Beta hydroxybutyrate

Beta-Hydroxybutyrate (BHB) is a ketone body produced by the liver from fatty acids during periods of low food intake (fasting), carbohydrate restrictive diets, starvation, prolonged intense exercise, or in untreated (or inadequately treated) Type 1 diabetes mellitus.

Production and Metabolism

Beta-Hydroxybutyrate is synthesized in the liver from acetoacetate, the first ketone produced in the fasting state. The production of beta-hydroxybutyrate is elevated in conditions of fasting, starvation, and low carbohydrate diets because the body needs to produce energy from sources other than glucose. This process is known as ketogenesis.

Beta-Hydroxybutyrate is then transported from the liver to other tissues, where it is converted back into acetoacetate and then into acetyl-CoA, which can enter the Krebs cycle to produce energy.

Physiological Role

Beta-Hydroxybutyrate serves as a circulating energy source for tissues in times of fasting or prolonged exercise. It is especially important for the brain, which cannot directly metabolize fatty acids for energy. Instead, under these conditions, the brain utilizes beta-hydroxybutyrate as a source of energy.

Clinical Significance

In diabetes mellitus, particularly type 1 diabetes, the levels of beta-hydroxybutyrate can become excessively high, leading to a condition known as ketoacidosis. This is a medical emergency and can be life-threatening if not treated promptly.

Beta-Hydroxybutyrate is also used clinically as a marker of insulin deficiency. In addition, it is used in some diagnostic tests for assessing metabolic activity and energy balance in the body.

See Also

• Ketone bodies
• Ketogenesis
• Ketoacidosis
• Diabetes mellitus