Sourdough & Diabetes



I have baked with active yeast for many years and have graduated from white rolls, white plait to multigrain made with a “poolish”. I have experimented with sourdough but never seriously and not with any success. My wife has been diagnosed with type 2 diabetes which requires her to reduce her consumption of carbohydrates to control her blood sugar levels.   In my research for options to improve our diet I came across references to an article in the British Journal of Nutrition that reported that “that sourdough bread had less blood glucose impact than both white and whole wheat bread” ( Interestingly the study found that white sourdough was more beneficial than whole wheat sourdough.[1]I also found another study done in Italy that supported this finding. Apparently the fermentation process of sourdough converts starches in the flour into digestible sugars.   This article was all I needed to move from experimentation to production. My 1st attempts are simply converting an old straight (yeast) dough recipe to a sourdough recipe. My starter was simply a mix of organic whole flour and distilled water with a 1:1 ratio that was refreshed daily. After a week it was bubbling nicely particularly after I found the perfect spot on top of the fish tank to keep the jar warm enough to promote growth.   Recipe    To make the sponge   200 gram starter 200 grams white bakers flour 200 grams water   Left the sponge to mature for 8 hours at room temperature. It looked just like a sponge I would have made with a yeast mix although in more than twice the time it usually takes.   Dough   500 grams white bakers flour 300 grams water 8 grams salt   The dough was much softer than my normal straight dough and had a more delicate feel. I may have to lower the hydration in future attempts. I was able to work it similarly to straight dough although probably didn’t work it enough. I left the dough to prove overnight in the study at room temperature. It rose really well and had a strongly alcoholic scent when I moulded it in 2 loaves.   I placed the loaves into 2 salad bowls lined with baking paper that I use in place of bannetons and left them to prove for a further 5 hours.   I baked the loves in my gas oven on a baking stone (just a sandstone paver from the hardware store – works brilliantly and only cost a $1.50). The results are shown below.


panfresca 2011 April 28

Nice looking loaf, jplio. It doesn't look to me as if the hydration is too high.

I'm interested in those findings on sourdough and diabetes... both my elderly father and my daughter's boyfriend have diabetes. I probably would have expected the whole grain to be better. Peter Reinhart suggests a method to "soften" whole wheat sourdough, resulting in a lighter more digestible loaf - I wonder if that would make any difference.

Here's something I found on (from "gwenni") which might be of interest:

"as a diabetic there are many breads that put my spike my sugar levels through the roof. Something that most diabetics have to try to avoid. 

"I've worked out that rye bread, made with white and dark rye flours, doesnt spike my levels, I add a heap of grains and seeds to it to help make it low GI as well.. was wondering though if others have had some luck with other flours?"


jplio1 2011 April 29

 Unfortunately the article I cited was published in 2008 and there doesn't seem to a further research published on this topic. I was surprised that white sourdough was better than whole wheat, it seemed counterintuitive but it may be that the comparision was sourdough against yeasted whole wheat. It would have been useful if there was some definitions provided in the article.

The word "sourdough' is used/misused to cover a variety of breadmaking techniques including many that aren't sourdough. The industrial baking sector is producing bread that it brands as sourdough but I suspect unless you bake it yourself or purchase from an artisan baker it may not actually be 'naturally fermented' sourdough. It is natural fermentation that is identified as the mechanism that reduces the blood sugar effect. I will be trying it out with other flours.


I did find an article that identified a range of health benefits from Sourdough. I tend to be sceptical of panaceas but you can judge for yourself.

zarniwhoop 2011 May 5

I think you have to be sceptical, and your concerns seem sound - *most* people have never come across sourdough, and most people don't use wholemeal bread in any shape or form [ indeed, in Britain wholemeal is _supposed_ to be unadulterated wholemeal flours, but in countries such as France it seems to be "bread containing (mostly, or even just some) wholemeal flour".


Me, I'm "type 1" (insulin-dependant since age 35, which is quite late), and I use the "balance the insulin to the amount of carbohydrate" method.  For many commercial breads, this is pure guesswork, but I've noted two things - first, there is a bakery in Northern England (Melmerby?) whose sourdough [ actually, sourdough and yeast, I think ] products are available in a local supermarket: the "wholemeal" was labelled as 52% CHO (carbohydrate) by weight, which is very high for wholemeal. Second, "german style" prepacked sliced coarse rye breads are commonly available in supermarkets, with a carbohydrate content around 35% (again, these are a mix of sourdough and yeast).

Also, when I last had an education session with a dietitican, she told me that granary bread is (in official tables) preferable to wholemeal because it may be marginally less CHO by weight, but crucially the added grains and seeds give it a lower glycaemic index, so it takes longer for the carbohydrate to be absorbed. Of course, the glycaemic index for a complete meal is different from that of the individual dishes.


Personally, I use predominantely wholemeal-based breads.  I haven't yet posted any of my recipes (nearly ready for the wheat, after revising from the "and then add more water as necessary" stage - my german-style wholemeal ryes still have temperature difficulties), but the only time I ever make white breads is in high summer when I'm eating enough fruit to think I won't miss the extra fibre.

I can't guess at the glycaemic index of my own breads, but what I've found is that my "wholemeal granary" (Allinson's flour available in UK, most granary is NOT wholemeal) works out at about 42% CHO, my Complet (wholemeal) and my Seigle (50% wholemeal rye, white flour) are both about 46%.  These are all with a wholemeal-only levain.  I don't have the CHO percentages for the wholemeal-rye-based breads handy, but they too are somewhere in the mid 40s. For comparison, (sliced), "chorleywood" [ a contribution to the destruction of civilisation as we knew it, I think ] wholemeal is labelled as 42%".


The other thing to remember is that the body is not a crude machine, we all have individual variations, so what works for one person doesn't necessarily work for another. As a diabetic, knowing the amount of carbohydrate in a loaf helps (i.e. check the percentages of the ingredients, weigh everything, and weigh the finished loaf so you can calculate), but so does keeping to fairly-consistent portion sizes (in my case, I need a *lot* more extra insulin if I have a 20% larger main meal, and have been known to hypo when taking smaller meals with proportionally reduced insulin). 


There does seem to be a general agreement that low GI is beneficial. I'm fairly sure that even if sourdough doesn't help directly, it will make the bread taste better, and therefore smaller meals may be more satisfying.



JohnD's picture
JohnD 2011 May 23

The studies have all been done, it will take years or forever for them to be conclusive or even reach the public, because "they" want to to develop marketable drugs to make money from diabetes.. Ive seen it in action, though just an anecdote officially, and what would we know by observation? but sourdough bread .... properly made...and i cant emphasise that enough. It has to be authentic....has more than just a G I or CHO relevance to diabetes, It appears to be restorative as well...also in the context of an appropraite diet.

ved12 2012 March 30

Diabetes cure is not an easy. But proper care and precautions are always require to keep control on blood sugar level. Type 1 diabetes can be control with the help of insulin. But In case of type 2 diabetes it is not possible because insulin can not work for type 2 diabetes. diet and exercise is only the way to control Type 2 diabetes. Always eat a Foods that Lower Blood Sugar and help to keep healthy body.


chicklady 2012 September 5

I feel that the longer ALL the flour is exposed to my starter, the better.  So.....I make a rye-white sourdough....about 30% rye....

mix my entire recipe and frig the whole thing for a day.   Pull  it  out of the frig, and wat until it starts to rise ...about 5 hour.

Note, I still have not kneaded  a this point.....I never do.....  Once the rise starts,  I take the dough about every hour  and  stretch and tuck it a few times.   I'll usually perform  this for 6-8 hours nd then set it into a loaf pan or cast rion kettle for a final rise.

This is the approx recipe I use for one long loaf & 2  10 inch pzza shells...I don't measure, so you will need to experiment...

1,25 cups milk

1.25 cups water

1 cup starter

1/4 cup oil

2 T sugar

1T salt

6-7 cups  flour   about 1/3 rye

JohnD's picture
JohnD 2012 November 13

Just to add to what Ive said above, and for the benefit of anyone with type 2 diabetes trying to keep blood sugar under control by eating sourdough bread...and in reference to the comments above re genuine sourdough...the altruistic idea which started the sourdough revolution, that is, to benefit people has been hijacked by some bakers who use ascorbic acid in their sourdoughs.

The addition of this chemical interferes with the sourdough process by disabling the proteolytic enzymes which break down the gluten and complete the proper fermentation...this is the oxidising function of ascorbic acid (which is NOT vitaminC), and this is why it is used, it oxidises the gluten, stabilising it. We have all read about the value of anti-oxidants, and it is widely acknowledged in food and nutrition studies. To add an oxidising chemical to a natural process is counter to current thinking about what is beneficial to eat. This adds oxygen radicals to the food, which is counter-intuitive and counter-scientific....some products are being released now which have an ORAC (oxygen radical absorbtion capacity) measurement along with the nutritional information, that is a measurement of the antioxidant capacity of the product.

This is why it is significant for anybody purchasing sourdough bread for frank health reasons, such as diabetics. You either have to make the bread yourself, properly, or make sure the baker does not add ascorbic acid to their bread.

mcrest 2016 February 2

Ayurvedic treatment is best solution for any health problem because there is no any side effect. A diabetic patient is also at risk of various other problems including heart related illnesses and eye problems. It's essential to keep the blood sugar in control if you want to lead a healthy life. While there are medications that could help, these medications can't be taken for a lifetime and they also have a number of side effects. A diabetic tumbler can assist you to control your blood sugar.

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