Top 10 Foods That Cause Bad Breath and How to Combat Them

Bad breath, medically known as halitosis, can be a difficult problem that affects people from all walks of life.

While poor oral hygiene is often the primary culprit, the foods we consume can also play a significant role in causing temporary but embarrassing bad breath. Sometimes this is because of the smell of the food itself, but some foods, such as coffee and dairy, cause bacteria in the mouth to produce bad-smelling hydrogen sulphide gas, known as volatile sulphur compounds (VSC). Here are some of the food items that often cause bad breath and why.

1. Garlic and Onions

Garlic and onions contain strong-smelling sulphur compounds that break down in the body. The smell we often refer to as ‘garlic breath’ does not come from residual garlic in the mouth but from our lungs. Our bloodstream carries these sulphates out of the body via the lungs, releasing them when we exhale. This makes your breath smell like the pungent food you’ve consumed.

Luckily, there is a way to combat garlic breath. Studies have shown that eating certain other foods alongside garlic and onions can chemically neutralise the sulphates during digestion.1 The best foods found to prevent garlic and onion breath include:

1. Raw apple
2. Mint leave
3. Parsley
4. Basil
5. Mushroom
6. Lettuce

2. Coffee

Coffee causes bad breath because the roasted beans form sulphur compounds, which, like garlic breath, are released through the lungs after digestion.2 It may be that eating the above foods will combat this aspect of ‘coffee breath’ as well.

However, coffee breath is worsened because it also causes more oral bacteria to grow. This happens on two fronts:

The tannins in coffee cause the mouth to produce less saliva, so less bacteria and food debris are washed away. The bacteria digest the food and release VSC which cause your breath to smell.

The acidity of coffee accelerates the growth of bacteria, creating more VSC and worsening bad breath.

Studies have found that milk and sugar worsen the effects, as they feed the bacteria further.2 To reduce the effect of coffee on your breath:

1. Drink a glass of water with your coffee
2. Don’t add milk and sugar
3. Reduce the amount of coffee you drink
4. Chew fresh raw parsley after a cup of coffee
5. Brush your teeth straight after drinking coffee
6. Use a toothpaste designed to reduce VSC-causing bacteria
7. Using an Oral Rinse designed to combat bad breath2

3. Dairy Products

Dairy products such as milk and cheese contain amino acids such as cysteine and lactose. When cysteine breaks down in the mouth, it produces both hydrogen sulphide which has a rotten odour and sulphydryl anions which promote the growth of oral bacteria.3 Limiting the consumption of dairy may significantly reduce halitosis.

4. Fish

Strong-smelling fish like tuna or salmon can leave behind an unpleasant odour. This is particularly true of canned fish as when the fish oxidises in the can it creates a smell that lingers in the mouth.3 This is simply the smell of the food residue and can be masked by rinsing the mouth with mouthwash.

5. Spices and Curry

Spices like cumin, curry, and fenugreek contain volatile aromatic compounds that can lead to bad breath. Similar to garlic and onions, these compounds are digested and released through the lungs later on, so the problem is not in the mouth. Eating apples, lettuce, mint, parsley and basil can neutralise the VSCs from these foods.4

6. Alcohol

Alcohol is dehydrating, and like coffee, this can lead to a decrease in saliva production. While saliva washes odour-causing bacteria away into the throat, when the mouth is dry, bacteria multiply.

Many alcoholic drinks also contain high levels of sugars and compounds that feed oral bacteria, causing more VSC releases. While drinking alcohol, drink water to rehydrate. Fresh breath spray can also help eliminate VSC-creating bacteria while away from the home.

7. Sugary Snacks

Sugars are carbohydrates, and when they are left behind in the mouth, oral bacteria digest them for energy and reproduction. This increases both the amount of bacteria and the VSCs they produce, causing bad breath from inside the mouth. Rinse excess sugars away from your teeth and gums with water or mouthwash.

8. Red Meat:

Red meat can produce ammonia during digestion, which is released through the lungs in the same way sulphates from garlic and onions are exhaled. Oral bacteria in the mouth can also break down the protein into ammonia, so this odour is produced both in the mouth by bacteria and in the digestive system.3

Why These Foods Cause Bad Breath

The volatile compounds that smell bad in your breath are usually hydrogen sulphide or ammonia-based. Some foods in this list can cause bad breath by promoting the growth of bacteria in the mouth which release these gasses. Additionally, some foods, like garlic and onions, contain sulphur compounds that are absorbed into the bloodstream and eventually expelled through the lungs, leading to breath odour.1

Tips to Combat Bad Breath after Eating

If these are the foods that you enjoy, how can you combat their effects on your breath? Here are some tips to help you enjoy the food you love without compromising your breath.
Swap acidic fruits for apples, which react with VSCs to neutralise their smell
Chew herbs such as parsley, basil and mint, which can mask and lessen odours
Breathe through your nose during exercise to avoid drying out the mouth

Drink 6-8 glasses of water daily to wash away food debris and bacteria and maintain saliva production

Reduce dairy and sugar to avoid feeding oral bacteria

Use UltraDEX® toothpaste and UltraDEX® mouthwash for daily protection. These products use clinically-proven iQ+ ActiveOxi Technology®, which breaks down bacterial plaque biofilm to eliminate VSC production, providing fresh breath for up to 12 hours. They’re also sugar- and alcohol-free.

In conclusion, while certain foods can cause bad breath, you don’t have to avoid them altogether. With the right knowledge and products like UltraDEX® that have been developed, used and recommended by dental professionals for 30 years, you can enjoy your favourite foods while keeping your breath fresh. So go ahead, savour that espresso, and let UltraDEX® take care of your breath.