Plant Pigments for Human Health: Impact of Lycopene and Anthocyanins on Bioefficacy of Provitamin A Carotenoids From Carrots

Plant Pigments for Human Health: Determining the Interactions the Impact of Co-ingestion of Carotenoids and Anthocyanins From Multicolored Carrots on the Bioavailability of Provitamin A Carotenoids and the Impact on Each Pigment Groups' Respective Antidiabetic Activity in Humans

The proposed research will help characterize the impact that simultaneous consumption of anthocyanins and carotenoids has on the bioavailability of the provitamin A carotenoids a-carotene and b-carotene and the non-provitamin A carotenoid lycopene, and on their respective antidiabetic activity in humans. The central hypothesis is that provitamin A carotenoids will be bioavailable from purple-red multicolored carrots in humans, and the co-ingestion of carotenoids and anthocyanins from these carrots will have synergistic impacts on their respective antioxidant and antidiabetic effects. This hypothesis will be assessed through a 53 day randomized crossover time course study that consists of three arms in which healthy males and females ages 18-40 (n = 12) will consume carrot juice prepared from red, purple-red, or purple carrots. During each arm, participants will switch the type of juice they consume and by the end of the third arm, all participants will have ingested juice made from all three carrot varieties. Blood will be collected at multiple time points over 72 hours following consumption.

Study Overview

• Status: Completed
• Conditions: Healthy
• Intervention / Treatment: Other: Purple-Red Carrot Juice; Other: Red Carrot Juice; Other: Purple Carrot Juice

• Study Type: Interventional
• Enrollment (Actual): 12
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Wisconsin
    • Madison, Wisconsin, United States, 53706
      • UW-Madison Department of Nutritional Sciences

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 40 years (Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Healthy
• Non-smoking
• Not pregnant (or planning to become pregnant)
• Body Mass Index (BMI) greater than 18.5 and less than 30

Exclusion Criteria:

• Major comorbidities (cardiovascular disease (CVD), diabetes, cancer, kidney/liver/bowel disease)
• History of malabsorptive/GI disorders
• Abnormal diet
• BMI less than 18.5 or greater than 30
• Food intolerances/allergies/hypersensitivities
• History of substance abuse or alcoholism
• Unwilling to restrict consumption of specific foods prior to study
• Unwilling to participate in blood draws
• History of difficulty drawing blood/health issues associated with blood draws (gets dizzy, etc).

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Triple

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Starting with Purple-Red Carrot Juice; Participants are randomized to consume purple-red carrot juice first (250 mL) in under 2 minutes. They will crossover to red carrot juice and to purple carrot juice.	Other: Purple-Red Carrot Juice; Purple-Red carrot juice contains provitamin A carotenoids (beta-carotene, alpha-carotene), the non-provitamin A carotenoid, lycopene, as well as anthocyanins; Other: Red Carrot Juice; Red carrot juice contains provitamin A carotenoids (beta-carotene, alpha-carotene), and the non-provitamin A carotenoid, lycopene, but does NOT contain anthocyanins..; Other: Purple Carrot Juice; Purple carrot juice does NOT contain provitamin A carotenoids (beta-carotene, alpha-carotene), nor the non-provitamin A carotenoid, lycopene, but contains anthocyanins.
Active Comparator: Starting with Purple Carrot Juice; Participants are randomized to consume purple carrot juice first (250 mL) in under 2 minutes. They will crossover to red carrot juice and to purple-red carrot juice.	Other: Purple-Red Carrot Juice; Purple-Red carrot juice contains provitamin A carotenoids (beta-carotene, alpha-carotene), the non-provitamin A carotenoid, lycopene, as well as anthocyanins; Other: Red Carrot Juice; Red carrot juice contains provitamin A carotenoids (beta-carotene, alpha-carotene), and the non-provitamin A carotenoid, lycopene, but does NOT contain anthocyanins..; Other: Purple Carrot Juice; Purple carrot juice does NOT contain provitamin A carotenoids (beta-carotene, alpha-carotene), nor the non-provitamin A carotenoid, lycopene, but contains anthocyanins.
Active Comparator: Starting with Red Carrot Juice; Participants are randomized to consume red carrot juice first (250 mL) in under 2 minutes. They will crossover to purple-red carrot juice and to purple carrot juice.	Other: Purple-Red Carrot Juice; Purple-Red carrot juice contains provitamin A carotenoids (beta-carotene, alpha-carotene), the non-provitamin A carotenoid, lycopene, as well as anthocyanins; Other: Red Carrot Juice; Red carrot juice contains provitamin A carotenoids (beta-carotene, alpha-carotene), and the non-provitamin A carotenoid, lycopene, but does NOT contain anthocyanins..; Other: Purple Carrot Juice; Purple carrot juice does NOT contain provitamin A carotenoids (beta-carotene, alpha-carotene), nor the non-provitamin A carotenoid, lycopene, but contains anthocyanins.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in serum retinol concentration	Blood draws will take place on the first, second, and fourth test day (days 8, 9, 11 of each arm)	Blood will be drawn on the first test day (treatment day) at baseline, 15 minutes, 30 minutes, 45 minutes, 1 hour, 2.5 hours, 4 hours, 6 hours, 9 hours, 24 hours, 72 hours
Change in serum carotenoid concentration	Blood draws will take place on the first, second, and fourth test day (days 8, 9, 11 of each arm)	Blood will be drawn on the first test day (treatment day) at baseline, 15 minutes, 30 minutes, 45 minutes, 1 hour, 2.5 hours, 4 hours, 6 hours, 9 hours, 24 hours, 72 hours
Change in serum anthocyanin concentration	Blood draws will take place on the first, second, and fourth test day (days 8, 9, 11 of each arm)	Blood will be drawn on the first test day (treatment day) at baseline, 15 minutes, 30 minutes, 45 minutes, 1 hour, 2.5 hours, 4 hours, 6 hours, 9 hours, 24 hours, 72 hours

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in antioxidant capacity of the carrots and carrot juice measured by enzyme activity assay	Three different antioxidant activity assays will be used including the Oxygen Radical Absorbance Capacity (ORAC), 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS+), and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assays, all of which will be analyzed by Ultraviolet (UV) spec. Each method analyzes different ways anthocyanins and carotenoids may act as antioxidants, and a combination of the three will more accurately represent the parameters of human biology. Data will be expressed as Trolox equivalent antioxidant capacity (TEAC).	up to 1 month
Change in alpha-glucosidase inhibition activities of the carrots and carrot juice measured by enzyme activity assay	Enzyme inhibition will be assessed using specific enzymatic assay kits for alpha-glucosidase and alpha-amylase, analyzed using Enzyme-Linked Immunosorbent Assay (ELISA), and results will be expressed as IC50 (% inhibition).	up to 1 month
Change in alpha-amylase inhibition activities of the carrots and carrot juice measured by enzyme activity assay	Enzyme inhibition will be assessed using specific enzymatic assay kits for alpha-glucosidase and alpha-amylase, analyzed using ELISA, and results will be expressed as IC50 (% inhibition).	up to 1 month
Change in serum glucose concentration	Blood draws will take place on the first, second, and fourth test day (days 8, 9, 11 of each arm)	Blood will be drawn on the first test day (treatment day) at baseline, 15 minutes, 30 minutes, 45 minutes, 1 hour, 2.5 hours, 4 hours, 6 hours, 9 hours, 24 hours, 72 hours
Change in serum insulin concentration	Blood draws will take place on the first, second, and fourth test day (days 8, 9, 11 of each arm)	Blood will be drawn on the first test day (treatment day) at baseline, 15 minutes, 30 minutes, 45 minutes, 1 hour, 2.5 hours, 4 hours, 6 hours, 9 hours, 24 hours, 72 hours
Change in serum incretin concentration	Blood draws will take place on the first, second, and fourth test day (days 8, 9, 11 of each arm)	Blood will be drawn on the first test day (treatment day) at baseline, 15 minutes, 30 minutes, 45 minutes, 1 hour, 2.5 hours, 4 hours, 6 hours, 9 hours, 24 hours, 72 hours

Collaborators and Investigators

• Sponsor: University of Wisconsin, Madison

Study record dates

Study Major Dates

• Study Start (Actual): October 31, 2022
• Primary Completion (Actual): May 11, 2023
• Study Completion (Actual): May 11, 2023

Study Registration Dates

• First Submitted: March 29, 2022
• First Submitted That Met QC Criteria: April 7, 2022
• First Posted (Actual): April 8, 2022

Study Record Updates

• Last Update Posted (Estimated): December 18, 2025
• Last Update Submitted That Met QC Criteria: December 11, 2025
• Last Verified: May 1, 2023

More Information

Terms related to this study

• Other Study ID Numbers: 2021-1544; A074600 (Other Identifier: UW- Madison); Protocol Version 6/9/2022 (Other Identifier: UW Madison); 59-5090-2-003 (Other Grant/Funding Number: USDA)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No