What is the SIBO diet and how does it work?

If you’re grappling with the digestive pain and discomfort of SIBO, keeping symptoms under control can be a minefield. Here’s what you need to know.

SIBO, or small intestinal bacterial overgrowth, occurs when gut bacteria from the large intestine overrun the small intestine, where food is digested.

This can cause problems such as malabsorption of nutrients, chronic diarrhea, weight loss, nutritional deficiencies and osteoporosis, according to a 2007 study.

Diet Solutions dietician Nick Dunn says common symptoms include abdominal bloating, wind, reflux, headaches, joint pain, inflammation, and fatigue.

While comparatively little is known about SIBO compared to other digestive complaints, research is beginning to reveal it’s far more common than once thought.

Up to 12 per cent of the world’s population has irritable bowel syndrome, and 78 per cent of those people also suffer from SIBO, according to research from the US.

How is SIBO can be treated

Everyday Nutrition dietician Joanna Baker says SIBO diagnosis is tricky.

“Although breath tests are easy to administer, they are not overly reliable,” Joanna says.

The most effective treatment for SIBO is antibiotics, followed by dietary modifications if symptoms persisted.

“Given that SIBO is a condition involving the overgrowth of bacteria, antibiotics targeting these bacteria are the most effective treatment,” she says.

Joanna says SIBO has a high incidence of recurrence, and risk factors include coeliac disease, inflammatory bowel disease, previous surgeries and PPI usage.

“Once SIBO has been treated, I like to see where the dust settles in terms of symptoms and then address symptoms either empirically or by addressing food sensitivities,” she says.

How do SIBO diets work?

SIBO diets aim to reduce inflammation and bacterial load in the digestive system through the elimination of certain foods.

Nick says while there are several SIBO diets, but they all generally work the same way – by restricting the carbohydrates that gut bacteria feed on.

“This means there is less fuel for the bacteria to consume, and therefore often an individual will experience fewer symptoms,” Nick says.

Can the low-FODMAP diet help SIBO symptoms?

The low-FODMAP is an elimination diet, and is sometimes recommended to manage SIBO.

Developed by Monash University, you remove FODMAP carbohydrates (fermentables, oligosaccharides, disaccharides, monosaccharides and polyols) for a two to eight-week period, then slowly reintroduce them to discover what is triggering your symptoms.

Studies have shown this diet is effective in reducing gastrointestinal symptoms.

Joanna says a low-FODMAP diet is relatively safe and effective and could be modified to meet individual needs.

“A low-FODMAP diet is also empowering as it puts the person in control of treating and managing symptoms,” she says.

Foods to avoid

  • Milk, ice cream and yogurt
  • Cereal and bread
  • Vegetables, including artichokes, asparagus, beans, cauliflower, garlic, lentils, onions and peas
  • Fruit, including apples, cherries, dried fruits, pears and peaches; high-fructose corn syrup, honey and soft drinks.

Foods to eat

  • Eggs and meat
  • Almond milk
  • Brie, camembert, cheddar and feta
  • Gluten-free biscuits, noodles and pasta
  • Oats, peanuts, quinoa, rice, seeds
  • Vegetables, including broccoli, carrots, cucumbers, eggplant, leafy greens, olives, potatoes, pumpkin, tomatoes and zucchini
  • Fruit, including blueberries, grapes, oranges, pineapple and strawberries.

What is the specific carbohydrate diet?

Another diet that may help SIBO is the specific carbohydrate diet, which limits carbohydrates to only those that are easily digested.

There have been very few clinical studies into SCD, most support comes from testimonials.

Foods to avoid

  • Potatoes
  • Grains, including rice, wheat, corn, quinoa, millet
  • Processed meats
  • Most dairy
  • Most legumes
  • Processed sugar and processed foods.

Foods to eat

  • Most unprocessed, fresh or frozen fruits and juices
  • Most vegetables
  • Most fresh meats, eggs
  • Homemade fermented yoghurt, some natural cheeses
  • Soaked dried legumes
  • Nuts and nut butters
  • Herbs and spices.

The SCD and low-FODMAP diet are sometimes combined to manage SIBO.

Written by Dimity Barber.