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Total flavonol and flavone contents of foods have been determined with validated state‐of‐the‐art methods. Quercetin dominates, and flavonol levels found in vegetables and fruits are below 10 mg kg⁻¹. However, high concentrations are found in onions (300 mg kg⁻¹), kale (450 mg kg⁻¹), broccoli (100 mg kg⁻¹), beans (50 mg kg⁻¹), apples (50 mg kg⁻¹), blackcurrants (40 mg kg⁻¹), and tea (30 mg l⁻¹). The dietary intake of flavonols varies 10‐fold between countries (6–60 mg day⁻¹). Flavones are of minor importance in the diet. Tea, wine and fruits are the most important sources of flavanols, but there are gaps in our knowledge on flavanol levels of many foods. The absorption of dietary quercetin glycosides in humans ranges from 20 to 50%. The sugar moiety is an important determinant of the bioavailability of flavonols. The presence of a glucose moiety significantly enhances absorption …