Ever wondered why your fart smells, what causes it and where it's coming from? This might sound rather unpleasant, but the truth is passing gas is a natural bodily function that can reveal interesting insights into our digestive health. So, what makes a fart smell bad?
Sefako Makgato Health Sciences University lecturer and registered dietitian Moloko Mehlape said farting, or flatulence, is a normal gut activity that occurs when there is production of gas in the colon, mainly due to swallowing air. The gas is also produced during food digestion, especially when consuming high fibre and gas-forming foods.
While farting is nothing new to men, Mehlape said research suggests women may have larger quantities of the stinky gas hydrogen sulphide, causing their farts to smell worse than men's.
According to studies by the National Library of Medicine, hydrogen sulphide is a gas-signalling molecule that affects multiple organ systems, including the nervous, cardiovascular, digestive and reproductive systems in men and women. It also produces the signature “rotten eggs” scent, where methanethiol produces hints of “decomposing vegetables and dimethyl sulphide adds a hint of “sweetness”.
Mehlape said during menopause the decrease in reproductive hormones in women can lead to slower digestion, causing bloating and gas. However, this hormonal shift doesn't necessarily make farts smell worse — it just means they might be more frequent or noticeable.
The unpleasant odour of farts can be attributed to various factors. According to Healthline, consuming high-fibre foods such as cabbage, broccoli and asparagus can contribute to smelly gas. Additionally, food intolerances such as lactose intolerance can also cause foul-smelling farts. This is because the body is unable to break down certain nutrients which are then fermented by gut bacteria, resulting in a strong, smelly fart.
Certain medications, such as antibiotics, can hurt your digestive health. While they're designed to fight off harmful infections they can also eliminate the beneficial bacteria in your gut that help break down food. This disruption can lead to uncomfortable symptoms such as smelly gas, bloating and constipation.
Mehlape points out that individuals born through natural birth have a more diverse and healthier microbiota than those born through C-section. This applies to those breastfed when they were infants, who have healthier gut health compared with those who were formula-fed, meaning their gut microbiota is more nutritious and diverse and they experience less flatulence and their farts won't be as intense.
Dalya Hockman, a registered dietitian specialising in functional food, said while odourless flatulence is a sign of normal, healthy digestion, people must incorporate regular exercise to help improve digestive health and reduce symptoms of bloating and gas.
“Exercise and other diet plans such as a high- fibre diet of whole grains, legumes and nuts with adequate fruits and vegetables such as oranges, lemons, grapefruit, spinach, lettuce, broccoli and cabbage can promote a healthy gut microbiome for men and women,” said Hockman.
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