Updated: May 20
Do you have digestive symptoms similar to Irritable Bowel Syndrome? Or always thought your digestive distress was due to indigestion. Recent research is showing us that SIBO (Small Intestinal Bacterial Overgrowth) is more prevalent than was previously thought and symptoms can range from very mild to chronic diarrhoea, bloating, gas, constipation, weight loss and malabsorption of nutrients (1).
What is SIBO?
Small Intestinal Bacterial Overgrowth is a condition where there is an accumulation of bacteria in the small intestine. This overgrowth of non-pathogenic bacteria (which should normally reside in the large intestine), has made its' way into the small intestine via an often faulty ileocoecal valve, and a deficient Migrating Motor Complex (MMC) in the small intestine. The MMC is responsible for moving the bacteria out of the small intestine and into the large intestine, and it should also prevent a back flow from the large intestine.
This can interfere with our normal digestion and the absorption of our food and nutrients. These bacteria consume our food and then produce gas within our small intestine. This gas can cause abdominal bloating, pain, constipation, diarrhoea, belching and/or flatulence.
Those affected often describe a flat belly in the morning, and then feeling 6 months pregnant by the end of the day. Sound familiar?
The main symptoms of SIBO are the same as Irritable Bowel Syndrome (IBS), and it is thought that SIBO is the underlying cause of IBS, as SIBO exists in up to 84% of IBS patients. It is also associated with many other diseases including Diabetes, Celiac disease, and Inflammatory Bowel Diseases, such as Ulcerative Colitis and Crohn's disease (2).
How do we know if we have it?
Breath testing can be used to measure hydrogen and methane gases produced by the bacteria. A sugary solution of either lactulose, glucose or fructose (or all 3) is consumed after a 1 or 2 day preparatory diet and then several breath samples are taken over a short period of time.
The results of this test can help your practitioner to determine the types and amounts of gas present. This is important to know because there are differing protocols for the
removal of the bacteria, which usually consists of antibiotics and/or specific antimicrobial herbs, specific probiotics, nutritional supplements, and a change in the diet.
As the relapse rate can be high, it takes perseverance and commitment to get the gut flora back into balance.
Those susceptible to SIBO and even Candida albicans overgrowth (which is often
associated with SIBO) are advised to follow a long-term diet low in carbohydrates, especially refined carbohydrates such as white bread, baked goods, pasta, and sugar. Cooking from scratch is usually the best way to ensure the diet is composed of plenty of fresh
vegetables, healthy fats, good quality protein sources with small amounts of complex carbohydrates such as quinoa, millet and buckwheat.
There are several different diets that may be recommended to follow, all of which reduce carbohydrates. These include the SIBO Specific Food Guide (SSFG), a 2-phase diet (SIBO bi-phasic diet), the Specific Carbohydrate diet (SCD), or a low FODMAP’s diet.
It is extremely important to remove the bacterial overgrowth as soon as possible, as SIBO left untreated can cause many potential health complications, due to malnutrition and
vitamin and mineral deficiencies (3). SIBO could potentially be a root cause of many food
intolerances such as gluten, casein, lactose and fructose, and it is also associated with
autoimmune diseases, chronic fatigue syndrome and fibromyalgia, and vitamin B12
What can you do about it?
If you think you may have SIBO, a full nutrition consultation can help to determine if
testing is suitable, and a dietary and supplement programme may be recommended.
Further detailed information about SIBO can be found at Dr. Allison Siebecker's website: https://www.siboinfo.com
Dukowicz, A.C., Lacy, B.E. & Levine, G.M., 2007. Small intestinal bacterial overgrowth: a comprehensive review. Gastroenterology & hepatology, 3(2), pp.112–22. Available at: http://www.ncbi.nlm.nih.gov/pubmed/21960820%5Cnhttp://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=PMC3099351.
Small Intestinal Bacterial Overgrowth website by Dr Allison Siebecker found at http://www.siboinfo.com
Murphy, M.F. et al., 1986. Megaloblastic anaemia due to vitamin B12 deficiency caused by small intestinal bacterial overgrowth: possible role of vitamin B12 analogues. British journal of haematology, 62(1), pp.7–12. Available at: http://www.ncbi.nlm.nih.gov/pubmed/3942698.