Are Smelly Farts Bringing You Down?

Posted November 2022
Avocado, Edamame & Chili Oil on Corn Thins slices

Are you suffering from frequently occurring smelly rotten egg farts? Your diet is a key driver to the health of your gut microbiome. Your gut microbiome is responsible for the amount, and smells of your flatulence.

A healthy gut microbiome which is in balance is less likely to create odorful flatulence, in particular rotten egg smelling varieties. Your lifestyle choices impact the balance in your gut microbiome. One important lifestyle factor which heavily impacts the balance of your gut microbiome is your diet. Balance in your diet is a key component to creating a healthy gut microbiome.

Through balance in your diet, you are promoting a healthy variety and distribution of microbes. Also, creating an environment for a healthy gut environment. This includes how acidic different parts of your gut are. The acidity levels in different parts of your gut (e.g., colon) can either inhibit or promote its normal functions. Your diet also impacts the ability of your gut barrier to act effectively. This includes preventing pathogens from entering your gut as well as having the ability to transfer substance into and out of your gut.

Your diet choices impact this delicate balance of healthy gut function. As part of a healthy gut function two gases called hydrogen sulfide and methane are produced by your gut microbiome. These gases play important roles in optimizing the health of your gut. Hydrogen sulphide promotes the health of your gut barrier. Both gases allow effective production of short chain fatty acids. Short chain fatty acids have a positive health impact in your body.

The saying “that more is not always better” is true for both methane and hydrogen sulfide. Problems can start to be seen if there is too much of these two gases. Excess hydrogen sulfide can promote inflammation and cause disfunction of your gut barrier. Excess hydrogen sulfide can also prevent your microbes from using butyrate, a short chain fatty acid, as an energy source.  You will notice if your body is producing excess hydrogen sulfide as it is responsible for the rotten egg smell in your flatulence.

When there is excess production of methane it can cause ill health consequences. This includes slowing the movement through your gut. This is seen particularly in those with irritable bowel syndrome, diverticulosis, or constipation.

The health promoting microbes in your gut function optimally when they are fed dietary fiber. Plant based foods like whole grains & whole grain containing foods like Corn Thins slices, nuts, seeds, legumes, beans, vegetables, and fruit as examples of foods which all provide different types of dietary fiber. The types of fuel within these plant-based foods include prebiotic fiber and polyphenols. These allow normal functioning of the microbes in your gut.

When you consume adequate amounts of dietary fiber, in particular resistant starch and fructo-oligosaccharides, your microbes will produce short chain fatty acids instead of hydrogen sulfide. An adult needs between 25-38g of dietary fiber each day.

If there is not enough dietary fiber in your diet, your gut will seek other sources of fuel which include sulfur containing amino acids such as cystine and methionine. These are found in foods like eggs, poultry, and fish such as cod. While these foods are health promoting, without the addition of adequate dietary fibre these foods can cause excess production of methane and hydrogen sulphide.

Structuring your meals to include half a source of plant produce and one quarter whole grains is a key component of meeting your daily dietary fiber needs. If you choose to snack, including half a source of plant-based food is another healthy habit.


Take home message: Like many things in life, it comes down to balance. To promote a balanced microbiome with optimal levels of methane and hydrogen sulfide include adequate dietary fiber each day. Allowing your gut microbiome to function at its best will ultimately improve your health in many ways including the amount of smell of your flatulence.





  1. Blachier F, Andriamihaja M, Larraufie P, Ahn E, Lan A, Kim E. Production of hydrogen sulfide by the intestinal microbiota and epithelial cells and consequences for the colonic and rectal mucosa. Am J Physiol Gastrointest Liver Physiol. 2021 Jan 1;320(2):G125-G135. doi: 10.1152/ajpgi.00262020. Epub 2020 Oct 21. PMID: 33084401.
  2. Hydrogen sulphide: why balance is key. Dr Paula Smith Brown. December 2021.
Ashleigh Felth…
Accredited Practising Dietitian
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    • Ashleigh Felth…