IBD: Does Nurture Affect Nature?
Inflammatory Bowel Disease (IBD) is a general term which describes chronic inflammation of the digestive tract. IBD includes Ulcerative Colitis (UC) and Crohn’s disease. Inflammation leads to ulcers and damage to underlying tissue leading the common symptoms such as:
- Fever and fatigue
- Abdominal pain and cramping
- Blood in the stool
- Reduced appetite
- Unintended weight loss
The exact cause of IBD is a mystery. Over 200 genes have been linked to this condition with the primary result being a dysfunction of the immune system. Instead of protecting the body like it’s intended, the immune system turns on the intestine leading to inflammation and ulceration! Genetics, however only hold one piece of the puzzle.
Our genetic make-up (our nature) doesn’t completely explain the disease as we learn how our lifestyle (our nurture) impacts the disease. We are starting to better understand how our environment affects our genes. Studies have shown that IBD is primarily a disease of industrialized nations – rising steadily since the 19th century and stabilizing in the mid 20th century in both North America and Europe. What is alarming is the rapid increase in UC (Ulcerative Colitis) and Crohn’s disease in developing countries such as India and China as they move towards a more Western culture and diet. Further studies show that individuals who emigrate from areas with relatively low incidence of IBD to North America have a significantly higher risk of developing IBD particularly among first generation immigrants.
One theory regarding increased IBD in industrialized countries is known as Hygiene Theory. When I was younger, my brother and I would come in from a day of being outside in less than clean states. My parents never worried because they knew that “a little dirt doesn’t hurt”. Hygiene theory takes that old adage even further; it theorizes that lack of exposure to bacteria (in particular the kinds that infect the gut) may lead to an immune system that cannot handle a similar infection later in life. Decreased exposure to a bacterium called helicobacter pylori showed an increased incidence of IBD. Similarly, observational studies have found a link between living in more densely populated areas (urban) vs less dense areas (rural).
Other environmental factors also have an impact on the development of IBD. Smoking has a strange effect on IBD. Researchers have repeatedly found that active smokers demonstrated a lower risk of developing UC. Now before you decide you take up a habit that is extremely difficult to break, in addition to all the other bad effects of smoking, I should also point out that smoking is possibly the single most important risk factor for developing Crohn’s. (You win some, you lose some! However, if you’ve ever read my previous articles, you’ll know that smoking is pretty much a risk factor for everything bad in the world!)
Exposure to antibiotics and anti-inflammatory drugs early in life also may increase the risk of IBD. Antibiotics are thought to interfere with the body’s natural response to gut bacteria. Anti-inflammatory drugs can damage the lining of the intestines and affect the normal immune response.
It should be pointed out that although our environment has an impact on the development of IBD, there is no one clear cause. Please don’t refuse to treat your children’s infection or their fever because of the increased risk. Nor should anyone feel guilt or pressure that something they did lead to IBD. It’s a complicated genetic disease influenced by environmental factors that we are only starting to understand. Take care of yourselves and each other.