The liver processes coconut oil differently than rapeseed oil
Coconut oil has increasingly found its way into German kitchens in recent years, although its alleged health benefits are controversial. Scientists at the University of Bonn from the Cluster of Excellence ImmunoSensation have now been able to show how it is metabolized in the liver. Their findings could also have implications for the treatment of certain diarrheal diseases. The results are published in the journal Molecular Metabolism.
Coconut oil differs from rapeseed or olive oil in the fatty acids it contains. Fatty acids consist of carbon atoms bonded together, usually 18 in number. In coconut oil, however, most of these chains are much shorter and contain only 8 to 12 carbon atoms. In the liver, these medium-chain fatty acids are partly converted into storage fats (triglycerides). Exactly how this happens was largely unknown until now. The new study now sheds light on this: "There are two enzymes in the liver for storage fat synthesis, DGAT1 and DGAT2," explains Dr. Klaus Wunderling of the LIMES Institute at the University of Bonn. "We have now seen in mouse liver cells that DGAT1 processes mainly medium-chain fatty acids and DGAT2 processes long-chain ones."
"The enzymes therefore seem to prefer different chain lengths," concludes Prof. Dr. Christoph Thiele of the LIMES Institute, who led the study and is also a member of the Cluster of Excellence Immunosensation. Surprising side effect whether fatty acids in the liver are used at all to build up storage fat depends on the current energy requirement. When the body needs a lot of energy at a particular moment, the so-called beta oxidation is fired up - the fatty acids are "burned" straight away, so to speak. Medically, this metabolic pathway is of great interest. In diabetes, for instance, it might be useful to reduce beta-oxidation.
Also interesting is a finding published a few years ago by Austrian and Dutch scientists: They had studied patients suffering from chronic diarrheal diseases. In 20 of them, they found alterations in the DGAT1 gene that rendered it nonfunctional. "We now want to find out whether the impaired processing of medium-chain fatty acids is responsible for the digestive complaints," says Wunderling. This is because the DGAT1 enzyme is active not only in the liver but also in the intestine. Perhaps this is why its disorder causes diarrhea when sufferers consume medium-chain fatty acids.
The study was funded by the German Research Foundation (DFG) as part of the Excellence Strategy. It additionally received funding from the Austrian Science Fund (FWF) of the Republic of Austria.
Klaus Wunderling, Christina Leopold, Isabell Jamitzky, Mohamed Yaghmour, Fabian Zink, Dagmar Kratky and Christoph Thiele: Hepatic synthesis of triacylglycerols containing medium-chain fatty acids is dominated by diacylglycerol acyltransferase 1 and efﬁciently inhibited by etomoxir; Molecular Metabolism; https://doi.org/10.1016/j.molmet.2020.101150
Dr. Klaus Wunderling
LIMES-Institut der Universität Bonn
Tel. 0228/ 7362820