A massive study of 116,000 adults followed for ~10 years found a clear link between ultra-processed food intake and IBD risk. Interestingly, the study wasn’t designed for IBD but for heart disease, which is why it only tracked adults 35–70. Still, it’s one of the strongest datasets we have.

They found no risk from unprocessed foods like meat, dairy, starches, fruit, veg, and legumes — suggesting it’s not the food itself, butthe way it’s processed. (Note: everyone's gut is unique, what works here might be different for you)

If there is one thing ive always thanked my IBD for - it taught me to check every ingredient. 

If you aren’t already avoiding these (you probably are), but for our new IBD friends, STOP eating these. 

Processed meats
e.g. sausages, bacon, deli meats, hot dogs

• ≥1 serving/day doubled IBD risk
  
  

Soft drinks (regular & diet)

• ≥3 servings/week almost doubled risk

Refined sweetened foods
e.g. cakes, cookies, pastries, candy, chocolate, puddings, jam/jelly

• ≥100g/day more than doubled risk
  

Salty snacks
e.g. crisps, crackers, popcorn, nachos

• ≥100g/day doubled risk

Fried foods
e.g. French fries, fried chicken, nuggets

• ≥1 serving/day tripled IBD risk

Emulsifiers & Stabilizers to avoid:

• Carboxymethylcellulose (CMC, E466)
  → Shown to thin the protective mucus layer, increase bacterial adherence to the gut wall, and trigger inflammation in animal models.
  
  

• Polysorbate-80 (E433)
  → Increases gut permeability and bacterial translocation, especially in Crohn’s patients.
  
  

• Carrageenan (E407)
  → Common in plant milks, deli meats, desserts. Linked to inflammation in lab models.
  
  

Artificial Sweeteners

• Aspartame (E951), Sucralose (E955), Saccharin (E954)
  → Alter the gut microbiome; some evidence of worsening glucose tolerance and inflammation.
  
  

• Acesulfame K (E950)
  → Also disrupts gut bacteria in preclinical studies.

Artificial Colours

• Titanium dioxide (E171)
  → Used as a whitening agent in candies, sauces, chewing gum. Can penetrate intestinal cells, promoting oxidative stress and inflammation.

Other Additives of Concern

• Maltodextrin
  → Often added to processed foods as a filler or thickener. Promotes adhesion of harmful bacteria like E. coli in the gut.
  
  

• Sodium benzoate (E211) & Potassium sorbate (E202)
  → Preservatives that can alter gut bacteria balance.
  
  

• Monosodium glutamate (MSG, E621)
  → While not universally harmful, some research suggests it may alter gut permeability and promote inflammation in sensitive individuals.
  
  

IBD teaches you to listen to your gut. It doesn’t want these ingredients.

This doesn’t mean you need to eat ‘perfectly,’ but being mindful of processed foods and additives could help lower risk of flare-ups. IBD is personal — what affects one person may not affect another — but the science is clear: processing matters.

Sources:

https://pmc.ncbi.nlm.nih.gov/articles/PMC8279036 

https://microbiomejournal.biomedcentral.com/articles/10.1186/s40168-020-00996-6

https://pmc.ncbi.nlm.nih.gov/articles/PMC4910713

https://pubmed.ncbi.nlm.nih.gov/34774538/

https://www.nature.com/articles/s42003-024-06224-3

[1] Narula N, Wong ECL, Dehghan M, Mente A, Rangarajan S, Lanas F, Lopez-Jaramillo P, Rohatgi P, Lakshmi PVM, Varma RP, Orlandini A, Avezum A, Wielgosz A, Poirier P, Almadi MA, Altuntas Y, Ng KK, Chifamba J, Yeates K, Puoane T, Khatib R, Yusuf R, Boström KB, Zatonska K, Iqbal R, Weida L, Yibing Z, Sidong L, Dans A, Yusufali A, Mohammadifard N, Marshall JK, Moayyedi P, Reinisch W, Yusuf S. Association of ultra-processed food intake with risk of inflammatory bowel disease: prospective cohort study. BMJ. 2021 Jul 14;374:n1554. doi: 10.1136/bmj.n1554. PMID: 34261638; PMCID: PMC8279036.