Small Intestinal Bacterial Overgrowth (SIBO) is characterized by diminished levels of ‘good’ bacteria’ and excessive growth of ‘bad’ bacteria in the gut (dysbiosis) that leads to impaired digestive health. SIBO is linked with several gut-related and systemic conditions including irritable bowel syndrome (IBS), Celiac disease, gastroesophageal reflux disease, autoimmune disorders, cystic fibrosis etc.
In modern medicine, SIBO is generally treated by antibiotic therapy with probiotics as adjuvant (complimentary) therapy, which cannot completely treat/cure the underlying cause(s). In most of the cases, antibiotic therapy may not be useful and recurrence is not uncommon.
Nutrition therapists generally prefer home remedies for SIBO due to its efficacy and safety. Non-medical SIBO management aims to limit fermentation potential (FP) rather than limiting all types of carbohydrates to prevent recurrence. This approach employs hard-to-digest carbs to feed and boost beneficial bacteria to treat SIBO and associated symptoms.
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Resistant starch (RS) is one of the important types of starch that resists digestion, feed symbiotic bacteria and aid recovery from SIBO symptoms. RS possess the ability to flush the bad bacteria from the small intestine to the large intestine. But you should start from very low doses of RS and gradually increase overtime. Unmodified, raw potato starch is the best example of resistant starch.
Some of the benefits of resistant starch are:
- Feed healthy (good) bacteria
- Promotes butyrate production
- Immune boosting
- Metabolic recovery and even weight loss
Fermentable carbohydrates with poor absorption potential have higher chance of bacterial fermentation that lead to aggravation or recurrence of SIBO symptoms. Some forms of RS (RS2) are less fermentable and hence pose slight risk of SIBO worsening.
Does resistant starch cause any side effects?
Yes, too much of anything is not good!
Consumption of too much of resistant starch can exacerbate SIBO symptoms in certain individuals.
Some of the reported gastrointestinal side effects of resistant starch are diarrhea, flatulence, stomach aches, general weakness, acid reflux, bloating or fullness, abdominal cramps and even intestinal blockage. Although, both studies are conducted in healthy individuals, these symptoms are same in SIBO patients but of varying degrees.
To treat dysbiosis, diets supplemented with resistant starch, high fiber and probiotics are often preferred. You may think about feeding the gut microbiome with plenty of fermentable carbohydrates. But in reality, this approach can backfire in cases like small intestine overgrowth of certain bacterial species including Clostridia and Firmicutes. These organisms thrive well in high fermentation burden that can contribute to bacterial overgrowth. You can aid your gut microbiome to recover by avoiding antibiotics and feeding the bacteria and also by reducing stress.
Adding certain probiotics such as Bifido infantis, lactic acid bacteria, bifidobacterium bifidus and other non-soil based probiotics can be helpful to alleviate SIBO. Our gut has evolved overtime to colonize it with beneficial bacterial species. Some of the species remain transient, while most of the species are really helpful for microbiome recovery in SIBO patients. Even fecal-oral transfer of certain good bacteria from house mates can also be helpful for recovery.
According to a placebo-controlled clinical trial study, Lactobacillus treatment has improved diarrhea symptoms with remarkable reduction in breath hydrogen levels that sustained over 21 days, even after stopping the treatment. These benefits can reduce the associated symptoms of SIBO.
An open-labeled study to investigate the benefits of Lactobacillus casei (65 billion bacteria/day) on SIBO patients has reported negative breath hydrogen test results in 64% of probiotics-treated patients without notable improvement in GI symptoms.
A pilot study published in World Journal of Gastroenterology has reported notable symptomatic relief in SIBO patients after probiotics therapy. The patients were randomized to receive either metronidazole (antibiotic) or a probiotic supplement that contains beneficial microbes including Bifidobacterium brevis, Lactobacillus casei, Streptococcus fecalis and Lactobacillus plantarum. When compared to the antibiotic-treated patients, statistically significant (remarkable) symptomatic response was observed in probiotics-treated patients.
Taken together, probiotics really possess treatment benefits against SIBO and associated symptoms. However, more double-blinded, long-term studies are needed to scientifically validate the therapeutic/adjuvant benefits of probiotics in clinical care setting.
Diet plan that keep SIBO at bay
Among the SIBO management tips, diet plan stands first to prevent the recurrence or aggravation of SIBO. Recently, Fast Tract Diet has gained steam among SIBO sufferers, which has been designed to limit the carbohydrate intake and to curb bacterial overgrowth. The dietary preferences of Fast Tract Diet includes gut-friendly foods to aide your digestion and to reduce SIBO symptoms.
Nutritionists usually consider the Fast Tract Diet as a newer way to treat SIBO, as it limits all difficult-to-digest carbohydrates by using mathematically-derived fermentation potential values for each food. This technique can help you to choose specific carb type without seeking professional help.
Fast Tract Diet is not akin to strict low-carb diet; but it contains too many difficult-to-digest carbohydrates and thus reduces fermentation in the intestine and SIBO symptoms.
Fast Tract Diet recommends limiting high amylose-containing rice, high amylose-containing root vegetables, sucrose and high fructose sources, excess lactose and sugar alcohols.
This diet plan includes:
- FODMAP diet
- Low starch diet
- Low carb diet
- Paleo diet
- Elemental diet
- GAPS or specific carbohydrate diet
FODMAP refers to Fermentable Oligo, DI and Monosaccharides and Polyols. The diet approach aims to limit sugar-derived alcohols, fructose, lactose, fructans, galactans and lactose.
According to human clinical trials, FODMAP has been shown to be effective in management of functional gut symptoms including IBS, which is linked with SIBO. FODMAP diet plan allows resistant starch and beneficial fibers that are widely present in cereals, bananas, sweet potatoes, corn, gluten-free pasta etc. In normal individuals, FODMAP diet has useful prebiotic effect.
Some of the FODMAP-containing vegetables are mushroom, Brussels sprouts, artichoke, asparagus, cabbage, celery, garlic, sweet corn, sweet potato, okra and onion. Fruits such as mango, watermelon, peaches, apples, apricots, pears, lychee, blackberries, cherries, grapes, plums and pears are FODMAP-containing fruits.
FODMAP-based diet is particularly useful for any individuals suffering from SIBO and IBS and chronic stress.
Modern Paleo diets are based on available food types that are consumed during human evolution. Some of the food items that are included are nuts, seeds, green veggies, fish, meat, eggs and herbs. Wild rice, sweet potatoes, cassava, yams are limited while most grains, beans, pulses and dairy products are not allowed.
Paleo diet limit or eliminates difficult-to-digest carb that are linked with SIBO. Tuber and root vegetables which contains significant amount of resistant starch are allowed, as it can reduce SIBO symptoms.
However, certain rice varieties like jasmine rice have zero fermentation potential; however, it is not suitable for diabetics and hypertension patients and these patients should avoid eating jasmine rice too much.
This diet plan consists of ‘predigested food’ that contains fatty acids, micronutrients and water instead of carbohydrates, proteins, fats and amino acids. Elemental diets are mostly available as commercial and ready-to-use dietary products that can be ingested either by mouth or via a tube (enteral). The diets are designed for full absorption in a variety of gut-related problems that are linked with SIBO.
Some of the limitations of this diet plan are: Need for proper medical supervision, high cost and ingestion of predigested foods which are really unappealing.
Specific Carbohydrate Diet
This diet plan limits all disaccharides as well as starch and grains but not simple sugars like glucose.
Although, the diet plan looks great, specific carbohydrate diets such as honey, fruits and fruit juices that are allowed in this plan can contribute to SIBO. This diet allows consumption of both amylose and amylopectin, which has high fermentation potential that can worsen SIBO symptoms.
Reducing starch in diet may improve the IBS and SIBO symptoms. The aim of this dietary approach is to limit all forms of starch including maltose, sucrose and lactose. In this way, the diet may limit intestinal overgrowth of certain bacteria including Klebsiella pneumoniea.
This diet plan unnecessarily limits all forms of starch without limiting fructose, which is considered as the disadvantage of this diet plan.
Low Carb Diet
Although, anecdotal evidences have shown that low-carb diet can improve reflux disease and IBS, which are associated with SIBO. On the downside, low-carb or ketogenic diets don’t restrict sugar alcohols and fiber, which can potentially worsen SIBO symptoms. Most of the dieters fail to stick with the diet due to underlying medical problems, which is a simple reason for failure of this diet.