The Microbiome Connection Part 3: by Mark A. Pimentel
Food poisoning can also disrupt your microbiome and cause IBS symptoms. To minimize your risk of food poisoning, follow these tips: Avoid eating raw foods, such as salads (especially at a salad bar) or raw fish, including sushi. Always heat your food thoroughly. Don’t eat foods that are left at room temperature for a prolonged amount of time (4 or more hours). Avoid eating from street vendors or food trucks, whose sanitation is usually different from that in a restaurant. Food may be unrefrigerated all day and thus be exposed to microorganisms that can cause food poisoning. Avoid eating uncooked vegetables as they are often sprayed or washed with local water. Cook the vegetables and serve them hot. Drink bottled or filtered water rather than tap water, and use bottled water to brush your teeth. Avoid the use of ice cubes, which are likely made from local water. When you bathe or shower, avoid getting water in your mouth. Eat at restaurants that have a reputation for cleanliness and avoid those with code violations. If you eat poultry that’s been frozen, be sure to thaw it fully before cooking it to avoid Salmonella and Campylobacter food poisoning. For the same reason, avoid eating raw eggs. At home, wash all fruits and vegetables thoroughly before eating. Use a non-toxic food detergent, which you may find at your local health food store. Peel the skins off fruit before eating. Wash or sanitize your hands before eating. In hotel rooms, use disposable cups instead of reusable glass or porcelain cups. In some hotels reusable cups are only rinsed rather than properly washed. If you plan to travel to an area that is high-risk for food poisoning, you may want to consider taking half of a rifaximin pill with every meal during your trip, although this is not an FDA-approved treatment. If you’re staying at a rental home or bed-and-breakfast, take further precautions: Clean the countertops. Clean all chopping boards, especially if they’re made of wood. Use separate chopping boards for meat and vegetables. Wash all sponges in the dishwasher. Sponges are known to carry tons of bacteria. To keep food from spoiling quickly, make sure the refrigerator is working properly. Pay attention to expiration dates on the food you buy. Expired food is more likely to contain microorganisms that lead to food poisoning. Let’s talk about our number 2: SIBO. SIBO occurs when there are greater than 1000 bacteria per milliliter (>103/mL) in the small intestine. In SIBO, this excessive quantity of bacteria is not an infection, but rather an over-colonization of specific bacteria in an area where they don’t belong. The bacteria aren’t invading or attacking you; they are your own resident bacteria. SIBO is, in effect, a phenomenon of bacteria dislocated from your large intestine to your small intestine. As the gut descends, the bacteria level varies. Your mouth contains millions of bacteria, but there are less than 100 bacteria per mL in your stomach. (We assume that the high acidity of the stomach kills many of the bacteria.) In the small intestine, the quantity of resident bacteria increases, but there are usually less than 1000 per mL. What causes SIBO symptoms? When food you’ve eaten makes its way into the small intestine to be absorbed, it’s broken down into small pieces and then digested. If you have more bacteria than normal, the bacteria consume the food before you digest it. When the bacteria digest and ferment the food, they produce various gasses: hydrogen, methane, hydrogen sulfide, and carbon dioxide. The excessive amount of gas leads to inflation —like a balloon—of the small intestine. The small intestine, which mostly deals with liquids or solids, isn’t equipped to deal with excess gas. When it fills with gas, it tries to move it forward. But unlike liquids or solids, gas can’t be easily moved, and it becomes trapped in the small intestine. That’s when you feel bloated and your belly may distend. You can’t get rid of the gas because the small intestine is incapable of pushing it forward, whereas when you have gas in the stomach, it can be relieved by belching. Excessive gas in the colon is passed as flatulence. There are, however, mechanisms for gas in the small intestine to disappear. Slowly, the gas is absorbed through your bowel wall into the blood circulation. When the blood passes through the lungs, gasses are released and you breathe them out. That’s why if you have SIBO, you often wake up with a flat belly because you haven’t produced any gas overnight and the gas you have in your bowel has been absorbed into your circulation. Also, the housekeeper waves are active at night while you are fasting, and the waves push the remnants of food toward the colon, thus limiting the amount of food left for the microorganisms to ferment in the small intestine. When you start eating again in the morning, your symptoms return and become worse throughout the day. The Causes of SIBO STAGNATION: Bacteria don’t build up magically without cause. Think of the colon as a swamp with slow-moving water and the small intestine as a fast-moving river. The most common cause of stagnation is a lack or impairment of cleaning waves in the gut, which occur every 90 to 120 minutes when you aren’t eating. During the fasting state, these waves strip out debris in the gut after a meal. The salad you had for dinner last night has to be cleaned out so that your gastrointestinal tract is ready for breakfast in the morning. WEIGHT-LOSS SURGERY: Bypass weight-loss surgery can also lead to SIBO. One-third of American adults are obese, so weight-loss surgery—or bariatric surgery—is more popular than ever. One of the most common types of weight-loss surgery is Roux-en-Y, known as gastric bypass. This nonreversible surgery works by decreasing the amount of food you can eat at one sitting and by reducing absorption of nutrients. Typically, the surgeon cuts across the top of your stomach and makes it into a pouch about the size of a walnut, drastically reducing the amount of food you can hold in your stomach. The surgeon then cuts a loop of the small intestine and sews it directly onto the pouch. Food bypasses most of your stomach and the first section of your small intestine, thus entering directly into the middle part of your small intestine. This loop of bypassed small intestine is blind to food or liquid passing through it. Because nothing flows through those three feet of the small intestine, they can become stagnant. There are no effective cleansing waves flowing through it, however bacteria can still grow—or overgrow—in it, leading to SIBO. Inflammatory diseases, such as Crohn’s disease and severe celiac disease, cause significant inflammation in the wall of the small intestine and inhibit bowel clearance. They can also lead to strictures (abnormal narrowing) that alter the gut as well and, again, lead to SIBO. Diabetes is one of the most common diseases that affect gut motility. This metabolic disorder causes your blood glucose (blood sugar) levels to be too high. One of the long-term consequences and the most common complication of diabetes is peripheral neuropathy, or nerve damage caused by chronically high blood sugar levels. This leads to numbness, loss of sensation, and sometimes pain in your feet, legs, or hands. The nerve damage can affect the nerves in the gut as well, leading to abnormal gut motility and subsequent SIBO. DRUGS: Narcotics can slow down the gut and lead to SIBO. The opioid crisis has led to many SIBO cases because narcotics precipitate bacterial overgrowth. The main effect of narcotics is pain relief, but they dramatically slow down the gut and cause classic constipation, as well as heartburn, gastric reflux, abdominal discomfort, and opioid-induced bowel dysfunction, which is a potentially debilitating side effect of chronic opioid use. Fortunately, we have drugs, such as methylnaltrexone, that can specifically negate the bad effects of narcotics on the gut without taking away the pain-killing effects. Anticholinergics used in urology and gastroenterology to decrease symptoms of urinary infrequency or abdominal cramps work by slowing down the gut to alleviate cramps, which, in turn, affects gut motility. Antacids used to neutralize stomach acid to reduce heartburn may decrease the amount of acid in the stomach, decreasing its efficacy in killing bacteria and potentially leading to more bacterial overgrowth. However, the link between acid-suppressing agents and SIBO is not yet clear. We have reported in a large study that stronger acid suppressing medicines—called proton pump inhibitors—are not associated with bacterial overgrowth or any drastic change in the small intestine microbiome. Although proton pump inhibitors significantly affect the acidity of the stomach, they don’t affect the acidity of the small intestine. If your small intestine is healthy, it can balance the effects of proton pump inhibitors without an overgrowth of bacteria. The primary—and easiest—method of diagnosing SIBO is through a breath test. Gut bacteria can produce carbon dioxide as a fermentation product, just like the bubbles in beer. We humans also produce carbon dioxide, so looking for this gas won’t reveal whether the carbon dioxide is made by bacteria or by us. Bacteria and other microorganisms also produce hydrogen and methane, which is unique to them. When we find these gasses in the breath, we know they come exclusively from microorganisms in the gut that have migrated to the breath.
