You might have heard of SIBO whilst looking for solutions to IBS. Small Intestinal Bacterial Overgrowth has only recently been researched and discovered. Many doctors still even aren’t familiar with the symptoms or treatment.

There is a growing body of research papers that are investigating treatment and prevention using conventional and natural methods.

What is SIBO?

SIBO is an infection where bacteria from the large intestine relocates into the small intestine. These are beneficial microbes that normally reside in our large intestine (colon) and shouldn’t be in the small intestine.


white woman's hands chopping a red cabbage on a light grey background


This causes problems because these microbes:

  • ferment food in your small intestine, causing excess gas and bloating
  • create a defensive structure called a biofilm around themselves. This helps to guard them because they are in the inhospitable environment of the small intestine, but makes it harder for us to treat. 

What are the symptoms?

SIBO has a big overlap with the symptoms of IBS, it’s thought between 4% and 78% of patients with IBS have SIBO.

These include excess gas, bloating, distended tummy, reflux, constipation, diarrhoea, as well as non digestive symptoms like fatigue, skin rashes, or mood changes like anxiety or depression.

There can also be issues with poor nutrient absorption leading to anaemia or loss of bone density.

SIBO seems to be more common in women, people over 50 and those with digestive issues.



Risk factors for SIBO

Anyone who has had a breach in the natural digestive defence systems is at risk for SIBO.

  • People who have existing conditions such as IBS, Inflammatory Bowel Disease such as Ulcerative Colitis or Crohn’s.
  • If you have Coeliac Disease but you’re not getting better despite a strict gluten free diet you could be struggling with a bacterial imbalance.
  • Those who take medication to prevent stomach acid working are also at risk (e.g. Gaviscon, Omeprazole, sometimes called proton pump inhibitors (PPIs). As we age the stomach acid can also get weaker, which reduces the amount of protection it can give.
  • Slow digestion – Stomach acid also boosts how quickly food moves through the intestines. If you have a slow transit time there is more change the bacteria can start to cling to the walls of the small intestine. This means food is hanging out in the small intestine longer than it should, and bacteria get a chance to cling on and grow.
  • Stomach surgery
How to diagnose SIBO

It’s important to rule out any other diagnoses so working with your GP to ensure they have completed any medical investigations they need to do. Most GPs won’t be familiar with SIBO, but a gastroenterologist may be able to test you. I can organise these tests as part of my 1:1 coaching work.

To find out if you’ve got it, SIBO is diagnosed with a breath test. This helps to identify if you are creating too much hydrogen or methane in your intestines.

Treatment for SIBO

If you have a positive test there are several options for supporting SIBO. The best antibiotic for SIBO is Rifaxamin but this isn’t available on the NHS, only prescribed by private GPs in the UK. It’s well tolerated and has fewer side effects than other antibiotics.

  • Natural anti-microbials are also available in the form of herbs that work like oregano, berberine, grapefruit seeds.
  • A low FODMAP diet for a short amount of time is very effective to support reduction in microbes because it will starve the bacteria in the small intestine. This should reduce the symptoms like bloating and pain after eating.
  • Digestive enzymes can support your body to break down food to make it easier to absorb the nutrients and prevent.
  • Breaking up the biofilms with other supplements may be necessary.
  • Lifestyle changes are also recommended to ensure you’re getting enough sleep, and movement of your body
Recovering from SIBO
  • Probiotics (beneficial bacteria taken as a supplement) are not normally used in the early stages of SIBO, but as recovery takes place,
  • Other supplements to support gut healing can be useful to care for the lining of the small intestine after the microbes have been killed off.

Contact me if you have digestive issues you want to address. I can help you find a diet that works for you and your body. Email me on info@goodnessme-nutrition.com.


Hi I'm Anna Mapson, registered Nutritionist (mBANT, CNHC). I help people with IBS, SIBO, reflux and other gut health issues.

I can help you to:

  • understand your digestion better, so you recognise your triggers
  • eat a well balanced diet, with tasty meals that are simple to prepare
  • develop healthy, sustainable habits for life

“Anna is amazing! I feel totally transformed"

Find more about 1:1 IBS nutrition consultations

Try my free 5 day No-Bread Lunch plan. Tasty, gut healthy dishes, perfect for working from home.