What is SIBO?
Small Intestinal Bacterial Overgrowth
You eat the salad. You eat the broccoli. You try to eat clean. But 30 minutes later, you feel terrible. You are bloated, gassy, and uncomfortable.
You ask yourself, “Why does healthy food make me feel sick?”
In my experience, the answer often comes down to four letters: SIBO. That stands for small intestinal bacterial overgrowth.
What Is Happening Inside Your Body
Your small intestine is designed to absorb nutrients. It is not supposed to be full of bacteria. The bacteria belong further down in the large intestine.
SIBO happens when those bacteria move up into the small intestine where they do not belong. So when you eat that salad, the bacteria ferment it too early, right in the middle of your gut. That creates massive amounts of gas.
Two Big Clues
There are a couple of signs that often tip me off that someone is dealing with SIBO.
The first clue is this. Have you ever taken a course of antibiotics for something unrelated, like a sinus infection or a UTI, and noticed that your bloating suddenly went away? That is a huge sign. It happened because the antibiotic temporarily knocked down the overgrowth in your gut.
The second clue is even more surprising. Do you feel worse when you take probiotics or eat fermented foods like yogurt or sauerkraut?
This one really confuses people. We are told that probiotics are good for us. But if you have SIBO, taking a probiotic is like throwing gasoline on a fire. You are adding more bacteria to a party that is already way too crowded.
Why Does This Happen?
Your gut has a cleaning wave called peristalsis. Think of it as a conveyor belt that pushes food and bacteria down to keep the system clear.
If that conveyor belt slows down, the flow stops. Bacteria are able to creep back up into the small intestine. Stress, past infections, and certain medications can all slow down peristalsis.
Does it feel like your food just sits in your stomach for hours? That is a sign your conveyor belt might not be working the way it should.
The Plot Twist
Here is something almost nobody talks about.
Sometimes, it is not bacteria at all. It is yeast. We call that SIFO, which stands for small intestinal fungal overgrowth. The symptoms feel exactly the same. Gas, bloating, brain fog. But antibiotics will not help because they do not target yeast. In fact, SIBO and SIFO often show up together.
The Big Question
Have you ever taken the breath test for SIBO? Or did your doctor just tell you it was “probably IBS”?
If you have been struggling with bloating that does not make sense, it is worth digging deeper. Knowing what is actually going on in your gut is the first step toward feeling better.
Authored by Gerard Guillory, MD
Gerard Guillory, MD, is a board-certified internist who practiced for nearly four decades with a focus on functional, root-cause medicine. He is the author of three books on irritable bowel syndrome and the founder of It’s My Health, where he and his team put current health news in context and help members understand the underlying causes of chronic symptoms.
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