Functional Gastrointestinal Disorders

Do you suffer from IBS- irritable bowel syndrome, SIBO, or SIFO? 

Small Intestinal Bacterial Overgrowth (SIBO) 

Small intestinal bacterial overgrowth (SIBO) is a chronic intestinal disorder characterized by excessive amounts of bacteria in the small intestine. Estimates report that 60-80% of all IBS cases are due to SIBO.

The majority of bacteria in our gut live in the large intestine. When the bacteria in the small intestine becomes more like the bacteria in the large intestine, one has developed SIBO.

Overgrowth from SIBO may contribute to increased intestinal permeability inflammation and alterations in gut function.

The current gold standard for diagnosis is the Hydrogen Breath Test.

Sub-types define SIBO results.

IBS-C (Constipation dominant) Has been reclassified as intestinal Methanogen Overgrowth (IMO).
IBS-D (Diarrhea dominant),
IBS-M (Mixed type)
Hydrogen Sulfide SIBO.

Signs, symptoms, and complications

Symptoms of SIBO, which may vary between individuals, can be non-specific and often overlap with many other associated disorders, making it difficult to recognize or diagnose if the practitioner is not well-trained in this disorder.

SIBO typically presents several gastrointestinal symptoms, such as abdominal pain, abdominal distension, bloating, flatulence, chronic diarrhea, or constipation.

SIBO may result in malabsorption of micro- and macronutrients, leading to nutrient deficiencies and other complications over time.

Complications and extraintestinal manifestations (outside of the gut) may include:

● Anemia
● Arthralgias (joint pains)
● Chronic prostatitis
● Hypoproteinemia/hypoalbuminemia (Low protein)
● Interstitial cystitis
● Neuropathies
● Osteoporosis
● Restless legs syndrome
● Rosacea
● Steatorrhea (Fatty Stools)
● Weight loss

Causes and risk factors 

SIBO's development is driven by a disruption in the homeostatic mechanisms regulating the intestinal microbiota. Inadequate gastric secretion (hypochlorhydria) and small intestine dysmotility (impairment in mobility) are the two most common factors predisposing individuals to bacterial overgrowth. Other factors that increase an individual's susceptibility to SIBO include:

● Age, resulting in increased risk in the elderly population
● Anatomic alterations or abnormalities of the GI tract, such as diverticula, strictures, fistulas, surgical loupes, and gastric or ileocecal valve resection
● Vagotomy, surgery that affects or removes part of the Vagus nerve
● Impairment of systemic and local immunity, immunodeficiency states
● Motility disorders, such as small intestine dysmotility, Celiac disease, and gastroparesis
● Irritable bowel syndrome (IBS)
● Certain metabolic conditions, such as diabetes (enteropathy) and hypochlorhydria
● Dysfunction of specific organs, such as cirrhosis, renal failure, pancreatitis, scleroderma, and Crohn's disease
● Certain medications, such as antibiotics, proton pump inhibitors for reflux (GERD), and antimotility agents
● Alcoholism
● Intake of FODMAPs, fiber, prebiotics, and probiotics have also been shown to alter the intestinal microbiota and may increase the risk of developing SIBO or exacerbate its symptoms.


Addressing SIBO 

SIBO treatment typically involves: 

  1. Identifying any underlying causes (See: What caused my SIBO?)
  2. Treating the bacterial overgrowth with antibiotics or antimicrobial herbs, such as oil of oregano, wormwood, Coptis root, thyme, red thyme, field horsetail, olive leaf, and berberine extracts, etc. (Self-treatment not advised).
  3. Correct nutrient deficiencies common in cases of SIBO, such as deficiencies in calcium, magnesium, vitamin B12, Iron, and fat-soluble vitamins A, D, E, and K.
  4. Preventing recurrence: Diet and SIBO. In cases of SIBO, carbohydrates, such as fructose, lactose, and fermentable oligo-, di-, monosaccharides, and polyols (FODMAPs), may be fermented by bacteria in the small intestine, leading to increased digestive symptoms, such as abdominal pain, bloating, and flatulence. Some individuals may experience improvements in bacterial overgrowth and associated symptoms by following a carbohydrate-restricting diet, such as the elemental diet, the low-FODMAP diet, the SIBO Biphasic diet, and its variants (See attached diets), the Specific Carbohydrate Diet (SCD), and the Gut and Psychology Syndrome (GAPS) diet. My good friend and colleague, Dr. Gerard Mullin, MD, associate professor of gastroenterology at Johns Hopkins University, published this study on the botanical treatment of SIBO.


Herbal Therapy Is Equivalent to Rifaximin for the Treatment of Small Intestinal Bacterial Overgrowth - NCBI Article Link 

 SIBO and SIFO, what's the difference?


SIBO stands for Small Intestinal Bacterial Overgrowth, and SIFO stands for Small Intestinal Fungal Overgrowth.

Many of the symptoms of SIBO, which are bloating, gas, constipation/diarrhea, abdominal pain, belching and or flatulence, nausea, and signs of leaky gut such as rashes, food allergies, and steatorrhea (fatty stools), can also present with small intestinal fungal overgrowth.

Dr. Satish Rao, a prominent gastroenterologist and researcher, states that 24% of patients with SIBO have concurrent SIFO. One may have SIFO alone, but interestingly, one-quarter of all SIBO patients have an overgrowth of yeast in their intestines. Understanding why conventional treatments may fail with antibiotics alone when both conditions are present is also essential.

Breath testing is the gold standard to diagnose SIBO, but that test cannot determine the presence of SIFO. The truth is that no direct tests are available besides culturing a sample from the small intestine that would be performed by a gastroenterologist in exceptional circumstances. The GI-Map, which is a stool test, does contain markers for some species of fungi; however, we cannot rely on this alone to identify it because fungal organisms tend to burrow into the mucus layer in the intestine known as a bio-film to evade detection. There is a particular urine test known as an OAT test (Organic Acids Test) that captures the metabolites of the fungus, so despite its stealth nature, we can see its by-products, which would indicate its presence.

There are specific botanicals used to treat both SIBO and SIFO effectively. Still, it's imperative to understand that diet and lifestyle play a pivotal role in eradicating and preventing reoccurrences.

 A low-sugar diet is mandatory, followed by a lower simple carbohydrate diet. Still, if you follow an SIBO-oriented diet, you will starve out the dietary constituents that contribute to its overgrowth. It takes discipline!


Loren Marks D.C., DACBN

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