Concentrations and plasma‐tissue‐diet relationships of carotenoids, retinoids, and tocopherols in humans

Abstract Micronutrients, such as β‐carotene and vitamins A and ?, are potential chemopreventive agents; however, their concentrations in human target tissues are largely unknown. Because these micro‐nutrients may exert their action at the site of target tissues, the tissue concentrations of the micronutrients need to be determined. In this cross‐sectional study, we have measured the concentrations of seven carotenoids, two retinoids, and two tocopherols in paired plasma, buccal mucosal cells (BMC), and skin samples from 96 healthy subjects (ages 26–82 yrs). The plasma‐tissue, as well as the diet‐plasma and diet‐tissue relationships of the micronutrients, and the impact of various potential confounders on the micronutrient concentrations were evaluated. The micro‐nutrient concentrations of plasma and BMC used in the evaluation were the average of three measurements over a one‐month period. Our data indicated that 1) the correlations between the plasma and BMC (Spearman r = 0.40–0.91, p < 0.05) and the plas...