GastroChef – Grain Free Gastronomy

Grain/sugar/gluten-Free Living! (SCD/Paleo/GAPS friendly)

Nutritional Yeast – Safe or Dangerous?

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.

If you have any questions, concerns or experiences you want to share please comment below or on our Facebook page (link on sidebar) or post to our twitter @Gastro_Chef



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.


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  1. Hey!
    First off, I’m thrilled to have stumbled upon your website. Holy Amazing! And in Canada too – booyah . . (i’m in Peterborough) I’ve been gluten-free, dairy-free for years (due to food intolerances) and a year ago transitioned this to grain free.
    Earlier this fall I discovered nutritional yeast and thought I’d discovered a gold mine of possibilities, however let me share a bit of what I dug up after I started having some ‘side effects’ while trying it out in my cooking. From what I’ve found, nutritional Yeast has significant amounts of glutamate (as in Mono-Sodium Glutamate or MSG) in it. When people are allergic to MSG it’s generally the G, or glutamate, that they’re reacting to. While I’d done research to see what the nutritional impact of Nutritional Yeast would have on my diet (I’m a competitive athlete with strict diet, training, etc regimen) I hadn’t delved the layer deeper into possible reactions to NY until I started reacting similar to how I remember reacting to MSG. I didn’t put 2 and 2 together until I did some further reading and discovered the little tidbit I outlined above. So, FYI…if you have an MSG issue. Maybe I started adding it too much, I’m not sure. I’ve been chicken to try it again for fear of the same results (not pretty).
    Anyway, stoked to have found your blog.

    • OMG!!! the MSG is causing my grandson to react by not sleeping!!!! He is only two months old and he NEVER SLEEPS!!! I’ve been using the process of elimination in the Weston Price infant formula, and it has to be the Nutritional yeast. THANKS!!!!

  2. I’m not sure where you’re getting your info,
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  4. Really liked you article. I’ve been on SCD for almost 2 years now. Very strictly, and I am now just beginning to think outside the box. Just wondering if you could post where you got your information. If one thing SCD teaches is check out sources. So again thank you for your interesting article looking forward to reading your resources too.

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  6. “As a scientist” you should know that yeasts DOES NOT contain Vitamin B12, because yeasts can’t produce B12, only bacteria can do it.
    Yeast sold on the market is artificially fortified with B12. Not that this is a problem, just stating a fact.

  7. Thought you might find this article interesting found at y Kimberly

    The last — and perhaps scariest — critique of nutritional yeast is that it contains MSG-like compounds, and MSG is a well known excitotoxin that damages the brain.

    Therefore nutritional yeast damages your brain, right?


    Nutritional yeast is different than yeast additives, often referred to under strange names such as “autolyzed yeast extract” and others.

    Natural yeast, without additives, contains approximately 6 to 11% naturally occurring glutamic acid, one of the nonessential amino acids, since our bodies can produce it.

    Our bodies are meant to be able to handle a certain amount of this form of glutamate. It is in a bound form, which is naturally broken down into its free form so that it can enter the bloodstream and be released by the liver to be used by the brain.

    Glutamate receptors have more recently been located in many other parts of the body, including the lungs, the breasts, heart and joints. When naturally occurring glutamate is broken down as it should be, slowly and as nature intended, there shouldn’t be a problem, unless we are born without the ability to process glutamate correctly.

    The problem most likely lies in the fact, that today, we are bombarded with processed foods that contain several sources of free, i.e. processed glutamate, which is the harmful and excitotoxic component of MSG.

    It is harmful because it is a form that needs no digesting, allowing large amounts into the bloodstream immediately, and also because it contains other forms of free glutamate, such a pyroglutamic acid, and D- glutamic acid and carcinogens. Actually, our brains have many receptors for glutamic acid and some areas, such as the hypothalamus, do not have an impermeable blood-brain barrier, so free glutamic acid from food sources can get into the brain, injuring and sometimes killing neurons.

    So free glutamic acid is a real and legitimate concern — please know that I’m not dismissing that. In my research, however, nutritional yeast is not rich in this artificially added/produced form of free glutamic acid and is therefore not in this category. It is the many other forms of artificial “flavoring” and yeast extracts found in processed foods that we should be avoiding.

    • I read that article, too, but to me, saying “not rich in…” is subjective and vague. The testimony in the comments on this page from those who have had experience with clear, definable reactions to the glutamate in NY is evidence that the amount is significant. I wouldn’t make it part of my diet, but if you must, it’s probably a good idea to be sparing with it.

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  9. Just FYI, IBD is “inflammatory bowel disease”, not “irritable”. It was kind of hard to trust any of the other info after reading that…

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