Last Updated on June 16, 2023 by Steven Root

Ulcerative colitis is a complex disease with an equally intricate web of causative factors. While genetics plays a role, environmental influences paint a large part of the picture. This article delves into how these environmental aspects contribute to ulcerative colitis causes.

The Whirlwind Called Ulcerative Colitis

Ulcerative colitis is an inflammatory bowel disease (IBD) that primarily affects the colon and rectum. It is characterized by the inflammation of the colon’s lining and the formation of ulcers. These ulcers can produce pus and bleed, leading to persistent discomfort and other symptoms such as diarrhea, abdominal pain, and fatigue.

In addition to the physical symptoms, ulcerative colitis can also have a psychological impact on those affected. Anxiety and depression rates are higher among IBD patients. It is important to consider this dimension as well, since mental health can affect the course of the disease and vice versa.

What causes ulcerative colitis is not completely understood. There is a consensus that genetics and immune system malfunction play a role, but there are also numerous environmental factors. Understanding these environmental contributors is crucial, as they may offer give clues as to the most appropriate treatment options.

Air Pollution: A Sinister Agent?

Air pollution has long been known for its detrimental effects on respiratory health, but recent research suggests that it may also contribute to diseases like ulcerative colitis. Among the pollutants, sulphur dioxide (SO2) seems to have a pronounced effect. An article published in Current Gastroenterology Reports revealed that individuals exposed to higher levels of SO2 were more likely to develop ulcerative colitis.

Fine particulate matter, another component of air pollution, has also been implicated. These pollutants can be ingested or inhaled, and can then reach the intestines. Once there, they may trigger an inflammatory response. With the rapid urbanization and increase in air pollution globally, it is extremely logical and even likely that these pollutants comprise some of the causative factors of inflammatory bowel disease.

Reducing exposure to air pollutants can be difficult, especially in urban areas. However, advocating for cleaner public transportation, supporting policies aimed at reducing emissions, and even using air purifiers indoors can be steps towards reducing exposure.

Food Additives: A Double-Edged Sword

Food additives, omnipresent in processed foods, are substances added to food to enhance flavor, texture, or shelf life. While they make food more palatable and convenient, there are concerns about their impact on gut health. Emulsifiers, for instance, are under scrutiny for their role in altering gut microbiota and promoting inflammation.

Artificial sweeteners, another common food additive, have been found to have adverse effects on the gut microbiota. Some studies suggest that they may increase the risk of developing IBD. Cutting back on processed foods and choosing natural alternatives can be beneficial.

Moreover, the increased use of genetically modified organisms (GMOs) and the pesticides associated with them may also play a role in the development of ulcerative colitis. A diet focusing on whole, unprocessed foods, and limiting the intake of artificial additives may be beneficial in reducing the risk of developing this condition.

The Role of Diet

Diet is intricately linked with gut health. What we consume can alter the composition of the gut microbiota. There’s growing evidence that the typical Western diet plays a role in the development of IBD, including ulcerative colitis.

The amount of high sugar, processed food in the Western diet is of particular concern. These high sugar, processed foods can lead to an imbalanced gut microbiota, known as dysbiosis. Dysbiosis is a known factor in the development of ulcerative colitis.

Focusing on whole foods improves the health of the gut microbiota. This, in turn, can fortify the gut’s defense against inflammation and reduce the risk of developing ulcerative colitis.

For help in building a whole foods diet that will help to keep symptoms away, enquire here.

The Curious Case of Smoking

It’s common knowledge that smoking has numerous adverse health effects, however, when it comes to ulcerative colitis, the relationship is more complex. Interestingly, multiple studies have shown that smokers are less likely to develop ulcerative colitis compared to non-smokers.

The main component of tobacco smoke, nicotine, is thought to be behind this protective effect. It is believed that nicotine may have anti-inflammatory properties in the context of the colon. However, this is not a license to smoke, as the general harmful effects of smoking far outweigh any potential benefits.

Nicotine and similar compounds should be studied further as potential therapeutic agents, in a controlled and safe manner, for people suffering from ulcerative colitis.

The Role of Drugs: More than Antibiotics

Drugs are essential for treating various ailments but they can also have unintended consequences. One of the environmental factors contributing to ulcerative colitis causes is exposure to certain drugs, particularly antibiotics and isotretinoin (Roaccutane).

Antibiotics are a double-edged sword. While effective against bacterial infections, they can also disrupt the delicate balance of the gut microbiome. This is particularly concerning when antibiotics are overused or used inappropriately. This study found that people exposed to antibiotics were more likely to develop ulcerative colitis later in life.

Isotretinoin, a medication used for severe acne, has also been linked to IBD (source). While the exact mechanisms are not well understood, it is important for patients and healthcare providers to be aware of the risks and monitor for symptoms of IBD during isotretinoin therapy.

Stress: The Silent Contributor

Stress is a part of life, but chronic stress can have far-reaching effects on health, including the health of the gut. There’s a growing body of evidence linking stress to the exacerbation of symptoms in people with ulcerative colitis, and perhaps even be causative of the condition.

The gut and brain are connected through the gut-brain axis, and stress can disrupt this communication highway. This can lead to alterations in gut motility, increase in gut permeability, and changes in the microbiota, all of which are increasingly becoming known to lead to the development of ulcerative colitis and the worsening of its symptoms.

Managing stress through lifestyle changes, such as incorporating exercise, practicing mindfulness, or seeking counseling, can be beneficial not only for general wellbeing but also for maintaining gut health.

Hygiene Hypothesis: Too Clean for Comfort?

The hygiene hypothesis proposes that living in an environment that is too clean can suppress the development of the immune system in childhood. This hypothesis suggests that a lack of exposure to microbes early in life could be one of the major ulcerative colitis causes.

Support for this hypothesis comes from studies showing higher rates of IBD in developed countries compared to developing ones. It is thought that in developed countries, early life exposure to a diverse array of microbes is lacking, leading to an immune system that may overreact to harmless stimuli.

Balancing hygiene practices to reduce the risk of infection, while also allowing for the immune system to be in essence ‘educated’ by microbes, especially in early life, could be key in preventing autoimmune diseases such as ulcerative colitis.


In summary:

  • Ulcerative colitis is an inflammatory bowel disease with both genetic and environmental causes.
  • Exposure to air pollution, including SO2 and particulate matter, may contribute to the development of ulcerative colitis.
  • Food additives, prevalent in processed foods, may also promote inflammation and alter gut microbiota.
  • A diet high in processed, sugary foods is linked with an increased risk of ulcerative colitis.
  • Smoking has been found to have a protective effect against ulcerative colitis, likely due to nicotine. However it is still not advised to smoke.
  • Certain drugs, including antibiotics and isotretinoin, can increase the risk of developing ulcerative colitis.
  • Chronic stress can exacerbate the symptoms of ulcerative colitis through the gut-brain axis.
  • The hygiene hypothesis proposes that lack of microbial exposure in early life can contribute to the development of ulcerative colitis.