Coconut oil contains medium-chain fatty acids, which may be a factor in stimulating appetite. Despite this, coconut oil often is promoted as a weight-loss aid due to the way it is metabolized in your body. This is just one of the contradictions connected to coconut oil, which is classified as a saturated fat but in virgin form has been shown to help reduce triglycerides and cholesterol.
Ghrelin
Medium-chain fatty acids appear to stimulate ghrelin, which is a peptide hormone produced by the endocrine cells in your stomach, according to Yoshihiro Nishi, lead author for a 2005 study published in "Endocrinology." This hormone, sometimes referred to as the hunger hormone, stimulates your appetite. After ghrelin is created in your stomach it circulates in your blood and then sends a message to your brain that stimulates appetite.
Activation
When you consume medium-chain fatty acids such as in coconut oil, they are used directly for the acylation of ghrelin. In this process, an acyl group replaces a hydrogen atom. This creates the major active form of ghrelin. Medium-chain fatty acids increase your stomach concentrations of acylated ghrelin, whereas this does not occur after consuming short-chain or long-chain fatty acids, notes Nishi.
History and Potential
Researchers are targeting ghrelin in obesity studies because it is the first appetite-stimulating hormone discovered. The discovery is somewhat recent. It was discovered by Japanese researchers in 1999. In 2000, researchers in the United States found that it drives appetite. Though blocking medium-chain fatty acids from activating ghrelin is of interest in the fight against obesity, it may not hold much promise in the developed world because the typical Western diet contains little of this type of fatty acid, note the experts at the American Society for Biochemistry and Molecular Biology.
Considerations
Despite the fact that the medium-chain fatty acids appear to stimulate ghrelin, some studies pinpoint them as possible weight-loss agents. For example, A.A. Papamandjaris, lead author for a 1998 study in "Life Sciences," notes that fatty acids have different metabolic fates depending on chain length. Medium-chain fatty acids are absorbed more efficiently than long-chain fatty acids. They are transported directly to your liver, whereas long-chain fatty acids go through your lymph. The medium-chain acids enjoy preferential oxidation. Optimizing fat oxidation helps you maintain a healthy weight and avoid conditions like obesity and diabetes, notes a 2004 study in "Nutrition." Post-meal energy expenditure, or calorie burn, is higher when medium-chain fatty acids are consumed than when long-chain acids are eaten, which results in a lower likelihood for weight gain. This means medium-chain acids have potential as weight-loss agents, according to Papamandjaris.
References
- "The West Indian Medical Journal"; Fatty Acid Composition and Possible Health Effects of Coconut Constituents; D.J. Pehowich, et al.; 2000
- "Endocrinology"; Ingested Medium-Chain Fatty Acids Are Directly Utilized for the Acyl Modification of Ghrelin; Yoshihiro Nishi, et al.; 2005
- "Coconut Oil"; Cynthia Holzapfel and Laura Holzapfel; 2004
- "Life Sciences"; Medium Chain Fatty Acid Metabolism and Energy Expenditure: Obesity Treatment Implications; A.A. Papamandjaris, et al., 1998
- "Clinical Biochemistry"; Beneficial Effects of Virgin Coconut Oil on Lipid Parameters and In Vitro LDL Oxidation; K.G. Nevin and T. Rajamohan; 2004
- American Society for Biochemistry and Molecular Biology: Medium Chain Fatty Acids Get Our GOAT
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