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5 key steps to ease symptoms of Small Intestinal Bacterial Overgrowth (SIBO)

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5 key steps to ease symptoms of Small Intestinal Bacterial Overgrowth (SIBO)

SIBO commonly occurs due to a complication following gastrointestinal surgery or a medical condition (i.e. gastroparesis, celiac disease) that slows down the passage of foods and waste products in the digestive tract. This creates the perfect breeding ground for bacteria in the small intestine.

Too many, in the wrong place

Small Intestinal Bacterial Overgrowth (SIBO) is defined as an abnormal increase in the numbers and types of bacteria in the small intestine.

Unable to pass through

SIBO commonly occurs due to a complication following gastrointestinal surgery or a medical condition (i.e. gastroparesis, celiac disease) that slows down the passage of foods and waste products in the digestive tract. This creates the perfect breeding ground for bacteria in the small intestine.

What are the common symptoms?

The excess bacterial digestion of food in the small intestine may cause:

  • Bloating or an uncomfortable feeling of fullness after food intake
  • Nausea
  • Constipation and/or diarrhea
  • Excessive gas and flatulence
  • Abdominal pain

These symptoms can be mild and intermittent or severe and persistent

Why is this important?

The symptoms associated with SIBO may escalate to issues such as loss of appetite, unintentional weight loss, malnutrition and kidney stones. Additionally, in some cases, the excess bacterial growth may cause poor absorption of:

  • Macronutrients (carbohydrates, protein and fats)
  • Vitamins ( particularly vitamin B12 and fat-soluble vitamins – A,D,K,E)
  • Minerals such as calcium and iron

Five key steps to regaining balance:

Step 1:  Investigate

Identify and treat the root cause of the SIBO. This may be a gastrointestinal surgical complication or a medical condition affecting the movement of foods through the digestive tract.

Step 2:  Medication

Complete a full course of antibiotics as prescribed, especially in the presence of significant maldigestion and malabsorption of foods. Ensure your doctor switches among different antibiotics to prevent  antibiotic resistance in the long-term.

In some cases, a prokinetic agent, such as metoclopramide, might be useful to propel food and bacteria through the intestine.

Step 3:  Diffuse stress

Adopt a daily stress management ritual that works the best for you (i.e. deep breathing, reading, knitting, yoga, walk in nature).

Step 4:  Gentle movements

It is important to do gentle physical activities such as walking that aids to regulate bowel movements. High intensity exercises may contribute to further unintentional weight loss. If in doubt, please consult a healthcare professional before starting any exercise program.

Step 5:  Medical nutrition therapy

Nutrition therapy is focused on:

  • Vitamin and mineral deficiencies correction (fat-soluble vitamins, vitamin B12, calcium and iron levels)
  • Nutrition support (enteral feeding, parenteral feeding or oral nutritional supplements) to achieve a healthier weight particularly for those who are underweight and/or malnourished.
  • Dietary modification to minimise and ease gastrointestinal discomforts and/or decrease abnormally high levels of intestinal bacteria.

To ease the symptoms associated with SIBO, A low FODMAP diet may be helpful to reduce gas production and the growth of bacteria in the intestine.

FODMAP stands for Fermentable Oligosaccharides, Fisaccharides, Monosaccharides And Polyols. These are short-chain carbohydrates (less than 10 sugars) that are poorly absorbed in the small intestine and they can be rapidly fermented by bacteria with consequent gas production, bloating and gastrointestinal discomfort. A low FODMAP diet is generally a 3-step elimination process over a short duration of 2-6 weeks:

Step 1: 
Eliminate all high FODMAP foods from daily diet ( see table below).

Step 2:
Every 3 days, reintroduce a high FODMAP food back into the diet, one at a time.  This allows to see which high FODMAP foods trigger symptoms – and this varies from person to person.

Step 3:
List the high FODMAP foods that trigger symptoms and avoid or limit them from daily diet.

Important: The low FODMAP diet is restrictive and can be challenging or even dangerous for some individuals– especially for those who are almost or  already underweight ( a body mass index below 18.5 kg/m2). Therefore, it is important to work with a registered dietitian to ensure you are maintaining your nutritional status while achieving the desired results.

High FODMAP: Key sourcesLow FODMAP choices
Fermentable Oligosaccharides· Grains: wheat and rye (breads, cereals, biscuits, pasta) – if having these, limit to ½ cup per meal
· Legumes: all beans, peas and lentils
· Fruits: bananas, watermelon, blueberries, pears, raspberries, cantaloupes, figs.
· Vegetables: garlic, white onions, asparagus, scallions, leek, cabbage, broccoli, artichoke
· Grains: rice, quinoa, oats, buckwheat, maize, polenta
· Fruits: grapes, oranges, honeydew melon, pineapple, ripe guava, starfruit, strawberries. Limit to 2 servings of fruits per day
· Vegetables: eggplant, cucumbers, zucchinis, carrots, collard greens, white potato, parsnip, watercress, english spinach. Cooked vegetables are easier to digest and absorb.
Fermentable Disaccharides· Sucrose: table sugar
· Lactose: milk and dairy products like yogurt and ice creams. Some individuals may tolerate some probiotic containing yogurts as the friendly bacteria may break down lactose naturally.
Maltose: wheat, cornmeal, barley, peaches, pears
· Almond milk or rice milk. Soy milk may cause bloating for some individuals.
· Eggs
· Fish, chicken, meat
· Certain cheeses: brie, camembert and feta
Fermentable Monosaccharides· Glucose: table sugar, honey, agave, molasses, fruits, fruit juices, dried fruits, sweet corn, lactose containing foods
· Fructose: table sugar, fruits (some are higher in FODMAPs than others), fruit juices, honey, high fructose corn syrup in many processed foods, vegetables such as asparagus, broccoli, leeks, mushroom, onions, peas, tomato, red pepper and shallots.
· Galactose: Lactose containing foods, soy sauce, plums, kiwi , avocados, sugar beets
· See fruit and vegetable list above
· Fresh fruits contain less fructose than dried fruits.
Fermentable Polyols (Sugar alcohols)· Certain fruits: apple, cherries, pear, peaches, plums
· Certain vegetables: green beans, bell peppers
· Certain mushrooms: button mushrooms
· Sorbitol, maltitol, xylitol, erythritol, isomalt, glycerol, lactitol, mannitol, hydrogenated starch hydrolysates – commonly used as a sweeteners in sugar-free products such as sweets, chewing gums and beverages.
· See fruit and vegetable list above
· Aspartame (Equal/ NutraSweet) as this sweetener is made from amino acids.
· Oyster mushroom
Table 1: Common sources of FODMAP.
For a more comprehensive guides to foods that a low and high in FODMAPs – including suitable recipes, consider downloading the Monash University FODMAP app.

Other simple dietary tips to ease SIBO symptoms include:

  • Hydrating well by including fluids in the daily diet. This includes drinking at least 1.5-2 litres of water daily. Hydration helps to maintain bowel movement.
  • Allowing at least 3 hours gap between meals to allow “cleansing” of the small intestine and minimise bacterial growth.
  • Avoiding dietary fibre supplements during the symptomatic phase.

How about introducing probiotics?

Studies that examined the effects of probiotics (friendly microorganisms with health benefits) in individuals with SIBO are mostly of poor quality. As such, it remains unclear if using probiotics to treat a condition with excessive bacteria will be helpful.

A check in is always helpful

Do check in with your doctor if you are concerned about SIBO symptoms. It is important to seek immediate medical care if you are experiencing any of the following issues:

  • Persistent diarrhea
  • Rapid and unintentional weight loss
  • Severe abdominal pain

And… that’s a wrap

We hope this article was helpful in improving your understanding of SIBO and how to ease its symptoms through:  

  1. Investigation
  2. Medication
  3. Diffusing stress
  4. Gentle movements
  5. Medical nutrition therapy

No content on this website should be used as a substitute for direct and individualised medical advice from a doctor or registered dietitian.


  1. Pimentel, M., Saad, R., Long, M. and Rao, S., 2020. ACG Clinical Guideline: Small Intestinal Bacterial Overgrowth. American Journal of Gastroenterology, 115(2), pp.165-178.
  2. Monash University. 2022. Low FODMAP Diet App [online] Available at: [Accessed 14 September 2022].
  3. Quigley, E., Murray, J. and Pimentel, M., 2020. AGA Clinical Practice Update on Small Intestinal Bacterial Overgrowth: Expert Review. Gastroenterology, 159(4), pp.1526-1532.

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