Small Intestinal Bacterial Overgrowth (SIBO)

Small Intestinal Bacterial Overgrowth, commonly called SIBO, occurs when bacteria that normally live in the large intestine begin to grow in the small intestine, where they do not belong.

Your small intestine is designed to absorb nutrients from food. It is meant to contain relatively low levels of bacteria compared to the large intestine. When bacteria begin to overgrow in this part of the digestive tract, they ferment food before your body has had the chance to properly absorb it.

For many people, this leads to symptoms that feel confusing and difficult to explain. You may feel fine when you wake up, but become progressively more bloated or uncomfortable after eating throughout the day. These symptoms are often dismissed as “just IBS,” even though the underlying cause is something much more specific.

SIBO is not random. It is usually the result of something slowing down digestion or altering the balance of the digestive system.

When Balance Shifts

The digestive system relies on a process called the migrating motor complex. This is a wave-like motion that moves food, bacteria, and debris through the small intestine between meals.

When this movement slows down, bacteria can begin to accumulate and multiply.

This slowdown can happen for many reasons. Chronic stress can shift the nervous system away from proper digestion. Low stomach acid can allow bacteria to survive where they normally would not. Thyroid dysfunction can slow gut motility. Food poisoning can damage the nerve signaling that controls digestive movement.

Over time, bacteria ferment carbohydrates in the small intestine, producing gas that leads to pressure, bloating, and discomfort.

Common Signals of SIBO

• Persistent bloating, especially after meals

• Excess gas or belching

• Abdominal pressure or distention

• Diarrhea, constipation, or alternating bowel patterns

• Brain fog or fatigue after eating

• Food sensitivities that seem to keep increasing

• Nutrient deficiencies, especially iron or B12

SIBO can feel incredibly frustrating because symptoms often fluctuate depending on what you eat, how stressed you are, and how well your digestive system is moving food along.

Understanding what is happening inside the digestive system is the first step toward restoring balance. When digestion, gut motility, and the nervous system are supported together, many people begin to see their symptoms improve and their digestion become more stable again.