Study: Quercetin for pollen allergies

reference

Yamada S, Shirai M, Inaba Y, Takara T. Effects of repeated oral intake of a quercetin-containing dietary supplement on allergic reactions: a randomized, placebo-controlled, double-blind, parallel-group study.Eur Rev Med Pharmacol Sci. 2022:26(12):4331-4345.

design

Randomized, placebo-controlled, double-blind study

Key to take away

The phytosome quercetin significantly reduced several key pollinosis symptoms over a four-week period in these Tokyo residents during the pollen season.

Participant

The study included 66 subjects (aged 22–78 years) with allergic symptoms of pollinosis during a pollen season in Tokyo, Japan. Ninety adults agreed to participate in the study and 66 qualified and were included in the study. Three subjects were later excluded and another three left the study. Ultimately, 60 test subjects were included in the analysis. There were 18 women and 12 men in the treatment arm and 15 women and 15 men in the placebo arm. The authors state that there were no significant differences at baseline; However, high-density lipoprotein (HDL) was lower in the placebo group compared to the treatment group (P=0.02).

Inclusion criteria:These included those with a relatively high score on the Japanese Rhinoconjunctivitis Quality of Life Questionnaire (JRQLQ).

Exclusion criteria:Patients with previous cancer, heart failure, myocardial infarction were excluded; pacemaker or defibrillator; Treatment of cardiac arrhythmias, liver dysfunction, renal dysfunction, cerebrovascular disorders, rheumatoid arthritis, diabetes, dyslipidemia, hypertension and other chronic diseases; intake of functional foods or drinks; continuous use of medication for allergic eye and nasal symptoms; use of herbs or dietary supplements; allergic to quercetin and lecithin; unable to follow instructions; Travel planning during your studies; practicing nasal gargling (nasal rinsing); pregnant, breastfeeding, or planning to become pregnant during the study period; have participated in a clinical trial in the past 3 months or are planning to participate in another clinical trial during the study period; and deemed unsuitable for this trial by the principal investigator.

Evaluated study parameters

Researchers assessed the JRQL questionnaire, height, weight, body mass index (BMI), body fat ratio, blood pressure, heart rate, complete blood count (CBC), aspartate aminotransferase (AST), alanine transaminase (ALT) and gamma-glutamyl transferase (GGT), lipid panel, glucose, hemoglobular A_1c(HbA_1c), complete urinalysis (UA), virological and immunoserological tests for hepatitis C, human immunodeficiency virus (HIV) andTreponema pallidafor all subjects.Primary endpoint was JRQLQ score and secondary endpoints were allergic symptoms, nasal discharge and self-administered questionnaire.

intervention

The researchers called the intervention a food because the quercetin was in the phytosome form with lecithin, available from Indena SpA, Milan, Italy. The study dose was 50 mg quercetin per tablet, 2 tablets twice daily with breakfast and dinner. The placebo contained the same amount of vehicle per tablet, also two tablets twice daily, at breakfast and dinner. The researchers found that it was impossible to distinguish between the test and placebo foods based on taste or appearance.

Primary outcome

Changes in JRQLQ scores

Key findings

The JRQLQ total scores were lower in the treatment arm after 4 weeks (P=0.04), total quality of life score (P=0.02) and sleep and body values ​​(P=0.00). In the detailed breakdown of the JRQLQ score at 4 weeks compared to baseline, the treatment arm was significantly better at sneezing (P=0.04), mental focus (P=0.01), ability to participate in outdoor activities (P=0.01), improved sleep (P=0.01), reducing fatigue (P=0.02); and facial swelling (P=0.03).

transparency

The authors declared that there were no conflicts of interest. Financing of the study according to the authors: “This study was carried out on behalf of Indena Japan Co., Ltd. and Indena SpA at the expense of the clients.” Indena SpA is the manufacturer of Quercetin Phytosome.

Effects on practice

Rhinitis is a type 1 allergic reaction associated with degranulation of mast cells due to excessive immunoglobulin E (IgE) response to the allergen, histamine release, mucus release, ocular conjunctivitis, hives and eczema, angioedema, asthma and even anaphylaxis.^1.2The incidence of anaphylaxis in the population can be as high as 2%, is increasing in younger populations, and can be as high as 20% to 30% in North America.²In Tokyo the main causes are Japanese cedar, sugi,Cryptomeria japonicaPollen (48.8% of the population), other allergens, air pollution and infections.

Quercetin, a bioflavonoid with extensive research, works by inhibiting mast cell activation, reducing histamine release and resulting inflammation through eosinophil activation, inhibiting lipopolysaccharide-induced tumor necrosis factor alpha (TNF-α), and inhibiting lipid peroxidation, platelet aggregation and capillary permeability. Its diverse effects include the stimulation of mitochondrial biogenesis.³It was identified in 1957 from oak trees (Quercus) and is yellow.³Dietary intake from fruits and vegetables can range from 4 to 500 mg/day, with oral bioavailability being only 2 to 17%.³Vitamin C, folic acid, and concomitant intake of other flavonoids can increase absorption rates.⁴Absorption occurs in the small intestine; Half-life studies show a range of 3.5 to 28 hours, with elimination occurring primarily via the kidneys.⁴

Vitamin C, folic acid, and concomitant intake of other flavonoids can increase absorption rates.

The phytosome formulation was quercetin fromSophora japonicaand sunflower lecithin in a 1:1 ratio, standardized to 40% quercetin.⁵In a single-dose trial in healthy adults aged 18 to 50 years, based on 12 blood samples from baseline to 24 hours post-dose and 3 doses of either 500 mg quercetin, 250 mg quercetin phytosome, or 500 mg quercetin phytosome, the area under the curve was 4,774.9 ng/ml, 50,401.5 ng/ml or 96,163.8 ng/mL, which corresponds to a 105-fold increase between 500 mg of quercetin and 500 mg of quercetin phytosome.⁵

In a three-month study of Covid-19 prevention in 120 healthcare workers (60 placebo, 60 treatment) who used quercetin phytosome 250 mg twice daily, there was less Covid-19 and faster recovery in the treatment group. At 5 months, Covid-free survival was 99.8% in the treatment group versus 96.5% in the control group, representing a 14% higher protective factor for not contracting SARS-CoV-2 infection.⁶A study using a combination product of 500 mg vitamin C, 500 mg quercetin and 50 mg bromelain for 3 months in healthcare workers found that 1 employee in the treatment group contracted Covid-19, while 9 out of 42 (21.4%) in the control group contracted Covid-19 contracted the SARS-CoV-2 infection.⁷Possible mechanisms in these experiments are likely to include immune activation, combating cytokine storms, and combating senescent cells.⁶

My clinical experience with quercetin typically includes 500 mg of quercetin with 500 mg of vitamin C in a two or three times daily prescription for allergies and early infections with good success, especially when treatment is started 7 to 14 days before local allergy onset. Pollen season, which confirms the above results. Since I didn't have access to the quercetin phytosome, I can't say how it compares, although it may appear to be more effective. The deciding factor for my use with patients will be the cost compared to the assumed greater benefit.