Crohn’s Disease: Scientists Say Bacteria in the Mouth May Be the Cause
Crohn’s disease affects 4 million people worldwide. It causes debilitating symptoms such as chronic fatigue, diarrhea, abdominal pain, weight loss, and malnutrition.
Crohn’s disease is a lifelong disease once symptoms appear, and there is currently no cure, although there are ways to deal with flare-ups of symptoms.
The exact cause of Crohn’s disease is unknown and is thought to be due to many complex and overlapping factors, possibly including genetics, environment (such as smoking), and an overactive immune system in the gut.
Research has also revealed that the gut microbiome plays an important role in the disease.
The gut microbiome is a collection of trillions of bacteria, viruses, and fungi. These microorganisms are present from birth and play an important role in helping our gut cells and intestines function as they should. Gut bacteria also help our immune cells function as they should and ultimately ensure their effectiveness.
According to many studies, people with Crohn’s disease have a low diversity of intestinal bacteria. They also have higher levels of certain types of bacteria that may trigger intestinal inflammation.
However, it is not only gut bacteria that show signs of dysfunction in Crohn’s disease patients.
Rather surprisingly, studies have shown that bacteria in the mouth may also be important in this inflammatory disease.
The Microbiome of the Mouth
When we are in utero, our gut is sterile. However, our gut microbiome begins to develop from the moment of birth. First, it comes into contact with vaginal bacteria at birth, and then it develops through other maternal and environmental sources, such as breast milk and skin.
By the time we reach adulthood, the gut is a thriving community of trillions of bacteria, estimated to outnumber our cells 10:1.
Most of the bacteria that reach our intestines must first pass through our mouths. Therefore, our mouths contain the second largest number of bacteria after our intestines. And we swallow millions of bacteria in our saliva every day.
The oral microbiome is complex. Whether it is the tongue, cheeks, or saliva, each part of the mouth is composed of different microbes depending on factors such as pH levels and oxygen levels.
These microbial communities form complex structures called biofilms, which allow bacteria to organize on oral surfaces (dental plaque is one example). The bacteria then interact with each other and our immune cells to create a state of harmonious health.”
There are several reasons why researchers believe the oral microbiome is involved in Crohn’s disease.
First, studies have shown that people with Crohn’s disease have different oral bacteria than those without the disease. This suggests that certain types of bacteria present in the oral cavity may be involved in Crohn’s disease.
Second, several species of bacteria that are more abundant in the intestine of Crohn’s disease patients than in healthy individuals are also present in the oral cavity. This may be unsurprising given that, in general, the route of bacterial entry into the lower intestine is through the mouth. Indeed, it is not uncommon for Crohn’s disease patients to develop ulcers in the oral cavity as well as ulcers commonly found in the intestine.
Studies in humans have suggested that an oral bacterium called Veillonella parvula is particularly prevalent in the intestines of Crohn’s disease patients. This bacterium has been associated with diseases such as periodontitis and meningitis.
Although this bacterium is normally found in the oral microflora, one notable study has shown that it has developed a way to inhabit the lower intestine.
If the bacteria that cause Crohn’s disease are also present in the gut, a better test could be developed to diagnose Crohn’s disease simply by collecting saliva samples. This would be much easier than requiring the patient to provide a sample of stool or intestinal tissue.
Researchers should also investigate whether the oral microbiome causes Crohn’s disease.
Studies in mice suggest that inflammation (which occurs when the immune system is triggered by pathogens) facilitates the growth of certain types of bacteria, leading to greater inflammation and immune cell overactivation.
If the oral bacteria associated with Crohn’s disease are the same, this suggests that bacterial overgrowth and inflammation in the oral cavity may be the underlying cause of Crohn’s disease.
Other Diseases
Crohn’s disease is not the only disease in which specific oral bacteria have been implicated.
For example, two toxic chemicals produced by the oral bacterium Porphyromonas gingivalis (implicated in periodontal disease) were detected in memory-related brain regions in over 96% of participants. Importantly, these toxic chemicals feed on human cells. In breast cancer, the oral bacterium Fusobacterium nucleatum has been implicated in promoting tumor growth and the spread of cancer cells. Many studies have also shown that the same bacteria are often found in colon cancer tissue.
In addition, it has long been believed that oral bacteria may have a significant impact on cardiovascular disease. The microbes leak into the bloodstream and take up residence in plaque in the heart, causing inflammation and increasing the likelihood of rupture and vessel blockage.
The oral microbiome has been linked to the development and progression of Crohn’s disease, but the exact pathways by which bacteria move from the oral cavity to the gut are not yet fully understood. And while much data is available from studies in mice, further research is needed to demonstrate this link in humans.
A better understanding of how oral bacteria are involved in Crohn’s disease and which bacterial species are involved will help to develop better diagnostic and therapeutic approaches, not only for Crohn’s disease but also for many other diseases.
Source: Crohn’s Disease: Scientists Say Bacteria in the Mouth May Be the Cause
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Crohn’s Disease: Scientists Say Bacteria in the Mouth May Be the Cause