Here's What I Learned From My SIBO Test

The first time I heard about SIBO (small intestinal bacterial overgrowth) was back in 2015. A gastroenterologist — a doctor who specializes in the gut — brought it up when I told him practically everything I ate made me bloated. To make a long story short, I tested negative. But one lifestyle treatment for SIBO helped me anyway.

Here's more about what I learned.

What is SIBO?

It's when you have too much bacteria in your small intestines. Experts aren't exactly sure what causes it, but it's more common today than it used to be. Antibiotic overuse might be partly to blame, but SIBO tends tends to show up in other inflammatory conditions, like Crohn's disease. So a link with endo wouldn't surprise me. Some animal studies found that monkeys with endo tend to have the kind of altered gut bacteria that might lead to bacterial overgrowth.¹ But research on SIBO and endo in humans is seriously lacking.

I didn't have SIBO, but I think it's important for endo warriors with certain symptoms to get checked for it. That includes symptoms that mimic other conditions like irritable bowel syndrome or celiac. You should mention SIBO to your doctor if you have:

• Bloating and lots of gas after you eat
• Diarrhea or constipation
• Nausea
• Stomach pain
• Weight loss without trying

What is a SIBO breath test?

One way doctors diagnose SIBO is by measuring gas in your breath. They're looking for excess hydrogen or methane. That's what unwelcome bacteria in your small intestine give off when they break down sugar.

What does a SIBO breath test feel like?

It was boring but painless. I went to a hospital, but sometimes you can get it done in a doctors office. I drank a sweet liquid that I know had glucose (a.k.a sugar) in it. Then I sat in a chair for about three hours while a nurse periodically had me breathe into a balloon attached to a machine.

There are more invasive tests for SIBO that I didn't get. One involves putting a tube down your throat to get a some intestinal fluid. Someone in a lab can look at that sample to check for bacterial growth. Since my breath was normal — meaning my methane and hydrogen levels weren't elevated — my doctor decided I didn't need further SIBO testing.

How the SIBO diet helped me

My GI doctor and I were surprised I tested negative. That's because I started the low-FODMAP diet — which is often recommended for people with SIBO — as soon as I left our consult. I felt better within 48 hours. That's not to say that I never get bloated, but that distention stopped happening after every meal. (For more about my diet journey, check out my three-part series.)

How I feel 5 years later

I started following the low-FODMAP diet back in 2015. I felt great for a couple years. But you're supposed to be able to add back foods after 6 weeks. For me, it seemed like I kept having to remove food from my diet. Then I started feeling really full on small meals. I also lost weight without trying and my vitamin D was too low.

In 2019, my new GI doc checked me for celiac. I was negative, but he diagnosed me with non-celiac gluten sensitivity and carbohydrate malabsorption. I've always known I was lactose intolerant, so I gave up dairy 20 years ago. But now I've cut out wheat — except for long-fermented sourdough — and added a carbohydrate enzyme that helps me digest things like oats and broccoli. My bowel issues flare up before my period, but these extra diet changes help make things a little easier the rest of the month.

I was pretty disappointed when I tested negative for SIBO; it was such an easy explanation for all of my problems. I hoped I could just take some special antibiotics to make it go away. But I'm still glad my doctor ruled it out and helped me figure out my next steps. If you think you have SIBO, bring it up with your doctor. If they have no idea what you're talking about, ask them to refer you to a gastroenterologist who does.