Fall has arrived and with the post-summer cool down, it’s the perfect time to cozy up, get in the kitchen and get your sourdough starter in full swing. When it comes to the nutritional and health benefits of sourdough, there is a lot of confusion out there. You might have some questions racing through your mind:
- Why do some people who can’t tolerate gluten seem to be able to tolerate sourdough?
- Is sourdough really better for your gut health?
- Does it help you lower your blood sugar?
We’ll tackle these questions as we #fallintosourdough! This YouTube collaboration is a great resource for all things sourdough and I'm covering sourdough health benefits as well as busting myths.
The Low-Down On Grains
Before we talk about sourdough, let’s talk about grains. Grains, including wheat, corn, rice, quinoa, millet, and so on are the seeds of the plant, and as seeds, they are specifically designed to survive the digestive tract of animals. It’s a pretty simple concept. If a seed can make it through the digestive tract of an animal, when the animal excretes the seed, it can be deposited into the soil ready to grow and carry on its lineage.
When you realize that seeds contain phytochemistry or chemical compounds that inhibit their digestion, like lectins and phytates, as a defense mechanism, then it becomes pretty clear why grains cause digestive issues for a lot of us! The phytochemistry in grains actually inhibits our digestive enzymes from penetrating the seed, which means we can’t digest them properly and can’t unlock their nutritional potential.
We’ve all heard the message that whole grains are very nutritious. Swap white rice for brown rice, they say! Well, the fact of the matter is, even if they do have higher concentrations of B vitamins and are rich in minerals, like magnesium and calcium, their protective phytic acids are making sure that we’re not getting at them so easily! Until that phytic acid is broken down, the nutrients in grains are mostly inaccessible.
And, it’s often because of this phytochemistry, maybe even more than the gluten, that many of us experience symptoms of gastrointestinal distress and inflammation when our bodies try to digest grains, including:
- Upset stomach
- Diarrhea or constipation
- Heartburn or GERD symptoms
- Joint pain and swelling
- Headaches and migraines
- Allergy symptoms
- Skin irritations
How Can Sourdough Help?
So, let’s bring in our frothy, bubbly sourdough starter friend and see how s/he changes the equation. Sourdough is a fermentation process that happens when you take yeast, usually wild yeast from the air, and lactic acid, and this begins to break down those phytates. (1) The combination of yeast and lactic acid reduces the pH of the grains, which causes the phytic acid to degrade. This breakdown allows us to digest the grains much more easily and more efficiently so that we can both avoid digestive discomfort and we’re able to unlock (and benefit from) all those stored nutrients.
Sourdough and Gluten
Many people ask if the fermentation process reduces the amount of gluten or if sourdough is gluten-free. While it’s not gluten-free if made from gluten-containing grains, some studies have shown that the sourdough fermentation process reduces the gliadin, a small problematic protein component of gluten, by up to 80 percent. (2) And, this is a very significant reduction, considering that gluten-intolerant and sensitive individuals and celiacs are reacting to gliadin. When you’re following a traditional gluten-free diet, you’re essentially eliminating gliadin.
For those of you who are sensitive to gluten, sourdough gives you the perfect opportunity to do a little self-test. When you eat gluten-full sourdough, how do you feel? Are you experiencing the same symptoms of digestive distress? If not, it’s possible that you have been reacting to the phytates or that by significantly reducing the gliadin, you can now tolerate the lowered level of gluten. Sourdough might allow you to branch out into a whole new world of easy-to-digest grain-based treats. And, if you’re celiac or sensitive to both gluten and phytates, like myself, you can go ahead and use a gluten-free sourdough starter to make plenty of easier-to-digest, gluten-free goodies.
In fact, one study from 2007, using a very specific strain of bacteria was able to completely eliminate the gliadin through the sourdough fermentation process. (3) Of course, this was a carefully crafted experiment, and not at all the same as commercially available products or an at-home starter using wild yeasts and lactic acid, but it’s cool nonetheless! And, if you’re experimenting with sourdough, you can try ancient grains, like einkorn wheat, that have a different gluten makeup, or try longer fermentation times to reduce gliadin levels further and improve digestibility.
Sourdough and Gut Health
Since sourdough is a ferment, you may think that it contains probiotics that are good for your gut health. This isn’t exactly the case. The truth is that it isn’t a probiotic unless you’re eating it raw. Throughout the baking process, all of those beneficial cultures get killed off. But, on the upside, it is in fact good for your gut health because it is a prebiotic, a starch that helps to feed and support the healthy bacterial strains in your gut microbiome.
A study from the University of Finland demonstrated that those who were eating rye sourdough were getting higher levels of beneficial microbes in their gut. (4) The prebiotic starches found in sourdough help keep the beneficial bacterial colonies well-populated and thriving.
Sourdough and Blood Sugar
You might have wondered about how sourdough impacts blood sugar. Can fermented grains or sourdough lower your blood sugar or help with blood sugar dysregulation? Well, it’s not a clear-cut yes or no. If you have high blood sugar, pre-diabetes, or an insulin-resistant metabolic disorder, no, sourdough products aren’t going to help you reduce your blood sugar, but the fermentation process does help to bring down the number of carbohydrates - sugars and starches - in those products.
I can't stress enough, how important it is for you to get your blood sugar handling under control. Chronically high insulin driven by frequent consumption of sugar and carbohydrates drives chronic inflammation, which can lead to the development or worsening of chronic illness.
This can make sourdough products a better option than regular yeasted bread products. When we consider the glycemic index, a regular yeasted wheat bread may fall around 70, whereas a sourdough loaf hits the index in the low 50s. So, while it of course will still raise your blood sugar, sourdough does offer a marked reduction in the glycemic index. (5) Since it won’t raise your blood sugar as high, it becomes a better option, provided you still pay attention to portion control and pair it with some healthy fats and proteins to lessen the blood sugar spike.
So, now that we’ve cleared up the confusion and brought a little clarity to some of the questions that surround the health benefits of sourdough, take a moment to pop into my kitchen to meet Chuck, my personal gluten-free sourdough starter, and then head into your kitchen and give it a try for yourself!
Sourdough bread is a better option than non-sourdough bread. It is lower in carbohydrates, higher in available nutrients, and serves as a pre-biotic.
The fermentation process of sourdough breaks the phytic acid that binds nutrient availability which makes B vitamins and minerals in the grains available to humans.
Sourdough bread is fermented reducing sugar content and increasing nutrient availability making it a healthier choice.
Gluten-Free Recipes You'll Love!
- Gabriele M, Sparvoli F, Bollini R, Lubrano V, Longo V, Pucci L. The Impact of Sourdough Fermentation on Non-Nutritive Compounds and Antioxidant Activities of Flours from Different Phaseolus Vulgaris L. Genotypes. J Food Sci. 2019;84(7):1929-1936. doi:10.1111/1750-3841.14672.
- Moroni AV, Dal Bello F, Arendt EK. Sourdough in gluten-free bread-making: an ancient technology to solve a novel issue?. Food Microbiol. 2009;26(7):676-684. doi:10.1016/j.fm.2009.07.001.
- Rizzello CG, De Angelis M, Di Cagno R, et al. Highly efficient gluten degradation by lactobacilli and fungal proteases during food processing: New Perspectives for Celiac Disease. Applied and Environmental Microbiology. 2007;73(14):4499-4507. doi:10.1128/aem.00260-07.
- Koistinen, V.M., Kärkkäinen, O., Borewicz, K. et al. Contribution of gut microbiota to metabolism of dietary glycine betaine in mice and in vitro colonic fermentation. Microbiome 7, 103 (2019). https://microbiomejournal.biomedcentral.com/articles/10.1186/s40168-019-0718-2.
- Ma S, Wang Z, Guo X, et al. Sourdough improves the quality of whole-wheat flour products: Mechanisms and challenges-A review. Food Chem. 2021;360:130038. doi:10.1016/j.foodchem.2021.130038.
- Anna Mihhalevski, Ildar Nisamedtinov, Kristel Hälvin, Aleksandra Ošeka, Toomas Paalme, Stability of B-complex vitamins and dietary fiber during rye sourdough bread production, Journal of Cereal Science, Volume 57, Issue 1, 2013, Pages 30-38, ISSN 0733-5210, https://www.sciencedirect.com/science/article/abs/pii/S0733521012002056.
- Fooddata Central Search Results. FoodData Central. https://fdc.nal.usda.gov/fdc-app.html. Accessed September 16, 2022.
- Greco L, Gobbetti M, Auricchio R, et al. Safety for patients with celiac disease of baked goods made of wheat flour hydrolyzed during food processing. Clinical Gastroenterology and Hepatology. 2011;9(1):24-29. doi:10.1016/j.cgh.2010.09.025.
- Nionelli L, Rizzello CG. Sourdough-Based Biotechnologies for the Production of Gluten-Free Foods. Foods. 2016;5(3):65. Published 2016 Sep 20. doi:10.3390/foods5030065.
- Nonaka Y, Izumo T, Izumi F, et al. Antiallergic effects of Lactobacillus pentosus strain S-PT84 mediated by modulation of Th1/Th2 immunobalance and induction of IL-10 production. Int Arch Allergy Immunol. 2008;145(3):249-257. doi:10.1159/000109294.
- Di Cagno R, De Angelis M, Auricchio S, et al. Sourdough bread made from wheat and nontoxic flours and started with selected lactobacilli is tolerated in celiac sprue patients. Applied and Environmental Microbiology. 2004;70(2):1088-1096. doi:10.1128/aem.70.2.1088-1096.2004
- Gobbetti M, Rizzello CG, Di Cagno R, De Angelis M. How the sourdough may affect the functional features of leavened baked goods. Food Microbiol. 2014;37:30-40. doi:10.1016/j.fm.2013.04.012.