Somewhat surprisingly, I receive quite a few emails about whether or not it is safe for those of us with celiac disease to consume fermented sourdough bread made with wheat flour.
Am I the only one who visualizes wheat and all other forms of gluten with a skull and cross bone?
Of course, I’m always happy to receive your questions, and in this case, especially so.
What caused you to ask these questions – and the likely reason you’re asking a scientist like me for the answer – is a bit of scientific research conducted by the University of Naples in the Department of Pediatrics and the European Laboratory for the Study of Food Induced Diseases.
It was published in 2011 in Clinical Gastroenterology and Hepatology, the official clinical practice journal of the American Gastroenterological Association.
The aim of the study was to evaluate the safety of consuming baked goods produced using a particular type of wheat flour for those with CD. (More on the flours used in a moment.).
Let’s take the study apart and examine it using real language so everyone is clear on what researchers did and what the outcomes were.
Then, you will be armed with information to allow you to make your own decision about whether or not you would consume a bread product like the one described.
The experiment lasted 60 days.
Thirteen individuals participated. Each was confirmed to have CD via blood antibody tests and a small intestine biopsy. Only participants with no antibodies to gluten and no intestinal damage were included in the study.
The participants had been on a gluten-free diet for at least five years prior to the study.
Participants were dived into three groups. Each group represented a different type of wheat flour based bread.
Daily, individuals consumed 200 grams (about 7 ounces) of the type bread assigned to their group.
Of the original 13, 11 participants completed the study. Only data collected on the 11 completing the study are included in the results.
The 3 Study Groups:
Note: When reading the amount of gluten in parts per million (ppm), keep in mind the acceptable “safe” amount of gluten proposed by the FDA for future US gluten-free labeling laws (if these ever come) is 20 ppm.
Group 1 – Fed regular bread made with regular wheat flour. The bread contained 80,127 ppm gluten.
This group started with 6 participants, but only 4 finished the study. Two exited the study due to illness (abdominal pain, diarrhea, bloating, etc.).
Group 2 – Fed bread made with extensively hydrolyzed wheat flour. The bread contained 2,480 ppm gluten.
Hydrolyzed is just a fancy way to say something is broken down into its smaller parts.
In the case of a protein like gluten, this means it is broken down into its most basic parts. For proteins, that means amino acids (these are the “building blocks” of all proteins).
The flour was hydrolyzed by fermentation using sourdough lactobacilli (similar to what we are familiar with as the “good” bacteria in yogurt and other fermented foods) and fungal proteases (I know that sounds kind of gross, but it’s a natural by-product of an organism breaking down protein, so no worries.).
(Now you see where sourdough bread enters the discussion. More on this in a moment.)
This group contained 2 participants.
Group 3 – Fed fully hydrolyzed bread containing 8 ppm residual gluten.
Bread that was further treated in the same manner as the bread in Group 2, which led to even fewer ppm gluten in the finished product.
This group contained 5 participants.
So, what happened when the Celiac patients ate the bread?
Group 1 – Well, you already know two of the 6 that started the study became so ill from gluten they were forced to drop out.
Everyone in this group, as well as in Group 2 suffered some degree of gluten toxicity, measured by follow-up antibody blood testing and small intestine biopsy.
(In other words, the same tests administered before the study to establish a base line were repeated after the study to determine level of gluten toxicity, if any. This was performed for all study participants.)
All those folks really could have used this article on what to do when you ingest gluten. ;)
Group 3 – These folks showed no signs of consuming gluten.
The scientists conducting the study were excited and hopeful about the findings for Group 3; however, they readily admit the need for larger and more long-term studies to confirm that fully hydrolyzed wheat flour bread like that used in the study is safe for those with CD.
- The study had too few participants to draw a valid conclusion that is applicable to the Celiac population at large.
(The point of a study is to have enough established validity to be able to apply findings to a population. This is why research is replicated many times before conclusions are drawn; thus the need for larger and more long-term studies in this area.)
- Tests to assess gluten damage, although currently the best available, do have the potential for false negative results, even when gluten toxicity exists.
In fact, some researchers and physicians argue a single small intestine tissue sample (from biopsy) is not enough to rule out CD in an individual with symptoms.
Some professionals recommend a minimum of 10 tissue samples from various areas of the intestine for CD diagnosis. (This is another topic we will cover in time. However, I did want to point out here that the single sample biopsy, often deemed the “gold standard” test for CD, is not necessarily 100% accurate all the time.)
- The study, and results from it, is an isolated case to be taken as an indicator future research in this area may be warranted. Unfortunately, when results like these trickle down to the media and the public, the facts tend to be diluted, or lost entirely.
In this case, what many extracted from the study was “Celiac patients can safely eat sourdough bread made with wheat, barley or rye flours”.
That is inaccurate, and potentially dangerous.
While I will not belabor the topic, I do believe a brief mention of sourdough bread is important for clarity.
What is Sourdough Bread?
Most bread labeled sourdough on the market today is not sourdough at all.
True sourdough bread contains no yeast. It uses a lactobacilli based starter culture.
(Note: I am not implying yeast contains gluten. You can learn; however, about the connection between yeast allergy and CD in this article if you’re interested.)
The art of creating true sourdough loaves fell out of favor over the centuries due to faster-paced lifestyles and a need for mass-produced goods (and the subsequent ability to create them).
In fact, records show as far back as the late 1600s, scientists were aware future gastrointestinal upset was on the horizon when baker’s yeast was introduced to “speed things up” in the baking world.
You see, real sourdough takes time and gets no help from yeast. The starter must ferment and be “fed”. The bread bakes long and slow.
Today, there is little time for such a process, at least in “the market”.
How does this relate to the research study looking at fermented sourdough wheat bread and Celiac patients?
Well, with CD and gluten sensitivity on the rise, many are looking to a time when gastrointestinal issues were less prevalent in an effort to understand what may have triggered a rise in CD diagnosis, causing this once “rare” disease to be a modern-day serious public health issue.
When we look to the time CD diagnosis was nearly non-existent, we look to a time when food production was non-industrialized. That is when REAL fermented sourdough bread would have been the norm.
Makes a bit more sense now, doesn’t it, Honey Bunch?
Enough on sourdough, especially since we can’t eat it anyway. ;)
The Bottom Line:
This study was s ingle instance where 5 individuals (those in Group 3) were fed a very low-level (8 ppm) gluten bread made in a special way modern-day grocery store (or bakery) sourdough breads are NOT made.
Based on the information we have here, I will not be eating sourdough bread made with gluten ingredients.
I hope this information is useful to you in making your own decision on the topic.
Please leave a comment below and let me know if YOU would eat fermented sourdough bread made from wheat or other gluten-containing flours.