Sweet-Smelling Urine: Causes & Treatment

The smell and appearance of your urine can tell you a lot about what is going on in your body. 

Depending on how concentrated it is, the smell of urine normally varies from being odorless to having a strong ammonia scent.

A sweet or fruity scent is not normal. 

And while some of the causes of sweet-smelling urine are harmless, it could be a sign that something wrong is happening in your body.

In this article, we tell you everything you need to know about the possible causes of sweet-smelling urine. 

We also discuss warning signs to look out for and tell you how some conditions that cause sweet-smelling urine can be prevented and treated.

What causes sweet-smelling urine?

Urine is produced when your kidneys filter your blood to remove toxic metabolites and waste products from your body. 

When the odor or color of your urine changes suddenly, it means that there has been a change in the composition of your urine. 

For example, when you drink less water and get dehydrated, your urine becomes more concentrated and could have a stronger smell because of the higher ammonia concentration.

A change in the odor of your urine can also occur when there are some additional substances in your urine that are usually not there. 

These substances could be harmless. They may come from changes in your diet. 

For instance, foods like asparagus, coffee, and honey can produce substances that change the smell of your urine temporarily.  

Vitamin B complex and certain antibiotics can also have the same effect.

That being said, sweet-smelling urine can point to more serious underlying conditions. Here are a few of them:

Urinary tract infection

Urinary tract infections (UTIs) are some of the most commonly occurring infections in humans. They occur when bacteria like E. coli infect parts of the urinary tract. These include the kidneys, ureters, bladder, and urethra.

When you have a UTI, some of the bacteria may end up in your urine as your immune cells try to fight off the infection. This can cause your urine to take on a scent that is stronger or sweeter than usual.

Some other possible symptoms of a UTI include:

• A burning sensation on urination
• Abnormal discharge
• Increased frequency of urination
• Fever and chills
• Vomiting
• Abdominal and back pain
• Cloudy urine
• Blood in urine

Maple syrup urine disease (MSUD)

Maple syrup urine disease, a.k.a. branched-chain ketoaciduria, is a rare genetic disorder in which a person cannot break down certain amino acids properly. 

As a result, these amino acids build up in the body and can give urine a distinctive maple syrup or burnt sugar scent.

The condition is commonly diagnosed in infancy. It often comes to the attention of parents when they smell the characteristic sweet scent of the affected infant’s urine.

Without treatment, the accumulation of amino acids can lead to various intellectual and physical disabilities. 

Other symptoms of MSUD include:

• Sweet-smelling sweat or earwax
• Poor feeding
• Irritability
• Vomiting
• Spasms and seizures
• Delayed development

Liver Failure

One of the major functions of the liver is to process toxic chemicals and convert them into forms that are non-toxic and easy to eliminate from the body.

When the liver fails, toxic metabolites accumulate in the body. This can lead to a distinctive sweet or musty odor that is often referred to as “fetor hepaticus” or “breath of the dead.” 

While this smell is usually perceived on the breath of people with liver failure, it can also be evident in their urine.

Pregnancy

In pregnant women, there are a few things that can cause sweet-smelling urine. Some are harmless, and some are potentially fatal to the mother and the fetus. 

Here are a few of them:

• Stronger sense of smell: During pregnancy, hormonal and physical changes can heighten a woman’s sense of smell and make it seem like her urine smells different.
• Dehydration: Because of various changes that occur in a pregnant woman’s body, the fluid requirement increases. In other words, pregnant women need to drink more water than usual, which makes them more prone to dehydration.
• UTI: Sweet-smelling urine in pregnancy can also be a sign of a UTI, which is very common in pregnant women. This can lead to serious complications like rupture of membranes before labor starts and low birth weight.
• Gestational diabetes: Another possible cause of sweet-smelling urine in pregnant women is gestational diabetes. Gestational diabetes is a type of diabetes that can develop when hormonal changes in pregnancy cause increased resistance of the body’s cells to insulin.

Is sweet-smelling urine a sign of diabetes?

Sweet-smelling urine is one of the most common symptoms of diabetes. In fact, some scientists have proposed using the scent of urine as a tool for detecting diabetes early. 

There are various ways in which diabetes can cause changes in the odor – and color – of urine. Below we discuss some of them.

Hyperglycemia

In people with diabetes mellitus, there is either a lack of insulin or increased resistance of the body’s cells to it. Insulin is a hormone that helps your body’s cells absorb glucose. 

If it is lacking or if cells don’t respond to it, glucose builds up in the bloodstream instead of being transported into your cells to produce energy.

This can lead to hyperglycemia, a condition in which blood sugar levels are too high. When that happens, your kidneys try to excrete the excess sugar in your urine which can change its scent.

Kidney damage and UTIs

High blood sugar can cause damage to blood vessels in your kidneys and affect their ability to filter blood properly. 

When the kidneys are not able to function properly, the composition – and, therefore, smell – of your urine can change.

Diabetes, especially type 2, can also affect the ability of your immune system to function properly. As such, people with diabetes are at higher risk of getting infections like UTIs.   

Diabetic ketoacidosis

Diabetic ketoacidosis (DKA) is a complication of diabetes that can be fatal. As mentioned earlier, when your body lacks insulin, it is not able to absorb glucose into the cells to produce energy. 

When cells cannot convert glucose to energy, they switch to breaking down fats. This process releases chemicals called ketones.

If the lack of insulin continues, ketones build up in the blood along with glucose. These ketones increase the acidity of the blood – hence the term diabetic ketoacidosis. 

The excess glucose and ketones in the blood get eliminated in the urine and may result in a sweet smell.

DKA is a medical emergency. Apart from sweet-smelling urine, here are some other signs and symptoms of DKA that you should be aware of:

• Excessive thirst
• Parched mouth
• Nausea, vomiting, and abdominal pain
• Extreme fatigue
• Fruity breath
• Difficulty breathing
• Confusion
• Loss of consciousness
• Coma

What does diabetic urine smell like?

Diabetes and its complications can cause urine to have a fruity or sweet scent. If you have never been diagnosed with diabetes, fruity or sweet-smelling urine may be one of your first symptoms of the disease.

If you are a known diabetic who is already on medication, having fruity-smelling urine may be a sign that your blood sugar is poorly controlled. It may also signify that you are developing complications like DKA.  

Possible accompanying symptoms and warning signs

If you have sweet-smelling urine transiently and have no other symptoms, there may be no need to panic. 

But, if you have any of the following symptoms in addition to smelly urine, you need to see a healthcare provider as soon as possible.

• Excessive thirst and urination: Feeling very thirsty and urinating frequently are common symptoms of diabetes and DKA. Frequent urination is also a symptom of UTI.
• Confusion, agitation, or irritability: These are common symptoms of DKA.
• Abdominal pain, nausea, and vomiting: Having DKA, liver damage, or a serious UTI can cause these symptoms.
• Fever: Having a fever may point to a UTI.
• Blood or pus in your urine: These could also happen when you have a UTI.
• Yellowish skin or eyes: This may be a symptom of liver failure.

When to see a doctor

If your urine smells fruity, but you have no other accompanying symptoms, it may be a temporary symptom caused by something you ate. Or, you might simply need to increase your fluid intake because you are mildly dehydrated.

However, if you have any of the accompanying symptoms listed above or if the odorous smell is persistent, you need to visit your healthcare provider to get tested and rule out serious conditions.

Diagnosis

One of the first tests a doctor will order if you complain of sweet-smelling urine is a urinalysis. 

A urinalysis involves dipping a test strip into a sample of your urine to detect things like blood, white blood cells, glucose, and ketones.

Depending on your other symptoms and what your doctor suspects may be causing the scent of your urine to change, other tests might be ordered. 

These include:

• A fasting blood sugar check
• Urine microscopy and culture
• Liver and kidney function tests
• Urine pregnancy test
• Abdominal and pelvic ultrasound scan

Treatment

The treatment of sweet-smelling urine depends on the cause. For instance, if you have diabetes, you need to control your blood sugar. 

There are various management options, such as lifestyle and diet modifications and the use of oral diabetic medications and insulin.

UTIs are often treated with antibiotics. You may also be given pain and fever-lowering medications. 

If you have a severe UTI that has spread to the blood, you may need to be admitted to a hospital to receive intravenous antibiotics and other strong medications.

For MSUD, intravenous amino acid supplementation can be used short-term. In the long run, the child may need a specialized low-protein dietary plan.

The treatment of liver failure depends on the underlying cause. Mostly, drugs are given to manage the complications of the disease. With chronic liver failure, the damage is usually irreversible, and the affected person will need a liver transplant.

Prevention of sweet-smelling urine

Not all of the causes of sweet-smelling urine are preventable. Below we discuss the ones that are and give you tips on how to avoid them:  

Dehydration

Be sure to drink enough water every day. Your ideal fluid intake depends on a variety of factors, including your weight, age, and level of physical activity. 

However, a good rule of thumb is to make sure you’re drinking at least eight glasses of water or two liters of fluid daily.

Diabetes

There are two main types of diabetes – type 1 and type 2. Type 1 diabetes is an autoimmune condition, and we currently have no preventive measures for it. 

Type 2 diabetes, on the other hand, can be prevented with lifestyle modifications such as:

• Exercising regularly
• Eating a well-balanced diet
• Getting your blood sugar checked regularly.

If you are already a confirmed diabetic, you need to avoid blood sugar spikes and keep your blood sugar levels stable. This helps to prevent hyperglycemia, DKA, and other causes of sweet-smelling urine that can occur in a person with diabetes.

Urinary tract infection

To reduce your risk of having a UTI, here are some things you can do:

• Try to remain hydrated, as drinking enough water helps to dilute your urine and prevent bacteria from accumulating in your urinary tract. 
• After you use the bathroom, wipe your genitals from front to back. This is especially important if you’re a woman. Wiping from back to front increases the risk of transferring E.coli, one of the commonest causes of UTIs, from your rectum to your urethra. 
• Don’t ignore the urge to urinate. Holding your pee in can give bacteria a chance to multiply and cause an infection. Peeing regularly is especially important for pregnant women who have an increased risk of developing UTIs.

Liver failure

Several conditions can lead to liver failure. Some of them can be avoided with behaviors such as drinking alcohol in moderation, staying up to date with vaccines, practicing safe sex, and taking medications only as they are prescribed. 

Conclusion

A change in the smell of your urine can be caused by a wide variety of conditions. Fortunately, you can prevent many of the possible causes with certain lifestyle modifications.

Even though sweet-smelling urine is not always a cause for concern, it is often the very first symptom of serious and potentially fatal conditions like diabetes and DKA.

If you have persistent sweet-smelling urine and/or have accompanying symptoms, it is important to get checked as soon as possible.

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