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Completed

NCT Number: NCT05319548

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

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.

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Key information

Conditions

Healthy

Age range

18 year–40 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

UW-Madison Department of Nutritional Sciences

Madison, Wisconsin, 53706, United States

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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).

Treatment and study plan

Purple-Red Carrot Juice

Other

Purple-Red carrot juice contains provitamin A carotenoids (beta-carotene, alpha-carotene), the non-provitamin A carotenoid, lycopene, as well as anthocyanins

Red Carrot Juice

Other

Red carrot juice contains provitamin A carotenoids (beta-carotene, alpha-carotene), and the non-provitamin A carotenoid, lycopene, but does NOT contain anthocyanins..

Purple Carrot Juice

Other

Purple carrot juice does NOT contain provitamin A carotenoids (beta-carotene, alpha-carotene), nor the non-provitamin A carotenoid, lycopene, but contains anthocyanins.

Primary outcomes

  1. Change in serum retinol concentration

    Time frame: 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

    Blood draws will take place on the first, second, and fourth test day (days 8, 9, 11 of each arm)

  2. Change in serum carotenoid concentration

    Time frame: 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

    Blood draws will take place on the first, second, and fourth test day (days 8, 9, 11 of each arm)

  3. Change in serum anthocyanin concentration

    Time frame: 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

    Blood draws will take place on the first, second, and fourth test day (days 8, 9, 11 of each arm)

Secondary outcomes

  1. Change in antioxidant capacity of the carrots and carrot juice measured by enzyme activity assay

    Time frame: up to 1 month

    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).

  2. Change in alpha-glucosidase inhibition activities of the carrots and carrot juice measured by enzyme activity assay

    Time frame: up to 1 month

    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).

  3. Change in alpha-amylase inhibition activities of the carrots and carrot juice measured by enzyme activity assay

    Time frame: up to 1 month

    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).

  4. Change in serum glucose concentration

    Time frame: 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

    Blood draws will take place on the first, second, and fourth test day (days 8, 9, 11 of each arm)

  5. Change in serum insulin concentration

    Time frame: 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

    Blood draws will take place on the first, second, and fourth test day (days 8, 9, 11 of each arm)

  6. Change in serum incretin concentration

    Time frame: 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

    Blood draws will take place on the first, second, and fourth test day (days 8, 9, 11 of each arm)

Sponsors and collaborators

Lead sponsor

University of Wisconsin, Madison

Other

Registry information

Official study title

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

Important dates

Study start
2022
Primary completion
2023
Study completion
2023
First posted
Apr 8, 2022
Registry last updated
Dec 18, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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