What is sourdough bread?

Sourdough is a leavened bread, which means the dough naturally rises as a result of the gas that is produced as the grain ferments. While most commercial breads use baker’s yeast as the raising agent, sourdough is made using a sourdough starter.


A sourdough starter is a culture of yeasts and beneficial bacteria that naturally occur and are allowed to ferment over the course of approximately five days. A portion of the starter, known as the levain, is mixed with bread flour to make sourdough.

Discover our full range of health benefit guides and check out some of our favourite sourdough recipes, from a rye sourdough loaf to a sourdough pizza.

Nutritional profile of sourdough

The blend of flour or flours used to make the sourdough will impact the macronutrient profile. However, a typical 100g portion (approximately two slices) of sourdough contains:

  • 230 kcals/974KJ
  • 7.8g protein
  • 0.7g fat
  • 47g carbohydrate
  • 2.9g fibre
  • 0.81g salt

What are the health benefits of sourdough?

Hands holding sourdough loaf
  • May support gut health
  • May aid blood sugar management
  • May reduce risk of heart disease
  • May be easier to digest
  • May be more nutritious
  • May be more satiating

1. May support gut health

Although the beneficial microbes in the starter tend to be lost during the baking process, the fibre and plant compounds, called polyphenols, become more bio-available. These act as an important fuel source for our gut microbes, which explains why sourdough is a gut-friendly choice.

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2. May aid blood sugar management

The fermentation process and higher fibre content makes sourdough a useful option for those with blood sugar management issues. This is because, unlike many commercially produced breads, sourdough has less of an impact on blood sugar levels.

3. May reduce the risk of heart disease

Hands cutting sourdough loaf in half

Typically, diets high in fibre are associated with a lower risk of heart disease. Sourdough appears to offer additional benefits thanks to the natural fermentation process these benefits are enhanced when wholegrain rye flour is used.

4. May be easier to digest

Traditional sourdough undergoes a slow fermentation, the result of which is an increase in the bioavailability of the bread’s vitamins and minerals. This process also starts the breakdown of protein (including gluten), making sourdough easier to digest.

5. May be more nutritious

Research suggests that fermentation improves the bioavailability of fibre and minerals. This is because a naturally occurring compounds found in grains, called phytic acid, are broken down, and this enables us to access the grain’s nutrients more readily.

6. May be more satiating

Sourdough appears to be more satiating than a baked product made using yeast, one study reported that rates of hunger at 45 minutes and 240 minutes post consumption were markedly lower when sourdough bakes were eaten.

Is sourdough safe for everyone?


For those following a gluten-free diet, such as those with coeliac disease, sourdough made from wheat, rye, barley or other gluten-containing grains must be avoided. However, as long as non-gluten flours are used, the sourdough process itself should not cause a problem.

So, is sourdough healthy?

Although commonly viewed as a healthier option, it is difficult to establish a clear consensus on the health benefits of sourdough. This is because there are so many variables involved in its production – these include microbial composition, fermentation conditions, type of flour and cereal – all of which may influence the nutritional properties of the finished loaf.

That said, in studies that have sought to standardise production by using specific strains of microbes and controlling fermentation conditions, improvements in glycemic response, satiety and digestion have been reported.

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Sourdough recipes

Wholemeal sourdough loaf
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Baked ratatouille with lemon breadcrumbs
Beans & feta on sourdough toast

This page was reviewed on 8th March 2024 by Kerry Torrens

Nicola Shubrook is a nutritional therapist and works with both private clients and the corporate sector. She is an accredited member of the British Association for Nutrition and Lifestyle Medicine (BANT) and the Complementary & Natural Healthcare Council (CNHC). Find out more at urbanwellness.co.uk.

Kerry Torrens is a qualified Nutritionist (MBANT) with a post graduate diploma in Personalised Nutrition & Nutritional Therapy. She is a member of the British Association for Nutrition and Lifestyle Medicine (BANT) and a member of the Guild of Food Writers. Over the last 15 years she has been a contributing author to a number of nutritional and cookery publications including Good Food.


All health content on goodfood.com is provided for general information only, and should not be treated as a substitute for the medical advice of your own doctor or any other healthcare professional. If you have any concerns about your general health, you should contact your local healthcare provider. See our website terms and conditions for more information.

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