Why is sourdough bread the healthiest bread?

Why is it that I can digest sourdough bread and not commercial bread?

So why is Sourdough bread healthier than ordinary bread?

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Day to day I at The Sourdough School,I teach people to make the healthiest bread in the world. I use Gut Microbiome testing and Genetic Analysis to identify specific areas where we can improve and optimise the digestibility of their bread. Many people ask me why they can digest sourdough bread, but not ordinary commercial bread. There are many reasons for this, and the answer for each person is different.

However, research (often linked with IBS) indicates that phytic acid, which is found in the bran part of wheat, can be a cause of digestive discomfort and bloating. In humans, and animals with one stomach, this phytic acid inhibits enzymes that are needed for the breakdown of proteins and starch in the stomach. This lack of enzymes results in digestive difficulties. Ironically, commercially produced wholegrain bread, generally perceived as ‘healthy’, is often the worst thing a person with a wheat intolerance can eat.

Luckily when it comes to IBS, bread and digestion we have an ally: sourdough. The wild yeast and lactobacillus in the leaven neutralise the phytic acid as the bread proves through the acidification of the dough. This prevents the effects of the phytic acid and makes the bread easier for us to digest. These phytic acid molecules bind with other minerals, such as calcium, magnesium, iron and zinc, which make these important nutrients unavailable to us. Long, slow fermentation of wheat can reduce phytates by up to 90%. There is an interesting study that compares the effects of different leavens (yeast, sourdough, and a mixture of both) on phytic acid degradation which assessed the repercussions of phytic acid breakdown on phosphorus and magnesium solubility during bread-making, that showed sourdough fermentation was much more efficient than yeast fermentation in reducing the phytate content in whole wheat bread (-62 and -38%, respectively). The lactic acid bacteria present in sourdough enhanced acidification, which lead to increased magnesium and phosphorus solubility.

Simply put, the phytase enzymes released by the yeasts as the dough acidifies effectively pre-digest the flour, which releases the micronutrients and in turn reduces bloating and digestive discomfort.

Sourdough bread also takes longer to digest; studies have shown that rye flour added to sourdough can help regulate blood sugar levels which helps ward off diabetes.

Sourdough is also a prebiotic, which helps to support the gut microbiome. It is one of the subjects that we go into detail on in the sourdough for health courses.

What are the ingredients in Sourdough?
Just flour, water and salt – all the other unnatural ingredients that commercially produced bread include are eliminated. Cheap, industrially manufactured, Chorleywood processed bread relies on enzymes, preservatives, emulsifiers and improvers to bake bread at speed. These additives are also to blame for some people’s wheat intolerance.

Is sourdough expensive to make?

No. Using ordinary strong flour means you can make an 800g loaf for as little as 28p, although I encourage my students to use organic locally milled stoneground flour if they are able to

Is sourdough easy to make?

Yes. It takes about 15 minutes spread over the course of 24 hours. Ironically sourdough has a reputation of being difficult, but it is just a matter of understanding how the dough behaves and what factors affect it.

You can learn to make sourdough at home using any of my books or healthy sourdough recipes or with The Sourdough Club’s 12 Month Online Course

References

Lopez HW, Krespine V, Guy C, Messager A, Demigne C, Remesy C. Prolonged fermentation of whole wheat sourdough reduces phytate level and increases soluble

magnesium. J Agric Food Chem. 2001 May;49(5):2657-62. PubMed PMID: 11368651.

First Published April 2014

Last updated December 2021

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All reasonable care is taken when writing about health aspects of bread, but the information it contains is not intended to take the place of treatment by a qualified medical practitioner. You must seek professional advice if you are in any doubt about any medical condition. Any application of the ideas and information contained on this website is at the reader's sole discretion and risk.

About Dr Vanessa Kimbell

Dr Vanessa Kimbell is acknowledged as one of the world’s foremost authorities on bread and human health — the first person to hold a doctorate in Baking as Lifestyle Medicine and Preventative Healthcare, and the pioneer who, long before gut health became a mainstream concern, first identified the crucial role bread plays in the gut microbiome and mental wellbeing. A fourth-generation baker of Italian descent, she has been baking sourdough since the age of 11, served her traditional apprenticeship in the Dordogne, and is a time-served, French-trained qualified baker who has worked alongside some of the world’s greatest bakers including Richard Hart and Gabriele Bonci. She has spent four decades asking the questions the food industry preferred no one asked: why was industrial mono bread slowly harming us, and what would it take to make bread that genuinely nourishes?

The answer became her life’s work. As founder and Course Director of The Sourdough School in Northamptonshire — a world-renowned centre of research and education — she has taught bakers from over 84 countries, integrated the BALM (Baking as Lifestyle Medicine) Protocol into NHS clinical practice at Bethlem Royal Hospital, and developed Proven Bread: the first bread built on clinical evidence, personalised to the individual through nutrigenetics and gut microbiome assessment. She delivered the Royal College of General Practitioners‘ approved course in the Nutrition of Bread, has been a regular contributor to BBC Radio 4’s Food Programme for many years, and collaborates with leading scientists and clinicians including Professor Tim Spector — who credits her with teaching people to make the healthiest bread in the world — and Professor David Veale. Named the Sourdough Queen by The Telegraph in 2013, her influence reaches far beyond the classroom — from artisan bakers and healthcare professionals to the world’s leading food scientists and multinational food corporations.

A bestselling international author of five books, her sixth — Proven — publishes in November 2026.

More information about Vanessa can be found at
The Sourdough School,
The Sourdough Club,
on Instagram at @SourdoughClub,
@SourdoughSchool and
@vanessakimbell,
on Facebook and
LinkedIn.