Small Intestinal Bacterial Overgrowth has only recently been researched and discovered, and many doctors still don’t know about it. There is a growing body of research papers that have investigated 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 the large intestine (colon) and shouldn’t be in the small intestine.

This causes problems because these microbes: 

  • ferment food in the small intestine, causing excess gas and bloating
  • create a defensive structure called a biofilm around themselves to guard them because they are in the inhospitable environment of the small intestine 

What are the symptoms of SIBO?


SIBO has a big overlap with the symptoms of IBS, it’s thought around one third of people 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


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. 

SIBO is diagnosed with a breath test 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 specialise in all things ‘digestive health’ and I help people with their IBS symptoms.

I can help you to:

  • track your symptoms in a really simple but meaningful way to understand them better
  • rebalance your digestive system
  • access group support to make long lasting changes to your digestive health

“Anna is amazing! I feel totally transformed"

To find more about out how I work and how I’ve helped people just like you, see my IBS Diet support page

Are you struggling with your digestion?

Get my eBook - 7 Secrets From a Nutritionist's Toolbox to reducing a bloated belly

If you're looking for a way to eat that doesn't leave you undoing the button on your jeans after meals get my guide to good digestion. Find out how to eat to help you feel better.