What’s causing your morning breath?

Does everyone get morning breath?

Everyone gets morning breath to some degree. This is because during sleep, your mouth produces less saliva and more odour-causing bacteria.

For most people, bad morning breath - also called halitosis - is mild and easily eliminated when you brush your teeth. However, if you're finding it particularly potent and unpleasant, or if your basic dental routine isn't fully resolving the problem, you need to identify if there's an underlying issue that needs to be addressed.

What causes morning breath?

What else besides sleep can make morning breath worse? According to cosmetic dentist Dr Sam Jethwa, possible factors include health conditions, our dental habits, and the food we eat.

Here are some of the most likely causes for your bad morning breath:

Dry mouth

When our bodies produce less saliva during sleep, this makes our mouths a little dryer first thing in the morning. Saliva keeps your mouth moist and also helps to keep your teeth clean and free from bacteria¹. A dry, saliva-free mouth is a breeding ground for bacteria that can cause bad breath.

This is known as dry mouth, or xerostomia, and this can be more of a problem for some people than for others. If this is a particular issue for you, alongside a dry mouth you may find it more difficult to swallow or to speak, due to your saliva becoming thick and sticky. Some people also experience a slight burning sensation in their mouths.

Dr Jethwa explains that dry mouth and morning breath tends to be more severe in people who sleep with their mouths open. This is why people who snore are more prone to bad breath in the morning. There are also certain conditions such as Sjogren's syndrome in which there is less saliva and tear production.

The food we eat

"The food we eat is broken down in our mouth and then absorbed into our bloodstream," says Dr Jethwa, "so it stands to reason that eating foods that contain a strong odour - such as garlic or onions - before going to bed can cause your breath to smell in the morning."

He adds that while brushing and flossing your teeth can temporarily help the smell fade, it won't usually disappear completely until the foods have passed through your body. While it could result in some mildly embarrassing social interactions, this issue is not anything to worry about.

Another common cause of morning breath is not eating enough, a common symptom of over-dieting, according to Dr Jethwa. "This is because when your body breaks down fat, chemicals are released that can cause your breath to smell bad."

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Common causes of bad breath

Most cases of bad breath (halitosis) come from germs (bacteria) or debris that build up within the mouth.

by Dr Hayley Willacy, FRCGP

Poor dental hygiene

If your morning breath is particularly potent, look at your oral hygiene habits and ask yourself if you're doing enough to keep your mouth clean.

Data from the Oral Health Foundation reveals that 1 in four adults do not brush their teeth twice a day with a fluoride toothpaste, and almost 1 in 3 have tooth decay².

Dr Jethwa describes what happens when you don't practise good dental hygiene: "Food particles remain in your mouth which causes bacteria to grow between the teeth and gums as well as on the tongue. This bacterial growth results in bad breath."

Tooth decay can cause several problems, including toothache, a dead tooth, and gum disease.

Gum disease

Gingivitis, a mild form of gum disease, can also cause bad morning breath. Look out for the other main symptoms, which are irritation, redness, and swelling or bleeding of the gingiva, which is the part of the gum around the base of your teeth.

In its more serious form, known as periodontal disease, your tooth may loosen or even fall out due to your gums pulling away from your tooth. Sensitive teeth, pain while chewing, and any change in the way your teeth fit together when you bite are all indicators of this problem³.

If you experience any of the above symptoms, you should visit your dentist as soon as possible so the damage can be treated and managed.

Other diseases and disorders

Sometimes, noticing that your breath has become worse is a sign of a serious issue somewhere else in your body. For example, some cancers and also digestive conditions like gastro-oesophageal reflux disease (GORD) produce chemicals in your body that cause a distinctive breath odour.

If you find that the good dental hygiene techniques that follow don't improve your breath, visit your dentist or GP to either rule out or identify a serious health issue.

Further reading

1. Oral Health Foundation: Dry mouth.

2. Oral Health Foundation: Oral health statistics in the UK.

3. Centers for Disease Control and Prevention: Periodontal disease.