The adrenomedullary response to a standard oral glucose load (1.75 gm/kg; maximum, 120 gm) and susceptibility to neuroglycopenia (assessed by the hypoglycemic clamp and measurements of P300 auditory evoked potentials [AEP]) were studied in 25 healthy children (8-16 years of age) compared to 23 young adults at the Children’s Clinical Research Center, Yale University School of Medicine, New Haven, CT. Baseline and oral glucose-stimulated plasma glucose and insulin levels were similar in children and adult groups. A late fall in plasma glucose level at 3 - 5 hours after glucose ingestion stimulated a rise in plasma epinephrine, twice as high in children compared to adults. Hypoglycemic symptoms (shaky, sweaty, weak, or tachycardia) increased in children but not in adults, in association with the late fall in plasma glucose. P300 amplitude, a measure of cognitive function, was significantly reduced when glucose concentration was lowered to 75 mg/dl in children, but was preserved until the level fell to 54 mg/dl in adults. Children are more vulnerable to effects of hypoglycemia on cognitive function than are adults. [1]
COMMENT. This study shows that consumption of glucose by healthy children may be followed by a fall in plasma glucose sufficient to induce hormonal changes and adverse behavioral and cognitive effects. The authors stress that their data do not prove a causative role for dietary sugar in children with hyperactivity. However, a balanced diet of protein, fat, and complex carbohydrate, to limit postprandial falls in glucose levels, should avoid symptoms associated with the enhanced adrenomedullary responsiveness demonstrated in healthy children.
Mild hypoglycemia (60 mg/dl) caused a significant decline in performance on a battery of cognitive tests in a study of adolescents with insulin-dependent diabetes mellitus at the University of Pittsburgh School of Medicine. Neither hyperglycemia, nor the rapid drop from acute hyperglycemia to euglycemia, affected symptoms, cognitive function, or counterregulatory hormone secretion. [2]