Study under review: Effect of curcumin on nasal symptoms and airflow in patients with perennial allergic rhinitis
Curcumin is the bright yellow compound found in the Indian spice, turmeric. It’s a known anti-inflammatory and anti-oxidant, with some potential therapeutic properties in cancer prevention. Curcumin has been shown to be effective in treating intestinal inflammation, symptoms of arthritic pain, anxiety, and for improving oxidative and inflammatory markers. Additionally, curcumin shows some efficacy in animal models as a treatment for certain types of pancreatic and ovarian cancers, but its effects in humans remain uncertain.
Curcumin has been shown to act upon the immune system, modulating cytokine activity after an allergic response. A recent area of interest has been curcumin’s effect in treating the symptoms of allergic rhinitis (AR, depicted in Figure 1). AR is a secondary condition that results from inflammation of the nasal mucosa, with symptoms including rhinorrhea (runny nose), sneezing, coughing, itching, and general discomfort. In cases of AR, the immune system responds to allergens by releasing histamine and chemical mediators. Downstream effects and comorbidities, however, can be more serious: sinusitis, nasal polyposis, sleep disorders, and a general decreased quality of life are possible complications.
The World Allergy Organization reported in 2013 that more than 40% of patients who have AR suffer from asthma, and more than 80% of patients with asthma have contracted AR. Moreover, 10-30% of adults, and 40% or more children have AR. The condition is most often caused by environmental allergens like pollens, dust mites, molds, and insects. There are several effective and safe treatment options, ranging from simple allergen avoidance, to pharmacotherapies (antihistamines) or immunosuppressive drugs (corticosteroids). Antihistamines work by blocking the effect of released histamine, which is present in high amounts during allergic reactions. While they are effective at controlling many symptoms of AR, they generally have little effect on treating nasal congestion. Corticosteroids act by decreasing inflammatory cells and inhibiting the release of cytokines, thus reducing inflammation of the nasal mucosa, leading to reduction in nasal congestion. Nasal, topical, and oral corticosteroids work similarly in reducing the symptoms of rhinitis, regardless of cause.
As an alternative to these drugs, researchers have been investigating the effects and underlying mechanisms of prolonged curcumin supplementation. One study using a mouse model found that curcumin improved rhinitis symptoms by decreasing a selection of inflammation markers (IGF, TNF-alpha, IL-1b,IL- 6, and IL- 8). Additionally a study using guinea pigs found that curcumin was able to prevent the elevation of inflammatory markers associated with onset AR as well as increase relevant antioxidant levels. Due to curcumin’s potent effect as an anti-inflammatory agent, and its early evidence in animal and in vitro trials, the present study sought to investigate the compound’s efficacy in human subjects as a treatment for the clinical management of AR.
Earlier research has yielded positive results on curcumin’s efficacy as general anti-inflammatory compound. Several animal trials suggest curcumin may have immunomodulatory effects similar to conventional treatment options like antihistamines and corticosteroids. The present study sought to build upon previous results and investigate the effects of curcumin supplementation as a treatment option for the management of AR in humans.
Other Articles in Issue #26 (December 2016)
Gelatin + vitamin C + exercise = joint benefits?
Exercise can help remodel soft tissue, including the collagen in joint tissue. Researchers already knew that vitamin C and gelatin are involved in collagen formation, and here they are tested along with exercise in a randomized trial.
What happens to diets when you control food quality?
Dieters often control their intake of either carbs or fat. But when dieting, the overall quality of food you eat can also change. Do low-fat and low-carb diet effects differ, even if you control for food quality?
Can diet soda ruin your diet?
Evidence is still quite mixed when it comes to diet soda effects on weight loss (or gain). Observational evidence often contradicts with trial evidence. This study adds to the body of evidence, specifically on those with type 2 diabetes.
Interview: Dr. Taylor Wallace, PhD
Dr. Wallace has done research in a variety of areas, including anthocyanins in plants. Here, we ask him about topics ranging from food additives to supplement side effects.
Cut out FODMAPs, cut out IBS symptoms?
If you have IBS, you know that physicians often lack well-supported dietary recommendations, so new research can be extremely valuable. This study is the first meta-analysis on the low-FODMAP strategy for curbing IBS symptoms
Can probiotics help with Alzheimer’s?
With an aging population, more and more people know someone with Alzheimer’s. As a disease of the brain, symptoms could be helped by supporting an organ that plays directly into brain health: the gut.
Interview: Grant Tinsley, PhD
Remember that neat intermittent fasting study in the previous issue of NERD? We were lucky enough to interview one of the study authors, Grant Tinsley.