In This Article
In nature, the diet of herbivores in the wild changes dramatically from season to season and, as if like a symphony, the microbes needed to digest each season’s harvest thrive with each seasonal shift. Seasonal microbes flourish on cue to digest the woody, branches and barks of winter, the greens of spring and the acorns of fall.
Microbes suited to digest the soft leaves and bitter roots of spring populate the rumen (the first chamber of the stomach) of herbivores in the spring and vanish by winter, while microbes that feed on the tougher wood fibers that flourish in the winter are replaced by a new population of microbes that digest the fruits and greens of summer. A similar microbial shift should take place in the human digestive system.
The Microbial Circle of Life
The microbes that make up the body’s microbiome come from the soil that nourishes the plants we eat. Each plant seasonally attracts certain beneficial microbes from the soil, creating a symbiotic relationship. Plants seem to benefit from certain microbes, and certain microbes seem to benefit from the nutrients of certain plants.
With each seasonal shift, the microbiology of the soil changes, the chemistry of the plants change and the microbes that attach themselves to the roots, stems and leaves of each plant shift like a changing of the guard. When we eat these plants in season, we consume the nutrients in the plant as well as the microbes that are attracted to and attached to that plant. We are also ingesting the foods that the microbes who are attached to these plants love.
These microbes make up a microbial community within us – which makes up 90% of the cells in our human bodies.
Consequences of Eating Out of Season
When we do not eat seasonally, our microbiome is quickly disconnected from the intelligence of nature, and much of our genetic dependence on seasonal microbes is lost.
Let me share a quote from the book The Forest Unseen to illustrate this point: (2)
“Sudden changes in the diet can disrupt this elegant molding of the rumen community and its environment. If a deer is fed corn or leafy greens in the middle of winter, its rumen will be knocked off balance, acidity will rise uncontrollably, and gases will bloat the rumen. Indigestion of this kind can be lethal.”
In other words, when an herbivore eats foods that are not in season, it causes a drastic shift in its microbiology, leading to severe indigestion that can actually kill the herbivore. Cows, for example, when taken from pastures and fed grain instead of seasonal grasses, have to be medicated to settle their stomachs.
I realize that we are omnivores and not herbivores, but clearly, this is food for thought! We are as connected to the cycles of nature as are the herbivores, albeit in a different way. If eating foods that are not in season can kill a deer, then is this a message for us to begin to respect the diet that has been right in front of us all these years?
There is no doubt that the microbes in our intestinal tract change according to diet and seasonal influences. Perhaps we are more resilient to these changes, but are we immune to them?
Without a diet rich in seasonally-changing microbes, our intestines are often populated by space-occupying microbes that, while not necessarily bad, are not beneficial either. They take up real estate in the intestines and render the gut, its immunity, and many other adaptive processes to function less than optimally. Without the influx of seasonal microbes to boost our digestive strength and support a diverse community of essential and beneficial bacteria, we become extremely vulnerable and often hyper-sensitive to our environment and foods.
A Holy Case for Raw Cheese
I cannot think of a better example of this than sharing a favorite story from one of my previous articles: (1)
Since the 1970s, Sister Noella, a Benedictine nun, has been making raw cheese on the abbey farm. This is not just any cheese. It is one of France’s most prized cheeses: Saint-Nectaire. It is a raw milk, semi-solid, fungal ripened cheese that has been the pride of France’s Auvergne region since the seventeenth century.
The problem is that her abbey is in Connecticut and, according to the FDA, raw cheese is illegal. According to the FDA, cheese must be made in a sterile environment in stainless steel containers. According to Sister Noella, Saint-Nectaire must be made in an ancient wooded barrel with a wooden spoon. Her spoon, of course, had a carved cross on the paddle to stir the cheese.
Nothing about her cheese room was sterile, or ever could be. In her thirties, she went back to school and got a Ph.D. in microbiology to be able to prove to the FDA her cheese was safe.
Ph.D. in tow, she made two batches of cheese. One batch in sterile stainless steel containers with pasteurized milk, and another batch in her unsterile room with her unsterile wooden barrel, unsterile wooden spoon and, of course, raw milk. Into both batches, she introduced a significant amount of E. coli – a toxic bacteria.
After the cheeses were made, the cheese made with E. coli in the sterile containers had high levels of E. coli, and the cheese made in the wooden barrel had next to none!
Interestingly, we all have E. coli in our guts from time to time. In a healthy gut with lots of good microbes, the introduction of E. coli will rally the good bugs to knock out the pathogens. In Sister Noella’s wooden barrel, the good bacteria that hid in the old wooden crevices out-performed the bad bacteria.
Since then, the FDA has left her alone to make her raw, unsterile cheese.
The evidence that our microbiome is deeply connected to the seasonal shift of microbes in the soil is mounting. To explore this further, we are launching a free year-long challenge to eat with the seasons. It is called The 3-Season Diet Challenge, named after my book on eating seasonally, The 3-Season Diet. Each month you will get a free guide of seasonal eating info that will include articles, videos, the latest research, recipes from the Food Network star, Emma Frisch, and much more. It is completely free and anyone can join in at any time throughout the year. Join the movement!
- Pollan, Michael. Cooked: A Natural History of Transformation. Penguin Press. New York, 2013.
- Haskell, David George. The Forest Unseen. Penguin Books, 2012.