The Human Brain Produces Fructose from Glucose

The issue about the activity of fructose and glucose on brain is a continuing investigation which may have profound implications. Excess consumption of fructose contributes to high blood sugar and chronic diseases like obesity.

Fructose and glucose had different effects on brain activity. The question arose about whether fructose is produced in the brain or crossed over from the bloodstream. In the article entitled “The human brain produces fructose from Glucose” Hwang et al., report the results of an investigation that was conducted to measure the nature and concentration of sugars in the brain. Using magnetic resonance spectroscopy the team measured intercerebral glucose and fructose level in the brain of eight patients who had been given infusion of glucose. Sugar concentrations in the blood were also assessed. The researchers found cerebral fructose levels rose significantly in response to a glucose infusion, with minimal changes in fructose levels in the blood. They surmised that the high concentration of fructose in the brain was due to a metabolic pathway called the polyol pathway (glucose → sorbitol → fructose) that converts glucose to fructose. This is the first time that the production of fructose in the human brain has been identified. While raising several key research questions. According to the researchers, the observed conversion of fructose into glucose may also occurs in other part of the body and that this pathway may be another mechanism by which high blood sugar can exert its adverse effects.