Determining the absorption of natural flavonoids from food in healthy subjects

-Name: Arm 1: low-dose quercetin capsule (150 mg/person) with placebo food (40 g quercetin-free food) Arm 2: high-dose quercetin capsule (300 mg/person) with placebo food (40 g quercetin-free food) Arm 3: low-dose quercetin-rich food (40 g food, containing 150 mg quercetin; served with water) with placebo capsule Arm 4: high-dose quercetin-rich food (40 g food, containing 300 mg quercetin; served with water) with placebo capsule -Aim: The aim of the trial is to compare the absorption of quercetin, a naturally occurring flavonoid antioxidant commonly found in vegetables, in both food and capsule form, and to assess differences between low and high doses. - any physical or informational materials that will be used in the intervention 1. explanatory statement 2. quercetin food list (a list of natural foods containing high amounts of quercetin) 3. participant consent form 4. diet checklist (for participants recording their consumption of the provided standard meals by ticking a box) - each of the procedures, activities, and/or processes used, including any enabling or support activities 1. participant screening and recruitment 2. providing study information and obtaining informed consent 3. baseline measurements, including weight, height, and body composition assessed by bioelectrical impedance analysis 4. baseline urine collection 5. administration of the assigned dose of quercetin capsules or quercetin-rich foods 6. 24-hour urine sample collection 7. participant consuming the provided standard quercetin-free meals throughout 24-hour urine sample collection period 8. recording dietary intake and lifestyle factors 9. data analysis and result interpretation - The intervention will be delivered face-to-face and provided individually. - Each participant will undergo all 4 arms in a random order. Each arm will be test only once. Each test will last approximately 30 minutes, followed by a 24-hour urine collection period, during which participants may leave the site and return the urine container the next day. A minimum washout period of 3 days will be observed between each treatment. -Location: BASE Facility (Be Active Sleep Eat), 264 Ferntree Gully Rd, Notting Hill VIC 3168, Melbourne, VIC, Australia - Strategies used to assess adherence to the intervention 1. direct observation: All food and capsules will be consumed within 15 minutes at the BASE facility. 2. diet checklist: Participants will record their consumption of the provided standard meals by ticking a box. 3. Baseline urine collection: Baseline urine will be collected to determine pre-existing quercetin levels before the test.