Effects of Flavonoid Foods on Carbonyl Stress
Human Health · Flavonoids · Carbonyl Stress
What this study involves
The registry says this study is recruiting. Individual locations may have different availability.
- Study type
- Interventional
- Phase
- Not applicable
- Age range
- 25 years - 70 years
- Sex eligible
- All sexes
- Healthy volunteers
- Accepted
- Participants
- 36 Estimated
These are starting points, not an eligibility decision. The research team must review the full requirements.
About the research
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).
Read the full description
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
Who may be able to participate?
The list below is the sponsor’s full registry wording. It can include conditions, prior treatment, test results and other requirements. A match in search does not mean you qualify.
Inclusion Criteria:
- Age 25-70 years
- BMI between 18 and 30
- Have no known allergy to test food
- Have no known allergies to green tea, apples, blueberries, soy milk, or pineapples
- Be not engaging in high-intensity exercise
- Having blood and urine clinical tests in the normal range.
- Be not taking antibiotics for six months
- Be not currently taking medication
- No taking any prescription drugs
- All flavonoid-enriched supplements should be avoided. The flavonoid-enriched supplements list includes soy isoflavones, Lipo-Flavonoid, Citrus Bioflavonoids Complex, Super Flavonoids, Super Antioxidants, Quercetin Supplement, Essential-C, flavonoids, and milk thistle. Also other flavonoid supplements, including but not limited to luteolin, Rutin, etc.
- No drugs or supplements within three weeks of the experiment
- Be nonsmoking
- Have no alcoholic intoxication
- No alcoholic addiction
- \< 3-4 drinks per week (less than 2 glasses (300 mL) per drink)
- No alcohol within three weeks of the experiment
- Have no extended exposure to industrial wastes
Exclusion Criteria:
- Disease: gout, heart disease, peripheral vascular disease, degenerative kidney, degenerative liver, diabetes, GI disorders, or endocrine disorders
- Cancer patients
- Currently diagnosed cancer patients will be excluded.
- Medication-free for \>2 years could be considered.
Treatment, groups and participation
The registry may describe treatments and study duration without a complete visit calendar. Ask the study team for the exact schedule, procedures, risks, costs and alternatives. Keep your usual care plan unless your treating clinician tells you otherwise.
- Assignment
- Random assignment
- Masking
- No masking
High-Flavonoid Diet, Then Low-Flavonoid Diet
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
Low-Flavonoid Diet Followed by High-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
High-Flavonoid Diet DIETARY_SUPPLEMENT
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.
Low-Flavonoid Diet DIETARY_SUPPLEMENT
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.
What researchers are measuring
Outcome measures describe what is being studied. They are not proof that a treatment works.
Primary measures
Plasma and Urine Flavonoid Metabolites
Time frame: After the 3-week dietary intervention period.
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).
Secondary measures
Association Between Carbonyl Stress Biomarkers and Flavonoid RCS Conjugates
Time frame: After the 3-week dietary intervention
Association between changes in urinary reactive carbonyl species and the formation of flavonoid RCS-conjugated metabolites measured by liquid chromatography-mass spectrometry (LC-MS).
Review the complete result tables and limitations in the official record.
Open official results ↗Research locations (1)
The overall study status and a local site’s status can differ. Confirm that location’s availability before traveling.
1 locations
North Carolina Agriculture and Technical State University/ NRI BuildingKannapolis, North Carolina, United StatesRecruiting
Study team and timeline
- Lead sponsor
- North Carolina Agriculture & Technical State University
- Study start
- Sep 2, 2026 Actual
- Primary completion
- Oct 15, 2027 Estimated
- Study completion
- Dec 31, 2027 Estimated
- First posted
- Aug 17, 2026 Actual
- Last updated
- Nov 10, 2026 Actual
Official study contacts
Official study title
Effects of Flavonoid-rich Foods on Carbonyl Stress
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Source: ClinicalTrials.gov API v2. Information is submitted by sponsors and investigators. NLM does not approve the safety or science of all listed studies. Registry disclaimer.
Retrieved: Nov 12, 2026 · Last registry update: Nov 10, 2026