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Ketones and diabetes

High levels of ketones in your blood or urine can mean you're at risk of developing diabetic ketoacidosis. This can be life-threatening, so it's important to be aware of your ketone level. 

On this page, we'll explain what ketones are and go through how to spot the symptoms. We'll also show you how to test for ketones using test strips, and explain what to do if your ketone levels are high

What are ketones?

Ketones are a type of chemical that your liver produces when it breaks down fats.

Your body uses ketones for energy typically during fasting, long periods of exercise, or when you don’t have as many carbohydrates. You can have low levels of ketones in your blood without it being a problem.

But high levels of ketones in your blood is a sign that something isn’t quite right. You can tell if you have high levels of ketones in your blood by checking for them. Your doctor should give you an idea of what your target range is and what to do if you go above it.

If you treat your diabetes with insulin, your body should be using the insulin you give it to change blood sugar into energy. But if you don’t have enough insulin, you’ll start to use fat for energy. And when you use fat for energy your liver starts to produce ketones. 

When ketones build-up in the blood, they can become acidic and lead to something called diabetic ketoacidosis (DKA). This can be life-threatening, so you need to know what the symptoms of DKA are, how to check for them and how to get treatment straight away. 

If you have type 1 diabetes, you’re more at risk of experiencing DKA than people with other types of diabetes. But if you have type 2 and use insulin then you should still look out for the signs of DKA. 

DKA is also common in people who have not yet been diagnosed with type 1 diabetes, especially children. So if you’re a parent and don’t know much about diabetes then this is good for you to know as well. You can also share this info with anyone who looks after your child, such as their teacher. 

High levels of ketones in your blood or urine can lead to diabetic ketoacidosis (DKA). 23% of children are diagnosed with diabetes in DKA.

When do ketones build up?

You’re most at risk of a build-up of ketones if you don’t inject enough insulin or if you miss a dose of insulin. It’s important to know that sometimes you need more insulin than usual and need to check for high blood sugars more regularly, like when:

  • you’re not feeling well
  • you have had an injury or surgery
  • you’re pregnant
  • you’re having your period.

All of these times are just part of normal life and that can be a reminder that diabetes is always there in the background. If you’re struggling to cope with your diabetes you can have a chat with us on our helpline. We can support you when you’re feeling down or tired with managing your diabetes.

Ketones symptoms

You should do what you can to stop ketones from building up in the body. Noticing when your body is starting to produce ketones is an important step. You should check for ketones in your blood or urine if you notice the following:

  • breath that smells fruity (this is the ketones on your breath)
  • high blood sugar levels (this is called a hyper)
  • going to the toilet a lot
  • being really thirsty
  • feeling more tired than usual
  • stomach pain
  • changes to your breathing (usually deeper)
  • confusion
  • fainting
  • feeling or being sick. 

You might notice these symptoms over 24 hours, but they can come on faster than that. If you do notice symptoms of high ketones or if you’re a parent and you see the signs in your child, you need to act quickly.

Ketone levels rising are a sign of things happening in the body that can be made better. Noticing the symptoms is the first step to doing that. Next you need to check for ketones, and seek medical help if this is high.

Testing for ketones

You can check blood or urine for ketones, but the results might be different. Checking blood for ketones will give you real-time results, just like when you check your blood sugar. A urine check will tell you what your ketone levels were a few hours ago. 

Check for ketones in your blood

The best way to check your ketone levels is using a ketone monitor to check your blood. The monitor works in a very similar way to a blood sugar monitor. You’ll prick your finger using a lancing device, get the blood on to the test strip in your monitor and wait for the result. 

There are different types of ketone monitors on the market, speak to your doctor about which one is best for you. And remember, if you have type 1 diabetes you should get a ketone monitor for free from the NHS. 

It’s also worth knowing that some blood glucose monitors have ketone checking as well. So you might not need to have two devices to check your different levels. 

Check for ketones in your urine

To check your urine for ketones, you’ll need to have the right test strips. You won’t need a monitor to do this, just pee on to the test strip and wait for the colour to change. You then need to match the colour of your test strip with a colour chart to see your ketone levels. 

What to do if you have high ketone levels

Normal blood ketone levels can be different from person to person. 

If the ketone levels in your blood are high, you’re at risk of DKA. If you suspect DKA, go to your nearest accident and emergency department straight away because you’ll need hospital treatment. If you’re not sure whether you need to go to hospital, call your GP or diabetes team as soon as you can. 

We have a lot more information about DKA and what you can do if your ketones levels are high. The most important thing to remember is that you shouldn’t ignore your results. If you’re not sure what to do next, speak to someone on our helpline or call your diabetes team. You aren’t alone with your diabetes and support is always available. 

“Lilly was told her body needed insulin and she also needs to check her blood sugars. Lilly’s ketones can’t be higher than 0.6 and if they are, we would need to go straight to hospital.”

Sara, mum of Lilly who has type 1 diabetes.

Ketones in the diet and weight loss

Ketones are produced when your body breaks down fat. This means that you might also notice weight loss when you have high levels of ketones. 

Ketogenic diet

Some people follow a ketogenic diet to lose weight, sometimes called the keto diet. This is a very low carb diet that produces ketones in their blood. We don't recommend the keto diet for treating diabetes because there is not enough evidence to say it is safe or effective.

Does the keto diet cause DKA?

Following a keto diet does not necessarily cause DKA. A keto diet leads to ketosis when your body breaks down stored fat to convert it into energy. You might think that more ketones in your blood this would increase your risk of DKA. But, this ketosis doesn’t lead to DKA if your pancreas is still producing insulin, or you inject the right amount of insulin for your diabetes, and  your blood doesn’t become acidic. But if you are considering a ketogenic diet you should speak to your diabetes team first . 

With DKA, the blood becomes acidic when ketones build up and blood glucose levels are usually high because there is no insulin. If you want to lose weight while managing your diabetes our information might help you.

Where to find support

If you’re still feeling unsure about your condition, don’t worry - you are not alone. There are many people on our forum who have been in the same position. Read through their experiences, or sign up to have a chat with people who are also getting used to managing their diabetes. 

If you need more help and support, give our confidential helpline a call. Our highly trained advisors are there for you, whether you have a question or just want to talk to someone who knows about diabetes.

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