Gas in The Gut

Excessive gas is formed by the bacteria in the large intestine when these intestinal bacteria ( microbiome) digest food. The food of the microbiome is primarily sugars and non digestible polysaccharides (for example, starch, cellulose), that have not been digested during passage through the small intestine.For most of us, passing gas is normal and can occur 14-23 times a day!


For those diagnosed with Irritable Bowel Syndrome (IBS) -gas made by your gut microbiome can cause one to feel bloat, pain and overall increased sensitivity to gas in the large intestines.


Unlike bacteria in the large intestine, when bacteria enter the small intestines they do not belong there! This is called Small Intestinal Bacterial Overgrowth (SIBO) . Another way gas is produced in the small intestine is through Archaea (single cell organisms) which cause Intestinal Methanogen Overgrowth (IMO) . Those experiencing SIBO often present with diarrhea and have excess bacteria Clostridioides Difficile and Escherichia Coli in the small intestine. Patients with IMO mostly present with constipation and have gasses produced by archaea Methanoanobrevibacter Smithii in the small intestine . A third gas produced in the small intestine is hydrogen sulfide- made by Klebsiella Citrobacter and Proteus Ecoli. This gas is being researched as we speak.

No matter what the diagnoses: the bacterias and bugs making the gasses from SIBO and IMO in the small intestine need medications from your gastroenterologist to “zap” them and manage them. Diet and specific over the counter medications are also a big part of managing these microbial overgrowth protocols.

So how does one know if they have gas producing micro-organisms in the small intestine? A test to measure the gas released by the bacteria in the small intestines are done by breath tests. These tests are new and can measure hydrogen or methane or hydrogen sulfide ( ) in your gut. The test can be obtained by your gastroenterologist or even through your digestive expert (GI) dietitian.

With excess gas in the gut, diet plays a role to identify what foods may be causing excess and painful gas within your system. You may have to go through a diet which eliminates gas or bloating foods and then brings them back into the diet one by one. This allows the targeting of those specific “trigger “ foods to find out which cause you the most gas in your specific case. Please reach out to me if you are interested in pursuing a low FODMAP diet for your IBS symptoms of bloat or for your SIBO/IMO excess gas diagnoses. I am trained by Monash Universities low FODMAP Diet. Together we can discover what food give you excess gas and come up with a diet plan for you and over the counter medications which may also help.

Some trigger foods for gas may include one or a few of these food groups. Remember that every person is different, so some of these foods cause you gas and others not.

  • Beans
  • Cruciferous veggies: broccoli, cabbage, brussel sprouts.
  • Whole wheat foods can cause gas in some people
  • Milk or milk products such as cheeses with lactose and dairy products
  • Foods with sugar alcohols like sorbitol mostly found in sugar free items like gum and sugar free soda.

Dietitians are set up to help you go through a diet which can decrease excessive gas production. If you would like more information on what Dietitians provide please read “Why work with a Registered Dietitian”