Reference Values for Retinol, Tocopherol, And Main Carotenoids in Serum of Control and Insulin-Dependent Diabetic Spanish Subjects (General Clinical Chemistry‪)‬

Carotenoids, retinol, and tocopherol are among the most widely studied compounds in various populations, for both serum concentrations and dietary intake [1-8], because of their inverse relationship with the development of several diseases, e.g., cancer, cardiovascular disease, and cataracts [9-12]. Several factors have been described as influencing serum concentrations of carotenoids, and to a lesser extent, the concentrations of tocopherol and retinol: sex, age, dietary intake, smoking and drinking habits, and seasonality [1, 2,13-16]. In the literature, a great variability is evident in carotenoid serum concentrations from various populations [1-4,17,18], a fact that has made it difficult to establish consensus cutoff points for application to different populations and for interpretation of carotenoid concentration in the context of disease prevention.