SIBO symptoms & what to look out for

Small intestinal bacterial overgrowth (SIBO) is a common condition where too many bacteria build up in the small intestine. Normally we don't normally see large numbers of bacteria in the small intestine. These bacteria disrupt digestion and nutrient absorption, leading to a range of uncomfortable symptoms.

In this article, we’ll explain the key SIBO symptoms to look out for, why they happen and what to do next if you suspect SIBO may be affecting you.

Abdominal pain

Abdominal or stomach pain is one of the most common SIBO symptoms. The overgrowth of bacteria in the small intestine produces excessive hydrogen or methane gas which stretches the small bowel wall. Furthermore, malabsorption and bacterial overgrowth can irritate the lining of the gut causing inflammation.

Inflammation and distention ultimately lead to cramping and discomfort. If you often notice stomach pain that worsens after eating or comes in waves, this could be a sign of SIBO.

Bloating and flatulence

Bloating is another hallmark of SIBO. As we said, bacterial overgrowth leads to excessive gas production as the bacteria ferment food. This gas production often makes you feel bloated and can cause visible swelling of the stomach. Unlike mild bloating after a large meal, SIBO-related bloating can occur after eating even small amounts and may last for hours. Bloating can also be accompanied by increased flatulence.

Diarrhoea or constipation

Many people with SIBO experience diarrhoea. The bacterial overgrowth interferes with how the gut absorbs nutrients and fluids, speeding up transit time and leading to loose stools. Persistent diarrhoea without another clear cause may point towards SIBO.

Although hydrogen-predominant SIBO is most commonly associated with diarrhoea, methane-predominant SIBO often results in constipation. This is because methane reduces gut transit time¹.

Vitamin and/or mineral deficiency

Because SIBO disrupts nutrient absorption, deficiencies in key vitamins and minerals are common. For example, bacteria may consume vitamin B12 before your body can absorb it. Over time, this can lead to fatigue, weakness, or other deficiency-related symptoms.

Interestingly, SIBO may actually lead to an increase in folic acid levels. This is because small bowel bacteria actually synthesis folate².

Unexplained weight loss

Unintended weight loss can occur in people with SIBO because nutrients from food are not being properly absorbed. If you notice weight loss despite eating normally, and especially if it occurs alongside other gut symptoms, this is definitely a red flag worth investigating.

Other symptoms and signs of SIBO

One of the difficulties in picking up SIBO is that is can affect other body systems, not just your gut. For example, people with SIBO are more likely to experience fatigue, brain fog, joint pain and skin rashes.

This is likely to be due to the complex interactions between the gut and the brain and the gut and the skin. In fact, SIBO is related to a number of other conditions including:

• Irritable bowel syndrome (IBS)
• Fibromyalgia
• Chronic fatigue syndrome (CFS)
• Rosacea
• Psoriasis
• Rheumatoid arthritis

What to do next if you have SIBO symptoms

SIBO symptoms overlap with those of other digestive conditions such as irritable bowel syndrome (IBS), coeliac disease or even bowel cancer. That’s why self-diagnosis isn’t reliable.

The best way to know if your symptoms are caused by SIBO is to take a SIBO breath test, which measures the gases produced by bacteria in your gut after consuming a sugar solution.

Get your SIBO symptoms checked with our SIBO test