Ketone bodies, from the breakdown of fatty acids to acetyl groups, are also produced during this state, and are burned throughout the body. Excess ketone bodies will slowly decarboxylate into acetone. That molecule is excreted in the breath and urine. When glycogen stores are not available in the cells (glycogen is primarily created when carbohydrates such as starch and sugar are consumed in the diet), fat (triacylglycerol) is cleaved to give 3 fatty acid chains and 1 glycerol molecule in a process called lipolysis. Most of the body is able to utilize fatty acids as an alternative source of energy in a process where fatty acid chains are cleaved to form acetyl-CoA, which can then be fed into the Krebs Cycle. It is important to note that acetyl-CoA can only enter the Krebs Cycle bound to oxaloacetate. When carbohydrate supplies are inadequate, however, the body naturally converts oxaloacetate to glucose for use by the brain and other tissues. When acetyl CoA does not bind with oxaloacetate, the liver converts it to ketones (or ketone bodies). If these ketones are not used for fuel by muscles, nerves, or the brain, they begin to accumulate and ultimately lead to a condition known as ketosis. During this process a high concentration of glucagon is present in the serum and this inactivates hexokinase and phosphofructokinase-1 (regulators of glycolysis) indirectly, causing most cells in the body to use fatty acids as their primary energy source. At the same time, glucose is synthesized in the liver from lactic acid, glucogenic amino acids, and glycerol, in a process called gluconeogenesis. Glucose is a simple sugar made by the body and is necessary for proper bodily function. This glucose is used exclusively for energy by cells such as neurons and red blood cells.
Whether ketosis takes place can be checked by using special urine test strips such as Ketostix.
Deliberately induced ketosis through a low-carbohydrate diet has been used to treat medical conditions although most such treatments remain controversial.
Predicting Risk of Ketosis in Dairy Cows Using In-Line Measurements of [beta]-Hydroxybutyrate: A Biological Model
Jul 01, 2005; ABSTRACT Automated monitoring of individual cows to determine health status is a potentially valuable management tool, especially...