Ketones

Ketones (or ketone bodies) are organic molecules produced by the liver when the body breaks down fat for energy instead of carbohydrates. They serve as an alternative fuel source when glucose levels are low, such as during fasting, low-carb dieting (keto diet), or prolonged exercise.

Types of Ketones

There are three primary ketone bodies:

  1. Beta-Hydroxybutyrate (BHB)
    • The most abundant ketone in the bloodstream.
    • Used as a primary fuel source by the brain, muscles, and heart.
    • Can be measured in blood ketone tests.
  2. Acetoacetate (AcAc)
    • The first ketone produced in the liver from fat breakdown.
    • Can be converted into BHB or spontaneously degrade into acetone.
    • Measured in urine ketone tests.
  3. Acetone
    • A minor ketone that is a byproduct of AcAc breakdown.
    • Quickly exhaled through breath, causing “keto breath” (fruity smell).
    • Can be measured with breath ketone analyzers.

How Ketones Are Produced (Ketogenesis)

  1. Low Glucose Levels – When carbohydrate intake is low (fasting, keto diet), blood glucose and insulin levels drop.
  2. Fat Breakdown in the Liver – The body starts breaking down stored fat into fatty acids.
  3. Conversion to Ketones – The liver converts fatty acids into ketone bodies, which are then released into the bloodstream for energy.

Why Are Ketones Important?

✅ Alternative Fuel Source – Ketones replace glucose as an energy source, especially for the brain and muscles.
✅ Efficient Energy Production – Ketones generate more ATP (energy) per molecule than glucose, leading to stable energy levels.
✅ Brain Health & Mental Clarity – The brain can efficiently use ketones, improving focus, cognition, and potentially protecting against neurodegenerative diseases (e.g., Alzheimer’s).
✅ Weight Loss & Fat Burning – The presence of ketones indicates that the body is burning fat for energy.
✅ Blood Sugar & Insulin Regulation – Ketones can help manage type 2 diabetes by reducing blood sugar spikes and insulin resistance.

How to Measure Ketones

  1. Urine Strips (Acetoacetate) 🟡 – Cheap, easy, but less accurate over time.
  2. Blood Test (Beta-Hydroxybutyrate) 🩸 – The most accurate way to measure ketosis.
  3. Breath Analyzer (Acetone) 😮 – Measures exhaled ketones but is less precise than blood tests.

Ketosis vs. Ketoacidosis: Key Difference

  • Ketosis – A natural, controlled state where ketone levels are moderate (~0.5-5.0 mmol/L). Safe and beneficial.
  • Ketoacidosis (Diabetic Ketoacidosis, DKA) – A dangerous medical condition where ketone levels become too high (>10 mmol/L), leading to blood acidity. Occurs mainly in uncontrolled diabetes (Type 1).

Conclusion

Ketones are fuel molecules produced from fat when glucose is scarce. They are essential for energy production, brain function, and fat metabolism. While ketosis (mild ketone production) is safe and beneficial, dangerously high ketone levels can lead to ketoacidosis, which is harmful.