Small Intestinal Bacterial Overgrowth (SIBO) is when bacteria decide to throw a party in your small intestine — and not the good kind. This overgrowth messes with digestion, appetite, and nutrient absorption, leading to weight loss and vitamin deficiencies. But what causes SIBO, who’s at risk, and how can you treat it? Let’s break it down.
What Is SIBO?
Your gut is like a bustling city where different bacteria live and work together to keep digestion running smoothly. But when the bacterial population in your small intestine spikes or the wrong types of bacteria take over (often migrating from the large intestine), you’ve got a problem — that’s SIBO. This imbalance throws your digestive system into chaos, causing inflammation and other health issues.
Symptoms of SIBO
Wondering if you might have SIBO? Here’s what to look out for:
- Bloating and gas – That uncomfortable, “about to pop” feeling.
- Constipation or diarrhea – Your gut can’t decide which way to go.
- Abdominal pain or cramps – Especially after eating.
- Loss of appetite – Food suddenly isn’t appealing.
- Fatigue and brain fog – Hard to focus? That could be SIBO talking.
- Muscle cramps – Your body isn’t absorbing nutrients properly.
If any of this sounds familiar, it might be time to dig deeper.
What Causes SIBO?
SIBO happens when harmful bacteria overstay their welcome in the small intestine, messing with digestion and nutrient absorption. This leads to weight loss and vitamin deficiencies — especially vitamins A, D, E, K, and B12. That’s when things get tricky. Low vitamin levels can cause nerve issues (like tingling and weakness), muscle cramps, and even bone problems (hello, osteoporosis and kidney stones). In rare cases, it can lead to lactic acidosis — a dangerous buildup of lactic acid in the blood.
Risk Factors for SIBO
A few things can raise your chances of developing SIBO:
- Structural issues – Problems with your small intestine’s anatomy.
- Low stomach acid – Often due to overuse of antacids or reflux meds.
- Immune system issues – A weak defense makes it easier for bacteria to take over.
- Slow digestion – When food lingers too long in your gut (due to surgery, hypothyroidism, or other conditions).
- Opioid use – Painkillers can slow down gut movement, creating the perfect storm for SIBO.
Certain health conditions — like Crohn’s disease, celiac disease, IBS, pancreatitis, diabetes, Parkinson’s, and liver or kidney issues — also increase your risk.
How Is SIBO Diagnosed?
If your doctor suspects SIBO, they might suggest a hydrogen breath test. You’ll drink a sugary solution, and then they’ll measure the hydrogen and methane levels in your breath. High levels mean your gut bacteria are working overtime.
Other tests include:
- Endoscopy – Collecting a small tissue sample from the small intestine.
- Blood tests – Checking for vitamin deficiencies and signs of inflammation.
- Imaging – Scans to spot structural issues in your gut.
How to Treat SIBO
Getting rid of SIBO isn’t always straightforward — but there are several approaches:
1. Treat the Root Cause
If SIBO is caused by an underlying condition (like structural issues or poor gut motility), treating that first is key. This might mean surgery or medication to help food move through your system more efficiently.
2. Antibiotics
Doctors often prescribe antibiotics like rifaximin to kill off excess bacteria. It works fast — but there’s a catch. Since antibiotics don’t fix the root cause, SIBO can come back. That’s why some doctors rotate antibiotics to prevent resistance. Treatment usually lasts 1–2 weeks.
3. Low-Lactose Diet
Many people with SIBO struggle to digest lactose, so cutting back on dairy can help reduce symptoms.
4. Liquid Diet
In severe cases, a liquid diet with pre-digested nutrients gives your gut a break and allows it to heal. For extreme malnutrition, IV nutrition might be necessary.
5. Vitamin and Mineral Supplements
Replenishing lost nutrients is critical. Focus on vitamins B1, B3, B12, A, D, E, and K, plus calcium, magnesium, and iron.
6. Fecal Microbiota Transplant (FMT)
Transferring healthy gut bacteria from a donor is being explored as a treatment, but more research is needed to confirm its effectiveness.
Best Diet for SIBO
While diet won’t cure SIBO, it can make symptoms more manageable. A low-FODMAP diet is often recommended. FODMAPs are fermentable carbs that gut bacteria love — but they also cause gas and bloating.
Here’s what to eat:
✅ High-protein foods (meat, fish, eggs)
✅ Gluten-free crackers and pasta
✅ Oatmeal, rice, quinoa
✅ Leafy greens, broccoli, carrots, potatoes, pumpkin
✅ Berries, oranges, and grapefruit
✅ Nuts, seeds, and lactose-free or almond milk
Small, frequent meals work best to keep your gut from feeling overwhelmed.
Final Thoughts
SIBO is more than just an upset stomach — it’s a complex gut imbalance that affects your whole body. If you’ve been dealing with digestive issues, unexplained weight loss, or fatigue, don’t ignore it. A doctor can help you figure out what’s going on and create a game plan to get your gut back on track. With the right mix of treatment, diet changes, and supplements, you can tame the SIBO beast and feel like yourself again.
