Post-gastric bypass hyperinsulinemic hypoglycemia: Fructose is a carbohydrate which can be safely consumed

Context: Postprandial hypoglycemia after gastric bypass surgery is a serious problem. Available treatments are often ineffective. Objective: The objective was to test the hypotheses that injection of rapid-acting insulin before a high-carbohydrate meal or replacement of other carbohydrates with fructose in the meal would prevent hypoglycemia. Design: This was a randomized, crossover trial comparing a high-carbohydrate meal with premeal saline injection (control), a high-carbohydrate meal with premeal insulin injection, and a high-fructose meal with total carbohydrate content similar to the control meal. Setting: The setting was an academic medical center. Patients: Ten patients with post-gastric bypass hyperinsulinemic hypoglycemia participated. Interventions: Interventions included lispro insulin injected before test meals and replacement of other carbohydrates with fructose in test meals. Main Outcome Measure: The main outcome measure was plasma glucose < 60 mg/dL after test meals. Results: After the control meal, mean peak glucose and insulin were 173 ± 47 mg/dL and 134 ± 55 mU/L, respectively; mean glucose nadir was 44 ± 15 mg/dL; and eight of 10 subjects demonstrated glucose < 60 mg/dL. Five subjects demonstrated a glucose nadir < 40 mg/dL. There were no significant differences in the corresponding values after premeal insulin treatment, except that the mean glucose nadir of 34 ± 10 mg/dL was lower (P < .05). After the fructose meal, mean peak postprandial glucose and insulin were 117 ± 20 mg/dL and 45 ± 31 mU/L, respectively (both P < .001 for comparison with control), mean glucose nadir was 67 ± 10 mg/dL (P < .001), and two of 10 subjects demonstrated glucose < 60 mg/dL (P < .05). Conclusions: People with post-gastric bypass hypoglycemia can consume a meal sweetened with fructose with little risk of hypoglycemia. Treatment with rapid-acting insulin before a carbohydrate-containing meal did not prevent hypoglycemia.