[Music] baker’s yeast in Crohn’s disease can it kill you well that’s an inflammatory title no bun intended Crohn’s disease is an inflammatory bowel disease might baker’s yeast which is the same yeast as brewers yeast which is the same yeast as nutritional yeast play a role in crohn’s disease it all started with this study published in 1988 showing that people with crohn’s disease tend to have more antibodies to yeast than people without Crohn’s disease antibodies are like homing devices our immune system makes to attack foreign invaders that’s one part of our immune system another is cell mediated immunity where our white blood cells attack invaders directly and the same hypersensitive reaction to yeast was found in the white blood cells of Crohn’s disease patients as well if you draw blood from healthy people even bakers who were around yeast all the time and you exposed their peripheral blood leukocytes their immune system white blood cells to yeast nothing happens I just kind of ignore it because it’s typically harmless but do the same thing with Crohn’s disease patients and their white blood cells go crazy now when I say typically harmless if you have cancer or AIDS or immunocompromised you could potentially get infected from like home brewed beer or probiotic yeast supplements but they don’t think that yeast is actually infecting Crohn’s patients people with Crohn’s may just be hypersensitive to exposure to the inactive dead yeast in typical food products which may help explain why when you rest their bowels when you make Crohn’s patients fast they get better in fact that’s why we add yeast extracts and proteins to vaccines as an adjuvant an irritant like aluminum to make the vaccines work better by heightening the immune response but might that be raising the risk of autoimmune disease boosting our immune response a little too much especially in people who may be genetically susceptible like with Crohn’s in the greater the anti yeast response the more severe of the disease in both children and maybe adults too so maybe we should try a yeast-free diet for Crohn’s patients and see if they get better but wait a second just because anti yeast antibodies are associated with crohn’s disease doesn’t mean the reaction to yeast is causing the crohn’s disease maybe the Crohn’s disease is causing the reaction to yeast what think about it Crohn’s causes an inflamed leaky gut so maybe the Crohn’s came first allowing yeast particles to leak into the bloodstream resulting in the anti yeast reaction so instead of the yeast reaction triggering the Crohn’s maybe the Crohn’s just triggers the yeast reaction whether the antibodies are actually triggering inflammatory bowel disease or only consequences of gut inflammation remained elusive so how could we test it well if anti yeast antibodies are just a consequence of food particles leaking through the gut Crohn’s patients should have antibodies to all sorts of common foods but no higher anti yeast antibodies and Crohn’s disease compared to controls but no greater reaction in Crohn’s patients to milk wheat or egg proteins which would presumably all leak through – or you can look at it the other way instead of other foods what about other inflammatory bowel disorders ulcerative colitis or acute gastroenteritis there you could get inflamed and leaky – yet no increased yeast reaction so there does appear to be something unique about the yeast Crohn’s relationship but may be inflamed Crohn’s intestine just uniquely and selectively allow yeast through if you cut out the Crohn’s can you stop the yeast reaction Crohn’s get so bad that most patients have to eventually go under the knife and get sections of their intestines removed so when the inflamed segments are removed does the yeast reaction go away no no change post-op so a changing crohn’s activity does not lead to a change in the yeast reaction but we still have to prove that the yeast reaction comes first thankfully the Israeli military systematically draws blood from their recruits follows their health for years so you can go back and check the blood of newly diagnosed Crohn’s victims and indeed those who went on to have Crohn’s were years earlier disproportionately reacting to yeast so it’s not like yeast reactions were low until Crohn’s hit and then they shot up yeast reactivity crept up year after year before the diagnosis now look it’s possible that there were some subclinical gut leakiness in the years preceding diagnosis that led to the yeast reaction but there doesn’t appear to be any association between yeast reactivity and gut leakiness so do high blood levels of anti yeast antibodies results from a leakiness of the gut barrier and crohn’s disease no that does not appear to be the case so if Crohn’s isn’t leading to the yeast reaction does that mean that the yeast reaction is leading to the Crohn’s anytime you have two things that appear to be associated in this case reacting to yeast and Crohn’s disease they both can appear tied together because X causes Y or because Y causes X well in this case it appears that Y does not cause X but does that mean that X causes Y well there’s another option maybe there’s a third factor that causes both of them independently maybe the only recent yeast reactivity and Crohn’s disease appear to go together is that there’s a third factor causing them both like for instance Candida which I’ll cover next [Music] you