Carbohydrates and the Brain: Roles and Impact

Abstract

Even if its size is fairly small (about 2% of body weight), the brain consumes around 20% of the total body energy. Whereas organs such as muscles and liver may use several sources of energy, under physiological conditions, the brain mainly depends on glucose for its energy needs. This involves the need for blood glucose level to be tightly regulated. Thus, in addition to its fueling role, glucose plays a role as signaling molecule informing the brain of any slight change in blood level to ensure glucose homeostasis. In this chapter, we will describe the fueling and sensing properties of glucose and other carbohydrates on the brain and present some physiological brain functions impacted by these sugars. We will also highlight the scientific questions that need to be answered in order to better understand the impact of sugars on the brain.

Analysis of the Effects of Pentose Phosphate Pathway Inhibition on the Generation of Reactive Oxygen Species and Epileptiform Activity in Hippocampal Slices

“…The mammalian brain is an organ that consumes a large amount of energy. Its activity largely depends on glucose being delivered by blood into the brain and a tight regulation of glucose metabolism is critical for reliable brain functioning [1,2]. Glucose is converted to glucose-6-phosphate (Glu6P) under the action of hexokinase, which primarily controls the metabolism of this monosaccharide [3,4].…”

A New Role for Hypothalamic Glucose-Sensing Neurons in Hypoglycemia Unawareness

“…In all these areas, neurons that detect decreased glucose levels are present. Nevertheless, glucose-sensing neurons that detect glucose levels that increase above 2.5 mmol/L, the theoretical brain level ( 2 ), seem to be restricted to circumventricular organs of the brain, where the blood–brain barrier is fenestrated ( 3 ). On the basis of this statement, it seems that the brain is mostly equipped to sense hypoglycemia rather than hyperglycemia.…”