Examining Validity and Sensitivity of Pressure-Mediated Reflection Spectroscopy as a measure of fruit and vegetable consumption in a diverse community - Project Summary/ Abstract
A diet rich in fruits and vegetables (F&Vs) is associated with lower risk of nutrition-related chronic diseases and
all-cause mortality. Despite these benefits, the US population under-consumes F&Vs, with particularly low
intake in disadvantaged populations. Low F&V intake results in higher rates of nutrition-related chronic disease
among disadvantaged populations when compared with more advantaged populations. Detecting and
addressing inadequate F&V intake in these populations is needed to reduce such disparities. Yet, there is still
no commonly used predictive, objective measure of F&V intake for surveillance or determination of policy or
intervention effectiveness. The current objective, “gold standard” marker of F&V intake is blood carotenoid
concentration—an expensive, time-intensive, and invasive measurement. Traditional methods of self-reported
dietary assessment are imprecise and have diminished utility in rural and disadvantaged populations due to
low literacy, numeracy, and internet connectivity. In the past decade, skin carotenoid status assessed by non-
invasive resonance Raman spectroscopy (RRS) has emerged as a promising biomarker of F&V intake.
Reflection spectroscopy (RS) is an improvement over RRS, offering stronger signals, faster data acquisition,
and greater portability in a commercially available device (Veggie Meter, Longevity Link Corporation).
However, a hurdle impedes deployment of RS for widespread use: to date, nearly all of the non-invasive skin
carotenoid validation has been conducted in non-Hispanic whites, primarily by RRS. Therefore, it is critical to
evaluate RS in racially and ethnically diverse populations. The central goal of this proposal is to examine
validity and sensitivity of RS-assessed skin carotenoid status as a marker of F&V intake in a racially and
ethnically diverse sample of individuals. First, we will examine the association (RS Device Validity) between
RS-assessed skin carotenoids and the primary outcomes of objectively-measured plasma carotenoids and
self-reported F&V consumption across four diverse groups: African-American/Black, Asian, White, and
Hispanic/Latino (n=80/group, 40/group per state, N = 320). Then we will conduct a randomized controlled trial
to define the relative skin carotenoid responses (RS Device Sensitivity) across racial-ethnic groups, in
comparison with plasma carotenoid responses. We will conduct an 8-week randomized controlled trial of a
carotenoid-containing juice intervention [placebo control, low (12 oz.) and high (24 oz.) dose juice (29.7 mg
carotenoids or ~1.1 c vegetable equivalents)/12 oz.] across 4 genetically-stratified racial-ethnic groups (n =
30/group*treatment, N = 360). Finally, we will investigate the genetic basis for racial/ethnic group differences in
skin carotenoid responses to diet through hypothesis-driven genomic analysis of participants from Aims 1 and
2. The results of this study will prepare RS for mass deployment in population surveillance studies and
community-based intervention trials, ultimately leading to more accurate determination of the most effective
strategies to reduce health disparities related to low F&V intake in the United States and beyond.
