Ketone Bodies Derived From Medium-Chain Triglycerides Support Brain Metabolism and Function Under Hypoglycemia in Type 1 Diabetes Mellitus

Impaired cognitive function caused by insulin-induced hypoglycemia is a complication of type 1 diabetes mellitus (T1DM) for which no protective strategies are currently available. In this first-in-human mechanistic study using magnetic resonance spectroscopy, the direct contribution of the infused ketone β-hydroxybutyrate (BHB) to brain metabolism during clamped hypoglycemia was greater in participants with T1DM than healthy participants. In a randomized dietary intervention trial of participants with T1DM and recurrent hypoglycemia, receiving medium-chain triglycerides (MCTs) as a dietary ketone precursor was associated with higher working memory performance and greater regional brain activation during clamped hypoglycemia compared with an isocaloric standard diet. Counterregulatory hormone responses to hypoglycemia were not affected by MCT supplementation. We conclude that ketone bodies are well suited to support brain metabolism in persons with T1DM experiencing insulin-induced hypoglycemia. Dietary MCT supplementation raising BHB may represent a novel strategy to prevent hypoglycemia-induced brain injury in this vulnerable patient population.

Article Highlights

There are currently no strategies to prevent cognitive impairment caused by insulin-induced hypoglycemia in type 1 diabetes mellitus (T1DM). We examined whether β-hydroxybutyrate (BHB) supports brain metabolism during clamped hypoglycemia and whether dietary medium-chain triglycerides (MCTs), by raising BHB availability, elicit this protective effect. BHB contributed more to brain metabolism in participants with T1DM than in healthy control participants, and long-term MCT supplementation improved working memory and brain activation during hypoglycemia. Dietary MCT supplementation may protect against hypoglycemia-related cognitive deficits in T1DM.