Intervention and Prevention
Obesity (2008) 16 6, 1355–1362. doi:10.1038/oby.2008.201
Effect of 6-Month Calorie Restriction and Exercise on Serum and Liver Lipids and Markers of Liver Function
D. Enette Larson-Meyer1,2, Bradley R. Newcomer3, Leonie K. Heilbronn1,4, Julia Volaufova5, Steven R. Smith1, Anthony J. Alfonso1, Michael Lefevre1,6, Jennifer C. Rood1, Donald A. Williamson1 and Eric Ravussin1 The Pennington CALERIE Team1
- 1Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, Louisiana, USA
- 2Department of Family and Consumer Sciences, University of Wyoming, Laramie, Wyoming, USA
- 3Department of Diagnostic and Therapeutic Sciences, The University of Alabama at Birmingham, Birmingham, Alabama, USA
- 4Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia
- 5Biostatistics Program, School of Public Health, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
- 6Present address: Center for Advanced Nutrition, Utah State University, Logan, Utah, USA
Correspondence: D. Enette Larson-Meyer (enette@uwyo.edu)
Received 6 March 2007; Accepted 20 July 2007; Published online 10 April 2008.
Abstract
Objective:
Nonalcoholic fatty liver disease (NAFLD) and its association with insulin resistance are increasingly recognized as major health burdens. The main objectives of this study were to assess the relation between liver lipid content and serum lipids, markers of liver function and inflammation in healthy overweight subjects, and to determine whether caloric restriction (CR) (which improves insulin resistance) reduces liver lipids in association with these same measures.
Methods and Procedures:
Forty-six white and black overweight men and women (BMI = 24.7–31.3 kg/m2) were randomized to "control (CO)" = 100%
energy requirements; "CR" = 25%
; "caloric restriction and increased structured exercise (CR+EX)"= 12.5%
CR + 12.5%
increase in energy expenditure through exercise; or "low-calorie diet (LCD)" = 15%
weight loss by liquid diet followed by weight-maintenance, for 6 months. Liver lipid content was assessed by magnetic resonance spectroscopy (MRS) and computed tomography (CT). Lipid concentrations, markers of liver function (alanine aminotransferase (ALT), alkaline phosphatase (ALK)), and whole-body inflammation (tumor necrosis factor-
(TNF-), interleukin-6 (IL-6), high-sensitivity C-reactive protein (hsCRP)) were measured in fasting blood.
Results:
At baseline, increased liver lipid content (by MRS) correlated (P < 0.05) with elevated fasting triglyceride (r = 0.52), ALT (r = 0.42), and hsCRP (r = 0.33) concentrations after adjusting for sex, race, and alcohol consumption. With CR, liver lipid content was significantly lowered by CR, CR+EX, and LCD (detected by MRS only). The reduction in liver lipid content, however, was not significantly correlated with the reduction in triglycerides (r = 0.26; P = 0.11) or with the changes in ALT, high-density lipoprotein (HDL)-cholesterol, or markers of whole-body inflammation.
Discussion:
CR may be beneficial for reducing liver lipid and lowering triglycerides in overweight subjects without known NAFLD.
