Ketones are acidic compounds produced by the liver when the body breaks down fat for energy instead of glucose. This metabolic shift can be a deliberate and controlled process, such as during a ketogenic diet, or a dangerous side effect of uncontrolled conditions like diabetes. Knowing when ketone levels cross the line from a normal metabolic function to a medical concern is essential for proactive health management.
Understanding Ketone Levels
For healthy individuals on a standard diet, ketone levels are typically very low, generally below 0.6 mmol/L in the blood. This indicates the body is primarily using glucose as its fuel source. However, for those intentionally inducing ketosis for dietary reasons, higher ketone levels are normal. The key is to understand the different thresholds that signal a potential problem. Testing can be done at home using blood ketone meters, which are considered the most accurate, or urine test strips.
What is a Concerning Level of Ketones?
Blood ketone levels are measured in millimoles per liter (mmol/L) and provide a clear indicator of metabolic status. For individuals at risk, particularly those with diabetes, these levels are critical for making health decisions.
Blood Ketone Level Breakdown
- Normal: A reading under 0.6 mmol/L is considered normal. For someone on a ketogenic diet, this may represent a non-ketotic state.
- Slightly High: Levels between 0.6 and 1.5 mmol/L are slightly elevated and indicate that ketones are building up. This is often the target range for nutritional ketosis. However, if a person with diabetes feels unwell at these levels, they should contact their healthcare provider.
- Moderately High (Increased Risk of DKA): Readings from 1.6 to 3.0 mmol/L suggest a significant risk of developing diabetic ketoacidosis (DKA). At this stage, a diabetic individual should contact their diabetes care team for advice on managing blood sugar and insulin levels.
- Very High (Medical Emergency): Any reading over 3.0 mmol/L is considered very high and potentially life-threatening. This means DKA is likely, and immediate medical attention is required. This often comes with severe symptoms.
Ketosis vs. Ketoacidosis: A Critical Distinction
It is crucial to differentiate between the controlled, metabolic state of ketosis and the dangerous, medical emergency of ketoacidosis.
| Feature | Nutritional Ketosis | Diabetic Ketoacidosis (DKA) |
|---|---|---|
| Cause | Controlled carbohydrate restriction (e.g., ketogenic diet) or fasting in a healthy individual. | Severe insulin deficiency, often due to uncontrolled type 1 diabetes, illness, or missed insulin doses. |
| Ketone Levels | Moderate and controlled, typically in the 0.5–3.0 mmol/L range. | Extremely high, often exceeding 3.0 mmol/L. |
| Blood Acidity (pH) | Normal. The body's buffering systems maintain a safe pH balance. | dangerously acidic. The excess ketones overpower the body's ability to maintain a healthy pH, leading to acidosis. |
| Blood Sugar | Can be stable or slightly lower than normal due to limited carbohydrate intake. | Very high blood sugar levels (hyperglycemia), often over 250 mg/dL. |
| Symptoms | Often mild, such as temporary fatigue, headache, or 'keto flu'. | Severe symptoms including intense thirst, frequent urination, nausea, vomiting, abdominal pain, fruity-smelling breath, confusion, and rapid breathing. |
| Outcome | Generally safe and may offer health benefits; not a medical emergency. | Life-threatening without immediate medical treatment. Can lead to coma or death. |
Causes of High Ketone Levels
High ketone levels can be triggered by several factors, which may differ depending on whether you have diabetes.
- Insufficient Insulin (Diabetics): The most common cause of dangerous ketone levels in people with diabetes is a lack of insulin. Without enough insulin, the body cannot use glucose for energy and turns to fat, producing a flood of ketones.
- Illness or Infection: Physical stress from an illness like pneumonia or a urinary tract infection can cause the body to release hormones that work against insulin, raising both blood sugar and ketones.
- Prolonged Fasting or Starvation: When a person goes without food for a long period, their body will start to burn fat for fuel, leading to higher ketone levels. In severe cases, this can lead to ketoacidosis in non-diabetics.
- Excessive Alcohol Consumption: Heavy alcohol use can disrupt the body's glucose and insulin balance, potentially leading to alcoholic ketoacidosis.
- Insulin Pump Failure: For individuals with type 1 diabetes who use an insulin pump, a mechanical failure or site issue can stop insulin delivery, leading to a rapid rise in ketones.
- Pregnancy: Gestational diabetes or severe, prolonged morning sickness (hyperemesis gravidarum) can increase ketone production.
Managing and Preventing High Ketones
Proactive management is the best strategy for preventing dangerous ketone levels. This is particularly important for individuals with diabetes, who should work closely with their healthcare team.
Action Steps for Managing Elevated Ketones
- Hydrate Immediately: Drink plenty of sugar-free fluids like water every 30-60 minutes to help flush ketones out of your system.
- Take Insulin (if diabetic): If a diabetic's ketone levels are elevated, they will likely need to administer extra rapid-acting insulin according to their sick-day plan.
- Monitor Closely: Recheck blood glucose and ketone levels frequently (e.g., every 3-4 hours) to track progress.
- Avoid Exercise: If your blood sugar and ketones are high, do not exercise, as it can worsen the situation and increase ketone production.
- Address the Underlying Cause: Treat any illness or infection that may be contributing to the high ketones. For those on a ketogenic diet, temporarily increasing carbohydrate intake may be necessary.
Conclusion
While a low level of ketones can be a harmless result of dietary choices, understanding what is a concerning level of ketones is a critical aspect of personal health, especially for those with diabetes. Blood ketone levels above 1.5 mmol/L warrant close monitoring and communication with a healthcare provider, while levels exceeding 3.0 mmol/L are a medical emergency requiring immediate action to prevent or treat diabetic ketoacidosis. Consistent monitoring, proper insulin management, and knowing the symptoms of DKA are the most effective ways to manage ketone levels and ensure safety.
For more information on ketones and diabetic ketoacidosis, consult the Cleveland Clinic's health library.(https://my.clevelandclinic.org/health/body/25177-ketones)
