Your bad breath can stem from poor oral hygiene. However, it may also be because of underlying metabolic disorders.

Halitosis emerges as a symptom of these disorders.

Hence, it should not be taken for granted, especially if you maintain good oral hygiene.

That said, 90 percent of bad breath results from poor oral health, for which, the bacteria are mainly responsible.

This article discusses the disorders behind bad breath and how you can treat them.

bad breath causes

Oral Hygiene Causes of Bad Breath

When you are not brushing your teeth properly, skipping flossing, are eating sugary plus acidic foods, then bacteria will start accumulating in your mouth.

These bacteria then break down the food particles after you eat.

That produces volatile sulfur compounds.

These sulfurous compounds have a pungent smell.

That odor ends up coming out of your mouth when you do not take care of your oral hygiene.

These bacteria also settle on your tongue and teeth.

Hence, they create a sticky film called plaque on your teeth that also keeps growing beneath the gum line.

Therefore, these toxins can end up irritating the gum, resulting in inflammation and also destroying the gum tissue.

While on your teeth, the bacteria can penetrate deeper resulting in cavities and decay.

Hence, if you want to get rid of these bacteria, you will first have to maintain good oral hygiene.

Do not skip on brushing and flossing regularly.

Plus, beware of what you eat, for instance, if you eat lots of sugary foods then bacteria metabolize that to produce acids that erode your enamel.

The presence of bacteria itself induces bad breath.

So as long as you brush your teeth, floss between them, use a tongue cleaner and occasionally a mouthwash, you will keep the bacteria at bay.

However, if you do not, they will cause several other oral problems.

Oral hygiene is certainly not the only cause behind halitosis.

In fact, chronic bad breath can be concerning.

Besides, bacteria, a constant unpleasantly smelling breath could result from:

  • diseases such as cystic fibrosis, gastric ulcers, hiatal hernia and leukemia
  • respiratory diseases and upper respiratory tract infections
  • taking specific medications
  • drinking alcohol and smoking
  • during menstruation
  • metabolic disorders

Let’s dig deeper into the metabolic disorders that can cause your breath to smell bad longer.

metabolic disorders causing bad breath

Metabolic Disorders Causing Bad Breath


Diabetes has a direct link with harmful oral bacteria.

If you are unable to control it then an increase in glucose levels increases bacterial growth too.

Therefore, these bacteria form plaque and then cause gum disease which eventually leads to bad breath.

Moreover, if patients have trouble producing insulin, the cellar does not receive enough glucose for energy.

The body instead produces ketones by burning fat.

They eventually build up in urine as well as blood causing halitosis.

Acetone is a ketone that produces bad breath smelling like nail polish.

This could point towards a more life-threatening diabetic ketoacidosis.

Liver Disease

The presence of volatile sulfur compounds in your breath, causing halitosis is a symptom of the disease itself.

The liver filters out toxic substances.

However, if it has a strong, musty smell then that indicates the liver isn’t filtering out the substances.


Chronic Kidney Disease

Those with kidney failure may develop a case of bad breath.

As the functions of the kidneys worsen, they cannot excrete the metabolite urea present in the urine.

Therefore, it keeps building up in the saliva and blood.

The body converts urea into ammonia and leaves a bitter taste in your mouth.

It gives the breath a urine-like odor.

This is a sign of kidneys beginning to fail when people are put into dialysis.


Phenylketonuria or PKU is a genetic condition.

In this medical condition, your body cannot break down the amino acid, phenylalanine.

It is present at birth and usually doctors scan babies for the disease shortly after they are born.

This metabolic disorder affects white Native American or Alaskan people more.

Other than these, there are genetic disorders that may influence your breath and metabolism alike.

More on that below!

metabolic disorders causing foul smell

Metabolic Disorders Behind a Foul Smelling Breath


This is another genetic metabolic disorder that causes mutations in certain genes such as GNMT, AHCY or MAT1A.

In this condition, a few people do not feel any symptoms at all.

Whereas others may have urine, breath or sweat that smells similar to a boiling cabbage.

This smell also arises from the body’s inability to break down one amino acid.

This amino acid, methionine keeps building up in the blood and as a result, produces an unpleasant smell.

However, this smell can also come if a person has liver problems caused by a disorder such as liver disease.

A less concerning cause is eating lots of protein that the body cannot break down.

Other than causing a foul smell, this disorder also results in neurological problems and liver issues.

Trimethylaminuria (TMA)

The other name for this condition is fish order syndrome.

Wondering why?

Well, because it releases a smell similar to that of a rotting fish.

It will be present not only in your breath but also in the reproductive fluids, urine and sweat.

This disease is found in families.

The genetic disorder happens because of a fault in the FM03 gene.

Those suffering from it cannot break down trimethylamine.

This is present in the food you eat.

Now in a normal person’s body, trimethylamine oxidizes into an odorless metabolite i.e. trimethylamine N-oxide.

However, people suffering from TMA cannot oxidize it.

Hence, it keeps accumulating and eventually produces that unpleasant smell.

All of these metabolic disorders play a part in your breath smelling bad besides oral hygiene.

So how can you treat it?

Chewing gum will just help mask it.

What you need is a proper treatment for the disorder itself. More on that below!

treating bad breath

Treating Bad Breath From Metabolic Disorders

In order to treat the foul smell stemming from your breath, first, address the causes behind it.

After all, solving the underlying problem will only be helpful in treating the breath rather than simply masking it.

Metabolites may be responsible for causing the breath.

If that’s the case, then adopt some lifestyle changes and treatments to manage your metabolism.

So firstly, do not delay bowel movements.

This will help to reduce the duration of the absorption of metabolites and digestive metabolism.

Therefore, fewer metabolites are absorbed hence, the breath may not smell as bad.

Also, if you suffer from constipation, you may want to treat it rather than keep suffering from it.

Moreover, you may want to increase your water intake.

Drink at least 8 glasses of water a day but more if this is what you drink regularly.

Drinking plenty water excretes the metabolites through the urine, hencing making your breath less smelly.

Other than that, you may want to reduce eating food that also causes an unpleasant smell.

For instance, eating garlic and onion can add to the smell already present due to the disorders.

Moreover, you can also try to reduce the metabolites produced in your gut.

For instance, taking prebiotic and probiotic treatments influences bacterial composition.

It changes the bacterial composition of the gut in order to make fewer metabolites.

Hence, reduced production of the metabolites, influences your breath making it significantly less smelly.

Though, your doctor will suggest an exact treatment depending on the metabolites causing the problem.

For instance, if high sugar levels in a diabetic are leading to this issue then your doctor may recommend taking medications that adjust your sugar levels.

constant bad breath

Constant Bad Breath- What to Do?

It is concerning when you have a consistent bad breath.

If the strong smell remains for a long time even if you are taking care of your oral health then this can indicate a serious problem, either stemming from oral or physical health.

The common causes for it besides poor oral hygiene are gum disease, bacterial vaginosis and urinary tract infection.

If these conditions are ruled out, your doctor will refer you to a specialist or carry out even more tests in order to diagnose the cause.

However, if you are diabetic and your breath has a strong smell similar to that of nail polish, it is concerning.

This could hint toward diabetic ketoacidosis.

This happens when ketones such as acetone, build up in the urine and the blood.

It is a medical emergency and you should contact your doctor soon.

Hence, if you are diabetic, you should constantly keep monitoring your breath.

Other than that, having good oral hygiene is one of the basics of preventing and treating bad breath.

Always brush your teeth twice a day and floss once.

Other than that, be wary of what you eat.

Limit the smelly foods in case they are causing you bad breath.

Final Thoughts 

If any of these metabolic disorders are behind your halitosis, reach out to your doctor soon.

Treating them is more important for your overall health including oral hygiene.

As they will treat the underlying condition, the bad breath will start dissipating on its own.

Hence, pay attention to your changing breath and take note if someone points out that it smells bad.