EP.316/ Is sourdough helpful or harmful for endo and endo belly?
Sourdough bread has been popular in the mainstream for a good number of years now, but I feel like there’s a big focus on it and its benefits in the wellness industry at present.
And I think for people with endo, when new health trends come round, it can be confusing, because foods we thought might bother us with endo, are being promoted to the masses as good for our health, so the question is - where does sourdough fit in with endo?
So, let’s first look at what sourdough is. Sourdough is a type of dough typically used for bread and pizza, which is fermented using yeasts and bacteria that occur naturally in the air and surroundings. It also has a longer fermentation time than your average yeasted dough. And to be clear, when I talk about fermentation, this is the process of bacteria and yeasts eating a food, in this case, starches in the flour, and chemically changing the dough due to the lactic acid, alcohol and carbon dioxide they produce in the fermentation process, which creates the sour flavour in sourdough and helps it to rise.
So let’s look at some of the areas that might be relevant to endo.
Is it gluten free?
Sourdough breads and products may contain less gluten, but it’s really important to emphasise that they are not gluten free.
Several studies on sourdough show that sourdough has a lower amount of gluten in, but not low enough to be classified as gluten free.
The lower gluten content can vary based on the fermentation process, the flour used, and other factors and in some cases, it can significantly reduce the gluten content. This occurs because the fermentation process of the bacterial strains and wild yeast eating the starch in the flour, breaks down some of the gluten.
This can make sourdough easier to digest for those with a gluten intolerance or sensitivity and studies have also shown that it may even lessen the immune reactions, however, this does not mean that it's safe for people with coeliac disease.
Coeliac disease is a very serious immune reaction to gluten, that can significantly damage the small intestine and whilst research showed some promising results for sourdough and coeliac disease patients, the sourdough used was carefully controlled and developed, to lower the gluten levels to extremely minute amounts, which is difficult to replicate in reality. There have also been other studies that show that the fermentation process is not enough to prevent the immune reaction in coeliac disease.
For people with a wheat allergy, whilst sourdough may help reduce immunoreactivity, it’s important to talk to your doctor and immunologist before you try sourdough.
So, how does this relate to endometriosis?
There is a fairly strong connection between endometriosis and coeliac disease, with studies showing an increased risk of people with endo developing the disease and vice versa. In the show notes, I’ve linked to my podcast episode on this topic!
Continual exposure to gluten may eventually trigger the immune changes that characterise the disease, though there are other factors involved.
A good way to rule out your risk is to check your genes, to see if you carry the genes the DQ2 and/or DQ8 gene variants. If you have one, you have a 3% increased risk of developing coeliac disease and if you have both, like me, you have a 10% increased risk. However, it’s important to note that there are plenty of people on the planet with these genes who never develop the disease, but only people with these genes develop coeliac disease. So whilst having these genes does not guarantee you’ll develop it, not having these genes does rule it out. Finding out whether you have these genes might help you to make more mindful decisions around gluten and how often you’d like to eat it.
Additionally, a study of 206 women with endo, showed 156 had symptom improvement after a year on a gluten free diet, however, there were weaknesses with this study so more research needs to be done, but typically I do see improvements in students and clients who adopt a lower gluten or gluten free diet. Does this mean you have to be perfect and avoid gluten like the plague? No, it’s about finding out your tolerance level and how much you can have without symptoms worsening, and it’s worth noting, that especially in the case of intolerances, symptoms don’t have to develop immediately - in fact, symptoms can develop or last for several days after exposure. The other thing to note is that it may be about how much you have and how often, this is also true for common allergens like lactose, for example.
That’s why when necessary, I use an elimination diet with clients, because this is the gold standard for working out intolerances and we can systematically work out how much of a food you can tolerate. If you’re interested in having some help doing this, I am now booking the last of my 2024 one to one coaching client cohort, and have three spaces available. If you’d like end this year knowing how to manage endo and what specific nutrition and lifestyle support you need to do this, you can apply through my show notes, where I’ve left a link to the application form.
Now, finally, gluten increases zonulin, a protein made by the intestinal cells. Zonulin regulates the tightness of the micro gaps in your intestinal lining, which allows for the uptake of nutrients. When zonulin increases, these gaps widen. While the body repairs these holes, eventually they can stop healing with repeated exposure and that’s when we get leaky gut, which if you’ve been listening to my episodes lately, you’ll know can allow for lipopolysaccharides from pathogenic and gram negative bacteria to leak into the pelvic area, and these toxins have been shown to contribute to endo development. Additionally, leaky gut also tends to lead to an elevated inflammatory immune reaction, because there are now food particles, bacteria, LPS, etc. leaking into the blood stream on the other side of the intestine, so this can create more inflammation and can in time, trigger autoimmune issues in people with genetic susceptibility.
So, if you’re eating gluten daily, there’s a chance that it’s triggering more leaky gut, which isn’t ideal for endo. Swapping for sourdough will likely lessen your gluten exposure, and it’s really down to your personal body whether this is enough to not cause any of the above issues, or whether you’re better off sticking to some good quality sourdough over the weekend, for example.
Blood sugar
Okay, now let’s look at blood sugar.
Blood sugar balance is a key part of how we manage endo. Blood sugar imbalances can negatively affect hormones and lead to oestrogen dominance and elevated testosterone; they can raise inflammation and the inflammatory chemicals linked to endo pain and growth like prostaglandins, and these imbalances can also raise oxidative stress in the body, another process linked to endo development.
Starchy foods, especially processed ones like bread, can quickly raise blood sugar levels because they break down easily in the small intestine, and that starch is broken down into glucose, which is absorbed into the blood stream, creating that spike.
You can measure the impact of a food on your blood sugar levels by using a glucose monitor, but you can also look at the glycemic load and glycemic index of food. The glycemic index looks at how quickly carbs in a food break down and are absorbed into the blood stream; high glycemic foods break down quickly and can cause a spike, and lower have less of an impact.
The glycemic load looks at both how quickly the food breaks down but also how high it is in carbohydrates. This is thought to be a better evaluation of the impact a food has on blood sugar, because sometimes a food may break down quickly, but doesn’t have a high amount of carbs per serve, so actually, eating it in a normal serving size wouldn’t necessarily cause a spike. This is also true for something that has a lower GI, but if a normal serving size is pretty high in carbs, it can actually spike blood sugar levels higher than its GI rating would indicate.
An average 30g slice of white bread has a glycemic index of 71 out of 100, and the glycemic load is 9, this is considered high glycemic index but because the serving size is fairly small, the load is just borderline between low and moderate. In contrast, the same size serving of sourdough has a glycemic index of 54 and a glycemic load of 8, which are both classified as low.
Now remember, the glycemic load is also calculated by how much carbohydrate there is in a serving of a food, so if you were to have more than 30g, the glycemic load would change, so just keep that in mind.
Additionally, people’s blood sugar responses really vary. For example, despite a slice of white bread having a lowish level score on the glycemic load, my blood sugar really spikes from it. And this isn’t just me, studies show that people have very individual blood sugar responses to the same food.
However, there are several studies showing a better blood sugar and insulin response with sourdough in contrast to regular bread made with yeast, even in people with impaired glucose tolerance.
This is because the chemical changes that occur to the starches in the bread due to the fermentation process, make the starch harder to break down and absorb.
The blood sugar response can be further improved by freezing the sourdough, whether that’s pizza, bread or sourdough baked goods. The starch chemically alters and some of it becomes resistant starch, a type of starch that resists digestion in the small intestine. You can learn all about resistant starch and its benefits for endo in my episode on the topic, which I’ve linked in the show notes, but in short, because less starch is available to digest, it has a lower impact on blood sugar.
So, whilst everyone’s blood sugar repspones are unique, based on the research so far, it’s very likely that eating sourdough, especially if you froze it overnight, will be better for your blood sugar than regular bread. Bonus points if you top it with healthy fats, protein and fibre, which all slow down the glucose response further. :)
Is sourdough better for IBS?
Okay, so we talked about the gluten in sourdough potentially being easier to digest, but there are also other factors that could influence whether you get bloating (endo belly) or abdominal cramping, etc. from bread.
Many breads contain FODMAPS, which are types of fermentable carbohydrates. These ferment rapidly and excessively in the intestines, resulting in bloating, cramping, and general IBS issues in people who are sensitive to them. For example, only 24g of white wheat-based bread and wholemeal bread is considered low fodmap. In contrast, spelt sourdough is low fodmap at 70g, which is a really big slice, or two small slices, and wholemeal wheat sourdough is low fodmap even at 97g.
This is because the bacteria and yeast are also eating and breaking down the fodmaps in the flour, like fructans and galacto-oligosaccharides, resulting in less fodmaps in the final product.
Whilst the low FODMAP diet is not for everyone, and is only supposed to be a temporary, therapeutic diet to work out your sensitivities, consuming bread that’s lower in fodmaps may help you to not have such dramatic endo belly or IBS reactions, if you do choose to eat bread, or pizza, etc.
Is sourdough probiotic?
Last week we looked at the benefits of probiotic foods for endo, specifically around short chain fatty acid production as well as inflammation.
As we’ve discussed, sourdough is a fermented food, so does that make it probiotic? Unfortunately not - the cooking process kills the bacteria, so sourdough doesn’t count towards the probiotic serving sizes we’re aiming for, however, it is a source of prebiotics.
Prebiotics are foods or specific nutrients or ingredients that feed our good gut bugs, and can also alter the gut environment to foster their growth.
Sourdough contains a range of these, including arabinoxylans and resistant starch, as well as inulin and fructo-oligosaccharides. For those of you who are familiar with the low FODMAP diet, you’ll probably be concerned that inulin and fructo-oligosaccharides are in sourdough, because these are FODMAPS, but remember, the fermentation process reduces the number of fodmaps, so you’ll be getting some, but still a green serve. Plus, many of the prebiotics in sourdough are not FODMAPS and you’ll still be getting these in good amounts.
Prebiotics
So, if you have endo, should you be eating it every day?
In my line of work, we typically advocate for a diet rich in whole, minimally processed foods. This is because we have lots of research showing better gut health, blood sugar and inflammation levels when we’re eating whole foods vs. A diet rich in processed foods.
However, more research has emerged lately showing a difference between ultra processed foods and processed foods. Ultra-processed foods contain additives, high amounts of sugar, salt and fats. These foods are being associated with the most negative health outcomes.
In contrast, we have processed foods, which include cheeses, sourdough bread (not like store bought Hovis, that would be an ultra-processed food) and other fermented foods.
So, including some sourdough, especially with a diet rich in whole foods like fruits, vegetables, nuts and seeds, etc. can fit into a healthy diet - providing, it agrees with you.
And this comes back down to the effects it personally has on your gut, on your blood sugar, etc.
If you really want to dive deep, you could get a glucose monitor and test yourself on sourdough, but if you don’t want to go that far, just consider making those blood sugar tweaks I recommended earlier, like eating your sourdough with healthy fats, and fibre, etc.
And as I shared earlier, you may need to test your tolerance on how much sourdough you can consume comfortably for your endo belly and your endo. Remember, if you gut starts to get inflamed, this can lead to low grade full body inflammation, which can impact your pain levels - and it won’t necessarily happen with one slice. It’s repeated exposure, not one offs, that can really start to make a change inflammation wise, whether that’s with sugary foods, fast food or foods we are sensitive to. So don’t worry about those weekend brunches unless you really do have a strong initial reaction - clearly, I don’t want you in pain or with IBS problems just because sourdough may be better than usual bread.
And remember, sourdough is not the only food to provide prebiotics - there are plenty of other ways to boost gut health, and my last several episodes are all on this topic. But the number one, main way to look after your gut health, is to eat a diet rich in whole plant foods like fruit, veggies, nuts, seeds, whole grains and herbs and spices - whether or not you eat meat.
So, I hope this has helped clear up the confusion on sourdough bread and has helped you to make an informed decision about whether to include it in your diet.
I’ll see you next week!
Show notes
Gluten and sourdough
https://pubmed.ncbi.nlm.nih.gov/14995138/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5302394/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10399781/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4425136/
https://pubmed.ncbi.nlm.nih.gov/20975578/
https://pubmed.ncbi.nlm.nih.gov/20951830/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5707687/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11013811/
https://www.sciencedirect.com/science/article/abs/pii/S1466856423000152
https://nationalceliac.org/celiac-disease-questions/understanding-gluten-levels/
http://celiacindia.org.in/gluten-free-beyond/gluten-free-diet/what-is-gluten-free/gluten-math
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10507348/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9271567/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7767453/
Endo and coeliac disease/gluten episode and references
https://www.theendobellycoach.com/podcast/endo-belly-coeliac-testing
Leaky gut and endo, inflammation, etc.
https://pubmed.ncbi.nlm.nih.gov/22109896/
https://bmcgastroenterol.biomedcentral.com/articles/10.1186/s12876-014-0189-7
https://integrativewomenshealthinstitute.com/leaky-gut-and-pelvic-pain/
https://pubmed.ncbi.nlm.nih.gov/19517230/
https://pubmed.ncbi.nlm.nih.gov/30430944/
https://pubmed.ncbi.nlm.nih.gov/29692669/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4519769/
https://pubmed.ncbi.nlm.nih.gov/9660426/
https://genomemedicine.biomedcentral.com/articles/10.1186/s13073-016-0303-2
Blood sugar and sourdough
https://pubmed.ncbi.nlm.nih.gov/7782904/
https://pubs.acs.org/doi/10.1021/acs.jafc.0c07200
https://pubmed.ncbi.nlm.nih.gov/18317680/
https://link.springer.com/article/10.1007/s40520-019-01392-3
https://pubmed.ncbi.nlm.nih.gov/18317680/
Blood sugar, endo and hormones
https://pubmed.ncbi.nlm.nih.gov/11511861/
https://pubmed.ncbi.nlm.nih.gov/2010896/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4888492/
https://pubmed.ncbi.nlm.nih.gov/1958541/
https://www.ijrcog.org/index.php/ijrcog/article/view/3211
https://pubmed.ncbi.nlm.nih.gov/7918300/
https://jamanetwork.com/journals/jama/article-abstract/202670
https://pubmed.ncbi.nlm.nih.gov/20497781/
https://pubmed.ncbi.nlm.nih.gov/19088375/
https://pubmed.ncbi.nlm.nih.gov/20537326/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7333061/
https://pubmed.ncbi.nlm.nih.gov/18508964/
https://pubmed.ncbi.nlm.nih.gov/12379575/
https://www.ncbi.nlm.nih.gov/books/NBK493173/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9783643/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC308109920
Blood sugar variability
https://pubmed.ncbi.nlm.nih.gov/26590418/
https://www.nature.com/articles/nature09944
https://www.nature.com/articles/s41588-018-0241-6
IBS/fodmaps in sourdough
https://www.monashfodmap.com/blog/sourdough-processing-fodmaps/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10399781/
https://pubmed.ncbi.nlm.nih.gov/37000015/
https://pubmed.ncbi.nlm.nih.gov/11972702/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5707687/
Prebiotics in sourdough
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8997659/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3705355/
https://www.mdpi.com/2304-8158/13/13/2132
https://www.sciencedirect.com/science/article/abs/pii/S0023643821009762
https://pubmed.ncbi.nlm.nih.gov/11972702/
Processed food
https://zoe.com/learn/what-is-ultra-processed-food
https://journals.asm.org/doi/10.1128/msystems.00031-18
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