Your dietary patterns can influence the smell of your farts, a new study has suggested.
Researchers from the University of Tübingen in Germany have found that regularly eating eggs and red meat will make your farts smell worse.
When large molecules from food start to break down into smaller molecules in your gut, gas is produced and can naturally escape the body, resulting in a fart.
Farts can sometimes smell bad because of hydrogen sulphide – a colourless, flammable gas with a characteristic ‘rotten egg’ odour.
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First author Dr Maximilienne Toetie 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.”
She added: “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 explained: “There’s no need to cut protein out of the diet altogether, as the body needs it. The microbiome’s activity also produces volatile fatty acids. These feed the cells lining the colon but can also hitch a ride out of the body with the released gas.”
Acetate, propionate and butyrate are the three most significant volatile fatty acids and are all associated with good gut health, but they also smell of gym socks, vinegar and vomit.
Volatile fatty acids are produced when gut bacteria break down foods high in fibre, including legumes, fruit, vegetables and whole grains.
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.
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“Farts are a sign that your gut microbes are working, and that exercise is a good way to make sure the digestive system can move everything around as it should.”
On average, people fart 13 to 21 times a day and they travel up to ten feet per second, prior research has discovered.
Other foods that are known to cause smelly farts include beef, pork, garlic, onions, chicken and artificial sweeteners.
Gastroenterologist Dr Patricia Raymond said: “High-fructose corn syrup can also cause excessive gas and diarrhoea.”
