When Good Bugs Go Bad
Small bowel overgrowth (SBO) is a condition of the small intestine that allows too many bacteria, typically Lactobacillus, to develop and thrive. "So what", you ask? Well the "so what" is that Lactobacillus bacteria are not welcome in that area. They compete with the host (that would be you) for food and the bacteria typically win the fight. Remember that bully in grade school who would always swipe your PB & J from you? You got pretty hungry by the end of the day did not you? It's like that with SBO because if the bacteria eat your lunch repeatedly you run the risk of malnutrition and a host of unpleasant symptoms.
The small intestine is where the digestion and absorption of your food occurs. Digestion breaks down your meals into the basic carbohydrate, fat and protein macronutrients that a healthy body needs to function at optimum efficiency. As food moves from the early part of the small intestine (duodenum) through the middle (jejunum) and latter parts of the small intestine (ileum), the bacteria increase from relatively small numbers until they reach their highest levels in the large intestine, the colon. In the small intestine, enzymes, acids, hormones and other chemicals manufactured by the body are added to the food mixture (now called chyme) and are there to help digestion and absorption. The presence of these digestive juices, especially the acid, is why only a few bacteria would have been expected to be found in a healthy small intestine.
The colon is where all the unusable material from your food is collected and where the bacteria are most numerous. The water content of this material is about of of the total mass. Of the remaining,, approximately 30% is bacteria by weight. The bacteria would include the lactobacillus and other probiotic species as well as approximately 400 other species. The weight of all the bacteria in the gut is about 15 pounds. The large intestine is where the bacteria belong.
The beneficial effects of this large biomass on human health can not be underestimated. The bacteria promote a cleansing of the intestinal cells, manufacture some vitamins like riboflavin, thiamine, B-12, and, possibly most importantly, produce vitamin K, which is important in blood clotting and bone formation. Short chain fatty acids (used as fuel for colonic cells) are also produced. The downside of all this bacterial activity is the amount of toxic waste produced while the bacteria work for us. If the toxins build up, it certainly would qualify as a Superfund site.
In a normally healthy gut, when intestinal cells are functioning in an optimal fashion, the cells are able to absorb the bacterial toxins and neutralize them directly or pass them on to other sites in the body for detoxification. We get sick when the cells and body can no longer neutralize the poisons such as when pathogenic bacteria are present in overwhelming numbers (Montezuma's Revenge) or when the normal ratio of "good versus bad" bacteria is altered (dysbiosis). If the toxins accumulate without control, and the acid / base balance in the colon is significantly altered and disrupted, serious diseases like cancer can result.
We see a decrease in the numbers of the good bacteria, and the development of dysbiosis, in those cases where there is an overuse of antibiotics, antacids, NSAIDs, poor diet, lack of proper nutrition, stress, or in association with hidden food allergies . When colonic dysbiosis occurs, the symptoms you see would include the typical non-specific bloating, gas, diarrhea (sometimes constipation), nausea, and general malaise. There are instances in gut ecology where, because of changes in the intestinal environment, bacterial populations, especially the probiotic Lactobacillus, can migrate into the small intestine. Environmental changes in the gut can happen because of aging when gastric acid production is in decline. As the stomach acid decreases more Lactobacillus survive the journey through the stomach and into the upper gut and it is easier for them to thrive there. The elderly are more prone to SBO than a younger population and, as a result, develop more issues with nutritional deficiencies. Environmental changes can also occur in cases of pancreatic insufficiency with diseases like pancreatitis or liver diseases like hepatitis. Diabetes, cirrhosis of the liver, Crohn's Disease, Irritable Bowel Syndrome, intestinal surgeries and Scleroderma are also suspected of contributing to SBO.
When SBO occurs, the symptoms would include the typical non-specific findings of bloating, gas, diarrhea, nausea, and general malaise. Sound familiar? The symptoms are pretty much the same as you would see in colonic dysbiosis and even in Irritable Bowel Syndrome or a Candida overgrowth. In addition, severe cases of SBO can lead indirectly to malnutrition by decreasing the intestine's ability to digest fats and, extremely, proteins and carbohydrates. With severe, chronic SBO we also see weight loss, B-12 deficiency induced anemia, bone softening, and impaired night vision as the body fails to absorb vitamins because of the diarrhea. In fact chronic diarrhea is considered to be the hallmark of SBO. A recent study in the Journal of Gastroenterology and Hepatology show SBO to be the causative factor of chronic diarrhea in up to 67% of reported cases. In another study in the same journal 48% of cases were diagnosed with SBO. A separate study showed that up to 83% of patients diagnosed with Irritable Bowel Syndrome had SBO instead. SBO is definitely good bugs gone bad.
So how do you know if you have SBO? How is it diagnosed? More importantly, if you have it what do you do about it? If you have the symptoms described above and these symptoms have persisted for more than several weeks you should see a physician who is familiar with functional testing. As its name implies, functional testing refer to lab testing that helps determine the function and interplay of a total organ system rather than an isolated portion of that system. Functional tests ask the question "Why"! Traditional testing requests "What"! When you ask "what" is wrong, it only allows for symptom management. If you ask "why" it's wrong, it allows for the complete management of the cause of the symptoms.
There are several types of functional tests important in SBO. One invasive procedure cultures a bacterial sample taken directly from the contents of the duodenum. Stool microbiology offered by some labs identifies an overgrowth of bacteria by direct observation of the bacteria cultured from a stool sample. There is also a breath test that identifies, indirectly, the metabolic waste of the bacteria. Lastly, your doctor can order an evaluation of your urine collected first thing in the morning. This test looks directly at the waste products given off by the bacteria. If SBO is present, several of these waste products will be elevated.
Once diagnosed, your physician can then determine the next steps to take. You certainly do not want to take Lactobacillus containing probiotic supplements until the overgrowth is controlled. You're simply feeding the fire if you do. In some severe cases, antibiotics may be necessary to control SBO. In less severe cases the natural compound approach may be best. This could include various bactericidal herbs like Oregano, Goldenseal, and Garlic. Adding digestive aids like proteolytics, pancreatic enzymes as well as Betaine HCl may be of benefit. Changing your diet to exclude Lacto-fermented and "aged" foods temporarily as well as reducing high glycemic carbohydrates would be advised. It would be important to resolve the underlying cause for the overgrowth if possible. If the condition that allowed the overgrowth to occur in the first place is not considered then the above dietary changes will only offer temporary relief. After the overgrowth is reduced to normal and the causative factors are controlled, it's OK, and advisable, to return the fermented foods and probiotics back into your diet.
So while you may not have heard a lot about SBO, it does mask itself as some other conditions like Irritable Bowel Syndrome and Candida, contributor to the symptom picture in many other conditions, and its proper control can definitely make your life a lot easier.