ABSTRACT

As described in other chapters, the intake of fructose in the diet has risen steadily over the past 30 years, as has the incidence of obesity and diabetes in the USA. One comorbidity associated with obesity and diabetes is nonalcoholic fatty liver disease (NAFLD) and recent observational studies have suggested a connection between dietary intake of fructose and NAFLD in children [1,2] and adults [3-5]. Given the strong interest in the metabolic causes of NAFLD, development of clinical research methods in this eld has been expanding rapidly. The present paper will review methods

Key Points ...................................................................................................................................... 315 Introduction .................................................................................................................................... 315 Current Biomarkers and Tests for Diagnosis of NAFLD ............................................................... 316 Imaging Techniques for Diagnosis of NAFLD .............................................................................. 319 Isotopic Turnover Methods to Measure Fructose Effects in the Liver ........................................... 320 Future Directions and Conclusion ................................................................................................. 322 References ...................................................................................................................................... 322

for assessing liver metabolism in humans, with special reference to research techniques that can be used to assess metabolic changes when fructose-containing foods are consumed. Other chapters in this volume have reviewed the basic biochemical and metabolic fates of fructose in animals and humans. Here, we will consider the most recently identied research biomarkers that can be used for the detection of liver injury in fructose studies. Described next are methods for imaging liver fat and brosis and for measuring liver function using nuclear magnetic resonance spectroscopy. Lastly, we will provide an in-depth review of the use of stable isotopes to measure liver fatty acid ux and fructose effects on the process of hepatic de novo lipogenesis. Data from animal studies provide multiple molecular and biochemical mechanisms by which overconsumption of fructose leads to liver dysfunction. For the translation of these ndings to human studies, the methods described herein hold much promise to allow the effects of fructose metabolism to be measured directly, noninvasively, and in vivo.