Does a low carbohydrate diet improve blood glucose control in type 1 diabetes?

This study investigated if a low carbohydrate diet improved glycemic control (blood sugar) and cardiovascular (heart and circulatory system) parameters in type 1 diabetes patients.

They found that a low carbohydrate diet resulted in improved glycemic control with no effect on cardiovascular markers. 

Glycemic control is essential for the treatment of type 1 diabetes. This prevents the development of diabetes-related complications. Patients with type 1 diabetes can have issues with glycemic control due to excess carbohydrate intake.

Unregulated carbohydrate intake and insulin dosing can cause glucose excursions (rapid increases in blood glucose). This contributes to variability in glucose levels. Glycemic variability is thought to significantly impact overall blood glucose management. It is thought that a low carbohydrate diet may have an effect on glycemic variability.

This study assessed the effects of a low carbohydrate diet on several glucose parameters including variability. 

10 patients with type 1 diabetes were included in this trial.  Patients were treated with insulin via a pump with sensor-based glucose monitoring. Patients were assigned either to a low (LCD) or high carbohydrate diet (HCD) for 1 week. Following a 1-week washout (break from diet), patients switched to the other diet for 1 week. Blood glucose parameters and cardiovascular parameters were measured.

LCD reduced glucose variability compared to HCD, however overall blood glucose control (Hba1c levels) were not different between the two groups. LCD patients had reduced hypoglycemia (dangerously low blood glucose) and more time in the ‘normal’ glucose range. Cardiovascular parameters including blood pressure, pulse rate etc., were not significantly different between LCD and HCD patients. The bolus insulin dose (dose at mealtime) was reduced 3-fold in LCD patients during the trial.

This study suggested that a low carbohydrate diet reduces blood glucose variability in patients with type 1 diabetes.

This was a short-term study in a small cohort. Larger numbers/longer studies are needed. The level of carbohydrate (low vs. high) was based on the quantity of carbohydrate. The quality (glycemic index) of carbohydrates could have impacted the results in the high carbohydrate group. 

Please discuss any concerns regarding diet and blood glucose control with your doctor.