Is IBS a sign of bowel cancer?


About 4-10% of people worldwide suffer from irritable bowel syndrome (IBS). It has been reported as the second leading cause of absence from work and/or school. And as if living with IBS is already not enough, there is now an even bigger question that IBS patients worry about. Several studies suggest that they might be at risk of developing colorectal cancer, known also as bowel/colon cancer. Is this really true?

What is bowel cancer?

Bowel cancer is the third most common cancer in both UK and USA. It is believed to be caused by bacterial imbalance (dysbiosis) in the bowel system. Your intestines are lined with mucus (sticky wet liquid) that creates a protective barrier. But an overgrowth of “bad” bacteria in the intestines can disrupt this barrier, resulting in inflammation and carcinogenesis (formation of cancer). Bacterial imbalance is very common in IBS patients and that is mostly where the fears arise.

Risk factors:

  • history of bowel cancer among close relatives
  • obesity and sedentary lifestyle
  • a diet high in fat and processed meat
  • smoking and frequent alcohol consumption
  • inflammatory bowel disease (IBD) and diabetes

Symptoms of bowel cancer:

  • bleeding from your bottom, and/or blood in your stool
  • alterations between constipation and diarrhea
  • unexplained weight loss
  • extreme fatigue
  • abdominal pain

Many symptoms of IBS and bowel cancer overlap and that makes it even more terrifying. It is however not common to see blood in the stool or experience unexplained weight loss in IBS. If you have any of these symptoms, you should notify a general practitioner.

Risk factors of bowel cancer.

If I have IBS, am I at a higher risk of bowel cancer?

A large-scale UK study with more than 500,000 participants and with 12 years of follow-up, found no increased risk in IBS patients. In some studies, researchers found a slight increase but not significant. In others, there was a lower risk of bowel cancer for patients with IBS.

This suggests that although the answer is still unclear, there is no need to worry preliminarily. Keep in mind that worrying causes stress that may worsen your IBS. You are at greater risk only if you meet other risk factors mentioned above. IBS is not a part of this list.

What can I do to lower the risk?

There are several things you can do to lower the risk of bowel cancer:

Move daily

It is not a secret that daily physical activity is important for overall health and well-being. Regular movement not only improves digestion and immune function but also contributes to the maintenance of a healthy weight. The World Health Organisation (WHO) recommends different levels of physical activity for every age group. You should, however, keep in mind that if you have IBS with diarrhea, intense exercise might worsen your symptoms. Find out more on our website about training with IBS.

Include more protective food ingredients in your diet

It is recommended to eat a diet high in fiber (oats, carrots, etc.), rich in vitamin D and omega-6 (found in fish). The diet should also consist of different types of fruits and vegetables and foods that contain vitamin B (such as seafood, eggs, and leafy greens). At the same time, it is important to avoid foods that are high in fat or very processed. These are very common in our diet nowadays which could explain why the cases of bowel cancer increased in the past few years, especially among young people.

These simple lifestyle changes make a big difference. 


Wu, S., Yuan, C., Liu, S., Zhang, Q., Yang, Z., Sun, F., Zhan, S., Zhu, S., & Zhang, S. (2022). Irritable Bowel Syndrome and Long-Term Risk of Cancer: A Prospective Cohort Study Among 0.5 Million Adults in UK Biobank. American Journal of Gastroenterology, 117(5), 785–793.

Thanikachalam, K., & Khan, G. (2019). Colorectal Cancer and Nutrition. Nutrients, 11(1), 164.