Is Small Intestine Bacterial Overgrowth (SIBO) contributing to your IBS?

Approximately 10 millions people in the UK are affected by Irritable Bowel Syndrome (IBS), a collection of symptoms associated with the digestive system. Considered an unpleasant but not life-threatening condition, IBS can be a trigger for more serious conditions.

IBS symptoms are non-specific, which can make identifying the root cause difficult and often IBS can be attributed to areas of the digestive system not functioning at an optimum level.

Those suffering with IBS will know that symptoms include diarrhoea, abdominal pain, bloating, flatulence and constipation and will be continually on the lookout for foods that can trigger these symptoms.

Small Intestine Bacterial Overgrowth (SIBO) does not cause IBS, but studies have shown that at least 50% of IBS patients have SIBO and therefore, this makes it important to take the health of the small intestine into consideration.

What is SIBO?

SIBO is a condition where abnormally high numbers of bacteria usually found in the large intestine (colon) start to grow in the small intestine. The small intestine, in a healthy individual, will have a very low number of bacteria – SIBO happens when the bacteria colonise, overgrow and then have the following effects:

  • Build up of gas caused by dietary sugars and carbohydrates fermentation, leading to symptoms of flatulence, pain and bloating.
  • Poor fat absorption as the bacteria separate the bile acids (necessary for emulsifying fat to allow absorption) from the fat, which in turn causes deficiency of essential fatty acids and vitamins A,D, E and K. The poor fat absorption can also cause diarrhoea due to excess fat in the stool.
  • Vitamin B12 deficiency caused by the bacteria removing B12 from gastric intrinsic factor, necessary for the absorption of B12.
  • If SIBO continues for a long time, it can lead to malabsorption and leaky gut syndrome.

How is SIBO caused?

Just as for IBS, the causes of SIBO are various and complex, but mainly associated with:

  • Low stomach acid – which allows excess bacteria to enter and colonise the small intestine.
  • Low gut motility – affects the movement of food through the gut giving bacteria present the opportunity to migrate from the large to the small intestine.
  • Low digestive (pancreatic) enzymes
  • Poor immune function
  • Previous bacterial infections

What are SIBO symptoms?

Symptoms that are generally associated with SIBO:

  • Flatulence, gas and feeling bloated
  • Diarrhoea
  • Abdominal cramps
  • Fat in the stool
  • Lactose intolerance
  • B12 deficiency

These symptoms, especially in combination, can indicate SIBO but a simple breath test can identify the presence of hydrogen or methane, which are produced through the fermentation of lactulose by the bacteria found in the small intestine.

Professional Nutritional Help for SIBO

There is dietary and supplementary help for SIBO and it is a good idea to consult a Professional Nutritionist who will take an individual case history and prescribe appropriately to the client.

A Nutritionist may examine the following areas specific to the client:

  • Water Intake
  • Stomach Acid/Pancreatic Enzymes
  • Possible trial FODMAPS/OTHER diet dependent upon medical conditions
  • Consumption of soluble/insoluble fibre
  • Foods responsible for abdominal cramps
  • Products to relax abdominal muscles
  • Bile Production/Fat Emulsification
  • Colon Bacteria
  • Food Intolerance Test


  • Increase water intake to 1.5-2 litres daily
  • Eat bitter foods; Lemon/rocket/chicory/watercress
  • Increase enzymes naturally by eating enzymic foods 10 minutes before cooked food: Salad/living sprouts such as alfalfa/ fresh pineapple
  • Take a teaspoon of apple cider vinegar in half a glass of water 20 minutes before eating
  • Massage Magnesium Oil Spray clockwise into abdomen if discomfort begins.