Effect of a Plant-Based or Vegan Diet On Ulcerative Colitis


A vegan diet is a well known tool against autoimmune diseases because it generally lowers inflammation.

Since ulcerative colitis is an inflammatory bowel disease (IBD), it’s a reasonable thought that perhaps a vegan diet can help manage the symptoms of it as well.

While there’s not much published research on this specific topic, I did find some research that I’ll summarize for you here.

The Effect of a Plant-Based Diet on Ulcerative Colitis

As far as I’m aware, this is the only study published so far that looks at the effect of a plant-based (semi vegetarian diet, not vegan) on ulcerative colitis.

While that’s not exactly what we’re looking for, it still may provide some insights.

They provided patients with a mostly lacto-ovo vegetarian diet while in the hospital, and educated them on how to follow a similar diet outside the hospital.

There were a few big findings.

First, by the time most of the patients left the hospital, they had already seen significant improvements in symptoms.

ulcerative colitis improvements

In total, 77% of patients had some sort of improvement, shown in the graph above.

On top of that, there were lasting effects that suggest treating ulcerative colitis patients with dietary education is more effective than just traditional medication (obviously this should be done with physician supervision):

Relapse rates after educational hospitalization providing a PBD were far lower than those reported with medication. Educational hospitalization is effective at inducing habitual dietary changes.

They followed up on a yearly basis and had relapse rates far better than expected, at just 2%, 4%, 7%, 19%, and 19%, respectively.

What can we take from this?

Well, there are some obvious limitations. It’s a single study with largely self-reported data, so you can’t make too many definitive conclusions.


While more research is needed, it does appear that a plant-based diet is effective at managing ulcerative colitis for most chronic sufferers.

Will a Vegan Diet Help Ulcerative Colitis?

The plant-based diet in this study we looked at above included fish and even meat occasionally.

We can guess that a vegan diet would be even more effective, but until that’s actually studied, we have no evidence behind it.

Unfortunately there’s not much more we can say. I’ll update this page if and when more research on vegan diets and ulcerative colitis come out.


Without more research, it’s impossible to say if a vegan diet would be more or less effective than a plant-based (vegetarian) diet for ulcerative colitis.

Other Research on Plant-Based Diets and IBD

There’s one other research paper published in 2018 that looks at why a plant-based diet is a good recommendation for most cases of IBD (particularly ulcerative colitis and Crohn’s disease).

The main argument is as follows:

  • While there’s a lot to learn about IBD still, it appears to be triggered worldwide by environmental factors (i.e. factors like diet, not genetics).
  • In particular, current research suggests that IBD is a result of mucosal inflammation that forms as a response to certain gut microbiota (that are formed from a typical “Western” diet).
  • Plant-based diets help improve the diversity of gut microbiota, and reduce inflammation, thereby helping to achieve remission of IBS symptoms in most patients.

While the outcomes look very promising, there’s a lot of research to be done still to discover exactly why a plant-based diet is effective and to have more confidence in this conclusion.

The graph below compares remission rates of Crohn’s disease after being treated with different diets and medications.

plant based diets and crohn's disease remission

The first column is a combination of a plant-based diet and infliximab (medication), which achieved an amazing 96% remission rate.


There’s some evidence that a plant-based diet combined with medication can treat other diseases related to ulcerative colitis like IBD.

About the author

Dale Cudmore

Your friendly neighborhood vegan from Toronto. Chemical engineer turned semi-professional soccer player and freelance nutrition writer. I've been vegan for years and try to make life easier for others by sharing what I've learned.