Effects of Flavonoid Foods on Carbonyl Stress

North Carolina Agriculture & Technical State University36 enrolled

Overview

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

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

NONE

Enrollment

Interventions

High-Flavonoid DietDIETARY_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 DietDIETARY_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.

Eligibility

Sex: ALLMin age: 25 YearsMax age: 70 YearsHealthy volunteers:

Medical Language ↔ Plain English

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.

Outcomes

Primary Outcomes

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.

Secondary Outcomes

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