Zinc nutriture in type I diabetes mellitus: relationship to growth measures and metabolic control

Zinc concentrations in plasma, hair, and urine from children and young adults with insulin-requiring or Type I diabetes mellitus were significantly correlated with height, weight, and age, as well as with indices of metabolic control, i.e., fasting serum glucose, percent glycosylated hemoglobin (HbA1), and 24-h urine glucose and insulin excretion. Urinary zinc excretion was greater in subjects than in controls (p less than 0.0001) and significantly correlated with urine glucose (p less than 0.004, r = 0.35) and volume (p less than 0.0007, r = 0.40). Urinary zinc and volume were not correlated in controls. Hyperzincuria in the subjects was not secondary to hyperinsulinuria, although zinc and insulin excretion were significantly correlated in controls (p less than 0.03, r = 0.63). Zinc in insulin preparations could not explain the excessive zinc excretion. Mean fasting plasma zinc was significantly higher than in controls, and positively correlated with height for age, while being inversely correlated with age, duration of diabetes, HbA1, urine volume, and glucose excretion. Both the mean and range of hair zinc concentration in the subjects were not different from controls. Male subjects with diabetes had a significantly lower hair concentration when compared with female subjects with diabetes (p less than 0.0009). Zinc homeostasis appears to be altered as a consequence of glucose intolerance in diabetes. Continued urinary zinc losses over time may result in a zinc deficiency state not demonstrable by altered zinc concentrations in plasma and hair.