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The aim of the current study was to determine whether dietary carotenoids influence skin pigmentation and UV photosensitivity in a healthy unsupplemented panel (n = 22) of Caucasian (skin Type II) subjects. Skin spectrophotometric and tristimulus (L*a*b*) CR200 chromameter readings were made at various body sites to objectively measure skin carotenoid levels and skin color, respectively. The minimal erythemal dose (MED) was also measured to determine the intrinsic UV photosensitivity of the skin. We found that tristimulus b* values (but not L* and a* values) were consistently and closely correlated with skin carotenoid levels at a number of body sites including the back (r = 0.85, P < 0.00001), forehead (r = 0.85, P < 0.00001), inner forearm (r = 0.75, P < 0.0001) and palm of the hand (r = 0.78, P < 0.0001). Skin carotenoid levels and MED were also correlated in these subjects (r = 0.66, P < 0.001), as were tristimulus b* values and MED (r = 0.71, P < 0.0002). From these observations, we conclude that carotenoids from a normal, unsupplemented diet accumulate in the skin and confer a measurable photoprotective benefit (at least in lightly pigmented Caucasian skin), that is directly linked to their concentration in the tissue. Carotenoids also appear to contribute measurably and significantly to normal human skin color, in particular the appearance of "yellowness" as defined objectively by CR200 tristimulus b* values. On the basis of these findings we believe that objective measurements of skin color, in particular tristimulus b* values, may be a potentially useful means of monitoring dietary carotenoid status and assessing UV photosensitivity in Caucasian populations. [ABSTRACT FROM AUTHOR]

An abstract of the study "Effects of a Dermatological Formulation Containing Mesembryanthemum Crystallinum Extracts on Skin Hydration Levels" by Christa Raak and colleagues is presented.

Background: About 50% of the sun's radiation arriving on earth is visible light (VIS). For a long time, its effects on human health have not been fully investigated. But recently, the influence of VIS has gained more attention, especially regarding skin physiology. Studies showed various effects, many of them harmful, comparable to UV radiation. As a result, there are now a few sunscreens commercially available which claim protection against VIS. The question of whether protection is necessary is still much discussed. Aims: The objective of this study was to develop an easy-to-perform high-energy visible (HEV) and low-end visible (LEV) light transmittance method to determine the direct VIS protection of sunscreens and other cosmetic samples. Furthermore, the influence of the brightness of the tested products on the HEV, LEV, and infrared A protection was investigated. Methods: An experimental setup consisting of a light source, a VIS-transmissible filter system, and a sensor unit was built to measure the direct VIS protection of sunscreens and other daily skin care products in two ranges of the VIS area. For a closer look, the brightness of the samples was evaluated by photometric assessment. Results/Conclusion: The experimental setup could be validated. It could be demonstrated for the first time that there is a strong positive linear correlation between transmittance and brightness of tinted sunscreen and daily skin care products with sunscreen properties in the HEV, LEV, and infrared A range. However, tinted samples worked best in the blue light region, and the higher the wavelength range, the lower the protection. [ABSTRACT FROM AUTHOR]

Background: Skin reaction to spaceflight has not really been studied yet, although the skin has a very important barrier function to protect the body and can contribute to a more general understanding of physiology. It is proposed here to make a more thorough investigation of the skin during long-term spaceflight, using noninvasive techniques. Aims: The aim of the present Skin-B study is to investigate the kinetics and range of possible skin modifications during long-duration spaceflights and their recovery. Methods: In order to investigate the effect on skin physiological parameters during spaceflight, measurements were carried out on 6 astronauts with respect to skin hydration, transepidermal water loss/barrier function, and surface evaluation of the living skin in orbit. Additional measured parameters on the ground were skin elasticity, skin density and thickness, as well as microcirculation. Results: Data from the Skin-B subjects (n = 6) contradict the results obtained in the previous pilot study SkinCare (n = 1 subject). In the present study, no deterioration of the skin was found but rather an improvement in skin hydration and skin barrier function, and no changes or improvement in the appearance of the skin surface. Furthermore, the skin density and skin thickness as well as skin elasticity values were unchanged from pre-flight values. Conclusion: In conclusion, we found that spaceflight under present conditions has no negative impact on skin physiological parameters. [ABSTRACT FROM AUTHOR]