If you have read Elaine Gottshall’s Breaking the vicious Cycle you have undoubtedly read the Legal / Illegal Food list like it was your own personal bible. Elaine has changed the prognosis for thousands of people out in the world suffering from various irritable bowel diseases. However, as science evolves, food changes and gaps are highlighted so too must we evolve in our understanding. As an immunologist, it is my job to understand how various factors can impact our immune system and affect disease pathogenesis. Today I want to focus one item that has not made it on to Elaine’s list and has been of subject to much debate and controversy, nutritional yeast.
If you refer to the legal/illegal list you will immediately find baker’s yeast listed as illegal with the description “Saccharamyces cerevisae is baker’s yeast and is illegal”. This is true, active yeast or bakers yeast, which allow breads to rise and beer to brew can cause severe upset in many people with an IBD (irritable bowel disease). In fact antibodies against Saccharamyces cerevisae, have been found in 60-70% of patients with Crohn’s disease and 10-15% of patients with ulcerative colitis1. This meaning, the body has identified these strains of yeast as bad and is trying to attack and kill them.
Deactivated yeast or nutritional yeast, is essentially a dead version of the same strain of Saccharamyces cerevisae, it can not replicate, come back to life or feed existing bacteria, it’s dead. Commercially, the yeast is grown on a sugar medium (glucose) and once it reaches a sufficient mass, heat is used to kill or deactivate the yeast (it can’t grow) it is then washed, dried and sold. The end product has no sugar, no gluten, no active yeast and no dairy. It therefore meets all the requirements of the specific carbohydrate diet. Further to this, nutritional or inactive yeasts contain a great source of Vitamin B12, protein, various B-vitamins, selenium, folic acid, zinc while also being low-cal, low-fat and low-carb. So what is with all the fuss?
As a scientist, I don’t think nutritional yeast should be incorporated into the diet during the initial stages of the SCD, GAPS, Paleo or any elimination diet. Wait until you have found a happy medium in your diet and slowly try it out with your body. Commercially bought kale chips and vegan products with a cheese flavor typically contain varying levels of nutritional yeast and it can be found at most bulk food stores for about $2 Canadian for 100 grams. Scientifically, there is no indication that this form of yeast would complicate or irate the digestive system, with that being said, however, it is always good to err on the side of caution and proceed slowly with any new food in your diet. I have started to use nutritional yeast with my SCD diet and found no complications so far and look forward to all the creations I can now create.
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1. Walker, L.J., Aldhous,M.C, Drummond, .E., Smith, B.R.K., Nimmo, E.R., Arnott, I.D.R., Satsangi, J. 2004. Anti-saccharomyces cerevisiae antibodies in Crohn’s disease are sassociated with disease seerity but not NOD2/CARD15 mutations. Clin Exp Immunol. 135 (3) 490-496.