An interventional study of High-Flavonoid Diet and Low-Flavonoid Diet in Human Health, Flavonoids and Carbonyl Stress, sponsored by North Carolina Agriculture & Technical State University. Recruiting at 1 site in United States. Open to participants aged 25 Years to 70 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-11-10.
Sponsored by North Carolina Agriculture & Technical State University · Not applicable, Interventional, and Treatment
This randomized crossover study will compare low- and high-flavonoid diets in healthy adults to identify flavonoid-derived biomarkers in urine and plasma. Using targeted liquid chromatography-mass spectrometry (LC-MS) metabolomics, researchers will measure known and novel flavonoid metabolites and evaluate whether a higher flavonoid intake reduces carbonyl stress markers, including reactive carbonyl species (RCS) and advanced glycation end products (AGEs).
Biomarkers of flavonoids and flavonoid-rich foods are needed to monitor diets. Monitoring diets and associating dietary patterns with health risks and outcomes is an essential step in the research process. The goal of this study is to determine the time- and dose-dependent formation of novel flavonoid metabolites in urine and plasma samples by conducting a randomized crossover trial of two dietary interventions with low (\~140 mg flavonoids/day) and high (\~420 mg flavonoids/day) flavonoid diets among healthy individuals.
Foods with high or low flavonoid content will be incorporated into participants' usual diets. Liquid chromatography-mass spectrometry (LCMS)-based targeted metabolomics will be used to assess flavonoid metabolites, including novel RCS-conjugated and oxidized flavonoid metabolites, and to determine whether consuming a flavonoid-rich diet will lead to a decrease in carbonyl stress as measured by RCS and related advanced glycation end products (AGEs). Investigators will determine the changes in the major RCS and related AGEs after each intervention period using LCMS and examine the relationship between changes in RCS and AGEs and the formation of flavonoid RCS conjugates
North Carolina Agriculture & Technical State University is the lead sponsor of 12 studies on the registry; 5 are open to participants now.
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Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
All participants will first complete a 2-week low-flavonoid wash-in period. Participants in this sequence will then consume the high-flavonoid diet for 3 weeks, complete a 3-week low-flavonoid washout period, and then consume the low-flavonoid diet for 3 weeks.
Dietary Supplement: High-Flavonoid Diet · Dietary Supplement: Low-Flavonoid Diet
All participants will first complete a 2-week low-flavonoid wash-in period. Participants in this sequence will then consume the low-flavonoid diet for 3 weeks, complete a 3-week low-flavonoid washout period, and then consume the high-flavonoid diet for 3 weeks.
Dietary Supplement: High-Flavonoid Diet · Dietary Supplement: Low-Flavonoid Diet
Participants will consume the high-flavonoid diet daily for 3 weeks. The diet includes 1 Red Delicious apple (approximately 160 g), freeze-dried whole blueberry powder (25 g), soy milk (240 mL), and decaffeinated Lipton green tea ( 2 g tea leaves), providing approximately 420 mg flavonoids per day.
Participants will consume the low-flavonoid diet daily for 3 weeks. The diet includes 1/3 of Red Delicious, 107 g of pineapple; 8.3 g of blueberry powder plus 16.7 g of blueberry placebo powder; 80 mL of soy milk plus 160 mL of 2% low-fat milk; and 0.67 g tea leaves, providing approximately 140 mg flavonoids per day.
Plasma and Urine Flavonoid Metabolites
Change in plasma and urine concentrations of flavonoid metabolites, including reactive carbonyl species (RCS)-conjugated flavonoid metabolites, measured by liquid chromatography-mass spectrometry (LC-MS).
Time frame: After the 3-week dietary intervention period.
Association Between Carbonyl Stress Biomarkers and Flavonoid RCS Conjugates
Association between changes in urinary reactive carbonyl species and the formation of flavonoid RCS-conjugated metabolites measured by liquid chromatography-mass spectrometry (LC-MS).
Time frame: After the 3-week dietary intervention
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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North Carolina Agriculture & Technical State University