High levels of ketones in urine, known as ketonuria, can indicate various conditions, from harmless dietary states to serious medical emergencies. This article explores the causes, risks, symptoms, and management of ketones in urine, especially in the context of a ketogenic diet.
What are Ketones?
Ketones are acids produced by the body when it burns fat for fuel. The human body uses simple carbohydrates from starchy foods, honey, and certain fruits to produce glucose (blood sugar). Glucose serves as the body’s main source of energy. When the body doesn't have enough glucose, or when it doesn't have sufficient insulin to use the glucose, it begins to use fat for energy instead. This process results in the production of ketones. Both fat and protein consist mainly of ketones.
Causes of Ketones in Urine
Diabetic Ketoacidosis (DKA)
High levels of ketones in urine are usually a sign of diabetic ketoacidosis (DKA), a severe complication of diabetes. People with uncontrolled diabetes require insulin to utilize glucose as energy. If the person does not have enough insulin in their body, they will use fats and protein as their energy source. This process leads to production of ketones and build-up of acid, called DKA. DKA may also occur in the setting of physical trauma, high levels of stress, infection, heart attack, or stroke. DKA is a potentially life-threatening condition, as well as one of the first signs that a person has diabetes prior to diagnosis. A doctor may test for abnormally high levels of ketones in the urine or blood to check for DKA, as well the first signs that a person has type 1 diabetes.
Dietary Factors
Ketones are most common in people who do not consume enough carbohydrates. People who are fasting or on low carb diets may also eliminate ketones in their urine. When following a ketogenic (keto) diet, which is high in fat, adequate in protein and very low in carbs, the body enters a state of ketosis. A typical keto diet consists of 70% to 80% fats, 20% proteins and 5% to 10% carbs. People who eat a strict keto diet typically have ketones in their urine.
Other Causes
Other reasons why a person may develop ketoacidosis include:
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- Pregnancy
- Substance use disorder
- Prescription medications such as diuretics or corticosteroids
- Pancreatitis or another illness
- Infection that results in higher levels of cortisol, adrenaline, or other hormones that counter insulin
- Prolonged fasting
- Stroke or heart attack
- Trauma
- Missed doses or inadequate amounts of insulin in the body
- Extreme exercise when blood sugar is high and there are high levels of ketones in the body as this can increase blood sugar levels
Symptoms of High Ketones
Symptoms of DKA vary in severity, however, they can include ongoing nausea, fatigue, or difficulty breathing. The most common symptoms of diabetic ketoacidosis or ketones in the urine are:
- Fatigue or exhaustion
- Sudden weight loss
- Sore or aching muscles
- More frequent urination
- Shortness of breath or labored breathing (dyspnea)
- Excessive thirst
- Nausea or vomiting
- Pain in the abdomen
A few other, less common symptoms associated with this condition include:
- Kidney failure
- Coma
- Cardiac arrest
- Swelling of the brain or cerebral edema
- Death
People with any of these symptoms or with type 1 diabetes should immediately consult a doctor or conduct a urine or blood test.
Testing for Ketones
The most common way to test for ketones is through a urine or a blood test. People who have type 1 diabetes, low blood sugar, or experience other symptoms related to DKA should consider taking a urine test to detect and measure the level of ketones they have.
Urine Test
There are two ways to administer a urine test:
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- In a medical facility: Prior to the test, the person should not consume anything for several hours. They must then collect between one and two ounces of urine in a sterile container and provide it to a doctor for testing.
- At home: For at home testing, a doctor may provide the person with a test strip and urine collection container. The test strip and the container will both have a color chart that indicates the ketone level. Again, the person must not consume anything for several hours before the test.
In both cases, the ketones in urine test will determine whether the level of ketones is small, moderate, or high. Various factors such as gender, age, medical history, existing medication, diet, and activity level may influence this number.
Blood Test
Ketones show up in the urine and in the blood. Blood levels of ketones require blood draw, usually in a hospital. People who take insulin shots should monitor their blood glucose at home. To check blood for ketones, blood draw will be done at a facility, usually in a hospital setting. While there are Over the counter home ketone meters, marketed for keto dieters, these are not standardized. The ADA does not recommend home blood ketone tests, only urine. This test is done in the hospital or emergency department when DKA is suspected. Other blood tests obtained when DKA is suspected include kidney function, electrolytes, glucose, liver function, pH (or acidity), and blood count.
Evaluating the results
The results from a urine test for ketones will either come back negative or abnormal. A negative test result means the ketone levels are normal for the individual. An abnormal result means the test detected ketones in the urine. This result falls into three categories:
- Small levels of ketones: Less than 20 mg/dL
- Moderate levels of ketones: Between 30 and 40 mg/dL
- Large levels of ketones: Above 80 mg/dL, which needs immediate medial attention
As for the blood test, the results fall into three main ranges:
- 0. 6 mmol/L or below: This is the normal range.
- 7. 6 to 1.5 mmol/L: There are ketones in the blood. The doctor will discuss a treatment plan and follow-up.
- 8. 6 mmol/L or above: This indicates a high risk of developing diabetic ketoacidosis. Your doctor will discuss immediate treatment measures.
A urine test only checks for current or recent ketone levels, so a blood test may be more accurate. However, an abnormal or high result could be due to other factors such as:
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- Recent illness or high fever
- Low carbohydrate or high protein diet
- Eating disorder such as anorexia
- Excessive alcohol consumption
- Hyperthyroidism (overproduction of the thyroid hormone)
- Breastfeeding
If a person is unsure of their results, they should contact a healthcare professional to interpret the results, especially for at-home testing.
Complications of High Ketones
DKA is a medical emergency that requires immediate medical care. Other health concerns related to high levels of ketones in the urine include hyperglycemia, dehydration, and acidosis. Complications of diabetic ketoacidosis may include:
- Cerebral edema
- Hypoglycemia
- Low potassium levels
- Acute kidney failure
- Shocks
- Stroke
- Pulmonary edema
These complications may lead to other problems such as a loss of consciousness or even death.
Treatment and Prevention
There are several effective ways to treat and prevent high levels of ketones in the urine and the onset of diabetic ketoacidosis. Popular treatments include insulin therapy, fluid replacement treatment, and electrolytes replacement.
Prevention for Type 1 Diabetics
People with type 1 diabetes should do the following to prevent ketones from building up in the body:
- Monitor insulin and blood sugar levels daily.
- Stay on top of any existing insulin therapy plan.
- Create a dietary plan that includes carbohydrates to increase glucose levels.
- Stay hydrated to help flush out the ketones.
- Get around 150 minutes a week of moderate exercise.
- Check for ketones in the blood and urine via at-home or in-lab testing.
By taking these steps and establishing and following an insulin therapy or treatment plan, people who are at higher risk of developing DKA can help prevent or manage it.
When to Seek Medical Attention
A person should seek medical attention if they experience any of the following symptoms:
- Frequent vomiting
- Difficulty breathing
- Stomach or abdominal pain
- Unquenchable thirst
- Frequent urination
- Fatigue
- Inexplicably fruity-scented breath
Additionally, it may be wise to speak with a doctor if the results from an at-home blood or urine test come back abnormal. People should seek emergency medical attention if these symptoms persist or get worse.
Ketones and the Keto Diet
The ketogenic (keto) diet is a low carb, high fat diet that aims to keep your body in ketosis. This is a metabolic state in which you burn fat as your main source of fuel rather than carbs. For many people, being in ketosis can help improve blood sugar levels, reduce appetite, and maintain muscle mass - all of which may contribute to weight loss.
Achieving Ketosis
After completely eliminating carbs, it may take your body 2 to 3 days to burn through its carb stores, which are stored in your liver and muscles as glycogen. Once these carb stores are depleted, you’ll start producing acid compounds called ketones. These are created when your body uses dietary fat or stored body fat for energy. This process is known as metabolic switching. At that point, you may have detectable levels of ketones in your blood. Blood ketone levels while on the keto diet typically range from 0.5 to 3 mmol/L. These are the optimal levels for nutritional ketosis, the state in which your body uses stored fat for energy instead of glycogen, or carbs.
To achieve optimal ketone levels, you must restrict your carb intake. The macronutrient ratio for total calorie intake on a keto diet is typically:
- Fat: 55% to 60%
- Protein: 30% to 35%
- Carbs: 5% to 10%
So, if you’re on a 2,000-calorie diet, this would equal 25 to 50 grams (g) of total carbs per day. Your body will not start to produce ketones on its own until it burns through your glycogen stores, which it will not do unless you cut off its supply of dietary carbs. Once you shift into ketosis, your body can produce ketones for energy from either dietary fat or stored body fat.
Monitoring Ketone Levels on Keto
The easiest way to measure ketones at home is in the urine. Urine ketone tests use a different unit of measure - milligrams per deciliter (mg/dL). Your test kit may list a specific number or simply indicate “small”, “moderate”, or “large” ketone levels. The urine test is done using urine stripes that change color based on the presence of the ketone acetoacetate. According to a study published in 2016, the best time to do this urine test is either very early in the morning or late at night after dinner.
Risks of the Keto Diet
While the keto diet may help support weight loss, there could be some risks associated with it. Some short-term side effects may include:
- Nausea
- Constipation
- Vomiting
- Headache
- Fatigue
- Dizziness
- Insomnia
In many cases, these symptoms will get better within a few weeks. However, the keto diet has also been associated with more severe health conditions, such as:
- Muscle loss
- Nutrient deficiencies
- Kidney stones
- Heart disease
It’s important to speak with a healthcare professional or a registered dietitian before starting the keto diet for weight loss. They can help you determine the best meal plan for you.
Ketosis vs. Ketoacidosis
It’s crucial to differentiate between ketosis and ketoacidosis. Ketosis is a metabolic process that occurs when the body breaks down fat for energy if it's not getting enough carbohydrates. Ketoacidosis, meanwhile, is typically a life-threatening complication of diabetes. It happens when insulin levels drop dangerously low, causing a buildup of ketones and acid in the blood.
Key Differences
| Feature | Ketosis | Ketoacidosis |
|---|---|---|
| Cause | Low carbohydrate intake, fasting, keto diet | Insulin deficiency, uncontrolled diabetes |
| Ketone Levels | Mildly elevated | Dangerously high |
| Risk | Generally safe for healthy individuals | Life-threatening, requires immediate care |
| Common In | People on keto diets | People with diabetes |