As the body slips further into ketosis, it transitions through stages involving different types of ketones, which are produced and utilized in a specific order depending on energy demand, adaptation level, and enzymatic efficiency. Here's how the process generally unfolds:
🔹 1. Acetoacetate (AcAc) – The First Ketone Formed
Primary ketone body produced in the liver from fatty acid oxidation.
Water-soluble, and serves as the precursor to other ketones.
When ketosis begins, AcAc levels rise first.
It can be:
Used directly for energy (mostly by muscle).
Spontaneously or enzymatically converted to:
β-hydroxybutyrate (BHB) (with NADH)
Acetone (via spontaneous decarboxylation)
🔹 2. β-Hydroxybutyrate (BHB) – The Most Stable and Abundant
Though technically not a true ketone (it’s a hydroxy acid), it's the most abundant circulating form in sustained ketosis.
Converted from acetoacetate via the enzyme β-hydroxybutyrate dehydrogenase.
Used by the brain, heart, and skeletal muscles after adaptation.
Has a longer half-life and is often used as the main marker in blood tests.
🔹 3. Acetone – The Volatile Byproduct
Produced non-enzymatically from acetoacetate.
Least stable and not metabolically useful.
Mostly exhaled through breath (causes "keto breath").
Minimal energy contribution, but early marker for ketosis.
Summary of Activation Order:
OrderKetoneFunctionMetabolic Role1AcetoacetateFirst ketone made from fatPrecursor to others, usable for energy2β-HydroxybutyrateMain ketone body in circulationMost efficient and stable energy source3AcetoneByproduct of AcAcExhaled; trace energy contribution
➕ Notes:
In early ketosis, you may see more acetoacetate and acetone.
As you become keto-adapted, BHB dominates and is the key fuel for the brain and body.
Urine ketone strips mainly detect acetoacetate.
Breath meters measure acetone.
Blood meters detect BHB (most accurate reflection of adaptation).
No comments:
Post a Comment