Is Nutritional Yeast Healthy for Everyone?

Is Nutritional Yeast Healthy for Everyone?


“Is Nutritional Yeast
Healthy for Everyone?” Thousands of years ago, some yeast
floated down into our flour and drinks, and we were like hmm yummy, and
we’ve been regularly exposed ever since. Not a problem for most people, but even
non-disease causing microbes could potentially trigger autoimmune diseases like Crohn’s
disease in people who are susceptible, because their finely tuned
immune balance is somehow off. Maybe that’s why bakers have the
highest Crohn’s disease mortality, and from a different data set, among
the highest rates of Crohn’s disease. Perhaps a hypersensitivity to yeast may
be playing a role in Crohn’s disease. If you take people with Crohn’s and
remove from their diets the three foods to which they have the most antibodies
to try to calm the disease, and then you add those foods
back, you can provoke the symptoms back,
restimulate the inflammation. So, anal fistula off
those foods, nice and dry, but then starts oozing
again once the foods are back. But then, the spigot’s turned back
off once the foods are removed again, to which I say,
“Why is that doctor not wearing gloves?” Anyways, without
a control group, you can’t exclude the possibility
of a really powerful placebo effect, but there haven’t been any such
randomized controlled trials…until now. A brilliant design. They tested people with Crohn’s for
antibodies to 16 different foods and then randomized the
people in two groups. Both groups were told
to avoid 4 foods, but one group was told to avoid
the 4 groups they most reacted to, and the other group told to avoid
the foods they least reacted to. But, it was all done
with sealed envelopes; so, no one knew who was
in which group until the end. So, did it matter? Yes, more than twice the probability
of major clinical improvement in the group that were told to stay away
from the things their blood reacted to. But, this wasn’t
just yeast. In fact, it was the exclusion
of milk, pork, beef, and egg that was most strongly associated
with clinical improvement, leading the researchers to suggest that maybe
instead of doing all the fancy blood tests, we should just tell our patients to cut
out meat and eggs and see how they do, which would be consistent with both
population studies that associate animal fat with an increased risk of inflammatory bowel
diseases; as well as interventional studies, showing that a plant-based
diet, in which you cut meat down to like one serving every
two weeks, can drop relapse rates as low as an extraordinary
8% over two years. Okay, but, what about the
whole yeast question? Can’t you just… stick some yeast up
someone’s butt and see what happens? Why yes, yes you can. They tested rectal exposure
to 6 different foods in Crohn’s disease
patients—including yeast. Kind of like a skin prick test,
but instead of pricking the skin, they pricked the inside of
people’s rectums with various foods. And, you can see in this example,
the various prick sites: cabbage, milk, citrus, cereal,
peanut, but whoa yeast. Yeast gave the most significant
reaction in Crohn’s patients. So, 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, but the good news would then be, hey,
it may have therapeutic relevance. Maybe if you put Crohn’s patients
on yeast-free diets, they’d feel better. You don’t know, though,
until you put it to the test. In fact, that’s exactly
what the original study linking yeast and Crohn’s
disease suggested back in 1988. A controlled trial
of a yeast-free diet for Crohn’s disease patients
may be worthwhile. So why did it take years before
such a study was done? Who’s going to fund
it, Big Soda-Bread? Thankfully, there
are charities, like the National Association
for Colitis and Crohn’s disease, willing to put up the dough,
the yeast-free dough, that is. 19 patients with Crohn’s
disease ate their regular diet and then switched to a
yeast-exclusion diet. And, there was a significantly higher
CDAI, Crohn’s disease activity index, which is symptoms like
abdominal pain and diarrhea during the period when they were eating yeast,
compared to the yeast-free period. So worse disease activity
with yeast than without. Yeah, but what was
this yeast-free diet? They didn’t just cut
out bread and beer; they switched people from dairy milk
to soy milk, from white flour to whole wheat. Just cutting out milk can sometimes
help with inflammatory bowel disease. So, with so many dietary changes, how
do we know what role the yeast played? This is how we know what
role the yeast played. After placing them on
the new yeast-free diet, they then challenged them with
a placebo or a capsule of yeast. A tiny amount of yeast, like giving them a
quarter teaspoon of nutritional yeast a day, and that made
them worse, suggesting yeast may indeed be important
in the disease process of Crohn’s disease. Now, for the vast majority of
people, yeast is not a problem, but in susceptible individuals, it may trigger
an abnormal immune response in the gut. But wait, I thought it was
the paratuberculosis bug that was considered a trigger
for Crohn’s disease? Well, hey, maybe infection
with paraTB is what induces the hypersensitivity
response to dietary yeast. Who knows? 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.