Node Smith, ND
Bile Acids Actually Help Change the Metabolism of Fat Cells
A recent study has supporting evidence that bile acids actually help change the metabolism of fat cells and could potentially be used as a new therapy for obesity.1 The study also inadvertently supports the use of cold conditioning for this same effect – an idea that older naturopaths may have called “hardening.”
Bile Acids: More than Emulsification
Bile acids primary function is thought to be the emulsification of dietary fats in the small intestine, which facilitates absorption. However, bile acids have many other functions, including the elimination of certain metabolic waste products – such as bilirubin – eliminating cholesterol, aiding the absorption of fat-soluble vitamins, increasing motility a regulation of gut flora. This new research study elaborates on the hormonal properties of bile acids, and their metabolic actions.
Secondary Bile Acids
Primary bile acids are produced in the liver as both cholic acid and chenodeoxycholic acid, and then conjugated with either taurine or glycine before being secreted into the small intestine. Once these bile acids (actually “salts” once conjugated) reach the colon, they are acted upon by bacteria which removes the glycine and taurine groups as well as partially dehydroxylates them forming “secondary bile acids.” It’s these secondary bile acids – deoxycholic acid and lithocholic acid – that are then taken back into the blood stream that are thought to have metabolic effects on fat metabolism.
From Secondary to “Beiging”
These secondary bile acids, acting on TGR5 receptors can change white fat cells into “beige” fat cells. Beige fat cells are similar to brown fat, in that they have thermogenic action, while still being located within typically white fat cell areas. These beige cells are very interesting because, whereas brown cells are relatively sparse within an adult body, beige cells can be upregulated, thus increasing the energy burning capacity of the cells (which are fat cells).
Freezing out the Beige
A known way for cells to undergo “beiging” is to be exposed to cold. This was only briefly mentioned within the research paper, but is extremely important. The body does have a way of naturally increasing its own ability to create heat when it needs to, and this process inherently uses more energy, which it gets from current fat stores – thus “beiging” of fat cells. Interestingly, cold exposure also changes the composition of bile acids, increasing the number of secondary bile acids, which are thought to be the mechanism by which this fat transformation occurs.
“Beiging” Increases Number of Mitochondria within Fat Cells and Triggers Lipolysis
The researchers found that this “beiging” increases the number of mitochondria within the fat cells as well as trigger lipolysis, which allows fatty acids to be used for energy. Because of these findings, it is thought that the administration of secondary bile acids may in the future be a viable treatment for obesity. In individuals who have little interest in cold exposure therapy, of course.
- Velazquez-villegas LA, Perino A, Lemos V, et al. TGR5 signalling promotes mitochondrial fission and beige remodelling of white adipose tissue. Nat Commun. 2018;9(1):245.
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Node Smith, ND, is a naturopathic physician in Portland, OR and associate editor for NDNR. He has been instrumental in maintaining a firm connection to the philosophy and heritage of naturopathic medicine among the next generation of docs. He helped found the first multi-generational experiential retreat, which brings elders, alumni, and students together for a weekend camp-out where naturopathic medicine and medical philosophy are experienced in nature. Four years ago he helped found the non-profit, Association for Naturopathic ReVitalization (ANR), for which he serves as the board chairman. ANR has a mission to inspire health practitioners to embody the naturopathic principles through experiential education. Node also has a firm belief that the next era of naturopathic medicine will see a resurgence of in-patient facilities which use fasting, earthing, hydrotherapy and homeopathy to bring people back from chronic diseases of modern living; he is involved in numerous conversations and projects to bring about this vision.