Processed foods and inflammatory bowel disease (IBD)

When you have inflammatory bowel disease (IBD) knowing what foods and drink affect your symptoms can be a bit of a minefield.

Some people with IBD have reported that some processed foods can cause a negative effect on their symptoms. Here we take a look at some of the reasons why that may be to help you make your own decision about whether processed foods may be having an effect on your symptoms.

What are processed foods?

A processed food is any food that has been altered from its natural state. Common examples of processed foods include:

  • Bread
  • Breakfast cereals
  • Cheese
  • Convenience foods (eg microwave meals)
  • Canned fruit and vegetables

Some foods may have been processed simply by being pre-chopped, frozen, baked or dried (mechanically processed) while others may have had other ingredients - such as salt, sugar, additives and preservatives - added to them when they were processed (chemically processed).

Processed foods often get a bad press but it’s important to understand that not all foods that have been processed are necessarily bad for you - for example a packet of vegetables which has been pre-chopped is not bad (unless they’ve had a load of preservatives added to them). But, a ready-meal packed full of salt, sugar and other additives is not so good.

To find out more about the food you are eating you should read any food labels and look at the list of ingredients on the back. By doing this you can quickly tell if a food has just been mechanically processed (such as chopped or ground) or chemically processed (by adding other ingredients). Of course, the best way to ensure you aren’t eating processed foods is by buying only fresh ingredients in their original form - but that’s not always possible (and not always convenient).


How do processed foods affect the body?

Chemically processed foods can affect the body in a number of ways depending on what has been added to it during processing:

  • Sugar - sugar is often added to bread, pasta sauces and other surprising foods. There are a number of processes that take place when our body eats sugar and too much sugar can lead to a number of problems and diseases
  • Additives are often added which make the food so appealing to our brains that we want to eat more. This can lead to obesity and food addiction, both of which have serious health consequences
  • Artificial ingredients - preservatives, colourants, flavouring, texturants. These are all chemicals that have been created to do a certain job in food (such as adding colour, flavour or texture). There have been many health concerns raised about different types of chemicals added to our processed foods
  • Refined carbohydrates. Refined carbohydrates contain empty calories and don’t provide the nutrients needed by the body
  • Added fats such as trans fat and processed vegetable oils. Eating these types of fats can stimulate inflammatory processes in your body and have also been linked to health problems such as heart disease and artery disease.
  • Salt (sodium) - too much salt can raise your blood pressure which can put you at risk of problems such as heart disease and stroke

Processed foods and IBD

A few studies have been done which relate to IBD and chemicals which are added to processed foods.

A study on mice published in 2015 found that emulsifiers, which are found in a lot of processed foods, can increase the risk of developing IBD1. Emulsifiers are molecules which are added to oil-water mixtures to bind them together - such as in mayonnaise and ice cream. Many foods contain emulsifiers - which can be natural such as lecithin, honey and mustard or synthetic emulsifiers like Alkoxykated Amides, Palmitate, Oleate and PEG compounds.

Research in 2016 concluded that industrial food additives are playing a role in the increase in autoimmune diseases, such as IBD2. The study lists additives such as glucose, salt, emulsifiers, organic solvents, gluten, microbial transglutaminase, and nanoparticles as playing a role.

Many processed foods are also low in nutrients - which if you have malnutrition or nutritional deficiencies as a result of your IBD then processed foods will not help you to resolve this problem.

When foods are highly processed other foods or chemicals are often added which can be ‘trigger’ foods for IBD symptoms for some people - such as sugar, gluten and dairy containing substances.


  1. Chassaing B, Koren O, Goodrich JK, Poole AC, Srinivasan S, Ley RE, Gewirtz AT. Dietary emulsifiers impact the mouse gut microbiota promoting colitis and metabolic syndrome. Nature. 2015 Mar 5;519(7541):92-6. doi: 10.1038/nature14232. Epub 2015 Feb 25. PMID: 25731162
  2. Lerner A, Matthias T. Changes in intestinal tight junction permeability associated with industrial food additives explain the rising incidence of autoimmune disease. Autoimmun Rev. 2015 Jun;14(6):479-89. doi: 10.1016/j.autrev.2015.01.009. Epub 2015 Feb 9. PMID: 25676324


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