[ association of dietary beta-carotene and beta-cryptoxanthin with the incidence of insulin resistance in adults: Tehran lipid and glucose study]

Background and Objective: Dietary intake of beta-carotene and beta-cryptoxanthin may be associated with reduce the risk of insulin resistance, due to their antioxidant properties. The aim of this study was to determine the relation between dietary intake of beta-carotene and beta-cryptoxanthin and the risk of insulin resistance in adults

Methods: In this prospective cohort study, 938 [421 men and 517 women], aged between 19 to 82 years were selected from among participants of the Tehran Lipid and Glucose Study in Iran. Dietary intake of beta-carotene and beta-cryptoxanthin were determined using a valid and reliable food frequency questionnaire. Fasting serum glucose and insulin were measured at base line and again after a 3-year of follow up. Logistic regression models were used to estimate the occurrence of insulin resistance across tetiles of beta-carotene and beta-cryptoxanthin with adjustment for potential confounding variables

Results: The mean age of participants was 40.7 +/- 12.1 years. beta-carotene was inversely associated with insulin resistance after adjustment for confounder variables [95% CI= 0.25-0.72, OR= 0.42, P-value for trend=0.01]. Also, an inverse association was found between dietary intake of beta-cryptoxanthin and insulin resistance risk [95% CI= 0.30-0.84, OR= 0.51, P-value for trend=0.01]

Conclusion: There was inverse association between dietary intake of beta-carotene and beta-cryptoxanthin and risk of insulin resistance in adults

[The association of red, orange and yellow fruits and vegetables with the incidence of insulin resistance in adults: tehran lipid and glucose study]

Introduction: although previous studies report the relationship of diabetes with various groups of fruits and vegetables, and also an inverse association between insulin resistance with dietary carotenoids and flavonoids, no studies have yet examined the effect of [Fruit and Vegetable] FV subgroups on insulin resistance. The aim of this study was to investigate the association of red, orange and yellow FV, with the 3-year incidence of insulin resistance in adults

Materials and Methods: in this longitudinal study, 940 men and women, aged>19 years were selected from among participants of the Tehran Lipid and Glucose Study. Dietary intakes of fruits and vegetables [FV] were determined using a valid and reliable food frequency questionnaire. Fasting serum glucose and insulin were measured at baseline and again after a 3-year of follow up. Logistic regression models were used to estimate the occurrence of IR across tertiles of color subgroups of FV with adjustment for potential confounding variables

Results: the mean age and body mass index [BMI] of participants were 40.34+/-12.1 years and 26.4+/-4.4 kg/m2 respectively. Mean residual energy adjusted total intakes of FV, red/purple, orange and yellow FV were 503g/d, 172, 108and 104g/d, respectively. Total intake of FV was inversely associated with IR after 3 years of follow up [OR=0.511P for trend=0.018]. and also an inverse association was found between red/purple [OR=0.48 P for trend=0.012], orange [OR=0.34 P for trend=0.001] and yellow [OR=0.34 P for trend=0.011] groups and the occurrence of IR

Conclusion: results of this longitudinal study, found an inverse association between dietary intakes of FV, red/purple, orange and yellow groups and the risk of IR in adults