Lactate and its many faces

• Lactate is traditionally seen as a marker of ischemia and a waste product.
• Lactate, however, may be a fuel for the brain of patients with GLUT1DS and GSD1.
• Furthermore, lactate infusion can be used therapeutically in traumatic brain injury.

BackgroundLactate is traditionally seen as a marker of ischemia and a waste product of anaerobic glycolysis. In the last thirty years a more beneficial side of lactate as an alternative 'glucose sparing' fuel has been demonstrated. However, the translation of these growing insights to clinical practice seems to appear with great delay.MethodsA review of the literature was performed, focusing on glucose and lactate in relation to cerebral energy metabolism, in the context of four typical clinical situations, namely (transient states of) low glucose availability for the brain due to hypoglycemia, combined with high blood lactate concentrations; permanent neuroglycopenia; lactic acidosis in mitochondrial disorders; and ischemic as well as traumatic brain injury.ResultsLactate is thought to be an alternative fuel in the brain of patients with glucose transporter type 1 deficiency syndrome and glycogen storage disease, and it has been demonstrated that lactate might have a protective role in ischemic and traumatic brain injury.ConclusionLactate has an apparently largely ignored, but potential beneficial role in the clinical management of several neurologic disorders.