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The top 5 causes of bad breath (and how to deal with it)

Updated: May 25, 2023

When it comes to embarrassing ailments, bad breath is a worry for many of us. In fact, 21 million Brits are concerned about falling foul of halitosis.

Probably because, despite the best oral hygiene routines, we all find times when our breath is less than minty fresh.

Here we look at the most common causes of bad breath and when it might be an indication of something more serious. We’ll also offer some tips to help get your breath smelling sweetly again.

How do you know if your breath smells bad?

If you’ve noticed someone flinching when you speak to them or you’ve got an unpleasant taste in your mouth, you might be worried you have bad breath.

There’s a simple test you can do: Lick your wrist, let it dry and give it a sniff. If it smells bad, it’s very likely your breath does too.

You could also ask a close friend or family member to smell your breath and give you feedback.

Build-up of plaque

The number one cause of bad breath is a build-up of plaque. Plaque is a thick substance made of saliva and bacteria from food particles. If plaque is allowed to develop and isn’t removed by regular brushing, it can attack the teeth and gum line, causing cavities and gum disease.

Rotting food particles and plaque itself can release foul-smelling volatile sulphur compounds (VSCs), which contribute to bad breath.

Bad breath and bleeding gums are among the first signs of gum disease, so make sure to step up your oral hygiene regime if you notice these symptoms. If it persists, make an appointment with your dentist, as untreated gum disease can lead to periodontitis, which is far more difficult to treat.

What to do: Thoroughly brush your teeth twice a day and floss once a day. This will help remove all food particles from your teeth to stop the formation of plaque.

Food particles can also stick onto the back of the tongue, making it a common source of bad breath. Clean your tongue regularly, either with a toothbrush or a tongue cleaner.

Strong-smelling foods

Are you a garlic lover? Can’t do without coffee? Big fan of spicy foods? As delicious as you might find them, certain food and drinks have a tendency to outstay their welcome in your mouth.

Garlic and onion, in particular, break down into chemicals that absorb into your bloodstream, and are excreted when you exhale.

What to do: If you’re affected by garlic or onion breath, try and reduce the amount you eat of these foods. Studies have shown that drinking milk can help counteract the effects, or you could try chewing parsley or fresh mint after meals.

Feeling hungry

You may have noticed your breath can start to smell bad when you’re hungry. This is because when you’re not eating, the amount of saliva in your mouth is reduced. Saliva helps to wash away food particles and bacteria, which if left to hang around, start to release VSCs.

You can also get bad breath if you’re on a low-carb diet. Strict low-carb diets, like the keto diet, trigger a chemical reaction called ketosis — when your body starts to break down fat for energy instead of carbohydrates. This process can make your breath smell strange. However, this shouldn’t last and probably only will occur while your body adjusts to a low-carb diet.

What to do: Keep yourself well hydrated to avoid dry mouth. Plenty of water will also help flush ketones out of your body.

If you’re on a keto diet and your keto breath doesn’t subside, try chewing sugar-free chewing gum. Or you may need to increase your carb intake slightly to see if it improves.

Health conditions

Sometimes bad breath can indicate more than that you’ve just had too much coffee.

If you’re wondering what bad breath says about your health, it can be a sign of various problems such as acid reflux, sinus infections, diabetes, kidney problems and even cancer.

What to do: If regular brushing and flossing doesn’t have an impact on your bad breath, make an appointment with your dentist. They will check for tooth decay, gum disease and infection.

If they can’t find the source of your bad breath, they may advise you to see your GP, who can look at any other symptoms you may be having to determine the cause.

Smoking and drinking

We all know that smoking and drinking is bad for us. But if you needed yet another reason, they’re key causes of bad breath.

Not only does the smell of cigarettes linger long on the breath but smoking also causes dry mouth. Not to mention making smokers more prone to plaque and gum disease.

Alcohol too, causes the mouth to dry out, plus the sugar in it can contribute to plaque formation. Drinking alcohol can also trigger stomach problems, such as acid reflux, another cause of bad breath.

What to do: Consider quitting smoking. There are lots of NHS resources to help you with this.

Along with cutting down the amount of alcohol you consume, try alternating each alcoholic drink with a glass of water. Ensure you brush your teeth thoroughly before bedtime to reduce the risk of plaque build-up.

How to get rid of bad breath

As we’ve discussed, bad breath can be caused by many things. But by following a good brushing and flossing routine, keeping yourself well hydrated and chewing gum to stimulate saliva production, you should be able to avoid some of the more common causes of bad breath.

Research has also suggested that eating probiotics, particularly K12 probiotic, can help fight halitosis.

We hope you’ve found this article on the causes of bad breath helpful. If you’re concerned about gum disease, don’t hesitate to contact Dr Gahan. He is a GDC registered specialist in gum disease with over 21 years’ experience, and can answer any questions you may have.


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