Concurrent validity of skin carotenoid status as a concentration biomarker of vegetable and fruit intake compared to multiple 24-h recalls and plasma carotenoid concentrations across one year: a cohort study

Abstract

BackgroundBiological markers of vegetable and fruit (VF) intake are needed both for nutrition surveillance and for the evaluation of nutrition interventions. Optically assessed skin carotenoid status (SCS) has been proposed as a marker of intake but there are few published validity studies to date. Therefore, the objective of the study was to examine the concurrent validity of multiple methods of assessing VF intake cross-sectionally and seasonally over one year and to discuss the relative merits and limitations of each method.MethodsFifty-two 40–60 y old women completed a 1-year longitudinal study that included 1) SCS assessment using resonance Raman spectroscopy (RRS) and using pressure-mediated reflection spectroscopy (RS) at 12 timepoints, 2) thirty-six 24-h recalls using the Automated Self-Administered 24-Hour Dietary Assessment Tool (ASA24; total 1866 recalls), and 3) plasma carotenoid concentrations measured every 3 months. Pearson correlation coefficients and mixed linear models were used to estimate pairwise correlations between RRS, RS, ASA24, and plasma carotenoids.ResultsRS and RRS were strongly correlated at baseline and over the year (r = 0.86 and 0.76; respectively, P < 0.001). RS was strongly correlated with plasma carotenoids at baseline (r = 0.70) and moderately across the year (r = 0.65), as was RRS (r = 0.77 and 0.69, respectively, all P < 0.001). At baseline, self-reported VF was weakly correlated with RRS (r = 0.33; P = 0.016), but not with RS or plasma carotenoids. Across the year, self-reported VF intake was weakly correlated with both RS (r = 0.37; P = 0.008), RRS (r = 0.37; P = 0.007), and with plasma carotenoids (r = 0.36; P < 0.008).ConclusionsSCS as measured by RS and RRS is moderately to strongly correlated with plasma carotenoid concentrations both cross-sectionally and longitudinally, indicating that it can be a powerful tool to assess carotenoid-rich VF intake in populations.Clinical trial registryThis trial was registered at ClinicalTrials.gov as NCT01674296.

Skin Carotenoid Level as an Alternative Marker of Serum Total Carotenoid Concentration and Vegetable Intake Correlates with Biomarkers of Circulatory Diseases and Metabolic Syndrome

“…Skin carotenoid levels measured in this study were positively correlated with serum total carotenoid concentrations ( Table 2 ). The correlation coefficient was high (0.678) and was comparable to that reported by Jahns et al (0.70) [ 16 ] and Meinke et al (0.6672) [ 19 ] although the measurement of our study was once per person and it contained some uncertainty. This suggests that skin carotenoid levels may be noninvasive measurable indicators of total serum carotenoid concentrations.…”

“…We speculate that we had a low correlation coefficient owing to limitations due to the uncertainty inherent in the dietary frequency method of the BDHQ [ 30 ], although this method has been validated. Jahns et al [ 19 ] reported that the correlation coefficients between skin carotenoid levels measured via RS and 24-h recall vegetable and fruit intake were 0.27 (not significant) and 0.37 ( p < 0.01), respectively, for baseline across the year, showing similar values to the coefficient of the present results. As green and yellow vegetables contain abundant carotenoids, the correlation coefficient between them was the highest in the present study.…”

“…Noninvasive measurements of carotenoids [ 12 , 13 ], which are abundant in vegetables (e.g., tomatoes, carrots, and spinach) and fruits (e.g., citrus and prunes), may be a potential candidate. These values can be measured via resonance Raman spectroscopy (RRS) [ 14 ] and have been shown to correlate with fruit and vegetable intake [ 15 , 16 , 17 , 18 , 19 ]. However, RRS instruments are too expensive to popularize this method.…”

Associations Between Farmers’ Market Shopping Behaviors and Objectively-Measured and Self-Reported Fruit and Vegetable Intake in a Diverse Sample of Farmers’ Market Shoppers: A Cross-Sectional Study

“…The Veggie Meter® uses pressure-mediated re ection spectroscopy on the index nger to assess skin carotenoids, which is a valid method to assess skin carotenoid status and approximate FV intake. 28,29 Three measurements were taken, and the mean of all measures was used in analysis.…”

“…As an alternative, skin carotenoids measured with pressuremediated re ection spectroscopy is a validated method to approximate FV intake. [27][28][29] In this paper, we explored associations between self-reported and objectively-measured FV intake and three measures of farmers' market shopping behavior: (1) monthly frequency of farmers' market shopping, (2) variety of FV purchased on one market day, and (3) money and/or bene ts typically spent on FV at the farmers' market per week, in both a rural population and a racially/ethnically diverse urban population. We hypothesized that FV intake, measured both by self-report and skin carotenoids, would be positively associated with shopping frequency at farmers' markets, variety of FV purchased, and money and/or bene ts spent on FV.…”