Associations between insulin resistance and three B-vitamins in european adolescents: The HELENA study

Abstract

Objective: To assess whether adolescents with high body mass index (BMI), or fat mass index (FMI), in combination with insulin resistance (assessed with the Homeostatic Model Assessment [HOMA] index), had also lower blood vitamin B6, folate and vitamin B12 concentrations. Methods and materials: Six hundred and fifteen adolescents from the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study, with data on B-vitamins (both intakes and status), and BMI, FMI, HOMA, were selected. Intakes were assessed by two non-consecutive 24-h recalls. B-vitamins biomarkers were measured by chromatography and immunoassay. Analysis of covariance was applied to elucidate the differences in B-vitamins between combinations of groups defined according to the median of the z-scores of markers of body composition and insulin sensitivity. Results: When considering energy intakes and education of the mother in the model, in females, vitamin B6 intakes were higher in the high BMI/ high HOMA group than in the high BMI-low HOMA group. Similarly, vitamin B6 intakes were higher in the high FMI/high HOMA group than in the low FMI/low HOMA group. Plasma vitamin B12 was significantly lower in males in the high FMI/high HOMA group than in the low FMI/low HOMA group, keeping also significant their trends throughout the groups, a fact that can be observed also for females (p < 0.05). Conclusion: Adolescents with combined higher adiposity and higher HOMA insulin sensitivity showed lower vitamin B12 plasma concentrations. These differences do not seem to be explained by dietary vitamin B12 intake.