Is there a link between sourdough bread and diabetes?

Eleven million Canadians live with diabetes or prediabetes. Those with diabetes can’t produce insulin or properly use the insulin it produces. Insulin is a hormone the pancreas produces. It regulates the amount of glucose (sugar) in the blood.

Regulating our blood sugar ensures our body functions properly. Too much blood sugar can cause damage to organs, blood vessels, and nerves. We also need insulin to use sugar for energy.

Refined or processed sources of carbohydrates such as white flour, cereals, white rice, potatoes, and pasta can have the biggest impact on blood sugar for people with type 2 diabetes because they can spike blood sugar levels. This can lead to an assumption they should avoid eating many carbohydrates.

Could sourdough bread help manage diabetes?

Fortunately, sourdough bread can be good for people who have or are predisposed to diabetes. Research suggests not only is sourdough an ideal part of a balanced diet, but it can also help to manage blood sugar levels and provide other benefits, which is important when dealing with diabetes.

Many types of breads are available and have varied nutritional value. Highly processed white breads are not healthy—for anyone. Breads with whole grains—especially those produced through a long and slow fermentation as with sourdough—are high in fibre and contain micronutrients in a form that can be more easily digested.

It will take time to discover the bread that’s suitable for you. Homemade breads and loaves or those from artisanal bakeries like ours are less processed and won’t contain additives (including sugar) common in industrial breads.

Is sourdough bread healthy for diabetics

Insoluble fibre (which can’t be digested by the human gut) found in breads made from whole grain flours is important in promoting a healthy gut microbiota. Diverse and healthy microbes in our gut have positive effects on our health. Insoluble fibre provides food for these microbes. They aid digestion and support a healthy immune system.

In a study linking the actions of gut bacteria with people at risk of type 2 diabetes, higher blood levels of indolepropionic acid were associated with those who did not develop diabetes. Our gut bacteria makes indolepropionic acid. These acid levels appeared to be positively linked to the amount of fibre and whole grains in the study participants’ diets.

Fermentation methods and the way flour is milled influence how we digest bread and assimilate it in our bodies. A Canadian study found blood sugar levels in overweight men showed a smaller spike after eating sourdough bread when compared with yeasted breads. Additional research suggested sourdough breads made with flours milled from sprouted grains are even more beneficial than either white or wholemeal sourdough bread.

Eating whole grain or sprouted grain sourdough breads can moderate blood sugar response. Sourdough’s fermentation process and fibre can have benefits for digestion and the immune system.

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Along with a whole-food, plant-based diet, sourdough can help to slow down the rate of assimilation of carbohydrates. Keeping your blood sugar levels even can also lower inflammation and hormone fluctuations.

Visit our rotating sourdough bread schedule. You can also learn our favourite dutch ovens for baking sourdough, and how to store sourdough bread & keep it fresh.

— Update: 06-01-2023 — found an additional article Sourdough Bread for Diabetes: Pros and Cons from the website for the keyword is sourdough bread healthy for diabetics.

Sourdough bread is certainly delicious. But what about eating it with diabetes? Is it a good option or the same as many other breads? Is it a yes or no food? Will it be friendly to blood sugar levels or not?

That’s what we’re here to discuss.

Is sourdough bread healthy for diabetics

What is Sourdough Bread?

Sourdough bread is famous both for its tangy flavor and its holey interior—two characteristics that are a result of the way it is made: via fermentation.

In order to make sourdough, you typically combine flour and water and then expose the mixture to oxygen until helpful bacteria begin to form.

Bacteria and wild yeast consume the natural sugars in the flour and give off gases like lactic acid and carbon dioxide. These gases cause the bread to rise slightly and create holes throughout it. That lactic acid is also responsible for putting the “sour” in sourdough.

Regular bread is made with baker’s yeast that works very quickly and the results in a softer, sweeter-tasting bread. In contrast, the process of making sourdough breaks down and releases nutrients much slower than a typical fast-acting yeast does.

Some of the natural sugar in the flour is devoured during the fermentation process, which is why many people claim that sourdough bread causes a gentler rise in blood sugar compared to white and wheat bread.

So is this just an urban myth or does sourdough actually contain fewer carbs than other kinds of bread?

Let’s see if sourdough really is the Holy Grail of bread for people with diabetes.

Sourdough Nutrition Facts

Like most breads, carbohydrates are the dominant macronutrient in sourdough bread. Although it is fermented, it is usually made from wheat or rye flour, which is naturally high in carbs.

Take a look at the nutrition facts for one slice (25g) of wheat sourdough bread:

  • Calories: 60
  • Total carbs: 12g
  • Fiber: 0.5g
  • Protein: 2.5g
  • Fat: 0.5g

Sourdough is relatively low in dietary fiber and just once slice contains 11.5g of net carbs (net carbs = total carbs – fiber). Of course, this can vary depending on who makes the sourdough bread.

Using the above nutrition facts, if you ate a sandwich with two slices of sourdough that would add up to 23g of net carbs with only 1g of total fiber – nothing to ring home about there.

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As a general rule you want to consume as much fiber as possible because fiber slows down the absorption of any carbs you eat, protecting your body from a large blood sugar spike. Fiber also enhances gut health, which has the offset of enhancing your overall health in many other ways – including helping to lower blood sugar levels.

Many people often think bread is high in fiber. Unfortunately though, most bread is notoriously high in carbs and low in fiber, making it a poor choice for diabetics who are looking for better blood sugar stability.

Speaking of gut health, sourdough bread is definitely going to be a better option than other breads. Making sourdough produces beneficial gut bacteria that help with digestion, and this does have some impact on how it then influences the blood sugar response. And overall, sourdough has a better glycemic index to many breads, coming in the lower ranges of 48-66, whereas others can be upwards of 75.

Some say that sourdough is a healthy option because it is rich in minerals like selenium, manganese, and iron.

And while sourdough does contain these micronutrients, you can also find even greater amounts of them in fish, green leafy vegetables, and clean meats that won’t raise you blood sugar to the heavens.

Sourdough vs. Other Breads

Now it’s time to answer everyone’s burning question about sourdough: does it have less sugar (fewer carbs) than other breads do?

This comparison chart should answer that question pretty quickly:

Is sourdough bread healthy for diabetics

And the final answer is… no.

Despite what some health gurus may say, sourdough bread isn’t that much lower in carbs compared to other breads. Which means that sourdough isn’t a miracle bread that people with diabetes can indulge on without consequences (sorry).

If your goal is to stabilize your blood sugar levels, then the best bread is a low carb bread made from naturally low carb flours like almond flour, coconut flour, or flaxseed meal.

Or you can skip the bread altogether and follow a meal plan that focuses on healthy proteins and fats while supplying healthy carbohydrates through vegetables – it works!

Is Sourdough Bread Gluten Free?

Many people think that those with gluten sensitivity, irritable bowel syndrome, or celiac disease may tolerate sourdough better than other breads because most of the gluten in sourdough bread is broken down during the process of fermentation.

And this is true—there is less gluten in sourdough bread than in regular white or wheat bread.

But, sourdough bread is not gluten free!

This is most important for those with celiac disease to be aware of, because consuming any gluten at all can be very dangerous.

If you do not have celiac disease, going gluten free can actually cause more harm than good if you are relying on “gluten free” breads and pastas.

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These products are often made from grains like rice, oat, and quinoa and may contain even more carbs than traditional wheat products.

If you’re looking to maximize your gut health and steer your blood sugar into a healthy range, skip the gluten free diet and go a step further by adopting a totally grain-free diet. It will not only help your gut health but also benefit blood sugar levels too.

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Is sourdough bread healthy for diabetics

Research on Sourdough Bread and Diabetes

The research on sourdough has varied results about how it affects your blood sugar and insulin levels.

A 2008 study found that adult subjects with impaired glucose tolerance had lower blood glucose and insulin responses when given a meal of sourdough bread than when given a meal of regular bread made with baker’s yeast.

In contrast, a 2012 study found that 50g of carbohydrates from sourdough bread produced a greater blood glucose response than 50g of carbohydrates from a sprouted-grain bread and a 12-grain wheat bread. They also found that 130 mins after the meal, the sourdough bread produced a greater insulin response than any of the other breads tested.

The ADA’s 2017 Standards of Medical Care in Diabetes, state that: “whole-grain consumption is not associated with improvements in glycemic control in type 2 diabetes.” Or in other words, whole grains of any kind do not help you regulate blood sugar and A1c – that’s what the research clearly shows. There is really no evidence to show any type of whole grain provides any benefit for treatment – sourdough or not!


Sourdough bread isn’t all that much healthier than other breads, especially for diabetics who are adhering to a low carb diet for better blood sugar and A1c control.

It turns out that sourdough isn’t very satiating (satisfying) either and won’t keep you from snacking throughout the day. In fact, the most satiating foods are actually fats, not carbs!

Next time you’re hungry, reach for healthy fats like eggs, nuts and nut butters, seeds, avocados, olive oil, and fatty fish like salmon to keep you full and satisfied longer.

At the end of the day, the formula for managing diabetes through diet is pretty simple: The fewer carbs you eat, the more stable your blood sugar can be.

A low carb diet does not mean a no carb diet. There are many delicious vegetables that should make up the abundance of your plate – these are also carbohydrates, the kind that are friendly to blood sugar. However, high carb foods like bread, pasta, potatoes and rice are better left on the shelf!

Have you found a bread that works okay for you? Feel free to leave your comments below.

Is sourdough bread healthy for diabetics


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About the Author: Tung Chi