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Small Intestinal Bacterial Overgrowth: What You Need to Know

Digestion | February 10, 2017 | Author: Naturopath

bacteria, Digestion

Small Intestinal Bacterial Overgrowth: What You Need to Know

Millions of Australians are affected by IBS, leaky gut, Crohn’s and celiac disease, as well as other digestive complaints such as nausea, bloating and diarrhoea. Researchers still can’t quite pinpoint why it is that so many people suffer these problems— perhaps "small Intestinal bacterial overgrowth" (SIBO) is the missing answer.

Our digestive system

The small intestine, otherwise known as the small bowel, is a part of the digestive system that connects the stomach with the colon. The main purpose of the small intestine is to digest foods that we eat and absorb the nutrients from it into the body. The small intestine comprises of three parts: the duodenum, the jejunum and the ileum which empties undigested food into the colon.

What is SIBO?

Small intestinal bacterial overgrowth, otherwise known as SIBO is a condition in which abnormally large numbers of bacteria inhabit the small intestine. These types of bacteria closely resemble those that are usually found in the colon. This causes problems as the small intestine should contain relatively small amounts of bacteria in comparison to the colon.

How does it happen?

Bacteria are usually moved from the small intestine to the colon by wave-like muscular contractions referred to as peristalsis. The ileocecal valve prevents movement of bacteria from the colon back into the small intestine. However disruptions in both protective mechanisms can occur which leads to the accumulation of bacteria in the small intestine.

The consequences

Bacteria overgrowth in the small intestine can lead to discomfort and common digestive complaints such as bloating, flatulence and nausea.

The bacteria can breaks down bile acids which are necessary for the absorption of fats and the fat-soluble vitamins A, D, E and K. A sign of this occurring includes excess fat being excreted from the faeces (steatorrhea), chronic diarrhoea and nutrient deficiencies.

In severe cases, the bacteria can damage the lining of the intestines, impairing the absorption of carbohydrates and proteins from food and resulting in malnutrition.

What are the symptoms?

  • Nausea
  • Vomiting
  • Bloating
  • Flatulence
  • Abdominal distention and cramping
  • Fatigue
  • Weight loss
  • Malnutrition
  • Malabsorption
  • Chronic diarrhoea
  • Steatorrhea
  • Anaemia
  • Nutritional deficiencies – including B12, iron and fat soluble vitamins

Just how prevalent is it?

An Australian study detected SIBO in 13% of healthy participants using a lactulose breath test. SIBO is also higher in people with IBS. A study in 111 patients with IBS, found 20% had abnormal test results indicative of SIBO.

Celiac disease is associated with a significant increase in the prevalence of SIBO. 

According to a study published in the American Journal of Gastroenterology, 66% of patients with celiac disease who maintained a strict gluten-free diet tested positive for SIBO.

Although data is limited, SIBO in young and middle-aged adults appears to be low at about 6%, whereas prevalence rates appear to be consistently higher in people over the age of 61 (15%).

Rosacea, a skin condition that causes skin rashes and inflammation on the face is also associated with higher rates of SIBO.

This shows that it is not just disorders of the digestive system that can be related to SIBO but it can also be associated with other conditions including chronic fatigue syndrome, asthma, eczema and even joint pain.

Causes and risk factors

There are many underlying conditions believed to contribute to SIBO. These include:

  • Ageing
  • Chronic pancreatitis
  • Diabetes mellitus
  • Diverticulitis
  • Scleroderma
  • Structural defects, obstruction and scarring in the small intestine
  • Fistula
  • Celiac disease
  • Certain medications: immunosuppressant’s and proton-pump inhibitors
  • Low stomach acid
  • Neurological conditions


SIBO is often treated with antibiotics. The problem with this is that is also kills off the good bacteria that is needed for healthy digestive function. Another concern is that antibiotic therapy also increases the risk of SIBO reoccurring with worsened gastrointestinal symptoms. The good news is that natural therapies have been proven to be particularly helpful in treating this condition. One study found herbal therapy even more effective than rifaximin, an antibiotic typically prescribed for SIBO.

Natural Therapies Can Help

The eradication process for SIBO is generally a 2-4 week program and you should consult an experienced Naturopath to be prescribed specific supplements that have been proven to eradicate SIBO. 

Support Digestion

Before and during eradication of SIBO it is important to support the organs involved in the detoxification process such as the liver, gallbladder, kidney and bowel. This can be achieved by supplementing with fibre, prebiotics, probiotics and additional herbs such as St Mary’s thistle, green tea, dandelion root and spirulina.

Reduce Inflammation

Anti-inflammatory herbs and nutrients that help to promote healing and repair can also be used and these include licorice, aloe vera, slippery elm, marshmallow, vitamin A and D and Zinc. It is important to support healthy digestive function with supportive agents such as ginger, gentian, glutamine and digestive enzymes.

Eradicate and Remove Bacteria over-growth

The herb Phellodendrum amurense contains a natural occuring compound called Berberine hydrochloride, taken in conjunction with the essential oils of oregano, clove and thyme oils has been shown to reduce bacterial load. It is important that these herbs are in an enteric coated capsule for targeted delivery to the small intestine. 

SIBO diet

Different diets may be used, depending on the individual and their symptoms. For people with IBS symptoms, following the FODMAP diet is suggested. FODMAPS’ are foods that ferment in the digestive tract, feeding the bacteria living in your small intestine. 

Foods to avoid include foods high in fructose, lactose in dairy, fructans (wheat, garlic, onion, broccoli, cabbage), galactans (legumes, soy, brussels sprouts) and polyols (sorbitol, malitol, xylitol). For more information refer to the article on FODMAPS diet.
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Other diets that may be suitable include a wholefoods diet, but gluten and dairy free, or an elimination diet with rechallenges to determine if there are any specific foods contributing to the problem.

  • Do not eat any foods high in sugar as this fuels the bacteria in the small intestine.
  • Avoid  any processed foods, alcohol, soft drinks and make sure you drink plenty of water.
  • Try small easy to digest meals to take the burden off your digestive system.

By following the above protocols, you will be ridding your body of the harmful effects of SIBO and improving the many problems that it creates. As SIBO commonly reoccurs, sometimes the elimination protocols must be repeated. Results can be maintained by taking a good quality probiotic, fibre supplement and maintaining a fresh, wholesome diet.

The information contained in this article should purely be used as a guide only. If you have any of the symptoms of SIBO or would like to undergo treatment to resolve the condition it is best to seek help from your Naturopath or GP.  Australia’s best online discount chemist


Dukowicz AC, et al. Small Intestinal Bacterial Overgrowth. A comprehensive review. Gastroenterol Hepatol (N Y). 2007 Feb;3(2):112-122

Tursi A, et al. High prevalence of small intestinal bacterial overgrowth in celiac patients with persistence of gastrointestinal symptoms after gluten withdrawal. Am J Gastroenterol. 2003 Apr;98(4):839-43

Egeberg A, et al. Rosacea and gastrointestinal disorders: a population-based cohort study. Br J Dermatol. 2017 Jan;176(1):100-106

Chedid V, et al. Herbal therapy is equivalent to rifaximin for the treatment of small intestinal bacterial overgrowth. Glob Adv Health Med. 2014 May;3(3):16-24

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