The latest video from Dr. Greger at NutritionFacts.org:

Check here for the transcript:
Is Nutritional Yeast Healthy For Everyone?

It appears that baker’s yeast, which is the same yeast as brewer’s yeast and nutritional yeast, may indeed have disease-causing importance in Crohn’s disease.
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The bottom line is that people with Crohn’s disease should not go out of their way to add baker’s, brewer’s, or nutritional yeast to their diet.