You Are What You Eat: Within-Subject Increases in Fruit and Vegetable Consumption Confer Beneficial Skin-Color Changes

R Whitehead was funded by an ESRC Studentship.Background: Fruit and vegetable consumption and ingestion of carotenoids have been found to be associated with human skin-color (yellowness) in a recent cross-sectional study. This carotenoid-based coloration contributes beneficially to the appearance of health in humans and is held to be a sexually selected cue of condition in other species. Methodology and Principal Findings: Here we investigate the effects of fruit and vegetable consumption on skin-color longitudinally to determine the magnitude and duration of diet change required to change skin-color perceptibly. Diet and skin-color were recorded at baseline and after three and six weeks, in a group of 35 individuals who were without makeup, self-tanning agents and/or recent intensive UV exposure. Six-week changes in fruit and vegetable consumption were significantly correlated with changes in skin redness and yellowness over this period, and diet-linked skin reflectance changes were significantly associated with the spectral absorption of carotenoids and not melanin. We also used psychophysical methods to investigate the minimum color change required to confer perceptibly healthier and more attractive skin-coloration. Modest dietary changes are required to enhance apparent health (2.91 portions per day) and attractiveness (3.30 portions). Conclusions: Increased fruit and vegetable consumption confers measurable and perceptibly beneficial effects on Caucasian skin appearance within six weeks. This effect could potentially be used as a motivational tool in dietary intervention.Publisher PDFPeer reviewe

In vivo distribution of carotenoids in different anatomical locations of human skin: comparative assessment with two different Raman spectroscopy methods

Background: The cutaneous antioxidants form an efficient protection system against the destructive potential of free radicals, produced by environmental factors, such as UV-sun irradiation, hazardous substances and lifestyle habits. Most of the antioxidants cannot be produced by the human organism. Thus, they have to be incorporated by food and beverages. Material and Methods: In the present manuscript, the distribution of carotenoids as a marker for antioxidative potential in human skin was investigated with two different in vivo Raman spectroscopy methods with an excitation wavelength of 785 nm ( Skin Analyzer) and at 488 nm ( resonance Raman spectroscopy). The carotenoid profile was assessed at three different anatomical locations ( palm, forehead and volar forearm) in 12 healthy volunteers. Results: In untreated skin, the major fraction of the carotenoids is located in the upper part of the stratum corneum (SC). The amount of carotenoid is lower in the upper part of the SC on the forearm compared to forehead and palm shown with both methods. Both methods detect similar distinction patterns of carotenoid levels for the three anatomical locations. Conclusion: The present study supports the hypothesis that antioxidative substances; here carotenoids, are secreted via eccrine sweat glands and/or sebaceous glands to the skin surface. Raman spectroscopic methods are an efficient tool to analyze the distribution of carotenoids in the human skin over time and with the Skin Analyzer over different layers of the epidermis. Resonance Raman spectroscopy is suited to analyze deeper parts of the skin