Physiological handling of dietary fructose-containing sugars: implications for health

• Published in: International Journal of Obesity 2016-03, Vol.40 (Suppl 1), p.S6-S11
• Main Authors: Campos, V C, Tappy, L
• Format: Article
• Language: English
• Subjects: 692/699/2743/393; 692/700/2814; 692/700/478; Adaptation; Amino acids; Animals; Beverages; Beverages - adverse effects; Biology; Blood glucose; Body weight; Body weight gain; Diet; Diet - adverse effects; Energy; Energy efficiency; Energy Metabolism; Energy sources; Enzymes; Epidemiology; Fatty acids; Fatty Liver - etiology; Fatty Liver - metabolism; Fatty Liver - prevention & control; Food; Food chains; Food industry; Fructose; Fructose - adverse effects; Glucose; Glucose transport; Health Promotion and Disease Prevention; Humans; Inflammation - etiology; Inflammation - metabolism; Inflammation - prevention & control; Insulin; Internal Medicine; Intestine; Lactic acid; Lipid Metabolism; Liver - metabolism; Medicine; Medicine & Public Health; Metabolic Diseases; Metabolic Syndrome - etiology; Metabolic Syndrome - metabolism; Metabolic Syndrome - prevention & control; Metabolism; Obesity; Obesity - etiology; Obesity - metabolism; Obesity - prevention & control; Organisms; Organs; Physiological aspects; Physiology; Public Health; Respiration; review; Soft drinks; Substrates; Sucrose; Sugar; Sweetening Agents - adverse effects; Syrup; Triglycerides; Weight Gain
• ISSN: 0307-0565; 1476-5497
• DOI: 10.1038/ijo.2016.8

Fructose has always been present in our diet, but its consumption has increased markedly over the past 200 years. This is mainly due to consumption of sucrose or high-fructose corn syrup in industrial foods and beverages. Unlike glucose, fructose cannot be directly used as an energy source by all cells of the human body and needs first to be converted into glucose, lactate or fatty acids in the liver, intestine and kidney. Because of this specific two-step metabolism, some energy is consumed in splanchnic organs to convert fructose into other substrates, resulting in a lower net energy efficiency of fructose compared with glucose. A high intake of fructose-containing sugars is associated with body weight gain in large cohort studies, and fructose can certainly contribute to energy imbalance leading to obesity. Whether fructose-containing foods promote obesity more than other energy-dense foods remains controversial, however. A short-term (days–weeks) high-fructose intake is not associated with an increased fasting glycemia nor to an impaired insulin-mediated glucose transport in healthy subjects. It, however, increases hepatic glucose production, basal and postprandial blood triglyceride concentrations and intrahepatic fat content. Whether these metabolic alterations are early markers of metabolic dysfunction or merely adaptations to the specific two-step fructose metabolism remain unknown.