PhD student Aryana Zardkoohi-Burgos, explains the facts behind the farting and her pea research investigating the parts of peas responsible for passing wind.
Peas, and other legumes, such as chickpeas, beans and lentils, are rich in a group of sugars that are called the raffinose family of oligosaccharides, or RFOs for short. These sugars are not broken down during digestion and therefore reach the colon mostly intact.
Fermentation of pea’s raffinose family of oligosaccharide sugars in the colon results in the production of intestinal gas.
Gas generated by the gut microbiome
Intestinal gas is a result of fermentation that occurs in the colon, where gut microbes either produce gas directly or generate products that through cross-feeding allow other members of the microbiota to produce gas. This happens because the bacteria in the colon can ferment compounds, mostly complex carbohydrates into smaller metabolites, which for RFOs, includes bacteria that have enzymes called α-galactosidases that can break these sugars down.
Various gases are released as a by-product or intermediates of this fermentation by the gut microbiome. Gases include hydrogen, carbon dioxide and methane among others.
The gas produced from eating peas can be a sign of your good gut microbes fermenting these raffinose family of oligosaccharides.
Positives of peas for our health and planet
Along with containing RFO’s that feed the gut microbiome, peas contain other compounds that are good for our health.
Most pulses, including peas, contain high amounts of dietary fibres, such as resistant starch. There is evidence that resistant starch can have positive effects on human health improving metabolism and body weight, as well as a prebiotic for intestinal function.
Moreover, peas contain nutrients such as vitamins and minerals. Plus, they are a great source of plant derived proteins.
Peas are also good for the planet. They are a crop that can fix nitrogen from the environment, which allows them to have their own nitrogen fertilisation system and improve soil health.
Researching the role of raffinose family of oligosaccharides
My project is looking at the role of the RFOs from peas on the plant and human gut health.
I’m part of the EDESIA Plants, Food and Health PhD programme, funded by the Wellcome Trust, which focuses on advancing major aspects of plant-based nutrition and health, from crop to clinic.
One of the objectives of my research project is to produce peas with different levels of RFOs. I work in collaboration with researchers at the John Innes Centre to develop and grow these peas.
I’m using the peas with different levels of RFOs to determine the influence on the composition and function of the gut microbiota and the effects this has on human gut health. I work in the Juge group at the Quadram Institute, where we study host-microbe interactions in the gut.
There are different ways to address this experimentally. I am currently working on using fermentation systems in the lab where I can supplement a human faecal sample with the different pea variants, and measure the effect on the gut bacteria, the metabolites and the gas they produce.
I’m hoping to find the right balance of RFOs in peas that would promote beneficial bacteria while limiting gas production.