CARROtS Collaborative

About the collaborative

A community of researchers advancing carotenoid assessment science — sharing methods, troubleshooting challenges, and building new collaborations across institutions.

Our purpose

Why we exist

The CARROtS Collaborative was formed to bring together researchers using the Veggie Meter® and related tools. Three goals guide our work.

Share research progress and plans
Members present ongoing work, discuss findings, and coordinate studies across institutions.
Troubleshoot carotenoid research challenges
Collective problem-solving on methodological questions and device variability, with an emphasis on the Veggie Meter®.
Brainstorm ideas and form new collaborations
New partnerships and research directions grow out of forum discussions and listserv conversations.
The Veggie Meter®

What it is and how it works

The Veggie Meter® is a portable, noninvasive device that measures skin carotenoids using reflection spectroscopy. Because carotenoids come only from fruits and vegetables, scores serve as an objective biomarker of intake without blood draws or dietary recall.

1
Dietary intake: A person consumes fruits and vegetables containing carotenoids.
2
Absorption & transport: Carotenoids are absorbed and carried through the bloodstream by lipoproteins.
3
Skin deposition: Carotenoids accumulate in the skin over time, reflecting habitual intake patterns.
4
Optical measurement: The Veggie Meter® applies supradermal pressure and shines a low-powered LED light onto the fingertip, measuring the reflected spectrum.
5
Score output: A skin carotenoid score (0–800) is displayed in approximately 15–20 seconds and compared to a reference population.
Validation
R = 0.81
Serum carotenoids are highly correlated with Veggie Meter® skin carotenoid scores (p < 0.001), supporting its use as a valid biomarker of fruit and vegetable intake.

Ermakov et al., Arch Biochem Biophys, 2018

Noninvasive — no blood draw required
Results in ~15–20 seconds per reading
Portable and field-deployable
Corrects for melanin concentration algorithmically
Validated in diverse populations including children and adults
Who we are

A growing research community

The CARROtS Collaborative brings together researchers from nutrition, public health, dietetics, and Cooperative Extension across the United States, spanning clinical trials to community-based interventions to school and childcare settings.

The collaborative is coordinated through NC State University and the University of California, Davis, with leadership from Drs. Virginia Stage, Rachel Scherr, and Marcela Radtke.

111
Listserv members and growing
67+
Institutions represented
9
Forums held since founding in 2022
2022
Year the collaborative was founded
Our history

How we got here

The collaborative grew from a shared recognition that Veggie Meter® researchers needed a way to compare methods and data.

2015
Veggie Meter® introduced to the research community
Longevity Link Corporation created the Veggie Meter® to commercialize pressure-mediated reflection spectroscopy as a proxy for fruit and vegetable intake.
2022
CARROtS Collaborative founded
Researchers from multiple institutions convened to form the CARROtS Collaborative, creating a structured community for sharing methods and advancing carotenoid assessment research.
2021
Standardized protocol published
Radtke et al. published the first standardized Veggie Meter® protocol in Current Developments in Nutrition, establishing common procedures for calibration, site selection, and data collection.
2026
CARROtS website launched
The collaborative launched carrotscollaborative.org as a central hub for protocols, profiles, publications, and forum recordings.
Get involved

Join the collaborative

The CARROtS Collaborative welcomes researchers at all career stages interested in carotenoid assessment.

Join the listserv
The listserv is how we share forum announcements, collaborative updates, and research news. Email Virginia Stage directly to be added.
virginia_stage@ncsu.edu
Add your profile to the website
Complete the survey to have your expertise, publications, and affiliation featured on the website.
Complete the survey