written by Adrian Sznajder, MD

SIBO Diet and Treatment: Comprehensive Guide to Managing Small Intestinal Bacterial Overgrowth

Introduction to SIBO and Its Implications

In this article we will delve into SIBO exploring its causes, symptoms and importantly effective management strategies.

What is commonly known as SIBO is short for “small intestinal bacterial overgrowth,” which means having high levels of bacteria in the small intestine.

In spite of what most people believe, the presence of a lot of negative or “bad” micro-organisms is not the only component of SIBO. It actually involves an imbalance, where bacteria that typically reside in the large intestine proliferate in the small bowel. This leads to a number of complaints such as abdominal pain, poor absorption of foods, and severe digestive symptoms (1). 

However, changes in diet form one of the important methods of controlling SIBO. SIBO symptoms can be different in different people. However, there are some signs to watch out for. The common signs of SIBO include acid reflux, bloating, excessive gas, constipation, or diarrhea. In addition, one can suffer from abdominal pain.

Recognizing the Symptoms of SIBO

The SIBO symptoms can vary from person to person (1). However there are some signs to watch out for:

- Acid reflux
- Leaky gut
- Abdominal pain
- Food sensitivities
- Constipation or diarrhea 
- Deficiencies in nutrients 
- Unintentional weight loss   
- Indigestion and heartburn
- Bloating and excessive gas
- Feeling full quickly after eating
- Abdominal pain, especially after eating

In certain cases, individuals with SIBO may also experience non-digestive symptoms like fatigue, joint pain, and skin issues. A functional doctor or a registered dietitian can assist in tailoring a diet to manage these symptoms while ensuring balanced nutrition.

Potential Causes Of SIBO

There are factors that can contribute to the development of Small Intestinal Bacterial Overgrowth (SIBO):

- Low stomach acid; When there is not enough stomach acid it can hinder the body's ability to eliminate bacteria, which allows them to multiply in the small intestine.

- Slow gut movement; Conditions, like hypothyroidism or gastroparesis that slow down the movement of food through the tract can create an environment for overgrowth in the small intestine.

- Obstructions in the gastrointestinal tract; Blockages caused by diverticula or adhesions from surgery can also contribute to SIBO.

- Certain medications; Proton pump inhibitors and opioids are examples of medications that have been linked to an increased risk of SIBO.

- Nerve and muscle disorders in the small intestine; Conditions like diabetes or scleroderma that affect the nerves or muscles in the small intestine can also be associated with SIBO.

- Underlying conditions; Irritable bowel syndrome (IBS) celiac disease and inflammatory bowel disease (IBD) are all conditions that have been found to increase the likelihood of developing SIBO.

By understanding these causes recognizing symptoms and being mindful of implications related to SIBO you can take steps, towards managing this condition effectively. (2)

The Link between SIBO and Hypothyroidism 

Interestingly research has discovered a connection between SIBO and hypothyroidism. Studies have shown that around 50% of individuals with hypothyroidism may also have SIBO. Additionally, the use of levothyroxine a prescribed medication for hypothyroidism has been linked to the development of SIBO. (3)

The Link between SIBO and Autoimmunity

The connection between SIBO and autoimmune disorders is significant. When there is an overgrowth of bacteria in the intestine it can lead to a gut where toxins, microbes, and undigested food particles enter the bloodstream and trigger a response. This immune response can further worsen conditions. (4)

How to detect and diagnose SIBO

Diagnosing SIBO can be quite challenging as its symptoms often overlap with disorders. However, the reliable method, for diagnosis is through a breath test. This test measures the levels of hydrogen and methane levels in your breath, indicative of certain types of intestinal bacteria.

To conduct the breath test for SIBO you will need to fast. Then consume a specific drink. Afterwards at intervals, over a period of 2 to 3 hours you will breathe into tubes to collect samples. These samples will then be analyzed to determine the presence of gas-producing bacteria. (5)

In cases where the results of the breath test are inconclusive or if SIBO treatments don't seem to be working, your doctor may need to take a sample of fluid from your small intestine to identify the types of bacteria present.

Treatment Options For SIBO

The main objective of treating SIBO is to decrease the growth of bacteria, in the intestine and relieve associated symptoms. There are three methods for managing SIBO; special diet, herbal antimicrobial agents, and antibiotics. The selection of treatment depends on factors such, as the severity of the condition, personal preferences, and medical background of the individual.

The Crucial Role of Diet in SIBO Management

The main objective of treating SIBO is to decrease the growth of bacteria, in the intestine and relieve associated symptoms. There are three methods for managing SIBO; special diet, herbal antimicrobial agents, and antibiotics. The selection of treatment depends on factors such, as the severity of the condition, personal preferences, and medical background of the individual.

When it comes to discussing the SIBO diet, the main goal is to reduce the intake of foods that feed the bacteria, in the intestine, which can help alleviate symptoms of intestinal bacterial overgrowth. There are strategies (diets) that specifically focus on this:

1. Low-FODMAP Diet for SIBO; This diet temporarily restricts fermentable oligosaccharides, aiming to decrease foods that are poorly digested in the intestines. FODMAPs are carbohydrates that may not be well absorbed in the intestine providing nourishment for gut bacteria. The approach here involves an elimination diet; first eliminating high FODMAP foods and then reintroducing them gradually to identify triggers. Common high-FODMAP foods to avoid include onions, and certain fruits like apples well as beans, lentils, and wheat. Following the diet can provide an improvement in symptoms for many with IBS and SIBO. (6)

2. Specific Carbohydrate Diet (SCD); This dietary approach aims to starve the bacteria by limiting carbohydrate intake. The emphasis is on unprocessed foods while avoiding grains, lactose, and most sugars (with honey being an exception).

3. GAPS (Gut and Psychology Syndrome) Diet; Similar, to SCD the GAPS diet aims to heal the gut lining and reduce inflammation. It emphasizes bone broths, fermented foods, and organic vegetables while avoiding processed foods and certain grains. GAPS Diet: Rooted in the gut and psychology syndrome concept, it focuses on healing the gut lining.

4. Cedars Sinai Diet; Compared to other diets this one is not as strict. It encourages reducing the intake of foods that're high, in lactose, fructose, and fibers. Instead, the main emphasis is on glucose and specific types of starches.

5. Elemental Diet; A liquid diet. It’s a very specific diet, which is particularly beneficial for cases of SIBO or when other treatments have been unsuccessful. The principle behind it is simple; because nutrients are rapidly absorbed in the intestine there is very little left for the bacteria to consume in the lower sections.

6. Bi-Phasic Diet; Combining elements of both the low-FODMAP diet and Specific Carbohydrate Diets this diet follows an approach with two phases; a restrictive phase followed by a gradual reintroduction of foods, in the subsequent phase.

When choosing a SIBO diet plan, we typically recommend starting with the Low FODMAP Diet as a step. If you don't experience any improvement, in your symptoms you can then consider transitioning to more restrictive diets, like the Elemental Diet. Although there are diets that may also be beneficial we suggest these two options initially because they have been proven to be effective.

The purpose of this diet plan is to allow the digestive system to rest, reduce inflammation and prevent the growth of bacteria. The restrictive phase of many SIBO diets, while essential in some cases of SIBO, is usually a short-term diet phase. This phase often entails avoiding many foods to rebalance the bacteria in your gut. However, for long-term management and to avoid potential pitfalls like poor absorption of nutrients, it’s important to work closely with a healthcare professional.

The Role of Probiotics in Managing SIBO 

Probiotics derived from soil sources can be an addition to a treatment plan for SIBO. Unlike probiotics that contain lactobacillus or bifidobacterium strains, soil based probiotics do not worsen symptoms associated with SIBO.

They do not colonize or contribute to overgrowth, in the intestine; instead they directly support a healthy gut flora by targeting the large intestine and colon. Numerous studies have indicated that probiotics, soil based ones could help control overgrowth alleviate abdominal pain and enhance digestive health in individuals, with SIBO. (7)

SIBO FOODS TO EAT AND AVOID

Certain foods can exacerbate symptoms while others can help control the overgrowth. Here are some dietary recommendations to manage SIBO effectively:

1. It's advisable to reduce the consumption of sugar, alcohol, and processed carbohydrates as they can provide fuel for bacteria in your gut. (8)

2. It's best to steer of foods that have levels of FODMAPs (oligosaccharides, disaccharides, monosaccharides, and polyols) since they can be tough to digest and may get fermented by the bacteria in your gut as they reach the colon. FODMAP foods include fruits, certain vegetables, grains, and legumes, as some examples. You will find the full list of foods below. 

3. Make sure your diet includes an abundance of vegetables lean proteins and healthy fats.

4. Ensuring hydration, by drinking water regularly can also be beneficial when dealing with SIBO.

5. Remember that everyone's reaction to food varies from person to person; what works for one individual may not necessarily work for another. It is crucial to collaborate with a healthcare provider who can create a plan tailored to you.

SIBO FOODS TO EAT AND AVOID

✅ SIBO FOODS TO EAT:

FRUIT:
🍌 Banana
🫐 Blueberry
🫐 Boysenberry
🍈 Cantaloupe
🫐 Cranberry
🍈 Durian
🍊 Grapefruit
🍇 Grape
🍈 Honeydew melon
🥝 Kiwi
🍋 Lemon
🍋 Lime
🍊 Mandarin
🍊 Orange
🍈 Passionfruit
🍈 Pawpaw
🫐 Raspberry
🍓 Rhubarb
🍈 Rockmelon
🍈 Star anise
🍓 Strawberry
🍊 Tangelo

VEGETABLES:
🌱 Alfalfa
🌱 Artichoke
🎋 Bamboo shoots
🎋 Beat shoots
🥬 Bok choy
🥕 Carrot
🌱 Celery
🌱 Choko
🥬 Choy sum
🌱 Endive
🌱 Ginger
🌱 Green beans
🥬 Lettuce
🫒 Olives
🥕 Parsnip
🥔 Potato
🎃 Pumpkin
🌶️ Red bell pepper
🥬 Silver beet
🌱 Spinach
🌱 Summer squash (yellow)
🥕 Swede
🍠 Sweet potato
🍠 Taro
🍅 Tomato
🍠 Yam
🥒 Zucchini

STARCH:
🍞 Gluten-free bread or cereal products
🍚 Rice
🍚 Oats
🍚 Polenta
Other: arrowroot, millet, psyllium, quinoa, sorghum, tapioca

MISC:
🍯 Sweeteners: sucrose, glucose, artificial sweeteners not ending in “-ol”, and sugar in small quantities
🍯 Honey substitutes: small quantities of golden syrup, molasses, treacle

DAIRY:
🥛 Milk - lactose-free milk, oat milk, rice milk, almond milk, coconut milk (check for additives)
🧀 Cheeses - hard cheeses, brie, and camembert
🍦 Yogurt (lactose-free)
🍨 Ice cream substitutes -coconut ice cream etc. 

❌ SIBO FOODS TO AVOID:

EXCESS FRUCTOSE
🍏Fruit: apple, 🥭 mango, nashi, 🍐 pear, 🥫 canned fruit in natural juice, 🍉 watermelon, persimmon

🍯Sweeteners: fructose, high fructose corn syrup, corn syrup, honey. Concentrated fructose: concentrated fruit, 🍇 large servings of fruit, 🍇 dried fruit, 🥤 fruit juice.

FRUCTANS:
🌱 Asparagus🥕 Beetroot🥦 Broccoli🌱 Brussels sprouts🥬 Cabbage🍆 Eggplant🌱 Fennel🧄 Garlic🌱 Leek🌱 Okra🧅 Onion (all)🌱 Shallots🌾

CEREALS:
wheat and rye in large amounts (e.g., 🍞 bread, 🍪 crackers, cookies, couscous, 🍝 pasta)

MISC:
chicory, dandelion, inulin

LACTOSE:
🥛 Milk: milk from cows, goats, or sheep.
🍮 Custard,
🍦 ice cream
🍨 Yogurt
🧀 Cheese: soft, unripened cheeses like cottage, cream, mascarpone, ricotta

POLYOLS:
🍏 Apple🍑 Apricot🥑 Avocado🍇 Blackberry🍒 Cherry🍈 LycheeNashi🍑 Nectarine🍑 Peach🍐 Pear🍑 Plum🍑 Prune 🍉 Watermelon

VEGETABLES:
🌶️ Green bell pepper, 🍄 mushroom, 🌽 sweet corn

SWEETENERS:
sorbitol, mannitol, isomalt, maltitol, xylitol

GALACTANS: 
Legumes:  Beans, baked beans, chickpeas, kidney beans, lentils

Intermittent Fasting For SIBO

Giving your digestive system a break is a good idea even if you don't have SIBO. A lot of us today are used to constant snacking! 

This study shows that during the IF (Intermittent Fasting) program, people lost an average of about 3.67 kg (around 8 pounds) of body weight and had better health measurements, no matter their initial body size or gut bacteria condition. What's more, poop samples were collected before and after the program, and were studied using a detailed DNA analysis method called shotgun metagenomic sequencing.

IF-induced changes in the gut microbiota, are not only beneficial for weight loss but also may be useful for SIBO treatment, from our experience and from working with a lot of people with IBS and other gut problems, we've seen that IF really helps to "reset" bad gut health.

If you'd like to check our IF 14-day weight loss challange, click here.