What your farts can reveal about the state of your health – and the diet swaps to ease the stench

HOWEVER uncomfortable or embarrassing they are, farts are a completely normal and healthy bodily function.

It's a sign your digestive system is very much alive, as the food you eat gets broken down quickly and efficiently.

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But if you find yourself letting rip and it's particularly smelly, it could provide clues for what's going on inside your tummy.

Your gut is home to a vast and diverse community of microorganisms, collectively known as the gut microbiome.

It includes bacteria, fungi, viruses, and other microbes, which play a crucial role in digestion, immunity, and overall health.

When it comes to digestion, gut microbes work together to turn large molecules (the sugars, fats, proteins and fibres present in the foods we eat) into small molecules, in the form of fatty acids and gases.

The fatty acids feed the cells lining your bowel, while the gases created naturally escape our body (which is when we fart).

While most the gas that's produced is ordourless, hydrogen sulphide, which smells like rotten eggs, can be particularly pungent - a scent we're all familiar with.

If your farts smell like this, your love of eggs and red meat could be to blame, said Dr Maximilienne Toetie Allaart, a gut microbiome researcher from the University of Tübingen.

Writing for The Conversation, Dr Allaart said: "There's a correlation between what you eat, how much gas your belly creates and how the gas smells.

"This is because each food affects your body and your gut microbes differently.

"For instance, hydrogen sulphide – the smelliest of the gases our gut microbes make – can only be produced if your food contains sulphur.

"Sulphur is typically found in the amino acids cysteine and methionine, which are part of proteins.

"There are generally higher levels of these amino acids in animal proteins - such as eggs and red meat - than in plant proteins."

She noted there's no need to cut protein out of your diet as the body needs it.

But moderation is key - as it's only when you eat too much that it ends up the bowel and smelly molecules are produced.

The fatty acid molecules can also be a culprit for certain smells.

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Dr Allaart explained: "Our fatty acid molecules mainly exist in the gut as dissolved compounds.

"But when there’s gas present, a part of these molecules becomes 'volatile'. This means they can be carried around by the gas, making them a bit like hitchhikers on their way out of the gut.

"The three most important volatile fatty acids are acetate, propionate and butyrate.

"While these are all associated with good gut health, they’re also rather smelly. They reek of vinegar, smelly gym socks and vomit, respectively, and I can tell you from experience with them in the lab that they’re quite pungent."

These are mostly produced when the gut bacteria breaks down fibrous food such as whole grains, fruits, vegetables and legumes.

And if you've ever wondered why someone has a unique smelling fart, it's because each person's microbiome is unique.

Dr Allaart said: "Your gut is a complex jungle of interactions between the body, its microbes and your food.

"And just as each person's microbiome is unique, so is the scent of the gas it produces."

So while smelly farts aren't exactly ideal, it's an important sign your microbes are working.

Dr Allaart advised: "Having a diverse microbiome is related to good gut health. Eating diverse foods will help you maintain a diverse set of microbes. 

"Exercise is also a good way to ensure your digestive system can move everything – including gases – around as it should."