Pressure-mediated reflection spectroscopy criterion validity as a biomarker of fruit and vegetable intake: A two-side cross-sectional study of four racial or ethnic groups

Authors: JILCOTT PITTS, STEPHANIE - East Carolina University; MORAN, NANCY - Children'S Nutrition Research Center (CNRC); WU, QIANG - East Carolina University; HARNACK, LISA - University Of Minnesota; CRAFT, NEAL - Craft Nutrition Consulting; HANCHARD, NEIL - Children'S Nutrition Research Center (CNRC); BELL, RONNY - Wake Forest School Of Medicine; MOE, STACEY - University Of Minnesota; JOHNSON, NEVIN - East Carolina University; OBASOHAN, JUSTICE - University Of North Carolina; CARR-MANTHE, PAMELA - University Of Minnesota; LASKA, MELISSA - University Of Minnesota

Submitted to: Journal of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/22/2021
Publication Date: 9/25/2021
Citation: Jilcott Pitts, S.B., Moran, N.E., Wu, Q., Harnack, L., Craft, N.E., Hanchard, N., Bell, R., Moe, S.G., Johnson, N., Obasohan, J., Carr-Manthe, P.L., Laska, M.N. 2021. Pressure-mediated reflection spectroscopy criterion validity as a biomarker of fruit and vegetable intake: A two-side cross-sectional study of four racial or ethnic groups. Journal of Nutrition. https://doi.org/10.1093/jn/nxab349.
DOI: https://doi.org/10.1093/jn/nxab349

Interpretive Summary: Carotenoids are colorful, fat-soluble compounds found predominantly in fruits and vegetables. When people eat carotenoids in foods, some of the carotenoids are deposited in their skin, and the amount of carotenoids can be measuring optically through a quick, non-invasive measurement. This study sought to determine whether skin carotenoid measurements are correlated with blood carotenoid concentrations and fruit and vegetable intake in diverse U.S. adults. The results showed that skin carotenoids were significantly correlated with plasma carotenoid concentrations and with fruit and vegetable intake and did not vary by self-described race, but did vary by skin melanin amounts. In conclusion, skin carotenoid measurements may provide a rapid, valid estimate of dietary intake in diverse U.S. adults.

Technical Abstract: Valid biomarkers of fruit and vegetable (FV) intake are needed for field-based nutrition research. Our objective was to examine criterion-related validity of pressure-mediated reflection spectroscopy as a proxy measure of FV intake, using plasma carotenoids and self-reported FV and carotenoid intake as primary and secondary criterion measures, respectively. Healthy adults 18-65 years of age, self-identifying as African American/ black (n = 61), Asian (n = 53), white (n = 70), or Hispanic (n = 29) in North Carolina and Minnesota were recruited. Skin carotenoids were assessed via pressure-mediated reflection spectroscopy (Veggie Meter), skin melanin via spectrophotometer, and total plasma carotenoid concentration by HPLC-PDA. Self-reported carotenoid and FV intake was assessed using a semi-quantitative food frequency questionnaire. Relationships between skin carotenoids, plasma carotenoids, FV and carotenoid intake, with differences by race or ethnicity, age, sex, weight status, cholesterol, and melanin index, were examined by bivariate correlations and adjusted multivariate linear regressions. The overall unadjusted correlation between skin and total plasma carotenoids was r = 0.71 and ranged from 0.64 (non-Hispanic black) to 0.80 (Hispanic). Correlations between skin carotenoids and self-reported FV intake ranged from 0.24 (non-Hispanic black) to 0.53 (non-Hispanic white), with an overall correlation of r = 0.35. In models adjusted for age, sex, racial or ethnic group, and body mass index, skin carotenoids were associated with plasma carotenoids (R2 = 0.55), FV (R2 = 0.17), and carotenoid intake (R2 = 0.20). For both plasma carotenoid and FV measures, associations with skin carotenoids did not vary by race; but these relationships did differ by skin melanin - those with lower melanin had a lower correlation between skin and plasma carotenoids. Reflection spectroscopy-assessed skin carotenoids may be a reasonable alternative to measurement of plasma carotenoids, a biomarker used to approximate FV intake.