Fat People have Elevated Oxidation of Fatty Acids which Correlates to Metabolic Syndrome
Ok so that’s a bit of a misnomer but I wanted to catch your attention. The truth is people who are significantly overweight DO oxidize more fat in the liver on a regular basis compared to a healthier lean person. That’s because their system is broken. The liver shouldn’t be burning this fat, but it has to because the bloodstream is flooded with lipids (excess fat). The body’s cells have had enough fat and are sick of it so it gets dumped into the blood all the time in people who have metabolic syndrome. And because these people aren’t exercising the fat off or controlling their food intake those fat molecules have nowhere to go but the liver where this precious organ will try and deal with it by burning it up. But the amount of fat burning here is so insignificant that I wouldn’t even call it that except to catch your attention.
Basically this study says they’ve finally found a pretty effective way to analyze the liver’s activity using a PET scan they developed first by using pigs. They then go on to show that obese people with metabolic dysfunctions have a liver that is on oxidation duty pretty much all the time trying to deal with mopping up the excess fat that is being stored.
Gastroenterology. 2010 May 25. [Epub ahead of print]
Liver Fatty Acid Metabolism in the Liver, Measured by Positron Emission Tomography, is Increased in Obese Individuals.
Iozzo P, Bucci M, Roivainen A, Ní¥gren K, Jí¤rvisalo MJ, Kiss J, Guiducci L, Fielding B, Naum AG, Borra R, Virtanen K, Savunen T, Salvadori PA, Ferrannini E, Knuuti J, Nuutila P.
Turku PET Centre, and Dept. of Medicine, University of Turku, Turku, Finland; Institute of Clinical Physiology, PET Lab, National Research Council (CNR), Pisa, Italy.
Abstract
BACKGROUND & AIMS:: Hepatic lipotoxicity results from and contributes to obesity-related disorders. It is a challenge to study human metabolism of fatty acids (FA) in the liver. We combined (11)C-palmitate imaging by positron emission tomography (PET) with compartmental modeling to determine rates of hepatic FA uptake, oxidation, and storage, as well as triglyceride release in pigs and humans. METHODS:: Anesthetized pigs underwent (11)C-palmitate PET imaging during fasting (n=3) or euglycemic hyperinsulinemia (n=3). Metabolic products of FAs were measured in arterial, portal and hepatic venous blood. The imaging methodology was then tested in 15 human subjects (8 obese subjects); plasma (11)C-palmitate kinetic analyses were used to quantify systemic and visceral lipolysis. RESULTS:: In pigs, PET-derived and corresponding measured FA fluxes (FA uptake, esterification, and triglyceride FA release) did not differ and were correlated with each other. In humans, obese subjects had increased hepatic FA oxidation, compared with controls (mean+/-SEM=0.16+/-0.01 vs 0.08+/-0.01 mumol/min/mL, P=0.0007); FA uptake and esterification rates did not differ between obese subjects and controls. Liver FA oxidation correlated with plasma insulin levels (r=0.61, P=0.016), adipose tissue (r=0.58, P=0.024), and systemic insulin resistance (r=0.62, P=0.015). Hepatic FA esterification correlated with the systemic release of FA into plasma (r=0.71, P=0.003). CONCLUSIONS:: PET imaging can be used to measure FA metabolism in the liver. Using this technology, we found that obese individuals have increased hepatic oxidation of FA, in the context of adipose tissue insulin resistance, and increased FA flux from visceral fat. FA flux from visceral fat is proportional with the mass of the corresponding depot. Copyright © 2010 AGA Institute. Published by Elsevier Inc. All rights reserved.
PMID: 20685204 [PubMed - as supplied by publisher]
