SIBO Small Intestine Bacterial Overgrowth

Smart Nutritioin specialise in Small intestinal bacterial overgrowth (SIBO)
SIBO refers to a condition in which abnormally large numbers of bacteria (at least 100,000 bacteria per ml of fluid) are present in the small intestine, and the types of bacteria present resemble that of the colon rather than the small intestine.

Bacterial overgrowth of the small intestine is a frequently overlooked contributing factor in several common disorders. 

Irritable bowel syndrome (IBS), responsible for up to 40% of referrals to gastroenterologists, is frequently associated with SIBO. One study of more than 200 IBS patients found that 78% tested positive for SIBO. Of those successfully treated for SIBO, 48% no longer met the Rome criteria for IBS.

Patients with fibromyalgia and chronic fatigue syndrome have also been observed to have a high rate of SIBO (78% and 77% of subjects, respectively). About half of such patients who tested positive for SIBO in one study reported marked improvement after antibiotic administration. Interestingly both of these disorders have overlaps with IBS.

Other groups of patients particularly prone to small intestinal bacterial overgrowth include those with intestinal dysmotility syndromes associated with systemic disease (eg diabetes, scleroderma and intestinal pseudoobstruction), strictures of the small bowel and those who’ve had intestinal surgery.

Both jejunal diverticulosis and Crohn’s disease have been associated with SIBO, particularly in Crohn’s patients who have had previous intestinal surgery. Most patients with Coeliac disease whose symptoms persist with a gluten-free diet have been shown to have SIBO, and symptoms improve after bacterial eradication.

The incidence of bacterial overgrowth increases with age, particularly in people 80 years and older. Studies show that 64% of individuals older than 75 with chronic diarrhoea have colonic-type flora in their small bowels, and that SIBO is the most common cause of clinically significant malabsorption in elderly people.


  • Gas, bloating and flatulence
  • Diarrhoea
  • Constipation
  • Abdominal cramping
  • Fatty stool
  • Lactose intolerance
  • B12 deficient anaemia

Further possible signs include:

  • Bloating / burping after meals
  • Alternating constipation with diarrhoea
  • Heartburn
  • GERD
  • Reflux
  • Nausea
  • Leaky gut / intestinal permeability
  • IBS
  • IBD
  • Food sensitivities
  • Fructose malabsorption
  • FODMAP sensitivity
  • A gas bubble that obstructs the view of the pancreas on a CT scan
  • Fibromyalgia
  • Chronic fatigue syndrome
  • Joint pain
  • Restless leg syndrome
  • Breathing difficulties
  • Difficulty swallowing
  • Rosacea or eczema
  • Cystitis
  • Headaches
  • Brain fog/memory problems
  • Iron deficient anaemia
  • Improvement of symptoms after antibiotics
  • Probiotics are not tolerated and can worsen symptoms
  • Probiotics such as FOS can worsen symptoms

Contributory factors

  • Food poisoning
  • Low stomach acid
  • Drug induced low stomach acid
  • Chronic constipation
  • Stasis resulting from structural changes (eg diverticulosis, blind loops, radiation damage, stricture, fistulas, intestinal pseudo obstruction, adhesions resulting from prior surgery)
  • Chronic pancreatic insufficiency
  • Disaccharidase deficiencies (lactase)
  • Damaged ileocecal valve
  • Immunodeficiency (especially of secretory immunoglobulin A)
  • Diabetes mellitus
  • Scleroderma
  • Crohn’s disease
  • Stress
  • Endometriosis
  • Appendectomy – removal of the appendix
  • ICV – ileocaecal valve issues
  • Scat tissue in the abdominal cavity

"I found Emma by chance whilst googling.­ And I'm so genuinely glad that I did. I­'d suffered for a year with symptoms tha­t my NHS consultant couldn't understand,­ he was keen to perform tests, taking months to plan appointments... However whe­n I found Emma I was able to have conven­ient appointments in the comfort of my own home via Skype. With Emma's expertise on SIBO, it was a quick diagnosis confirmed with hydrogen breath testing - something that you may find rare within the NHS. This was affordable and easily completed and I received my results within 10 days. I am currently workin­g with Emma to improve my quality of lif­e - I'm positive for the first time in m­onths. So I want to take this opportunit­y to say thank you Emma, thank you for s­haring your expertise and working hard t­o help me beat SIBO."

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Please do not return samples to the laboratories that may arrive after Wednesday 27th March and up to and including Monday 2nd April.

The laboratories are closed from the 28th March – 2nd April for the Easter Holiday.