What's causing your bad breath?

Around 25% of us experience halitosis, or bad breath, but the cause could be a lot deeper than simply overdoing the garlic.¹

We’ve all worried about having bad breath after a spicy meal, and ‘morning breath’ is only something to inflict on someone who loves you very much.

Luckily, these causes of halitosis are easily solved.

But for the quarter of Brits who regularly experience bad breath, there could be an underlying cause that’s tougher to treat.

What causes bad breath?

The most common cause of bad breath is bad dental hygiene. Bacteria builds up on your teeth, known as plaque.²

When they break down food, this produces gases that can have an unpleasant smell. Any bits of food trapped between your teeth can also break down and make your breath smell.

Eating ‘smelly’ foods, such as garlic and onions, will also give you bad breath, as can some drinks such as coffee, alcohol – which can dry your mouth out, contributing to bad breath – and smoking.

Cleaning your teeth, flossing regularly, and eating a healthy diet can all help beat these causes of halitosis.

Handpicked content: 7 foods that are good for your teeth

Poor digestion and bad breath 

A study published in the Canadian Journal of Gastroenterology in 2010 found that 57% of those with halitosis also experienced gastrointestinal conditions, namely H.pylori bacteria, which can cause ulcers, and gastro-oesophageal reflux disease (GORD).³

Also known as acid reflux, GORD is a condition where acid from the stomach ‘leaks’ back up into the oesophagus.⁴

This can cause heartburn, a burning sensation in the throat, and a bad taste in your mouth.

You might also experience bloating, smelly and/or loud burps and a croaky voice in the mornings.

How to improve poor digestion

If you are experiencing any of the symptoms above, see your GP to rule out anything more serious.

They may recommend certain medications to help treat H.pylori or GORD, including those that reduce your stomach acid.

Your bad breath could be caused by an imbalance of bacteria in your gut, rather than in your mouth.

A study by the University of Bristol in 2012 concluded that 'friendly' bacteria could help treat bad breath caused by ‘micro-organisms’, so try taking a supplement to help replace the ‘bad’ bacteria in your gut with ‘friendly’ bacteria.⁵

You can also make some lifestyle changes to beat gut-related bad breath, such as eating smaller meals, losing weight.

American researchers found even a small amount of weight gain was linked to an increase in acid reflux – and avoiding foods that irritate your stomach, like coffee or curries.⁶

Are friendly bacteria the future for your mouth's health?

Most of us know that brushing, flossing and regular trips to the dentist are a great way to maintain good dental health.

But a secret weapon to protect your teeth and gums could be hiding in friendly bacteria supplements.

Discover the medical research that connects ‘good’ bacteria to beautiful pearly whites.

What are friendly bacteria?

‘Friendly’ or ‘good’ bacteria work by balancing out the ‘bad’ bacteria in your body.

They have been shown to help improve conditions such as irritable bowel syndrome (IBS), diarrhoea, and urinary tract infections.

But scientists now believe they could be good for our dental health too.

Handpicked content: What is IBS and how can you treat it?

How friendly bacteria improve dental health

The theory is that replacing bad bacteria in the mouth with good bacteria can protect your teeth and gums.

A study published in the Swedish Dental Journal in 2006 found a friendly bacteria called Lactobacillus reuteri could help reduce bleeding gums in patients with gingivitis.⁷

Meanwhile, Korean researchers discovered that using a mouthwash containing good bacteria could cut the formation of plaque by 20%.⁸

The future of using friendly bacteria

A clinical review published in Spanish journal Medicina Oral, Patologia Oral Y Cirugia Bucal in 2017 concluded that friendly bacteria supplements were beneficial to help maintain oral health.⁹

But more studies were needed to measure the long-term effects and to work out which bacteria could help specific dental conditions such as cavities or bad breath.

In fact, there has already been some progress in this area.

A trial by the University of Florida in 2016 identified a new kind of oral bacteria, called A-12, which can prevent cavities.¹⁰

A-12 works by reducing the acid level in the mouth and preventing plaque from forming.

The research team are now working on putting the good bacteria into a pill to stop cavities even before they start.

Handpicked content: 15 top tips for healthy teeth

Last updated: 3 September 2021