What are ketones?
Ketones are produced when the body burns fat for energy. Normally, your body gets the energy it needs from carbohydrates in your diet. But stored fat is broken down and ketones are made if your diet does not contain enough carbohydrate to supply the body with sugar (glucose) for energy or if your body can't use blood sugar (glucose) properly.
Having some ketones in your urine is normal. However, high ketone levels in urine may be a sign of too much acid in your body (ketoacidosis). The most common and life-threatening type of ketoacidosis is a complication of diabetes called diabetic ketoacidosis (DKA). If left untreated DKA can cause damage to organs and even death. This is why it is important to know the signs of ketonuria and when to check your ketone levels with a urine or blood test.
Where are ketones formed?
Ketones are usually formed in the liver and are broken down so that normally very small amounts of ketones appear in the urine.
When are ketones produced?
Ketones are produced when the body burns fat for fuel. Normally these ketones will be completely broken down (metabolised) so that there are very few ketones in the urine. If for any reason the body cannot get enough glucose for energy it will switch to using body fats, causing an increase in ketones in the body. This results in more ketones in urine.
When does fat become the main source of energy for your body?
When carbohydrates are unavailable (for example, in starvation) or when they cannot be used as an energy source (for example, in diabetes), fat becomes the main source of energy and large amounts of ketones are made. Therefore, higher levels of urine ketones indicate that the body is using fat as the major source of energy.
Is there a link between ketones and diabetes?
Severe insulin deficiency causes an increase in blood sugar (glucose) levels (hyperglycaemia) and a very high level of ketones in the blood and urine (ketoacidosis).
References:
American Diabetes Association; c1995-2022. Diabetes & DKA (Ketoacidosis); https://www.diabetes.org/diabetes/dka-ketoacidosis-ketones
Hinkle J, Cheever K. Brunner & Suddarth's Handbook of Laboratory and Diagnostic Tests. 2nd Ed. Philadelphia: Wolters Kluwer Health, Lippincott Williams & Wilkins; c2014. Ketones: Urine; p. 351.
Ghimire P, Dhamoon A. Ketoacidosis. StatPearls Publishing https://www.ncbi.nlm.nih.gov/books/NBK534848/
Joslin Diabetes Center [Internet]. Boston: Joslin Diabetes Center, Harvard Medical School; c2022. Ketone Testing; https://www.joslin.org/patient-care/diabetes-education/diabetes-learning-center/ketone-testing-0
Masood W, Annamaraju P, Uppaluri KR. Ketogenic Diet. StatPearls Publishing https://www.ncbi.nlm.nih.gov/books/NBK499830/
National Institute of Diabetes and Digestive and Kidney Diseases https://www.niddk.nih.gov/health-information/diabetes/overview/managing-diabetes
Paoli A. Ketogenic Diet for Obesity: Friend or Foe? Int J Environ Res Public Health https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3945587
Saint Francis Health System [Internet]. Tulsa (OK): Saint Francis Health System; c2010. Patient Information: Collecting a Clean Catch Urine Sample; https://www.saintfrancis.com/assets/documents/lab/collecting-a-clean-catch-urine.pdf
Testing.com https://www.testing.com/tests/urinalysis/#ketones
The Johns Hopkins Lupus Center https://www.hopkinslupus.org/lupus-tests/screening-laboratory-tests/urinalysis/
UF Health: University of Florida Health - Ketones urine test: Overview; https://ufhealth.org/ketones-urine-test
University of Rochester Medical Center https://www.urmc.rochester.edu/encyclopedia/content.aspx?contenttypeid=167&contentid=ketone_bodies_urine
Luethi N, Cioccari L, Crisman M, Bellomo R, Eastwood GM, Mårtensson J. Prevalence of ketosis, ketonuria, and ketoacidosis during liberal glycemic control in critically ill patients with diabetes: an observational study. Crit Care. 2016;20:297. doi:10.1186/s13054-016-1462-7
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