Meta description: Diversity Bread® is a long, slow fermented bread developed by Dr Vanessa Kimbell and made to defined standards, including a minimum 18-hour fermentation and thirty different plants in a slice.
What is Diversity Bread®?
Diversity Bread is a standard for bread that brings diversity back into the system – from the soil and the crops we grow to the flour we mill, fermentation, the gut microbiome and the people we feed.
What is Diversity Bread®?
Diversity Bread® is a long, slow fermented bread developed by Dr Vanessa Kimbell and made to a set of standards rather than to one fixed recipe. At its heart are two requirements: a minimum of 18 hours of fermentation and thirty different plants in a slice of bread.
The bread is the culmination of Kimbell’s work on bread, fermentation, nutrition and digestibility, which began in 1997. Over the following decades, that work developed into a much wider investigation of what had been progressively lost through the industrialisation of bread.
Central to that work was diversity.
Kimbell observed a progressive narrowing throughout the bread system: loss of microbial diversity in agricultural soils; narrowing of the grains and crops being grown; disappearance of many of the seeds, pulses, herbs, flowers and botanicals that had historically formed part of diverse food systems; increasingly refined flour; and the replacement of complex fermentation ecologies with breadmaking dominated by selected strains of Saccharomyces cerevisiae.
She came to describe the resulting bread as Mono Bread.
Diversity Bread® asks what happens when we move in the other direction.
It brings grains, pulses, seeds, herbs, flowers and other botanicals together with long fermentation. The aim is to restore biological richness to something we eat every day and, in doing so, reconnect the diversity of the agricultural system with the diversity of our diet and our gut microbiome.
What is Mono Bread?
Mono Bread is the term developed by Kimbell to describe bread that has been reduced in diversity.
Think about the bread humans evolved eating and compare it with the dominant model of modern industrial bread. Grain diversity has narrowed dramatically. Milling removes substantial parts of the grain in refined flour. The herbs, seeds, pulses and botanicals that historically formed part of much more diverse food systems have largely disappeared from everyday bread.
The ferment was also narrowed.
Traditional bread fermentation involves communities of microorganisms, including yeasts and lactic acid bacteria. Industrial breadmaking increasingly came to depend upon selected strains of Saccharomyces cerevisiae – baker’s yeast – enabling bread to be produced rapidly and consistently, while reducing much of the microbial diversity and microbial transformation associated with long, spontaneous and sourdough fermentation.
Bread is such an important staple that this matters. When a food is eaten every day, what it contains – and what has disappeared from it – becomes significant.
Diversity Bread® grew from the idea that bread could help put some of this missing diversity back.
Where does the diversity come from?
Some of it comes from the flour and some from fermentation.
Diversity Bread® uses diverse blends of grains, seeds, pulses, herbs, flowers and botanicals. Botanical Blend Flour® and Meadow Blend flour were developed at The Sourdough School to bring ingredients together that would rarely meet in an ordinary loaf.
These blends are allowed to change. Plants grow in seasons, harvests differ and regenerative farming systems depend upon rotations rather than uniformity. So the precise character of Diversity Bread® can move with the landscape from which it comes.
That variation is part of the bread.
Fermentation then transforms those ingredients. During a long sourdough fermentation, cereal enzymes and the metabolic activity of yeasts and lactic acid bacteria alter the dough: carbohydrates, proteins, phytochemicals and other compounds are transformed as the microbial community ferments the flour.
This is one of the reasons Diversity Bread® is a system rather than simply a recipe. The diversity of the ingredients and the biology of fermentation work together.
Why thirty plants?
The thirty plants have a history.
The number came from the American Gut Project, a large citizen-science study exploring relationships between diet, lifestyle and the human gut microbiome. One of its most interesting findings was that people who reported eating more than thirty different types of plants each week had greater gut microbial diversity than those reporting fewer than ten.
When Kimbell saw that work, it gave scientific context to something she had already been observing through her work with bread.
By 2016, Kimbell had begun formally applying a Diversity Score to the botanical flour blends and breads being developed at The Sourdough School. The American Gut findings provided an important piece of the emerging framework because they demonstrated a relationship between dietary plant diversity and the ecology of the gut microbiome.
Kimbell applied that observation to bread.
The idea went considerably further than putting thirty ingredients into a loaf.
Diversity is a continuum.
Microbial diversity has been lost from soils as agricultural systems have intensified. The range of crops and grains being grown and eaten has narrowed. Many of the herbs, seeds, flowers and botanicals that historically accompanied grains within diverse food systems have disappeared from everyday bread.
Then the ferment was narrowed.
Traditional bread fermentation involves complex microbial communities. Industrial breadmaking increasingly came to depend upon selected strains of Saccharomyces cerevisiae – baker’s yeast – replacing much of the microbial ecology associated with spontaneous and sourdough fermentation. With that narrowing came a reduction in the range of microbial transformations taking place in the dough.
At the same time, industrialisation progressively reduced diversity in the wider diet.
These changes are usually studied separately: soil scientists study microbial diversity in soil; agricultural scientists study crop diversity; cereal scientists study grain; fermentation scientists study yeasts and lactic acid bacteria; nutrition scientists study dietary diversity; microbiome scientists study the ecology of the gut.
Kimbell’s work brought these relationships together.
The diversity in the soil, the diversity of the crops, the diversity within the flour, the diversity of the ferment, the diversity of our diet and the diversity of our gut microbiome belong to the same continuum.
Bread sits extraordinarily close to the centre of that relationship because it connects agriculture with microbial fermentation and with a food that many people eat every day.
The thirty-plant observation therefore led to another question: what would happen if that diversity were put into the bread?
That became one of the defining standards of Diversity Bread®: thirty different plants in a slice.
The thirty is grounded in microbiome research, while its application to bread forms part of a much wider principle. Diversity Bread® is designed to restore some of the biological diversity that has progressively disappeared along the journey from soil to grain, through fermentation, into our diet and ultimately to the gut.
That is the principle behind:
Diversity counts.
What did the research show?
As part of Kimbell’s doctoral research, Diversity Bread® was compared with standard white and wholemeal breads.
The differences were striking.
Diversity Bread® contained nearly three times more polyphenols than the wholemeal bread and eight times more than the white bread. It also showed twice the antioxidant activity of the wholemeal bread and three times that of the white bread.
The research identified ten polyphenols in Diversity Bread® that were not detected in either of the standard breads, including caffeoylcholine.
Further metabolomics work with Puratos confirmed the distinctive polyphenol profile of Diversity Bread®.
Polyphenols are bioactive compounds produced by plants. Many reach the colon, where they interact bidirectionally with the gut microbiota: microorganisms can transform polyphenols into metabolites with different biological activities, while polyphenols and their metabolites can also influence the microbial ecosystem.
So diversity in bread means considerably more than counting ingredients. The interest lies in what those plants bring with them, what fermentation does to those compounds and what subsequently becomes available to us and to our microbes.
Why does Diversity Bread® matter for farming?
There is another part of this story that begins before the flour reaches the bakery.
Diversity Bread® was designed to use crops from across the regenerative farming rotation. A healthy rotation may include cereals alongside pulses and other crops that perform different functions within the agricultural system.
If farmers are to grow diverse rotations, there also needs to be a market for what those rotations produce.
Bread can help create that market.
Instead of valuing only the wheat crop, Diversity Bread® creates a place for ingredients grown throughout the rotation. This means supporting the farmer across the rotation rather than purchasing only the crop that conventionally becomes bread.
In this sense, the loaf connects what is happening in the soil with what eventually happens in the gut.
Soil ? crop ? mill ? ferment ? bread ? gut ? community.
These are usually discussed as separate subjects. Diversity Bread® brings them back into relationship.
This is why Diversity Bread® is a bread for planetary as well as human health. The agricultural system, the food system and the microbial system are connected.
How did Diversity Bread® develop?
The development of Diversity Bread® is the result of more than two decades of work by Dr Vanessa Kimbell.
Kimbell began this work in 1997, initially through bread, fermentation and digestibility. Over time, the work expanded to include nutrition, microbial ecology, agricultural diversity, botanical ingredients, the gut microbiome and the relationship between bread and health.
The botanical blends developed through this work brought grains together with pulses, seeds, herbs, flowers and other botanicals. By 2016, Kimbell was formally using a Diversity Score as part of the development of these blends and the breads made from them.
The principles were progressively researched, taught and refined at The Sourdough School and developed into the standards that define Diversity Bread®.
This work has also been supported by the development of The Sourdough School Research Database, which brings together the scientific literature underpinning the school’s work on sourdough, fermentation, fibre, diversity, the gut microbiome and Baking as Lifestyle Medicine.
Diversity Bread® is therefore the named and codified application of a body of work developed by Kimbell over decades: bringing agricultural diversity, diverse flour, microbial fermentation and microbiome science together through bread.
How is Diversity Bread® used?
The principles behind Diversity Bread® have been taught at The Sourdough School for over two decades, and Diversity Bread® is the bread specified within the Baking as Lifestyle Medicine (BALM) Protocol.
Home bakers can learn the principles and bake it themselves, including through Kimbell’s 10 Minute Sourdough method and in PROVEN. Professional bakers can bake Diversity Bread® under licence for their own customers.
The purpose has always been bigger than producing one loaf at The Sourdough School. For Diversity Bread® to make a difference, people need to be able to bake it, buy it and participate in the system it supports.
Every loaf is therefore part of something larger: demand for greater crop diversity, support for regenerative farming, a more diverse food supply and bread designed with the gut microbiome in mind.
You are the system change.
Diversity Bread® and Botanical Blend Flour® are registered trade marks.
All reasonable care is taken when writing about the health aspects of bread, but the information contained on this website is not intended to replace treatment or advice from a qualified medical practitioner. You should seek professional advice if you are in any doubt about a medical condition. Any application of the ideas and information contained on this website is at the reader’s sole discretion and risk.