That’s gas
Researchers at Teagasc Moorepark’s Food Research Centre are evaluating the propensity of certain food groups to cause bloating and associated conditions.
Understanding how certain foods produce gas may ultimately improve understanding of gastrointestinal bloating and related conditions. Photo credit: Timolina/magnific.com.
Bloating and associated flatulence are relatively common conditions in the general population and are linked to a complex interplay involving an individual’s diet, their gut microbiome profile and other factors.
In extreme cases, bloating can cause severe gastrointestinal discomfort – as well as socially embarrassing situations associated with flatulence. The main types of gases involved in bloating and associated flatulence include hydrogen sulphide, methane, carbon dioxide and hydrogen.
In Vitro modelling
Researchers at Teagasc Moorepark’s Food Research Centre have developed a simple in vitro method in the lab to evaluate the propensity of various foods to either cause or alleviate bloating. Research Officer Harsh Mathur explains more.
“This in vitro model involves adding the particular food being tested to pooled faecal samples with a particular microbiological media which is used for growing gut microbes derived from faecal samples.”
These specific types of experiments are called ‘faecal fermentation experiments’, in which faecal samples from a healthy population are pooled together to form what is known as a faecal slurry.
This faecal slurry is then mixed with the microbiological media known as a faecal fermentation media. Lastly, the particular food being tested is added to the slurry and media to perform these faecal fermentation experiments.
In order to validate this newly developed, experimental in vitro model, the researchers at Teagasc decided to test foods that are notorious for causing bloating and flatulence, including baked beans, kidney beans, cannellini beans, black beans and soybeans.
“These types of foods are rich in components called FODMAPs – a type of short-chain carbohydrate noted for their poor absorption in the small intestine,” Harsh notes.
“High-FODMAP foods can sometimes be difficult to digest, and incomplete digestion is one common cause of gastrointestinal bloating.”
The research team then measured the total amount of gas production that these foods caused in these faecal fermentation experiments. Their findings shows that these foods did indeed cause a significant increase in the total amount of gas produced by the gut microbes.
Mimicking media
Another substrate tested included a type of complex sugar called raffinose. Raffinose is found in some vegetables and grains that are difficult to digest and thus known to cause bloating, adds Harsh.
“As was expected, it was found that the addition of raffinose in these faecal fermentation experiments did indeed cause a significant increase in the total amount of gas produced, compared to negative controls where no raffinose or other foods were added.”
The researchers also tested these foods and sugars using two different faecal fermentation media. The first media mimicked a diet low in fibre, protein and complex nutrients, while the other media mimicked a diet high in fibre, protein and complex nutrients.
“Our testing found that the more complex and richer faecal fermentation media already triggered a relatively high amount of gas production by the gut microbes,” Harsh explains.
“By contrast, the faecal fermentation media that was low in fibre components and complex nutrients triggered a much lower amount of total gas production by the gut microbes. Therefore, adding the selected bean varieties to media that were low in fibre triggered a much more pronounced increase in total gas production than adding these beans to an already rich media high in fibre and protein.”
A useful proxy
The research group is currently in the process of sequencing samples from these faecal fermentation experiments to try to ascertain which particular microbes are implicated in bloating.
“For example, it may be the case that certain groups of gut microbes are increased as a consequence of adding these beans,” Harsh continues. “These may be associated with an increased amount of gas production, which likely triggers bloating and flatulence in physiological conditions.”
Similarly, certain groups of gut microbes may decrease as a consequence of these types of foods rich in FODMAPs and a decrease in these groups of microbes may be associated with bloating.
Combined with their in vitro model, the researchers have used a simple mechanical system to measure gas production.
“Ultimately, we hope that this can serve as a useful model for quickly screening a variety of food substrates to assess their potential to increase or decrease total gas production,” Harsh concludes.
“As such, these faecal fermentation experiments can serve as a proxy for bloating-associated conditions and can help shortlist foods for further testing.”
Funding
This work was funded by a Grant in Aid Walsh Scholarship (2023006). Research in Harsh Mathur’s laboratory is supported by Enterprise Ireland, Biostime Institute of Nutrition & Care (BINC) and PepsiCo.
Acknowledgements
The authors acknowledge the contributions of the full project team: Carl Ng, Colin Kelleher, John Jones, Manfred Klaas, Pete Hedley, Malcolm Macaulay.
Contributors
Harsh Mathur, Research Officer, Food Research Centre, Teagasc Moorepark.
Contact: harsh.mathur [at] teagasc.ie
Jane Lavin, Teagasc Walsh Scholar, Food Research Centre, Teagasc Moorepark.
Samuel Breselge, Research Officer, Food Research Centre, Teagasc Moorepark.