Ultra-processed foods and IBD

Even more research showing that less-processed foods are better for your gut

We know that ultra-processed foods, sometimes known as “junk,” “fast,” or “convenience” foods, are not exactly healthy foods. Consuming too much can increase your risks for cancer and heart disease, etc. A new study shows that you can add inflammatory bowel disease to that list, too.

Inflammatory bowel disease (IBD) is a chronic inflammation of the intestines (the lower part of your gut. IBD includes Crohn’s disease and ulcerative colitis. Estimates show that over 3 million Americans (1.3% of the population) have IBD.

More and more research shows how much your food choices impact your gut health. There is a big link between what you eat and the health of your gut. One reason why is that a big part of your immune system lives in and around your digestive system. 

IBD is thought to happen in people who seem to be genetically susceptible when their immune systems get activated and cause inflammation in their gut. 

A 2021 study published in the British Medical Journal looked deeper into these links between the foods people eat and their risk for IBD. The researchers found that the more ultra-processed foods people ate, the more likely they were to get diagnosed with IBD over time. Their definition of ultra-processed foods included packaged foods and beverages such as processed meat, cold cereal, sauces, soft drinks, candy, chocolate, puddings, potato chips, ice cream, pastries, cookies, and fruit drinks.

This was a “prospective cohort study” which is a fairly strong study design. This means that people were contacted several times over about 10 years. They were periodically asked what they ate and if they were diagnosed with IBD. In this particular study, there were 116,087 adults aged 35-70 years old across 21 countries. Each participant completed a questionnaire at least once every three years.

The results showed that eating five or more servings of ultra-processed foods each day almost doubled the risk of eventually getting diagnosed with IBD compared to someone who eats no more than one serving per day. That’s right, the more junk foods you eat, the more likely you are to get digestive problems.

The researchers wanted to look even deeper to see if age played a role. They split their results into two groups: those under 50 years old and those over 50 years old. They did not find a significant difference between the age groups. This shows that regardless of age, the more ultra-processed food consumed the higher the risk of IBD. 

“Our findings support the hypothesis that intake of ultra-processed foods could be an environmental factor that increases the risk of IBD,” said the study authors.

This study didn’t discern what exactly it was about ultra-processed foods that increased the risk of IBD. Was it a specific process or ingredient? More research is needed to sort that out. The effect of high levels of ultra-processed foods on the gut over time may be partly due to the food’s impact on the friendly gut microbes that live there. Regardless of the particular reasons why, the link is clear: The more ultra-processed foods that you consume—regardless of your age—the higher your risk for eventually being diagnosed with IBD.

How to reduce your intake of ultra-processed/junk/fast/convenience foods?

Try reducing the number of servings of ultra-processed foods you eat each day—especially if you’re at risk of IBD. For example, you can swap in some minimally-processed foods such as:

  • Instead of soda pop or fruit drinks, try diluting real juice or adding fruit to your water
  • Instead of sugary desserts and refined sweetened food, try fruit.
  • Instead of packaged cold cereal, try homemade oatmeal or chia pudding.

Backgrounder articles:

About the study:

  • This study shows that the more ultra-processed foods that are consumed, the higher the risk of eventually being diagnosed with IBD, regardless of age. It does not show that ultra-processed foods “cause” IBD, but rather that these foods are probably one factor that can increase IBD risk in those who seem to be genetically susceptible. 
  • How is it possible that ultra-processed foods can increase risk for IBD? The hypothetical link is via their interaction with gut microbes and the immune system, although more research is needed.
  • Note that all studies have limitations. That’s why it’s important to look at multiple studies, giving more weight to the ones that have a better design to answer the questions being asked. This study did not note any specific types of ultra-processed foods or ingredients that may be riskier than others. An overall diet of more ultra-processed foods eaten per day (of any type of ultra-processed food) increases risk.
  • This particular study is a cohort study, so that’s a pretty strong observational study, but not quite as strong as a randomized control trial (which would be even better than observational because it would be experimental). 
  • This study has a lot of participants (116,087 adults aged 35-70 years old across 21 countries!) which partially makes up for the not-so-strong data captured for each one i.e., self-reported diagnoses and food intake (via food frequency questionnaires).
  • Study strength is rated a 5/7 according to this chart: https://www.compoundchem.com/2015/04/09/scientific-evidence/