# Ketones --- **Ketones** are any molecule with a CO group in the middle of a carbon chain (if it's on the end it's an aldehyde). A **ketone group** (R$_2$C=O) is a [[functional group]] that has a [[carbonyl]] group and two alkaline R groups. ![[ketone.png]] There are two main classes of biologically important ketones, [[ketoacids]] and [[ketone bodies]]. Sometimes "ketone" and "ketone body" are used interchangeably, but a "ketone body" is one of three specific ketones. In other words, all ketone bodies are ketones, but not all ketones are ketone bodies. "keto acids" on the other hand, are a different thing, and they have a CO group in the middle *and* a [[carboxyl group]]. ## Ketosis & Ketoacidosis **Ketosis** is a state of elevated level of ketones in the bloodstream. If there is insufficient [[blood glucose]] available (or indeed a condition like [[diabetes mellitus]]) then cells switch to [[lipolysis]] for energy. This is problematic because ketones are acidic, and inappropriately lower the [[pH]] of the blood. A healthy person might have 3 mg/dL, but sever ketosis can reach up to 90 mg/dL. If ketosis becomes severe enough, it is called **ketoacidosis**, which is very dangerous, and can happen for people with type 1 diabetes because there is no alternative other than ketone-producing lipolysis for the body to use as fuel. Clinically relevant forms of ketoacidosis include **diabetic ketoacidosis** (or **DKA**), **alcoholic ketoacidosis** (or **AKA**), and **starvation ketoacidosis**. [[Diabetic ketoacidosis]] is a potentially life-threatening complication of uncontrolled diabetes. It typically occurs in the setting of [[blood glucose|hyperglycemia]] and [[insulin]] deficiency, which causes too high a rate of [[lipolysis]] which results in [[ketone bodies|ketone body]] production and a subsequent drop in blood [[pH]]. **Alcoholic ketoacidosis** occurs in patients with chronic [[alcohol]] abuse, [[liver]] disease, and acute alcohol ingestion. **Starvation ketoacidosis** occurs after the body is deprived of [[glucose]] as its primary source of energy for a prolonged time, causing fatty acids to replace glucose as the major metabolic fuel. ___