Study: Saturated Fat Lays Groundwork for Metabolic Disease
The intake of saturated fat "rapidly increases" hepatic lipid storage, energy metabolism, and insulin resistance, which increases the risk for metabolic disease, according to a new study.
Noting that, while dietary intake of saturated fat is a likely contributor to non-alcoholic fatty liver disease (NAFLD) and insulin resistance, the mechanisms that initiate this abnormalities remains unclear, a team including researchers from the German Center for Diabetes Research examined the effects of a single oral saturated fat load on insulin sensitivity, hepatic glucose metabolism, and lipid metabolism in humans. Similarly, initiating mechanisms were examined after an equivalent challenge in mice.
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The authors evaluated 14 lean, healthy individuals, who randomly received either palm oil (PO) or vehicle (VL), analyzing hepatic metabolism by using in vivo 13C/31P/1H and ex vivo 2H magnetic resonance spectroscopy before and during hyperinsulinemic-euglycemic clamps with isotope dilution.
Overall, PO administration decreased whole-body, hepatic, and adipose tissue insulin sensitivity by 25%, 15%, and 34%, respectively, while hepatic triglyceride and ATP content rose by 35% and 16%, respectively. Hepatic gluconeogenesis increased by 70%, and net glycogenolysis declined by 20%, according to the authors.
"The big takeaway for primary care physicians in this case is to recommend limiting intake of saturated fats as much as possible, especially for patients who are at high risk of developing metabolic disease," said study co-author Elisa Alvarez-Hernandez, MD, MSc, a physician and researcher from the German Center for Diabetes Research.
"Doctors should take the time to educate their patients about what the different types of fats are and which types of foods contain them," said Alvarez-Hernandez, adding that these findings "signify that it is likely that the liver is already relying on compensatory mechanisms after one high dose challenge of a saturated fatty acid, in order to maintain metabolic homeostasis."
Therefore, physicians "should also educate their patients on how fast these effects take place, and the fact that 'the point of no return' is still unknown," concluded Alvarez-Hernandez. "We do not yet know at which point or why the body loses its ability to adapt, paving the way for chronic insulin resistance or non-alcoholic fatty liver disease to ensue. Because of this, it is critical to minimize exposure to metabolic aggressions."
Alvarez Hernandez E, Kahl S, Seelig A, et al. Acute dietary fat intake initiates alterations in energy metabolism and insulin resistance [published online January 23, 2017]. Journal of Clinical Investigation. doi:10.1172/JCI89444.