Small Intestinal Bacterial Overgrowth

By Ruth Werner
[Pathology Perspectives]

Here’s a scenario: your client is a 67-year-old woman who struggles with her health. She has a history of diabetes and hypothyroidism, both of which she has treated with inconsistent success. Now she tells you she may not be able to stay through a whole session, because she may have to use the bathroom: gas, bloating, and diarrhea are her constant companions. She has lost a lot of weight in the last several months, her skin is dry, and her hair is thinning and brittle. What may be happening?

SIBO: What Is It?

Small intestinal bacterial overgrowth (SIBO), sometimes called bacterial overgrowth syndrome, is the condition of having either too many bacteria in the upper small intestine, having the wrong types of bacteria there, or a combination of both. While this condition has been recognized for a long time, it is difficult to know how many people may be affected. This is because SIBO occurs in conjunction with several other similar-looking conditions, and diagnostic techniques are not very precise.

While many of us may have non-optimal or non-average levels of bacteria in our proximal small intestine, SIBO only becomes a problem when these bacteria interfere with nutrient absorption, leaving us vulnerable to vitamin and mineral deficiencies and a host of other complications.

How Does SIBO Start?

SIBO occurs when the intestinal microbiome is disrupted and bacteria at the proximal end of the GI tract proliferate. (More on the wonders of the intestinal microbiome is covered in the video that accompanies the digital edition of this article.) Depending on how they are described, the contributing factors to SIBO fall in four main categories.

Problems with Motility

Any situation that interferes with healthy, strong peristalsis can raise the risk of SIBO by interfering with the appropriate clearance of bacteria in the gut. Gut motility can be limited by Parkinson’s disease, diabetic neuropathy that affects the vagus nerve, scleroderma, hypothyroidism, and other conditions. In addition, treatment for cancer and narcotics use can slow peristalsis.

Structural Problems in the Intestines

Any structural congenital problem with the intestines can contribute to SIBO, but more common structural issues are associated with gut surgeries, including gastric bypass, or the strictures and scarring that can accrue with Crohn’s disease or intestinal diverticulitis. A dysfunctional ileocecal valve that allows backflow from the colon into the small intestine is another structural anomaly seen with some people who have SIBO.

Changes in Intestinal Chemistry

If the chemical environment of the proximal intestine is abnormal, unwelcome bacteria can flourish. This may happen with the use of proton pump inhibitors (PPIs) that change gastric secretions, or cirrhosis, pancreatitis, and diabetes, all of which can alter the secretions that enter the duodenum.

Immune System Deficiency

Any situation that impairs immune system function may open the door to SIBO. HIV and AIDS, treatment for autoimmune diseases, and chemotherapy are all contributors to immune system challenges.

Any one or any combination of these factors may tip the balance so bacteria in the proximal intestine proliferate. If these microorganisms become aggressive, they can produce metabolic wastes that damage the villi, interfere with the action of bile, and cause the transformation of normal nutrients into toxic metabolites. The result: pain, gas, bloating, diarrhea, and potentially dangerous malabsorption with deficiencies of important vitamins and minerals. SIBO can become life-threatening, especially if the patient is very young, very old, or constitutionally weak. We see it as a particular threat for older people with chronic diarrhea, neonates who are malnourished, and those with chronic conditions that interfere with digestive function, like scleroderma or diabetes.

SIBO Signs, Symptoms, and Complications

The simplest signs and symptoms of SIBO can be fairly subtle: gastrointestinal discomfort, mild gas, and diarrhea. Weakness and fatigue follow. Food exacerbates symptoms, and the person cannot normally absorb nutrients. Symptoms typically worsen over time. Left untreated, and especially if the person has other contributing factors, SIBO can lead to some serious complications.

People with SIBO may become anemic, for several reasons. With impaired absorption, it is impossible to get enough iron, folate, and other blood building blocks from the diet. A deficiency in vitamin B12 eventually causes neuropathy, heart palpitations, problems walking, and vision loss. The wastes excreted by gut bacteria can interfere with the function of bile, leading to steatorrhea, the presence of fat in the stools, while important fat-soluble vitamins like A, D, E, and K are inaccessible. Vitamin A deficiency leads to night-blindness; lack of D vitamins can contribute to fatigue, depression, hair loss, bone density loss, and more; deficiency of vitamin E means we lose a major source of antioxidant activity; and lack of vitamin K can cause excessive bleeding. Lack of access to calcium can cause muscle cramps and eventual osteopenia. In addition, the nutrient deficiencies seen with SIBO are associated with dermatitis, rosacea, and many other conditions.

Diagnostic Challenges

This condition is sometimes identified through carbohydrate or lactulose breath tests, although these tests have been shown to be potentially inaccurate, with a high rate of both false positives and false negatives. Extracting fluid from the duodenum or jejunum to count bacterial colonies is intrusive and complicated, and typically isn’t recommended unless an endoscopy is already being conducted. Consequently, many doctors rely on patient-reported symptoms, tests for nutritional deficiencies, and an attempt to rule out conditions with similar presentations, such as celiac disease, Crohn’s disease, and irritable bowel syndrome. This is a special challenge, because SIBO can and frequently does occur simultaneously with these other causes of chronic digestive system dysfunction.


The goals of treatment for SIBO are fourfold: to interrupt any possible contributing factors, to treat the bacterial overgrowth, to supplement needed nutrients, and to restore a healthy gut microbiome. This turns out to be a lot harder than it sounds.

Interrupting contributing factors may be the simplest part of SIBO treatment. This means identifying whether the patient is using medications like PPIs or narcotics that might change the intestinal environment, or whether they are successfully treating conditions like diabetes or hypothyroidism that can interfere with proper gut motility.

Addressing bacterial overgrowth in the intestines is challenging for many patients. Different antibiotics are used for aerobic bacteria than for anaerobic bacteria, so a first attempt may not be successful. Further, antibiotics don’t discriminate for location: they can help with bacterial overgrowth in one area, but they may badly disrupt a healthy environment elsewhere. And the SIBO relapse rate after a typical course of antibiotics is very high. Many patients find they need to repeat treatment several times over the course of many months before their digestive tract is functioning well again. Some naturopathic doctors opt to try to treat SIBO nutritionally, recommending foods that promote or limit specific types of bacteria.

SIBO patients may be dehydrated from chronic diarrhea, and they are often deficient in key nutrients, depending on how severe their case is. Replacing these vitamins and minerals is a high priority.

Once the SIBO is under treatment, the effort to restore a healthy gut microbiome can be confusing and complicated. Contradictory “how-to” guides are everywhere, each one touting a different approach and different rules about appropriate or inappropriate foods. The question of whether to use probiotics is an example: a quick tour through half a dozen “Treat Your SIBO” websites yields advice both in favor and against probiotic products. I saw the same contradictory advice with bone broth and some other foods. The takeaway is that what works for one person may not work for another, and strategies must always be customized for the individual. Treatment may also be complicated by the presence of other digestive tract problems like Crohn’s disease or irritable bowel syndrome that carry their own restrictions. It is important to work with a trusted nutritional counselor through what is, for most people, a lengthy and frustrating process.

Massage Therapy and SIBO?

Think back to the client we described at the beginning: she is 67, struggling to manage her chronic conditions, and now she has digestive pain and constant bloating, gas, and diarrhea. She hopes you can help.

Persistent digestive discomfort, especially in a new pattern, is a red flag for massage therapy. Most of the time it’s an indicator of something that isn’t terribly threatening—stress or irritable bowel syndrome, for instance, and massage may provide some relief. In some cases, digestive symptoms can indicate very serious problems, and massage can still provide some temporary relief. That’s wonderful—unless it causes the client to delay in getting an important diagnosis.

The chronic pain, gas, and diarrhea seen with SIBO are signs that this is a situation that needs to be pursued with a primary care provider. SIBO itself can be a serious disorder, and other conditions that look like it—celiac disease, small intestinal diverticulitis, Crohn’s disease, and so on—can also make people very ill. It is not within our scope of practice to determine whether someone’s persistent and repeating stomachache is dangerous or not, and in this situation it is important to refer out.

If a client has been diagnosed with SIBO and wants to receive massage, then some special accommodations may be necessary. It would be irresponsible to suggest that massage therapy can help treat this condition, but we may be able to make living with it less stressful. Gentle work to the abdomen, offering positioning adjustments like side-lying, and simply putting a warm hand on the belly may be very soothing and calming to a person with chronic digestive pain. Of course, we must also anticipate the need for a sudden and urgent trip to the bathroom. 

Therapists who have advanced education in visceral manipulation may be able to offer work that promotes intestinal motility to help move materials through the system more efficiently. But this is not something to do for clients with diagnosed GI tract disorders unless the therapist has extensive training.

Clients whose conditions are severe may find rigorous massage uncomfortable and overwhelming. Further, long-term nutritional deficiencies may create substantial health problems that impact decisions about massage therapy. Examples include bone brittleness and muscle spasms related to low calcium absorption, skin rashes related to a lack of selenium and essential fatty acids, and easy bruising related to a shortage of vitamin K.

Are you likely to have clients who have SIBO? At this point, it’s hard to know, because the medical community’s diagnostic capacity for this condition is so limited. But many massage therapists have clients whose digestive systems do not operate at optimal levels. Let’s be sensitive and sensible about how we structure our work with these clients, and let’s be sure to give them ethical and responsible advice for their self-care.



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Ruth Werner is a former massage therapist, a writer and an NCBTMB-approved continuing education provider. She wrote A Massage Therapist’s Guide to Pathology (available at, now in its sixth edition, which is used in massage schools worldwide. Werner is available at or