Magnesium and Pediatric Obesity

Studies have shown that overweight adults tend to have lower serum and intracellular magnesium levels when compared to healthy controls of normal weight.  Studies have also found an association between lower magnesium levels and the incidence of type II diabetes mellitus, metabolic syndrome, hypertension and insulin resistance.  There are several magnesium-containing enzymes necessary during carbohydrate metabolism so physiologically it makes sense that chronic magnesium deficiency could cause glycemic dysfunction. 

The most recent study regarding this subject compared the serum magnesium levels of overweight children to the serum magnesium levels in normal weight children.   Since it is being increasingly recognized that the foundations for obesity and metabolic syndrome are laid down in childhood this study was designed to test the hypothesis that the association of lower serum magnesium with obesity and metabolic syndrome develops in childhood.  The study “compared fasting levels of serum magnesium, insulin, glucose, total and HDL-cholesterol, triglycerides and dietary magnesium intake” between the overweight children and the normal weight children.  The data gathered was somewhat surprising.  Overall, the serum magnesium levels were significantly lower in the overweight group compared to the normal weight group which was somewhat expected based on serum magnesium measurements in adults.  The dietary intake of magnesium, though, was significantly higher in the overweight group.  The authors of the study controlled for the difference in caloric intake and even after the adjustment, the overweight children consumed more magnesium per calorie than the normal weight children.  Surprisingly, the overweight children consumed more magnesium than the Recommended Daily Allowance (RDA) but still had low serum levels of magnesium. 

The correlation between serum magnesium and several components of metabolic syndrome were also explored in this study.  The researchers discovered an inverse correlation between serum magnesium and serum insulin, body mass index (BMI), waist circumference, systolic blood pressure and diastolic blood pressure.  In other words, the lower the serum magnesium, the higher the serum insulin, BMI, blood pressure and waist circumference.  This study does not give a clear answer to the question “which comes first, low serum magnesium levels or endocrine pathology?” but it does provide some insight. 

The researchers concluded that overweight children must have either a decreased absorption or an increased excretion of magnesium.  This study did not measure the amount of magnesium excreted by the children but an increase in urinary magnesium excretion has been found in adults with type II diabetes mellitus, hypertension and obesity.  The study suggests that whether overweight children are excreting their magnesium more rapidly than their normal weight peers or not absorbing the magnesium, overweight children most likely need more magnesium on a daily basis.  This study also suggests that overweight adults might need to supplement with extra magnesium and/or eat more magnesium-rich foods to raise their serum magnesium levels as well.  Hopefully future research will discover the cause of the lower serum magnesium levels in overweight individuals as well as the mechanism behind the correlation between low magnesium levels and endocrine disorders.  It would also be fascinating to study the physiologic effects of magnesium repletion in an overweight population.  

If you wish to increase your magnesium intake, foods such as wheat bran, almonds, cashews, leafy green vegetables, oatmeal, peanuts, baked potatoes with skin (when potatoes are boiled the minerals leach into the water), black-eyed peas, pinto beans, lentils, bananas, raisins and halibut are good sources of magnesium.  Magnesium can also be efficiently absorbed from whole food supplements. 

Reference:     Jose, Bipin, Vandana Jain, et al. "Serum Magnesium in Overweight Children." Indian Pediatrics. 49.2 (2012): 109-12.