Global Lifetime Non-invasive Spectroscopy-based RRS Quantification of Skin Carotenoids Provides Evidence for Enhancing the Human Healthspan – A Narrative Review

People worldwide are living longer. However, the number of years with quality of life or ‘healthspan’ is decreasing due to age-related disorders/diseases. Carotenoids (health-promoting phytonutrients) benefit or enhance healthspan due to their powerful antioxidant and anti-inflammatory actions via daily fruit and vegetable consumption (FVC) that are metabolized and found in blood, skin and other tissues. Skin scanner spectroscopy-based technology that non-invasively quantifies carotenoid levels addresses bias/error found in dietary questionnaires and difficulties with processing invasive blood samples. The objective of this review was to determine whether skin carotenoid measurements are a predictor of antioxidant activity for improved healthspan by understanding: a) the chemical nature of carotenoids, the basic distribution of carotenoids in food products plus nutraceutical supplements and a comparision of the antioxidant activities of carotenoids, b) the benefits of carotenoids antioxidant activity in health/disease and how carotenoids antioxidant activities enhance health, c) the methods of spectroscopy quantification of skin carotenoids, and d) how data mining of published studies can determine global skin carotenoid antioxidant scores (via non-invasive methods) can contribute to helping address the declining trend of healthspan and provide people with actionable measures to increase their carotenoid intake via FVC and/or supplementation. In general, the findings of this review support the use of spectroscopy-based carotenoid antioxidant quantification for estimating and validating FVC in diverse populations of adults and children. However, further research is warranted to confirm this concept, especially with the ongoing advancements in spectroscopy-based technologies that will better quantify skin carotenoids in the future.