Examining fruit and vegetable intake in low-income older adults using the Veggie Meter®

Differences of skin carotenoids and adherence to the Mediterranean Diet pattern in adults from Southern Italy and Dominican Republic

BACKGROUND

The measurement of the skin carotenoids using the Veggie Meter® has emerged as a rapid objective method for assessing fruit and vegetable intake, highly recommended by the Mediterranean Diet (MD), which represents one of the healthiest dietary patterns, worldwide. This study aimed to examine differences in skin carotenoid content and degree of adherence to the MD pattern between two adult populations from Southern Italy and the Dominican Republic.

METHODS

This cross-sectional study enrolled a total of 995 adults, 601 subjects from Italy and 394 from the Dominican Republic. All participants underwent anthropometric measurements and skin carotenoid assessment by Veggie Meter®. Adherence to the MD and lifestyle were evaluated using the Mediterranean Diet Adherence Screener (MEDAS) and the Mediterranean Lifestyle Index (MEDLIFE) questionnaires. Correlations between the skin carotenoid and MEDAS score were estimated using Pearson's correlation coefficient. Multiple linear regression models were created to determine variables that affect skin carotenoid score for both populations.

RESULTS

Mean total skin carotenoids were higher in the Italian compared to the Dominican Republic population (342.4 ± 92.4 vs 282.9 ± 90.3; p < 0.005) regardless of sex (women: 318.5 ± 88.9 vs 277.3 ± 91.9, p < 0.005 and men: 371.7 ± 88.3 vs 289.5 ± 88.1, p < 0.005), and remaining statistically significant after age-adjustment of the Dominican Republic sample. Using the MEDAS questionnaire, we found a higher MD adherence score in the Italian than in the Dominican Republic population also after age-adjusting data (7.8 ± 2.1 vs 6.2 ± 3.7; p < 0.005) and even when categorized by sex (Italian vs age-adjusted Dominican Republic women: 7.9 ± 2.1 vs 6.3 ± 2.6; Italian vs age-adjusted Dominican Republic men: 7.7 ± 2.2 vs 6.0 ± 4.7; p < 0.005). Using the MEDLIFE test, total Italians presented a lower score with respect to the age-adjusted Dominican Republic population (3.2 ± 1.2 vs 3.4 ± 1.4; p < 0.05). In multiple regression analysis, skin carotenoids were associated with sex and negatively associated with BMI in the Italian population (sex: β: 54.95; 95% CI: 40.11, 69.78; p < 0.0001; BMI: β: - 1.60; 95% CI: - 2.98,0.86; p = 0.03), while they resulted associated with age and sex in the Dominican Republic population (age: β: 2.76; 95% CI: 1.92, 3.56; p < 0.001; sex: β: 23.29; 95% CI: 5.93, 40.64; p = 0.009). Interestingly, skin carotenoids were positively correlated with MEDAS score in both populations (Italy: r = 0.03, p < 0.0001, Dominican Republic: r = 0.16, p = 0.002).

CONCLUSIONS

This study provides the assessment of the adherence to the MD and skin carotenoid content in adults living in Southern Italy and the Dominican Republic, showing a higher MD adherence score and a skin carotenoid content in inhabitants from the Mediterranean region. Our findings highlight the need to globally encourage fruit and vegetable intake, particularly in non-Mediterranean area.

Validation of resonance Raman spectroscopy-measured skin carotenoid status as a biomarker for fruit and vegetable intake in Korean adults

Blood carotenoid concentration measurement is considered the gold standard for fruit and vegetable (F&V) intake estimation; however, this method is invasive and expensive. Recently, skin carotenoid status (SCS) measured by optical sensors has been evaluated as a promising parameter for F&V intake estimation. In this cross-sectional study, we aimed to validate the utility of resonance Raman spectroscopy (RRS)-assessed SCS as a biomarker of F&V intake in Korean adults. We used data from 108 participants aged 20-69 years who completed SCS measurements, blood collection and 3-d dietary recordings. Serum carotenoid concentrations were quantified using HPLC, and dietary carotenoid and F&V intakes were estimated via 3-d dietary records using a carotenoid database for common Korean foods. The correlations of the SCS with serum carotenoid concentrations, dietary carotenoid intake and F&V intake were examined to assess SCS validity. SCS was positively correlated with total serum carotenoid concentration (r = 0·52, 95 % CI = 0·36, 0·64, P < 0·001), serum β-carotene concentration (r = 0·60, 95 % CI = 0·47, 0·71, P < 0·001), total carotenoid intake (r = 0·20, 95 % CI = 0·01, 0·37, P = 0·04), β-carotene intake (r = 0·30, 95 % CI = 0·11, 0·46, P = 0·002) and F&V intake (r = 0·40, 95 % CI = 0·23, 0·55, P < 0·001). These results suggest that SCS can be a valid biomarker of F&V intake in Korean adults.

A Narrative Review of Factors Associated with Skin Carotenoid Levels

Despite consistent evidence that greater consumption of fruits and vegetables (FV) is associated with significant reductions in chronic disease morbidity and mortality, the majority of adults in the United States consume less than the amounts recommended by public health agencies. As such, there is a critical need to design and implement effective programs and policies to facilitate increases in FV consumption for the prevention of these diseases. To accomplish this, an accurate, inexpensive, and convenient method for estimating the dietary FV intake is required. A promising method for quantifying the FV intake via proxy that has gained interest in recent years is the measurement of skin carotenoid levels via spectroscopy-based devices. However, there exist certain dietary and non-dietary factors that may affect the skin carotenoid levels independently of the dietary intake of carotenoids. In order to validate the ability of this method to accurately estimate the FV intake among diverse demographics, these factors must be identified and taken into consideration. Therefore, this narrative review seeks to summarize the available research on factors that may affect the skin carotenoid levels, determine current gaps in knowledge, and provide guidance for future research efforts seeking to validate spectroscopy-measured skin carotenoid levels as a means of accurately estimating the FV intake among various populations.

Reflection Spectroscopy-Assessed Skin Carotenoids Are Sensitive to Change in Carotenoid Intake in a 6-Week Randomized Controlled Feeding Trial in a Racially/Ethnically Diverse Sample

BACKGROUND

Reflection spectroscopy, utilized by the Veggie Meter, is a less-expensive, noninvasive method to quantify skin carotenoids and is a valid approximation of fruit and vegetable (FV) intake. However, it is unknown to what degree Veggie Meter-assessed skin carotenoid score change is responsive to changes in carotenoid intake.

OBJECTIVES

This study aimed to evaluate Veggie Meter-assessed skin carotenoid score response in a 6-wk randomized controlled trial of a carotenoid-containing juice to determine whether the Veggie Meter can be used to detect nutritionally relevant changes in carotenoid intake; and to compare skin and plasma carotenoid responses with the 6-wk trial.

METHODS

In this 6-wk trial, participants (n = 162) who self-identified as one of 4 US racial/ethnic groups (25% Black, 25% Asian, 27% non-Hispanic White, 23% Hispanic) were randomized to a control group, receiving negligible carotenoids (177 mL apple juice/d), moderate-dose group, receiving 4 mg total carotenoids/d (177 mL orange-carrot juice/d), or high-dose group, receiving 8 mg total carotenoids/d (355 mL orange-carrot juice/d). Skin carotenoid score and plasma total carotenoid concentrations (α-carotene, β-carotene, β-cryptoxanthin, lycopene, lutein, zeaxanthin) were assessed at baseline, 3 wk, and 6 wk (n = 158 completed the trial). Repeated measures linear models were used to examine skin and plasma carotenoids over time and between groups.

RESULTS

At 6 wk, participants in the high-dose and moderate-dose groups had significantly higher mean skin carotenoid scores [414.0 (SD = 100.6) and 369.7 (SD = 100.3), respectively] compared with those in the control group [305.2 (100.5)]. In the high-dose group, there was a 42% change in skin carotenoids from baseline (mean = 290.4) to a 6-wk follow-up (increase of 123, 123/290 = 42.4%). There was a 61% change in the plasma carotenoids in the high-dose group.

CONCLUSIONS

The Veggie Meter is sensitive to increases in daily carotenoid intake in diverse racial/ethnic groups over 6 wk.

CLINICAL TRIALS REGISTRY NUMBER

This trial was registered at clinicaltrials.gov as ID: NCT04056624. Study URL: https://clinicaltrials.gov/ct2/show/NCT04056624.

Recommendations for the Use of the Veggie Meter® for Spectroscopy-Based Skin Carotenoid Measurements in the Research Setting

Carotenoids are a class of phytochemical compounds found in a variety of fruits and vegetables (F/V) and, therefore, are commonly used as a biomarker for F/V intake. The Veggie Meter® is a noninvasive research-grade instrument that detects and quantifies carotenoids in the skin. To determine current practices and examine variability among users, a survey was administered to researchers using the device (n = 19, response rate = 35.8%) and variation in anatomical site preparation, calibration, number of measurements, measurement site, and documentation was observed. A protocol was developed in partnership with Veggie Meter® users to outline the preparation, calibration, and data collection procedures for using this device for research purposes. Although many protocol conditions will benefit from additional validation, this standardized protocol supports the development of a universal data repository to establish usual observed ranges, with the ultimate goal of examining associations between skin carotenoid scores and diet-related health outcomes.