Eat as many different plants as you can find, your gut bacteria will do the rest!
#EatNZKaitaki Isabel Pasch is a microbiologist & baker/owner of Bread & Butter Bakery in Tāmaki Makaurau. She shares a fascinating piece about the link between our gut microbiome & the food we eat.
I’m Isabel Pasch, the owner of Bread & Butter Bakery & Café in Grey Lynn, Auckland, New Zealand. Originally from Berlin Germany, I first came to New Zealand in 1999 to study marine microbiology. I fell in love with the wild beauty of Aotearoa/New Zealand, particularly the open friendly people, the bright sunshine and the many beaches. I had a brilliant time during my master's thesis at the University of Auckland studying the bacterial fermentation in the gut of fish. But life’s twists and turns took me back to Germany for most of the 2000s until my kiwi husband and I decided to move back to allow our kids to grow up in this beautiful country. Having moved from a half-finished PhD to study Science Communication during my time in Berlin I had a sense that in New Zealand I wanted to do something altogether different. I wanted to put what I had learned into practical, real world action.
Like many immigrants, the food we have grown up with is often the thing we miss the most, and since New Zealand was in dire need of better bread I started my own organic sourdough bakery in 2010. Both the lack of synthetic chemicals in food and proper slow fermentation meant organic and sourdough were crucial aspects in my ‘expert’ opinion for making ‘real bread’. Over the years I have learned a lot about grain agriculture, fermentation and nutrition, and the effects of chemicals on the microbiome. I have had thousands of conversations with people about bread, food and their health. I would no longer call myself a scientist, but I have gained a real world understanding of how badly the processed foods that so many of us eat affect our health and well-being. In the following article I aim to explain, how food affects the microbiome, the bacterial community living in our gut and how important the range of foods we eat are to our overall well-being.
The state of food today
75 percent of plant genetic diversity has been lost, because farmers around the world are abandoning older plant and seed varieties in favour of uniform hybridised seeds that promise ‘higher yields’. Of the 250,000 to 300,000 known edible plant species, humans today use only 150 to 200.
These numbers threaten our chances of feeding ourselves in the future. Imagine if diseases evolve wiping out those few species we have left. This is not an unthinkable scenario if you look at what is presently happening to the Cavendish banana *1.
Whether you’re a pessimist who believes that climate change will end the world as we know it in a few decades, or an optimist who believes in the adaptability of humans and nature, changing micro and macro climates and rising sea levels are something we won’t be able to avoid one way or another. Therefore the way we grow food and where we grow it will change in many parts of the world, so reducing the amount of food sources to just a handful of crops and animal species seems like a bad idea.
Even worse the supply of the seeds that provide 90% of the worlds calories (FAO) is tightly controlled by just four giant agri-chemical companies; Bayer (Monsanto), Corteva, ChemChina, and Limagrain. These companies own the seed patents meaning farmers have to buy seeds again every year, rather than being able to save and resow seeds themselves. These companies also sell the chemicals without which these hybrid plants would not grow.
Further down the food chain, the same companies also make processing chemicals that are used widely in the production of highly processed foods. These processing aids include enzymes, artificial flavours, colours, preservatives, emulsifiers and supplements which are necessary to create the mirage of diversity of foods you see in the supermarket. When a lifetime of eating nutritionally empty calories devoid of real nutrients causes obesity, allergies, food intolerances, or other diet related chronic diseases the same companies also sell the drugs you need to keep going a bit longer. It seems like a pretty good deal as a shareholder of Monsanto and co, but less so from the point of an ordinary human.
It wasn’t always this way and it doesn’t have to be in the future either. A growing number of farmers, bakers, food-makers, chefs and eaters around the world understand that it is the way we grow and process food that makes us and the planet sick, and that the power for change lies within each of us, every time choose what to eat.
And at the very heart of this understanding is that diversity is the most important thing about food. Here is why…
The evolution of human diets
Anatomically modern humans are thought to have existed for about 300,000 years. For most of that timespan, we were hunter-gatherers, agriculture is believed to have emerged for the first time about 10,000 years ago in the fertile crescent or modern-day Iran/ Iraq. We know from studies of the few remaining hunter-gatherer societies still in existence, such as the Hazda people of Tanzania, that their diets were/are vastly more diverse than modern diets. About half of their daily caloric intake came from plants, seeds, fruits, nuts, leaves, stems, roots and tubers, the other half came from animal proteins*3. Proportions of plants vs. protein varied according to seasons and animal migration patterns. Of course what people ate also varied greatly from place to place. To get to the 250,000 -300,000 known edible plant species someone at some point was eating them, otherwise, we wouldn’t know that they are edible.
Studies*4 of skeletal remains of hunter-gatherers show that they were healthier, stronger, taller and had better teeth than the early farmers that succeeded them and this is mirrored in modern-day hunter-gatherers like the Hazda.
This all makes perfect sense. We humans are animals in clothing, our bodies function in largely the same way as those of our ancestors and animal relatives- we are literally made up of the food we eat. The molecules of our cells and the fluids within our bodies are made from the food we eat. Since these biological bodies of ours have slowly evolved over millions of years the systems that make our bodies have adapted to work with what was available. They extract simple nutrients like sugars, proteins and fats from food, turning them into the parts that are necessary for our bodies to function. Using ‘ready-made’ molecules such as vitamins, (i.e. vitamin K), amino acids, and co-factors (parts of enzymes) from food but also from the metabolic products of bacteria living within our guts.
Billions of symbiotic bacteria live in our gut
Our digestive system consists of the mouth (with its teeth), oesophagus, stomach, small and large intestine, rectum and anus. While the teeth mechanically break the food apart the acid in the stomach dissolves food, so that the components of sugar, fat and protein can then be absorbed through the vast surface of the villi covering the small intestine. The villi are small finger like structures that contain mechanisms to selectively absorb nutrients from food. However certain components of food, most notably fibre, cannot be broken down and absorbed by us (or any other vertebrate species) because we lack the right enzymes to break fibre down. Therefore fibre, and with it other indigestible parts of food as well as the waste products our bodies excrete into the intestine, get dragged through the small intestine and end up in the large intestine. In the large intestine trillions of microorganisms break down whatever comes through. It is when we consider the role of these microorganisms where conventional dietary advice and more recent findings in microbiome studies really come to blows.
Most conventional diet ‘wisdom’ and with it the vast industry of processed foods completely ignores the role of bacteria in our health. Up until not that long ago, the idea that these bacterial communities had anything to do with our health was completely dismissed. In the last 15 years or so the science of microbiology has been accelerated by cheaply available DNA sequencing technology. As a result scientists are starting to get a better understanding of the vast number of organisms living inside us. This community is called the microbiome and , is a whole ecosystem – thousands of different species – trillions of individual single cellular organisms, bacteria, fungi and protozoa. The way our system processes the food that gets in and then gets passed on to us, and the role it plays in training the immune system (influencing allergies and auto-immune status of the host) is only slowly emerging to show the full picture.
What scientists have established by now is that the microbiome breaks down everything that comes out of the small intestine, the fibre and other metabolic waste. The microorganisms break down complex molecules into simpler one, which allows us to extract remaining nutrients. They synthesise all sorts of components we are unable to make ourselves. They also break down toxins and train cells of our own immune system about ‘good or bad’ bacteria. We are reliant on their work for our health, the proper functioning of our bodies depend on them doing a good job. As such we should do everything we can to keep them happy, healthy and most of all diverse
What to eat to keep your microbiome happy
There is no simple answer to what to eat as food can affect people in different ways. There are many foods and combinations that seem to result in healthy people. However one thing is clear - the wider a range of foods you eat, the more diverse a microbiome you have. Cutting whole food groups out, reduces the diversity of the microbiome as the groups of bacteria dealing with the remnants of this food group then disappear. Eating foods high in fibre (wholegrain foods and legumes), and eating foods fermented in a traditional slow ferment such as wholemeal sourdough bread, sauerkraut, kimchi and pickles etc seems to be very beneficial. As with all other ecosystems on this planet, the more diversity there is, the more stable the system runs. This has been shown in many studies that looked at the microbiome of healthy individuals and compared them with individuals suffering from metabolic diseases like obesity, irritable bowel syndrome (IBS)*5, coeliac disease (gluten intolerance)*6 . The people with metabolic diseases showed a reduced diversity of bacterial species and often a dramatic shift to a few dominant groups.
Food additives such as preservatives, emulsifiers, colours and flavourings are deemed ‘safe’ on a case by case basis, but there are no studies exploring the potential harm of an array or cocktail of these substances on a long-term basis, and this is the way that many people consume them. Their effect on the bacteria in our microbiome has also not be studied. As a result the term ‘safe’ should be held very lightly indeed!
The whole field of microbiology is still in the early stages of understanding about what is actually going on inside our guts. However observational studies*7 and many real world conversations with people suggest that a diet high in fibre and from wide a variety of plants is beneficial to the diversity of our gut microbes. And the more diverse the gut microbiome is, the more stability it has and the better the health outcomes for us.
So eat a diet with lots of diversity. Try eating 30 different plant sources per week - including herbs, spices, coffee, tea, legumes, grains, leafy greens and fruits. They should be processed as little as possible but cooking, baking, soaking and fermenting is fine. Avoid the use of antibiotics unless you really need them, don’t use disinfectants and household cleaners that ‘kill 99.99% of bacteria’ (because they actually do!) -use soap and hot water instead. Use naturally derived skin products without too many preservatives and most of all avoid highly processed foods made from the same 12 hybridised crops controlled by the giant multi-national companies.
Support local growers, farmers, community gardens, bakers and butchers and ask where they source their ingredients from. Alternatively, grow some greens in your own garden and get your hands dirty with soil (this also has been shown to be increasing the microbiome’s diversity).
By building a connection with your food and your environment when you have the option, you’ll choose real food, and little by little you’ll have the power to affect genuine change.
See more from Isabel on her personal blog: breadpolitics.com, or the Bread & Butter website: breadandbutter.nz or on Instagram: @breadandbutter.nz
Sources and Studies:
*2 https://atlasbiomed.com/blog/the-hadza-people-what-can-a-hunter-gatherer-microbiome-tell-us/
*3 https://academic.oup.com/ajcn/article/71/3/682/4729121
*4 https://thehealthbeat.com/the-prequel-how-much-meat-and-plants-did-hunter-gatherers-eat/
*5 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6039952/
*6 https://www.mdpi.com/2624-5647/4/3/12
*7 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4837298/
This is a post in collaboration with #FOODDIVERSITYDAY taking place on Jan 13th in the UK. Learn more here.