Dietary fat increases quercetin bioavailability in overweight adults

Area of Science:

• Nutritional Science
• Pharmacokinetics
• Cardiovascular Health

Background:

• Epidemiological studies suggest dietary quercetin intake is associated with reduced cardiovascular disease (CVD) risk.
• However, the oral bioavailability of quercetin is notably low, limiting its potential health benefits.
• Understanding factors that enhance quercetin absorption is crucial for optimizing its therapeutic effects.

Purpose of the Study:

• To investigate the impact of dietary fat on quercetin bioavailability in adults at high risk for CVD.
• To assess the in vitro effect of lipids on quercetin micellarization.
• To determine if increased dietary fat enhances the absorption of quercetin and its metabolites.

Main Methods:

• A randomized, cross-over study involving overweight/obese men and postmenopausal women.
• Participants ingested 1095 mg of quercetin aglycone with breakfasts varying in fat content (fat-free, low-fat, high-fat).
• Plasma quercetin and metabolite concentrations (isorhamnetin, tamarixetin) were measured over 24 hours; in vitro micellarization was also assessed.

Main Results:

• Compared to a fat-free meal, a high-fat meal significantly increased plasma quercetin maximum concentration (Cmax) by 45% and area under the curve (AUC0-24h) by 32%.
• Absorption of quercetin metabolites, isorhamnetin and tamarixetin, also showed significant increases with high-fat intake.
• In vitro studies confirmed that dietary fat dose-dependently enhanced the micellarization efficiency of quercetin.

Conclusions:

• Dietary fat demonstrably improves quercetin bioavailability in humans.
• Enhanced absorption is likely mediated by increased micellarization of quercetin in the small intestine.
• These findings suggest a practical dietary strategy to increase quercetin's potential cardiovascular benefits.