Relationships between Skin Carotenoid Levels and Metabolic Syndrome

Abstract

Carotenoids have potential antioxidant and anti-inflammatory effects; their protective roles are of particular interest in the pathogenesis of metabolic syndrome (MetS). The reflection spectroscopy method has been recently developed to noninvasively measure skin carotenoid (SC) levels, which highly correlates with serum concentration of carotenoids. The relationship between SC levels and metabolic syndrome has been investigated. We aimed to identify the differences in patient characteristics and SC levels between participants with and without MetS in a large health examination population. In addition, the relationships between SC levels and various clinical parameters related to MetS were investigated. SC levels were measured using a reflection spectroscopy. A total of 1812 Japanese participants (859 male, 953 female; mean age ± standard deviation (SD), 57.8 ± 11.0 years) comprised the study population, i.e., participants with MetS (n = 151) and those without MetS (n = 1661). Multivariate logistic regression analysis was performed to identify variables associated with MetS. Compared to controls (377.3 ± 122.8), SC indices were significantly lower in patients with MetS (340.7 ± 112.5, p = 0.0004). Multivariate models also suggested that lower SC was significantly associated with MetS after adjustment for age, sex, smoking habit, and other potential risk factors for MetS. Furthermore, male gender (p < 0.0001), smoking habit (p < 0.0001) and worse lipid profiles (i.e., serum triglyceride (r = −0.1039, p < 0.0001), high-density lipoprotein (r = 0.1259, p < 0.0001), and usage of hypolipidemic agents (p = 0.0340)) were significantly associated with lower SC levels. The current study indicated that lower SC levels were significantly associated with MetS. This study highlights the antioxidant capacity of carotenoids in patients with MetS and the clinical utility of non-invasive and cost-effective SC measurement to detect participants who are at risk of developing MetS in a large population.

Relevance of Diabetic Retinopathy with AGEs and Carotenoid Levels Assessed by Skin Sensors

“…The study did not find a difference in Veggie scores among the control, NDR, and DR groups, whereas female sex, nonsmoking status, and better BCVA were associated with higher Veggie scores (Table 10). Higher carotenoid levels in women and nonsmoking status have been reported previously [19][20][21]. Higher dietary intake of carotenoids in women than men has also been reported [22]; thus, the current results are consistent with previous studies.…”

“…Provitamin A carotenoids, which are converted into vitamin A, are essential for maintaining the photoreceptor cell function. Macular pigment xanthophylls, such as lutein and zeaxanthin, are the major protectants of the foveal region via their antiphotooxidative stress effects [ 19 ]. Filtering of the harmful shorter wavelength blue light and/or elimination of singlet oxygen species explains the cellular protection activities of these macular pigment carotenoids [ 19 ].…”

“…Macular pigment xanthophylls, such as lutein and zeaxanthin, are the major protectants of the foveal region via their antiphotooxidative stress effects [ 19 ]. Filtering of the harmful shorter wavelength blue light and/or elimination of singlet oxygen species explains the cellular protection activities of these macular pigment carotenoids [ 19 ]. Carotenoids were associated with better visual function by maintaining lens transparency [ 23 ] and macular function [ 24 ].…”

Carotenoids in Human Skin In Vivo: Antioxidant and Photo-Protectant Role against External and Internal Stressors

“…A number of studies have shown an association between a diet that is rich in carotenoids, e.g., fruit and vegetables, and the risk of developing certain types of cancer according to the following principle: the more carotenoids in a diet, the lower the probability of cancer development [ 209 , 210 , 211 ]. The same relationship has been observed between a carotenoid-rich diet and the risk of cardiovascular [ 212 , 213 ], eye [ 214 ], and other diseases [ 11 , 215 ]. The inverse relationship for the development of lung cancer has been reported for heavy smoking individuals after supplementation of a high single dose of ß-carotene, which strongly exceeds the physiological concentration [ 68 ].…”

Fingertip-Measured Skin Carotenoids and Advanced Glycation End Product Levels in Glaucoma

“…The instrument can measure in the 350–850 nm range, which includes the absorption wavelengths of carotenoids around 480 nm. The association between skin melanin content and carotenoids is weakly correlated, indicating that SC levels are not affected by melanin absorption [ 35 , 36 ].…”