A lot people have been writing me with questions on the relationship between gluten and sourdough. Specifically, people want to know if sourdough contains gluten. In essence, what people want to know is if sourdough is digestible.
In this blog post we are going to cover this relationship between sourdough and gluten, what makes sourdough superior to “normal” bread and exactly why you can most likely enjoy sourdough bread without the symptoms of gluten intolerance.
What is Gluten?
As always, let us start out with defining a few terms.
At basic, gluten is a protein and therefore to fully understand what gluten is, we need to understand what a protein is and in order to understand what protein is, we must know what amino acids are.
Proteins are nitrogenous, complex organic compounds that consist of one or more long chains of amino acids.
Amino acids are the smallest unit of a protein.
Together, these two have an interesting, divine and magical relationship, it is as if the mysteries of the universe exist within the human metabolism. You see, proteins are made up of amino acids, which are then broken down by the metabolic system back into amino acids, which are used for cellular function. That’s right, amino acids form proteins, which are intentionally broken down into amino acids, to form tissues, hair, skin, cells, etc.
Seems unnecessary right? Why not just stay amino acids if thats their destiny? The simplified answer is that a form of alchemy takes place in which two amino acids come together and create a new whole that is greater than the sum of their parts, which is later broken down into amino acids that are even more useful.
Through the bonding of amino acids, different molecules are formed, each which the sum is greater than the source parts.
For example, when two 2 amino acids bond together, they form what’s called a dipeptide.
When three amino acids bond you get a Tripeptides.
When four amino acids bond you get a oligopeptide.
Finally, when you get a complex, long-chain of bonded amino acids, you have a protein, which is essential for all living organisms. Proteins make up the tissues, hair, skin, organs, and most of the physical structure of the body, without them, the body would be a ‘puddle’ of bacteria.
Getting back to bread, through the process of fermentation, the amino acids and proteins in grains go through a very interesting transformation.
In all grains, there are two categories of gluten proteins: glutelins and the prolamins.
In wheat specifically, the glutelin and prolamin proteins are what as known as glutenin and gliadin. And interestingly enough, it is gliadin, not gluten that causes the negative symptoms of gluten intolerance.
Glutenin and Gliadin
Together, it is glutenin and gliadin that are responsible for the desirable characteristics of bread dough, like its sticky texture that makes a soft, moist, melt-in-your-mouth bread. For bakers, it is this protein combination that makes dough easy to knead, shape and form, which is essential for a good rising bread, bubbly bread.
Through the process of fermentation, the glutenin in wheat grain is broken down into digestible amino acids. Then, through the process of kneading a fermented wheat dough, the glutenin proteins form into long chains.
Gliadin proteins are dense and with a low surface area-to-volume ratio, which allows glutenin chains to pass freely into the protein network.
Both glutenin and gliadin proteins have high concentrations of the amino acids proline and glutamine.
The exact proportions of glutenin and gliadin differs between types of wheat grain (einkorn, teff, spelt, kamut, etc.), which gives the bread different texture. In generally, ancient grains seem to have less gluten protein.
Gluten & Gliadin Digestion
Being that glutenin and gliadin are proteins, they digested in the stomach and small intestine by HCL and enzymes.
The proper digestion of gluten goes through a few phases: HCL and enzymes break the long-chains into oligopeptides, then into tripeptides, dipeptides, and then finally free amino acids. These free amino acids are what the body assimilates and utilizes for fuel.
Gliadin; on the other hand, often breakdowns much differently. In individuals with weak stomach acid and enzyme production, gliadin is broken down into oligopeptides but no further. This is also a result of the density and unique amino acid sequences in gliadin, which inhibits enzymatic activity.
Because gliadin is rich in proline, its cyclic structure makes gliadin a very difficult to breakdown protein. The enzyme transglutaminase (tTG) also plays a role in the tough structure of gliadin. It creates bonds between gliadin proteins and other amino acids, making it even more difficult to digest.
The enzyme transglutaminase also converts glutamine into glutamic acid via a process called deamination. Glutamic acid is known to cause immune reactions in some people, where the body views the protein as a pathogen and evokes an inflammatory response.
Sourdough & Gluten Relationship
We have learned all about the troublesome proteins present in wheat grains that inspire inflammation. However, the question is, does sourdough have gluten? Does the alchemical process of fermentation solve the it actually solve issues that gluten and gliadin can cause in the body?
Before we answer that specifically, let’s talk about lactic acid bacteria (LAB), the bacteria responsible for sourdough fermentation. In short, LAB convert the sugars in wheat to lactic acid, which causes the acidity to increase. This ignites the hydrolysis of gluten and gliadin proteins by penetrating and loosening their protein structure. It also stimulates the production of enzymes, which are otherwise locked away in the phytic acid of the grain. T
It is known that specific strains of lactic bacteria are capable of hydrolyzing wheat proteins (including gliadin) by more than 50% within a 24-hour period of fermentation. That means a proper fermented sourdough (with a strong culture and proof time of 24-48 hours), can result in a sourdough that contains 50-100% less gluten and gliadin than non-fermented bread.
In other words, lactic bacteria and the associated enzymes secreted through the process of sourdough fermentation can effectively “pre-digest” the gluten and gliadin proteins, resulting in a bread that is incredibly delicious and highly more digestible. Not to mention, the process of fermentation dramatically increases the bio-availability of B vitamins, fatty acids and other nutrients in the bread, making it more nutritious.
Why Some People Digest Bread Better Than Others
In a healthy gut, there are simnifically greater numbers of lactic acid bacteria and other probiotic “gluten digesting” bacteria that aid in the digestion of both gluten and gliadin. All the more reason to get your gut micro-biome into optimal shape. To achieve this, you’l want to take a three step approach, which I go into great detail about in my online course Perfect Digestion.
The good news is that you can heal from gluten intolerance and all food intolerances, simply by improving the diversity and health of your gut micro0biome. While the goal is simple, the path there involves discilipine. While you may need to eliminate bread and gluten temporarily, once your gut is healed, you can enjoy bread regularly if you properly ferment it!
If you have done significant work to heal your gut and still have trouble digesting sourdough bread, you can try bread from ancient grains such as einkorn, spelt or teff. These ancient grains are non-hybridized and were some of the first to be cultivated and therefore, are more recognizable by the immune system.
In conclusion, grains contain hard to digest proteins, sourdough does contain gluten, but through the process of lactic bacteria fermentation and having a healthy gut, you can digest bread and enjoy it!
To learn how to make a proper sourdough (like the ones you see me make on my Instagram), be sure to grab a copy of my latest book Succulent Cuisine. I go into detail about sourdough, its benefits, (some of the data I used to write this blog comes from it), and provide a step-by-step recipe for making the perfect sourdough.