Dietary magnesium intake in relation to body mass index and glycemic indices in middle school students from the HEALTHY Study

BACKGROUND

Data on dietary magnesium intake on the risk of type 2 diabetes mellitus (T2DM) among children and adolescents is limited.

AIM

We examined whether dietary magnesium intake was related to body mass index (BMI) percentile, and glycemic indices at baseline and at end of the HEALTHY Study for both intervention and control schools. The HEALTHY Study was a multi-component, school-based intervention, to prevent T2DM in children and adolescents from 6th to 8th grades.

METHODS

A secondary data analyses of 2181 ethnically diverse students with completed dietary records, BMI percentile, and plasma insulin and glucose concentrations at baseline (6th grade) and end of study (8th grade) were included from the HEALTHY Study. Dietary magnesium intake was self-reported using the Block Kids Food Frequency Questionnaire. A hierarchical multiple regression model was used to determine the relationships between dietary magnesium intake, BMI percentile, and glycemic indices at baseline and end of the HEALTHY Study, adjusting for magnesium intake from supplements, total energy intake, and fitness level.

RESULTS

Dietary magnesium intake was related to BMI percentile at baseline and at end of the HEATHY Study (β = -0.05, 95% CI = -0.02 to 0, p = 0.04; β = -0.06, 95% CI = -0.02 to -0.003, p = 0.004); R ² [regression coefficient effect size] = 0.03; R ² = 0.06). Dietary magnesium intake was not related to plasma insulin and glucose concentrations at baseline and end of the HEALTHY Study.

CONCLUSION

Dietary magnesium intake was inversely related to BMI percentile among middle school students from the HEALTHY Study. Research is required to evaluate the dose-response relationship between fruit and vegetable consumption (good sources of magnesium) and risk of T2DM in children and adolescents. This relationship also needs to be explored among different BMI categories.

Dietary intake and prospective changes in cardiometabolic risk factors in children and youth

Only few studies examined the effect of diet on prospective changes in cardiometabolic (CM) risk factors in children and youth despite its importance for understanding the role of diet early in life for cardiovascular disease in adulthood. To test the hypothesis that dietary intake is associated with prospective changes in CM risk factors, we analyzed longitudinal observations made over a period of 2 years among 448 students (aged 10-17 years) from 14 schools in Canada. We applied mixed effect regression to examine the associations of dietary intake at baseline with changes in body mass index, waist circumference (WC), systolic and diastolic blood pressure (SBP and DBP), and insulin sensitivity score between baseline and follow-up while adjusting for age, sex, and physical activity. Dietary fat at baseline was associated with increases in SBP and DBP z scores (per 10 g increase in dietary fat per day: β = 0.03; p < 0.05) and WC (β = 0.31 cm; p < 0.05) between baseline and follow-up. Every additional gram of sodium intake at baseline was associated with an increase in DBP z score of 0.04 (p < 0.05) between baseline and follow-up. Intake of sugar, vegetables and fruit, and fibre were not associated with changes in CM risk factors in a statistically significant manner. Our findings suggest that a reduction in the consumption of total dietary fat and sodium may contribute to the prevention of excess body weight and hypertension in children and youth, and their cardiometabolic sequelae later in life.