Sensitivity of pressure-mediated reflection spectroscopy to detect dose-dependent changes in skin carotenoids: A randomized controlled trial

Authors: Casperson, Shanon; Jahns, Lisa; Larson, Kate; Hess, Julie; PALMER, DANIEL - University Of North Dakota; Roemmich, James

Submitted to: Journal of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/4/2023
Publication Date: 2/1/2023
Citation: Casperson, S.L., Jahns, L.A., Larson, K.J., Hess, J.M., Palmer, D., Roemmich, J.N. 2023. Sensitivity of pressure-mediated reflection spectroscopy to detect dose-dependent changes in skin carotenoids: A randomized controlled trial. Journal of Nutrition. 153(2):588-597. https://doi.org/10.1016/j.tjnut.2023.01.002.
DOI: https://doi.org/10.1016/j.tjnut.2023.01.002

Interpretive Summary: Carotenoids are the pigments which give fruits and vegetables their yellow, orange, and red color and are deposited in the skin when consumed. A new device called the Veggie Meter can measure the level of carotenoids that have been deposited in the skin. However, the sensitivity of the Veggie Meter to detect changes in skin carotenoids in response to changes in fruit and vegetable consumption is not yet known. As a result, this study was conducted to determine the capacity of the Veggie Meter to detect changes in skin carotenoids in response to different amounts of carotenoids intake. Healthy adults drank either water or three different amounts of vegetable juice (0.8 cups, 1.5 cups, or 2 cups) every day for 8 weeks. Skin carotenoids levels were measured each week with the Veggie Meter. We found that the Veggie Meter can detect changes in the consumption of the vegetable juice, but that amount consumed and how long it was consumed were important factors.

Technical Abstract: Background: Technological advances have produced compact, portable analyzers that provide a rapid, noninvasive measure of the level of carotenoids that have been deposited in the skin. However, the sensitivity of these devices to detect changes in skin carotenoids is not known. Objective: To determine the capacity of pressure-mediated reflection spectroscopy (RS) to detect changes in skin carotenoids in response to different amounts of carotenoids intake. Methods: Adults 18–65 years of age without obesity were randomly assigned to one of three carotenoid-containing vegetable juice amounts – 1) the LOW group (n=22) consumed 5.5 fl. oz./day; 2) the MED group (n=22) consumed 10 fl. oz./day; 3) the HIGH group (n=19) consumed 13 fl. oz./day or to a control group (water; n=20). All beverages were provided in premeasured containers for daily consumption. RS-assessed skin carotenoids were measured weekly. Plasma carotenoid concentrations were assessed at weeks 0, 4 and 8 by HPLC-MS/MS. Data were analyzed using mixed models. Results: RS-assessed skin carotenoids were greater than baseline starting at week 1 in the HIGH group (p=0.01), week 2 in the MED group (p=0.03), week 3 in the LOW group (p=0.03). Compared to the control group, skin carotenoids were greater at weeks 2–8 ((p=0.01) except for week 3 (p=0.08)) in the HIGH group and weeks 6–8 (p=0.03) in the MED group. No differences were observed between the control and LOW groups. There was a positive between-subject correlation between skin carotenoids and plasma total carotenoids concentrations (r=0.65, p<0.001). Conclusions: These findings demonstrate that RS can detect changes in V/F consumption in a week if differences in consumption amounts is at least 2 cup-equivalents of carotenoid-rich V/F. However, when using RS to detect differences between groups a minimum of 1.5 additional cup-equivalents of carotenoid-rich V/F needs to be consumed per day for at least 6 weeks.