Spectroscopic biofeedback on cutaneous carotenoids: A powerful tool for primary prevention in advanced age.

Antioxidants exhibit a powerful defense mechanism against aging and chronic disease. The human skin reflects the overall antioxidant status of the body. The cutaneous carotenoid concentration is a biomarker for individual nutritional intake of antioxidants, as it correlates with the overall antioxidant status. The cutaneous carotenoid concentrations of 44 adults were measured using a multiple spatially resolved reflection spectroscopy. During the first phase of the study, measurements of carotenoid concentrations were performed without revealing the antioxidant status, followed by an intervention phase during which the volunteers were informed about their individual values by biofeedback. During the third phase, biofeedback was combined with an additional intake of fruit juices. Across time points, participants showed increasing levels of carotenoid status. Thus, biofeedback leads to an improvement of the carotenoid value of the skin. Providing a biofeedback measurement to monitor the individual antioxidative status may be an easy and cost-effective way of primary prevention.