The influence of dietary carbohydrate content on glycaemia in patients with glucokinase maturity-onset diabetes of the young.

Mutations in the glucokinase (GCK) gene result in maturity-onset diabetes of the young (MODY). Pharmacotherapy is not effective in GCK MODY. Thus, nutritional intervention seems to be the only therapeutic option. This study evaluated the effect of the quantity of dietary carbohydrate on glucose levels in 10 GCK mutation carriers: seven with MODY and three with prediabetes. All patients were exposed to high-carbohydrate diets for 2 days and then switched to low-carbohydrate diets (60% versus 25% of the daily calorie intake) for another 2 days, after a 1-day washout. Glucose levels were assessed by continuous blood glucose monitoring. In patients with GCK MODY on high-carbohydrate diets, glucose levels were significantly higher, and more hyperglycaemic episodes occurred, compared with patients on low-carbohydrate diets. This short-term observational study suggested that diets with a modestly limited carbohydrate content may improve glycaemic control in patients with GCK MODY.