Perinatal plasma carotenoids and vitamin E concentrations with glycemia and insulin resistance in women during and after pregnancy

Abstract Background: Carotenoids and vitamin E play beneficial roles against insulin resistance and β-cell dysfunction. Objective: To examine the associations of perinatal plasma carotenoids and E vitamers concentrations with glycemia, insulin resistance, gestational and type-2 diabetes mellitus at mid-pregnancy and post-pregnancy in women of the Growing Up in Singapore Towards healthy Outcomes (GUSTO) cohort. Methods: Plasma concentrations of carotenoids and E vitamers were measured at delivery, and principal component analysis derived patterns of their concentrations. Fasting and 2-hour plasma glucose, and fasting plasma insulin were measured at 26-28 weeks’ gestation and 4-6 years’ post-pregnancy, with derivation of homeostatic model assessment for insulin resistance (HOMA-IR). Associations were examined using linear or logistic regressions adjusting for key confounders. Results: In 678 women, two patterns of carotenoids (CP1: α-, β-carotene, lutein; CP2: zeaxanthin, lycopene, β-cryptoxanthin) and one pattern of E vitamers (VE: γ-, δ-, α-tocopherols) were derived. A higher CP1 score (1-SD) was associated with lower gestational fasting glucose [β (95%CI): -0.06 (-0.10, -0.02) mmol/L], and lower gestational and post-pregnancy HOMA-IR [gestational: -0.17 (-0.82, 0.01), P=0.065; post-pregnancy: -0.11 (-0.15, -0.08) mmol/L]. In contrast, a higher VE score (1-SD) was associated with higher gestational and post-pregnancy fasting and 2-hour glucose [gestational: 0.05 (0.01, 0.08) and 0.08 (0.01, 0.16); post-pregnancy: 0.19 (0.07, 0.31) and 0.24 (0.06, 0.42) mmol/L], but there were no associations with HOMA-IR. Conclusions: Higher α-, β-carotene and lutein may lower gestational fasting glycemia, and gestational and post-pregnancy insulin resistance; but higher vitamin E may increase gestational and post-pregnancy glycemia. Further investigation in cohorts with prospective longitudinal measurements of these vitamins are needed.