Fermented food and drink
Fermented foods offer rare nutritional benefit to our bodies and our gut microbiota in a single package. Luckily, fermented food is easy to make at home because their full health benefits are delivered unpasteurized, and because home fermenting allows us to eat real seasonal food produced locally.
Selected How-To Books from My Collection
One of the best things about fermented food is that we can make it ourselves from seasonal and locally-sourced produce. If you’re interested in trying fermented food, I’ve listed five books from my collection that you might find useful to get started. If there is such a thing as a spectrum of books on fermentation ranging from very comprehensive and practicable at one end and narrowly focused on food with specialized equipment at the other, I’d direct you to Sandor Katz’s fermentation bible [1] and Noma’s guide [2], respectively. Between those two, you’ll find James Read’s beautifully illustrated and narrated addition [3]and Assa Simonsson’s Scandinavian how-to [4]. I also recommend looking at what Sally Fallon has to say about fermentation where she describes traditional real food more broadly [5].
What are Fermented Foods?
Fermented food (and drink) is created by the metabolic action of beneficial microorganisms on our food. Healthy fermentation by certain microorganisms (as opposed to unhealthy spoilage) can occur in the presence of oxygen from the air or when oxygen is excluded. We can create the conditions necessary for healthy fermentation by using certain tried and tested recipes that will encourage health-producing organisms and discourage unhealthy ones.
As an example of what I mean, consider the fate of a cabbage (I bet you never woke up this morning and thought you’d be doing that…!). If we leave a cabbage on an open countertop at room temperature, dark oxygen-loving moulds will grow on its surface and eventually reduce it to smelly slime. Alternatively, when we salt, cover with water, and exclude oxygen, we encourage microorganisms that can live in salty and low-oxygen conditions and produce delicious and healthy sauerkraut [1].
“Fermented dairy and vegetable products contain important probiotics (microorganisms that can benefit our gut microbiome), prebiotics (food for our gut microbiome), and microbial metabolites that are active and provide significant benefit to the human body”
The Health Benefits of Fermented Foods
The health benefits of fermented foods are covered extensively in a number of books [1-5]. Sandor Katz summarises things well [1]:
“Fermented foods, as a group, are highly nutritious and digestible. Fermentation pre-digests foods, making nutrients more bioavailable, and in many cases fermentation generates additional nutrients or removes anti-nutrients or toxins. Ferments with live lactic-acid-producing bacteria intact are especially supportive of digestive health, immune function, and general well-being”
Fermented dairy and vegetable products contain important probiotics (microorganisms that can benefit our gut microbiome), prebiotics (food for our gut microbiome), and microbial metabolites that are active and provide significant benefit to the human body [8, 9]. For example:
Ferment prebiotics and probiotics can increase the biodiversity of our gut microbiota. Microbiota diversity imparts resilience that supports good health and guards against ill-health. A healthy, diverse gut microbiome guards against intestinal permeability and inflammation and avoids infection, illness, and psychological imbalance
Vitamins – ferments contain a range of B vitamins which may not be present in our modern food because of processing during manufacturing and cooking
Nervous system communication component - GABA is a major component of the nervous system in the brain and other parts of the human body. It has an important role in maintaining healthy blood pressure and reducing symptoms of depression
Complex carbohydrates – these have a role in communication within our gut microbiota and in benefitting healthy microorganisms in their role of holding back harmful bugs
Protein metabolites – when animal and plant proteins are metabolised by microorganisms the resulting protein building blocks (peptides) can be beneficial to humans. For example, bioactive peptides are being actively investigated for their benefits to the human heart, digestive, hormone, immune, and nervous systems
Kefir is a nutritious base for a tasty smoothie
How did fermented foods come about?
Real human food of every type (plant and animal) ripens, rots, or spoils after harvest or hunt. These natural processes are caused by the microbes naturally found on our food, and eventually they render them unpalatable and even dangerous to our health.
Our ancestors had to find ways to extend food stability to overcome periods of poor hunting and off-season crop cultivation. This they did by implementing practices for each food type and climactic zone.
People in cold climates froze whale and seal meat, those in hot climates sun-dried their food, those at high altitudes used daily temperature variations to freeze-dry, and people in temperate zones developed practices to ferment their foods. Thus, in the temperate zones was borne the practice of enriching and preserving food using their respective natural microbiota for the benefit of human health [6].
“The chronic diseases we are currently suffering from may be caused by a mismatch between the environment for which we are adapted and the environment we have created.”
Diseases of Low Microbiota Diversity
I have described previously how humans did not evolve alone but did so in symbiotic integration with microorganisms. We, the host, and our microbiota are so closely metabolically linked that we are what is called a human holobiont.
Changes to the social and technological nature of our lives, especially over the past five hundred years (the blink of an eye in evolutionary terms) have impacted our host-microbiota interaction in part because of reduced microbiota diversity. This appears to have happed as we migrated into cities, had less contact with soils and animals, developed better sanitation through things like soap and water purification, and ate more processed foods.
Also, infant microbiota development has been affected by an increase in processed maternal food, more Cesarean deliveries, administration of antibiotics to the mother during pregnancy, and an increase in the use of early formula nutrition.
In the aggregate, these environmental changes have reduced human illness and death caused by infections and have increased human lifespan.
Unfortunately, at the same time, we have witnessed an increase in autoimmune and inflammatory diseases [7], as follows:
Social and technological changes to our lifestyles may, therefore, have created environmental pressures on our gut microbiota for which it is not evolved and may be promoting a state of ill-health in our bodies. To put this another way, the human host and our microbiota adapted to the environment within which we evolved. Unfortunately, our bodies and our microbiota may not be well adapted to the modern environment we have created. The chronic diseases we are currently suffering from may be caused by a mismatch between the environment for which we are adapted and the environment we have created [10].
Can Fermented Food Heal a Damaged Gut?
This question goes beyond acknowledging the delivery of nutrition provided by ferments [1] to consider a longer lasting benefit. From what I can find the answer seems to lie somewhere between “we can’t be sure” and “things look promising” (those are my words, I’m not quoting) [8, 9].
Given that we can’t be sure, what evidence exists for the promising nature of things? Consider how ferments may provide energy for and increase the diversity of human microbiota in ways a modern diet cannot:
The microbial density of ferments is high enough to positively impact our gut microbiota
Fermentation adapts microbes to acid conditions which makes it more likely that they will survive passage through our acidic stomach
The microbes in ferments are less diverse than those found in nature but ferments contain more of the microbes commonly found in the human gut
Fermentation pre-adapts microbes to the breakdown of complex dietary carbohydrates in the human gut
Ferments provide dietary fibres that act as food for gut microbiota
Ferments provide beneficial microbial metabolites that nourish gut microbiota
I have personally benefitted from fermented foods
As close to every day as I can manage, I have a Kefir smoothie. I use kefir grains to make about 1L of ferment every three days. If I’m in a rush I’ll simply drink about 300mL of the kefir. Typically I try to make a simple smoothie that gives me the added benefit of some fruit, veg, and amino acid, such as:
300mL of unpasteurized home-made kefir
Handful of blueberries
Handful of raspberries
Handful of spinach leaves
3g of glycine powder
1 tsp of flax seeds
Mix together with a highspeed blender
You can vary the recipe to suit your taste. I would note that the glycine powder does add some sweetness to the overall taste, in case you want that kind of thing.
My daily dose of kefir does appear to provide stability to my gut health. I occasionally still fall off the low carb wagon when on holiday and visiting friends. Without my daily kefir, I’d experience gut upset but on kefir, I have no such issues. I also find that a glass of kefir or smoothie can reduce bothersome sugar cravings (I’m a recovering chocoholic).
I’ve also fermented seasonal vegetables of various types using recipes from my small book collection [1 – 5]. I eat them as fermented in various dishes and occasionally as a slaw with low carb mayonnaise.
“The only way for each of us to decide if fermented food makes sense is to jump in and give it a go”
In summary
Fermented food is an excellent way to nourish our body and our microbiota at once using real seasonal food produced locally. The health benefits of ferments are well understood and there are many recipes available to us to make them at home. Aside from the immediate nutritional value, ferments may offer a way to re-establish gut microbiota that has been damaged by our modern human environment. The only way for each of us to decide if fermented food makes sense is to jump in and give it a go. Experiment and find what tastes good to you and what, if anything, makes you feel at the top of your game.
Selected references
The Art of Fermentation: An In-Depth Exploration of Essential Concepts and Processes from Around the World. Sandor Elix Katz (2012) – If there is such a thing as the fermentation bible, this is it. It contains close to 500 easy-to-read pages on co-evolution between humans and microbes, health benefits of fermentation and recipes for all types of fermented food and drink. If you’re interested in fermentation, this book should be in your collection.
The Noma Guide to Fermentation. Rene Redzepi and David Zilber (2018) – Noma is a (soon to close) Michelin-rated restaurant in Copenhagen, Denmark. Every dish in the restaurant includes some form of fermentation, and this book is written by the restaurant’s co-owners. In it you’ll find chapters on fermentation principles, equipment, and over 100 recipes. Of all of the books in my collection, this one contains lists of the most specialized equipment, tightly controlled fermentation recipes, and instructions on how to add fermented ingredients to your food.
Of Cabbages and Kimchi: A Practical Guide to the World of Fermented Food. James Read (2023) – This is the most recent addition to my collection of books on fermented foods. It covers ten fermented foods and (non-alcoholic) drinks and describes each with a mixture of history, folklore and recipes. The book is beautifully illustrated and is probably the most accessible to the lay-person in my collection.
Fermentation: How to Make Your Own Sauerkraut, Kimchi, Brine Pickles, Kefir, Kombucha, Vegan Dairy, and More. Asa Simonsson (2019) – The author is a Swede living in the UK where she is a practicing naturopath and chef. As with all of the books listed here, she provides guidance of fermentation principles before describing the traditional techniques, equipment and recipes she grew up with. I like this book for the Swedish insight.
Nourishing Traditions: The Cookbook that Challenges Politically Correct Nutrition and the Diet Dictocrats.. Sally Fallon (2001) – This isn’t strictly a book about fermentation (it has sections on sprouts, stocks, sauces, and dressings) but it does have some useful guidelines and recipes not covered elsewhere.
Whittington, H.D. et al (2019) Production and Conservation of Starter Cultures: From Backslopping” to Controlled Fermentations. In Azcarate-Peril, M.A. et al, editors. How Fermented Foods Feed a Healthy Gut Microbiota: A Nutrition Continuum. Springer, pp. 125-140
Salvucci, E. (2019) The Disappearing Microbiota: Diseases of the Western Civilization. In Azcarate-Peril, M.A. et al, editors. How Fermented Foods Feed a Healthy Gut Microbiota: A Nutrition Continuum. Springer, pp. 325-348
Pelaez, C. et al (2019) Fermented Dairy Products. In Azcarate-Peril, M.A. et al, editors. How Fermented Foods Feed a Healthy Gut Microbiota: A Nutrition Continuum. Springer, pp. 35-56
Perez-Diaz, I.M (2019) Fermented Vegetables as Vectors for Relocation of Microbial Diversity from the Environment to the Human Gut. In Azcarate-Peril, M.A. et al, editors. How Fermented Foods Feed a Healthy Gut Microbiota: A Nutrition Continuum. Springer, pp. 91-124
Lieberman, D. (2013) The Story of the Human Body. London: Penguin