Quercetin Anhydrous
Also known as: Quercetin, Quercetina, Sophoretin, 3,3',4',5,7-Pentahydroxyflavone
Overview
Quercetin is a flavonoid, specifically a flavonol, found abundantly in various fruits, vegetables, and grains, celebrated for its antioxidant properties. As a dietary supplement, it's primarily used for its potential cardiovascular benefits, anti-inflammatory effects, and antioxidant capabilities. Research indicates that quercetin can help reduce blood pressure, improve lipid profiles, and lower plasma uric acid levels. It exists in multiple anhydrous polymorphs and solvates, affecting its stability and bioavailability. The research on quercetin is extensive, including numerous randomized controlled trials (RCTs) and meta-analyses, providing a solid base of evidence supporting its health effects. Its widespread availability in common foods contributes to its accessibility as a health supplement.
Benefits
Quercetin supplementation has demonstrated several evidence-based benefits. A meta-analysis of RCTs showed a significant reduction in both systolic and diastolic blood pressure with doses ≥500 mg/day. Another study indicated improvements in lipid profiles, including reduced total cholesterol, LDL-cholesterol, and C-reactive protein (CRP) levels, particularly in patients with metabolic syndrome. Additionally, a randomized, double-blinded, placebo-controlled crossover trial found that quercetin (544 mg/day) lowered plasma uric acid in pre-hyperuricaemic males. Quercetin also exhibits anti-inflammatory and antioxidant effects, potentially benefiting conditions like COVID-19. These effects are generally observed within a few weeks to months of consistent supplementation.
How it works
Quercetin exerts its effects through multiple biological pathways. It acts as an antioxidant by scavenging free radicals and inhibiting lipid peroxidation. Its anti-inflammatory activity involves inhibiting pro-inflammatory enzymes like lipoxygenase and phospholipase A2. Quercetin also enhances nitric oxide production, improving endothelial and vascular function, which contributes to blood pressure reduction. It interacts with the cardiovascular system, immune system, and metabolic pathways. The bioavailability of quercetin is influenced by its solid-form landscape, with different polymorphs and solvates exhibiting varying stabilities and solubilities, affecting its absorption and efficacy.
Side effects
Quercetin is generally considered safe when taken as a dietary supplement. Common side effects are rare, but some individuals may experience gastrointestinal disturbances. There are no well-documented rare side effects. Quercetin may interact with blood thinners due to its antioxidant and anti-inflammatory properties, potentially increasing the risk of bleeding. Caution is advised for individuals with bleeding disorders or those taking anticoagulant medications. Pregnant or breastfeeding women should consult healthcare providers before using quercetin supplements. While generally well-tolerated, it's important to be aware of potential interactions and to consult with a healthcare professional, especially if you have pre-existing conditions or are taking other medications.
Dosage
For cardiovascular benefits, the minimum effective dose of quercetin appears to be around 500 mg/day. Optimal dosage ranges from 500 mg to 1500 mg per day have been associated with favorable outcomes in studies. There is no established maximum safe dose, but doses above 1500 mg/day are less commonly studied. It is generally advised to take supplements with meals to enhance bioavailability. The anhydrous form of quercetin may have different stability and bioavailability compared to other forms. Bioavailability can be enhanced by consuming quercetin with fatty meals or using formulations that improve solubility. There are no specific cofactors required for quercetin absorption.
FAQs
Is quercetin safe to take?
Quercetin is generally safe, but individuals with specific health conditions or taking certain medications, like blood thinners, should consult healthcare providers before use.
When is the best time to take quercetin?
There is no specific timing recommendation, but taking quercetin with meals, especially those containing fats, may enhance its bioavailability and absorption.
What results can I expect from taking quercetin?
Users may experience improvements in blood pressure, lipid profiles, and inflammatory markers over several weeks to months with consistent quercetin supplementation.
Is quercetin a cure-all?
No, quercetin is not a cure-all. It should be used as part of a comprehensive health strategy that includes a balanced diet and regular exercise.
Can quercetin help with allergies?
Some studies suggest quercetin may have anti-allergy properties, but more research is needed to confirm its effectiveness in treating allergic reactions.
Research Sources
- https://pubs.acs.org/doi/10.1021/acs.cgd.3c00584 – This article discusses the complex solid-form landscape of quercetin, highlighting the existence of multiple anhydrous polymorphs and solvates. These different forms can significantly impact the stability and bioavailability of quercetin, which is crucial for its effectiveness as a supplement. Understanding these variations is essential for optimizing quercetin formulations.
- https://pubmed.ncbi.nlm.nih.gov/27405810/ – This systematic review and meta-analysis of 7 trials involving 587 patients found that quercetin supplementation significantly reduced both systolic and diastolic blood pressure, particularly at doses of 500 mg/day or higher. The study provides high-quality evidence supporting the use of quercetin for blood pressure management. However, the authors noted heterogeneity among the included studies.
- https://pubmed.ncbi.nlm.nih.gov/31017459/ – This systematic review and meta-analysis of 16 RCTs involving patients with metabolic syndrome showed that quercetin supplementation significantly reduced total cholesterol, LDL-cholesterol, and CRP levels. The study suggests that quercetin may be beneficial for improving lipid profiles and reducing inflammation in individuals with metabolic syndrome. The authors acknowledged high heterogeneity among the included studies.
- https://www.cambridge.org/core/journals/british-journal-of-nutrition/article/quercetin-lowers-plasma-uric-acid-in-prehyperuricaemic-males-a-randomised-doubleblinded-placebocontrolled-crossover-trial/93630E7EE14144BEC5FE9ED2AF9A2190 – This randomized, double-blinded, placebo-controlled crossover trial involving 20 pre-hyperuricaemic males found that quercetin (544 mg/day) lowered plasma uric acid levels. The study suggests that quercetin may have a role in managing uric acid levels in individuals at risk of hyperuricemia. The trial was well-designed, but the small sample size and short duration are limitations.
- https://clinscinutr.org/article/view/86 – This article discusses the anti-inflammatory and antioxidant properties of quercetin, highlighting its potential therapeutic effects in conditions like COVID-19. Quercetin exhibits anti-inflammatory characteristics by inhibiting pro-inflammatory enzymes and has robust antioxidant properties. These properties may contribute to its therapeutic effects.
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