The effects of oral fructose, sucrose, and glucose in subjects with reactive hypoglycemia.

We have evaluated the acute effects of orally administered 100-g loads of fructose, sucrose, or glucose given as drinks and of 100-g loads of fructose and sucrose given in cakes on the postprandial serum glucose, insulin, and cortisol responses in seven subjects with reactive hypoglycemia. We defined reactive hypoglycemia as a serum glucose nadir of 65 mg/dl or less, symptoms compatible with hypoglycemia occurring at or after the serum glucose nadir, a hypoglycemic index of greater than 1.0, and a rise in serum cortisol to greater than 20 micrograms/dl after the serum glucose nadir. The data demonstrated that (1) pure fructose given as a drink resulted in relatively flat serum glucose and insulin responses and did not cause a hypoglycemic reaction in any of the subjects, compared with the glucose drink, which caused a hypoglycemic reaction in any of the subjects; (2) ingestion of pure sucrose as a drink elicited significantly flatter serum glucose and insulin responses than did the glucose drink and was associated with some episodes of chemical hypoglycemia and symptoms, but did not result in a hypoglycemic reaction by our definition in any patient; and (3) ingestion of fructose cake led to serum glucose and insulin responses that were lower than those caused by ingestion of sucrose cake, but ingestion of neither fructose nor sucrose cake led to a hypoglycemic reaction by our definition in any patient. In conclusion, the use of fructose as a sweetening agent given either alone, in a drink, or with other nutrients in a cake resulted in markedly flatter serum glucose and insulin responses in subjects with reactive hypoglycemia. Fructose may thus prove useful as a sweetening agent in the dietary treatment of selected patients with reactive hypoglycemia.