DrOver the past 60 years, experts have documented a sharp rise in the incidence of both ulcerative colitis and Crohn’s disease — the two medical conditions that make up most cases of inflammatory bowel disease (IBD). For decades, this rise was confined to North America, Western Europe, and other industrialized nations. While there is some evidence that the rise in IBD has slowed or even stabilized in those places, IBD is becoming increasingly common in the newly industrialized countries of Asia and other parts of the world.
There is no doubt that genetic factors play a role in a person’s risk of developing IBD – particularly Crohn’s disease. But the increases in the incidence of IBD and the clear geographic patterns of the disease strongly suggest that environmental factors also play a role. “After World War II, we saw a rapid rise in the incidence of IBD throughout the developed world,” says Dr. Gilad Kaplan, a professor and gastroenterologist at the University of Calgary in Canada. “It seems that something about the Western lifestyle is allowing this disease to thrive.” What is this thing? This is the unsolved puzzle.
There are many theories – or rather, suspects. Researchers found associations between IBD and air pollutionfood additives, early exposure to antibiotics, and other environmental variables. Kaplan says that many of these risk factors, not just one, likely underpin the increases in IBD. And they all have one thing in common: the gut microbiome. “Most people feel that the driver of the inflammatory response we see, as the body’s immune system attacks the gut, lies in the gut microbiome,” he says.
Your digestive system is filled with billions of microorganisms that are essential to the health and functioning of your gut. These bacteria help digest the foods you eat, and the metabolites they produce help regulate your immune system. Kaplan says that a strong file and Diverse microbiome It is the hallmark of a healthy digestive system, whereas anything that disrupts or upsets the microbiome is associated with digestive malfunctions, including inflammatory bowel disease. “A lot of the widely studied environmental risk factors are now being looked at through the lens of the microbiome,” he says. This new perspective offers important insights, including some related to the treatment of IBD.
Here you will find a summary of the environmental risk factors experienced by researchers Associated with IBDIn addition to expert guidance on reducing these risks.
Air pollution and inflammatory bowel disease
In a first-of-its-kind study published in 2010, researchers examined the relationship between ambient air pollution and IBD. They found that young adults who grew up around high concentrations of nitrogen dioxide were more than twice as likely to grow as other children. Crohn’s disease.
Since that groundbreaking study, more work has linked air pollution to higher rates of IBD. “We have found that early exposure to both nitrogen dioxide and ozone is associated with an increased risk,” says Eric Lavin, chief epidemiologist at Health Canada (the Canadian government equivalent of the US Department of Health and Human Services).
Both of these pollutants are associated with vehicular traffic. Fuel-powered cars and trucks emit nitrogen dioxide in their exhaust. When nitrogen dioxide mixes with heat and sunlight, it undergoes a chemical reaction that produces ozone. “In areas where there is a lot of traffic, we may see elevated levels of this group,” Lavigne says. “Living near those areas may be a risk factor for IBD.”
How can air pollution affect gut health? Research has shown that after pollutants are inhaled, the lungs may actually push these pollutants into the throat until they are swallowed. This process is known as ciliary mucosal removal. Once in the gut, Lavigne says, these contaminants may cause harm to the gut microbiome in ways that promote inflammation.
Based on his own work and that of others, he says exposure to air pollution during childhood — not in utero or in adulthood — appears to pose the greatest IBD risk. Staying away from heavily congested roads, especially on hot sunny days, is one way to avoid these risks. “Levels of these pollutants are highest within 50 meters” — about 160 feet — “of busy roads,” he says.
Lavigne also studied the impact of parks and other urban green spaces on air pollution risks. His research found that children who grew up near green spaces were less likely to develop IBD. “Tree leaves may trap particles in the air, so having more trees and green environments may actually create a barrier that reduces people’s exposure,” he explains.
Food choices and dietary exposures
The things you ingest can affect the composition of your microbiome, and in turn, the health of your gut. Researchers have identified a number of them Diet-related variables Which appears to play a role in IBD risk.
Some of the strongest actions involve the first foods a newborn eats. “Breastfeeding seems to be very important,” Kaplan says. Research has shown that breastfed babies, unlike formula, are more than 25% less likely to develop inflammatory bowel disease. “As a baby, when you have breast milk, there seem to be tangible benefits that support the development of a strong and diverse microbiome,” he explains.
After childhood, there is evidence that consumption sugary drinks– Especially soft drinks – increase a person’s risk of developing ulcerative colitis. The more a person consumes soft drinks, the higher his risk. On the other hand, eating vegetables is associated with lower rates of ulcerative colitis, while eating whole fruits or foods rich in fiber appears to reduce a person’s risk of Crohn’s disease.
“There is also some really interesting research on preservatives that extend the shelf life of food,” Kaplan says. Study 2021 in the journal BMJ It found that high intakes of ultra-processed foods — soft drinks, as well as salty snack foods, processed meats, and other packaged goods — were associated with a sharp rise in IBD. Compared with people who ate less than one serving of these foods per day, those who ate five or more servings had roughly the same risk of developing IBD.
“Things like emulsifiers, additives, and heavily processed food particles can actually lead to changes in the microbiome that may be linked to IBD risk,” Kaplan says. “Choosing whole foods and staying away from processed or packaged things may reduce risk.”
Early hygiene and antibiotics
Antibiotics It can save lives when someone has a bacterial infection. But these drugs kill indiscriminately – meaning they kill both good and bad bacteria. There is evidence that when antibiotics are taken early in life while a child’s microbiome is still forming, the antibiotics may cause imbalances that promote IBD.
“Antibiotics can alter the composition of the human gut microbiota by reducing taxonomic richness and diversity,” the authors of a 2019 research review wrote in the journal. Gastrointestinal diseases. They note work linking widespread antibiotic use early in life – anything other than penicillin – to an increased risk of IBD by more than 50%.
“If you have a bacterial infection, you need antibiotics,” Kaplan says. But often, these medicines are prescribed when they are not really needed – for example, when a child has a respiratory infection that will likely resolve on its own without antibiotics. Doctors are increasingly aware of the risks posed by the overuse of antibiotics. But he says parents still need to be careful.
Meanwhile, while hygiene is usually considered a good thing—and not just a good thing but a safety measure that has saved countless lives—there is strong evidence that excessive hygiene, especially during infancy and childhood, may actually impair the gut microbiome. The “hygiene hypothesis,” as it is called, argues that children who interact with siblings, farm animals, pets, dirt and other sources of germs tend to have healthier and more resilient microbial ecosystems, and research has linked all of these factors to lower rates of IBD (as well as allergic reactions). and autoimmune diseases).
Early exposure to life [to germs] “It plays an important role in programming on the microbiome and the immune system,” says Dr. Emeran Mayer, founding director of the Microbiome Center at the University of California, Los Angeles. The theory is that when a developing microbiome encounters germs and bacteria, that exposure trains its sensitivity and reactivity in ways that reduce a person’s risk of IBD. Thus raising children in clean environments and regardless of children, animals or other germ sources can jeopardize their gut health as well as their immune competence. (Some experts have even speculated that COVID-19-specific safety measures, such as heavy use of hand sanitizers, may inadvertently lead to an increase in IBD among young adults.)
While researchers have made significant progress in studying environmental risk factors for IBD, they say the relationship between a person’s gut health and these variables is very complex. Kaplan notes that “the risks to a person may be very different when they are in the womb, in childhood, or in adulthood.” Cigarette smoking is an example. Smoking during adolescence, more so than in adulthood, may be a greater risk factor for bowel disorders. Or vice versa. A person’s risk may also depend on the amount they smoke, as well as their genetic predisposition to developing gastrointestinal disease. “There are many variables that create a lot of heterogeneity,” he says. “Saying that this is a risk factor and that is not very difficult.”
With this warning in mind, Kaplan says there are steps everyone can take to reduce their IBD risk. “Often these are things that promote healthy living in general,” he says. “Eating more whole foods, getting regular physical activity, and trying to reduce stress in your life are all on my go-to checklist with patients.” For those who live in parts of the country where there is little sunlight, he says taking a vitamin D supplement may be beneficial. “If you look at people with IBD, you often see a vitamin D deficiency,” he explains. This may just be a byproduct of the condition – not its cause. However, he says that taking a 1,000 IU supplement daily is a low-risk bulwark against gut issues that may be linked to a deficiency.
The role of external factors such as diet, medications and pollution in IBD is complex. But medical science is making great strides in looking at the effects of environmental factors. “The way the field has opened up is very revolutionary,” Mayer says.
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