Serum carotenoids and Pediatric Metabolic Index predict insulin sensitivity in Mexican American children

High concentrations of carotenoids are protective against cardiometabolic risk traits (CMTs) in adults and children. We recently showed in non-diabetic Mexican American (MA) children that serum alpha-carotene and beta-carotene are inversely correlated with obesity measures and triglycerides and positively with HDL cholesterol and that they were under strong genetic influences. Additionally, we previously described a Pediatric Metabolic Index (PMI) that helps in the identification of children who are at risk for cardiometabolic diseases. Here, we quantified serum lycopene and beta-cryptoxanthin concentrations in approximately 580 children from MA families using an ultraperformance liquid chromatography-photodiode array and determined their heritabilities and correlations with CMTs. Using response surface methodology (RSM), we determined two-way interactions of carotenoids and PMI on Matsuda insulin sensitivity index (ISI). The concentrations of lycopene and beta-cryptoxanthin were highly heritable [h(2) = 0.98, P = 7 x 10(-18) and h(2) = 0.58, P = 1 x 10(-7)]. We found significant (P <= 0.05) negative phenotypic correlations between beta-cryptoxanthin and five CMTs: body mass index (- 0.22), waist circumference (- 0.25), triglycerides (- 0.18), fat mass (- 0.23), fasting glucose (- 0.09), and positive correlations with HDL cholesterol (0.29). In contrast, lycopene only showed a significant negative correlation with fasting glucose (- 0.08) and a positive correlation with HDL cholesterol (0.18). Importantly, we found that common genetic influences significantly contributed to the observed phenotypic correlations. RSM showed that increased serum concentrations of alpha- and beta-carotenoids rather than that of beta-cryptoxanthin or lycopene had maximal effects on ISI. In summary, our findings suggest that the serum carotenoids are under strong additive genetic influences and may have differential effects on susceptibility to CMTs in children.

Automated summary

High concentrations of carotenoids, particularly alpha-carotene and beta-carotene, have protective effects against cardiometabolic risk traits in both adults and children. Genetic influences play a significant role in determining the levels of these carotenoids in serum, and they show correlations with various cardiometabolic risk factors. Further research suggests that carotenoids may have differential effects on susceptibility to cardiometabolic diseases in children.