstrated anti-allergic activity in the lungs and airways7.
Vitamin C has been found to exert a number of effects on histamine. It appears to prevent the secretion of histamine by white blood cells and increase its detoxification8. In another study, histamine levels were found to increase exponentially as ascorbic acid levels in the plasma decreased9, which could be a good indicator for the anti-histamine effects of vitamin C.
All these components separately exhibit anti-histamine, anti-inflammatory and anti-allergy actions which demonstrate their potential benefits in treating and managing allergic conditions including hayfever.
Reviewed by Laura Murphy BSc (Hons) MSc
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2. Fox CC et al. Comparison of human lung and intestinal mast cells. J Allergy Clin Immunol 1988; 81.
3. Otsuka H et al. Histochemical and functional characteristics of metachromic cells in the nasal epithelium in allergic rhinitis: studies of nasal scrapings and their dispersed cells. J Allergy Clin Immunol 1995; 96.
4. Sakai-Kashiwabara M and Asano K. Inhibitory action of quercetin on eosinophil activation in vitro. Evid Based Complement Alternat Med 2013.
5. Taussig S. the mechanism of the physiological action of bromelain. Med Hypothesis 1980; 6.
6. Ryan RE. A double-blind clinical evaluation of bromelains in the treatment of acute sinusitis. Headache 1967; 7.
7. Secor ER et al. Oral bromelain attenuates inflammation in an ovalbumin-induced murine model of asthma. Evid Based Complement Alternat Med2008; 5.
8. Murray MT. A comprehensive review of vitamin C. Amer J Nat Med 1996; 3.
9. Clemetson CA. Histamine and ascorbic acid in human blood. J Nutrition 1980; 110.