Health Hotline Magazine | April 2024

But quercetin does more than just quench an allergy attack—it is also frequently used to treat a variety of respira tory conditions, including asthma and chronic obstructive pulmonary disease (COPD). Quercetin is also beneficial for the prevention and treatment of bronchitis. It relaxes airway smooth muscle, modulates inflammation, and supports healthy respiratory function in the respiratory tract, as well as the sinuses. Quercetin can also offset the harmful effects of air pollution caused by carbon dioxide and wildfire smoke, and even cigarette smoke. One in vitro study examining the effects of quercetin combined with vitamin C on bronchial cells when exposed to fine particulate matter (PM2.5), an especially dangerous type of air pollution, found that the combination of quercetin and vitamin C “strikingly” reduced PM2.5’s negative health effects to the cells, in part by reducing inflammation, oxidative damage, and mitochondrial damage. Quercetin Is a Potent Antiviral

Most of us are familiar with the importance of vitamins C and D and zinc for immune health. In addition to these core supplements, quercetin is another valuable sup plement to add to your immunity toolkit because it displays an impressive range of antiviral properties, including inhibiting virus entry, virus replication, and virus protein assembly. This helps us fight upper respiratory infections like the common cold, as well as influenza. Quercetin also alleviates infection-related symptoms through its ability to reduce the release of inflammatory cytokines, proteins released by certain immune cells as part of the immune response.

In one study, participants 40 and older had a 36 percent reduction in upper respiratory infection severity and a 31 percent reduction in total sick days when taking 1,000 mg of quercetin, plus 1,000 mg of vitamin C

and 40 mg of niacin, for 12 weeks, compared to the placebo group. Quercetin Combats COVID-19

A 2023 meta-analysis reviewed five randomized controlled clinical trials examining quercetin’s effect on 544 COVID-19 patients. The study examined the impact of quer cetin (when given alongside standard treatment) on various biomarkers of COVID-19 illness, as well as hospital and ICU admission, and mortality rates. The dose of quercetin used in the studies varied from 480 to 1,500 mg/day and the duration of supplementa tion ranged between one and four weeks. The form of quercetin supplement also varied with several studies using quercetin phytosome, one using pure quercetin, and one using an IV and oral quercetin combo.

Some of the biomarkers they looked at included C-reactive protein (CRP) & ferritin (markers of inflammation), and lactate dehydrogenase (LDH) enzyme (released from damaged cells, indicating tissue damage). The results showed significant reductions in LDH activity following supplementation with quercetin, im plying less tissue damage. Supplementation also reduced the risk of hospitalization by 70

percent, risk of admission to the ICU by 73 percent, and mortality by 82 percent. Quercetin Is a No-Brainer for Healthy Brain Aging A 2022 study further supports quercetin’s brain health benefits—even in those without cognitive impairment. Eighty men and women aged 60–75 years old participated in a placebo-controlled, randomized trial where the experimental group regularly consumed 500 mL of a beverage containing 110 mg of quercetin as isoquercetin (also called enzymatically modified isoquercetin, or EMIQ) for 40 weeks. At the end, participants were assessed for cognitive function, cerebral blood 28 | Health Hotline ®