Are Bad Bacteria the Culprit in Crohn's?

Study: Bad gut bacteria outweighs the good in kids and teens with Crohn's disease.

Microscopic view of bad gut bacteria, which could be the cause Crohn’s disease, according to one study.

Medically reviewed in November 2021

Doctors still don’t know what causes Crohn’s disease, a puzzling syndrome that causes severe inflammation and damage in the digestive tract. But a growing body of research is pointing to some tiny culprits: the bacteria that live in your gut. 

Gut bacteria goes under the microscope 
In one large study published in the journal Cell Host & Microbe, researchers from 28 gastroenterology clinics across America examined biopsies from 450 children and teens newly diagnosed with Crohn’s disease, as well as more than 200 with other bowel problems. The researchers looked at samples from different parts of the gut to see what kinds of bacteria were present in the tissue. They found that kids and teens with Crohn’s had an abnormal balance of gut bacteria, with an excess of certain harmful types and a lack of some strains known to be beneficial. The imbalance of bad gut bacteria to good was even worse in subjects who were taking antibiotics. 

In Crohn’s disease, the immune system attacks the cells in the digestive tract, leading to severe diarrhea, abdominal pain, bleeding ulcers and weight loss. The condition is usually treated with anti-inflammatory or immune-altering medications. One theory is that bacteria or a virus sets off the immune attack. The authors of the current study say it’s impossible to tell whether the imbalance of microbes they saw triggers that attack or is a result of it, though. 

While the study doesn’t point to a cure for Crohn’s yet, it does suggest that therapies targeting the bad gut bacteria could help. The researchers say it also could lead to a better test to diagnose Crohn’s. 

Get a better handle on your symptoms 
Sometimes the best offense is a great defense, and that’s a good way to think about tackling Crohn’s disease—and its symptoms—head on. These tips may help, but remember to discuss them with a healthcare provider first: 

  • Go gluten-free. Many people with Crohn’s are sensitive to this wheat protein, as well as dairy and eggs. A food diary can help you pinpoint which foods trigger your symptoms. 
  • Talk it out. Counseling can improve your outlook and coping skills. People who receive psychotherapy tend to have fewer relapses and need fewer operations. 
  • Consider B vitamins. Crohn’s can often lead to nutritional deficiencies, especially the B vitamins you need for energy.

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