Individual carotenoid concentrations in adipose tissue and plasma as biomarkers of dietary intake.

BACKGROUND: Plasma and adipose tissue concentrations of carotenoids are thought to reflect short- and long-term intakes of carotenoids, respectively. The ability of adipose tissue carotenoid concentrations to reflect dietary intake in population studies is unknown.
OBJECTIVE: We examined the relation between intakes of the major dietary carotenoids and their concentrations in plasma and adipose tissue.
DESIGN: A blood sample and an adipose tissue biopsy sample were collected from 115 women and 344 men in Costa Rica after they had fasted overnight, and a dietary interview based on a 135-item food-frequency questionnaire was administered. After carotenoid intake was adjusted for total energy intake and plasma concentrations were adjusted for HDL-, LDL-, and VLDL-cholesterol concentrations, we calculated partial Spearman correlation coefficients that were adjusted for age, sex, smoking, and body mass index.
RESULTS: In women, the correlations (r) between intakes and concentrations of alpha-carotene, beta-carotene, beta-cryptoxanthin, and lutein+zeaxanthin were 0.25, 0.29, 0.44, and 0.17, respectively (P < 0.05 for r > or = 0.19), in adipose tissue and 0.26, 0.13, 0.55, and 0.22 in plasma. In men, these values were 0.04, 0.07, 0.23, and 0.06 in adipose tissue and 0.24, 0.22, 0.44, and 0.20 in plasma. In women and men, correlations for lycopene were higher in plasma (r = 0.19 and 0.35, respectively) than in adipose tissue (r = 0.14 and 0.26). The relative abundance of each carotenoid in the diet was similar to its distribution in plasma but not in adipose tissue.
CONCLUSION: The usefulness of adipose tissue and plasma carotenoids as biomarkers of intake is similar, although correlations for individual carotenoids vary substantially.