Most people with diabetes — and anyone who has read about low-carbohydrate diets — has probably heard of ketones, but how many people really know what they are? Messages about ketones can be confusing: Some sources say they are toxic and dangerous, while others suggest that ketones are a positive sign of weight loss through fat burning.
When you have diabetes, it’s important to know the facts about ketones, as well as when to check for them, how to check for them, and what to do if you detect them. Take this quiz to see how much you know about ketones. (You’ll find answers later in this article.)
1. What are ketones?
A. Acids created in the liver.
B. Fats released when blood glucose is high.
C. Antifungal drugs.
D. Hormones that are created only under special circumstances.
2. Which of the following statements about ketones is not true?
A. Consuming very little carbohydrate can lead to the formation of ketones.
B. Trace levels of ketones are generally harmless.
C. There must be a very low level of insulin for dangerous amounts of ketones to form.
D. Ketones cause weight loss.
3. All persons with diabetes should check for ketones when their blood glucose level is over 240 mg/dl.
4. Ketones can only be measured in the urine.
5. What is the role of ketones in the development of diabetic ketoacidosis (DKA), the acute diabetes complication characterized by high levels of ketones, high blood glucose, and dehydration? (More than one answer may be correct.)
A. Ketones make the blood more acid.
B. High levels of ketones cause dehydration.
C. Ketones play a role in electrolyte loss.
D. Ketones raise blood glucose.
6. People with Type 2 diabetes cannot develop diabetic ketoacidosis.
7. What steps are necessary to reduce ketones in the body? (More than one answer may be correct.)
A. Increase the level of insulin in the body.
B. Increase fluid intake.
C. Inject glucagon.
D. Determine what caused the elevated level of ketones and treat the underlying cause.
1. A. Properly called ketone bodies, ketones are acids that come in three varieties: acetone, acetoacetic acid, and beta-hydroxybutyric acid. Ketones are released by the liver when insulin levels are insufficient for glucose metabolism and the liver switches to hepatic lipid metabolism — burning of fat to fuel the body. Low to moderate levels of ketones in the blood cause no symptoms, but higher blood levels, especially of beta-hydroxybutyric acid, may cause nausea and vomiting.
2. D. Ketones are formed when the body burns fat for energy. When the body simultaneously burns glucose for energy, few ketones are formed. But if there is no (or very little) glucose available for fuel, or if there is no (or very little) insulin available to metabolize glucose, larger and potentially dangerous amounts of ketones are formed. The low levels of ketones created when following a low-carbohydrate diet are generally regarded as harmless. Ketones rarely build up to a dangerous level unless the level of insulin is very low.
While ketones are by-products of fat burning, which can lead to weight loss, ketones themselves play no active role in weight loss.
3. FALSE. People with Type 1 diabetes are advised to check for ketones when their blood glucose level is high, but medical experts differ over the level at which to check, with most recommending a level between 240 mg/dl and 300 mg/dl. In addition, some care guidelines advocate testing for ketones on the first occurrence of an elevated blood glucose number, and others only if two readings in a row are elevated. People with Type 1 diabetes are also advised to check for ketones every 4–6 hours when ill. Persons with Type 2 diabetes generally do not need to check for ketones unless their high blood glucose is accompanied by nausea or vomiting. Women with gestational diabetes have still different recommendations for checking for ketones.