“Let me explain. No, it’s too much. Let me sum up.” -Inego Montoya (The Princess Bride)
Michael Pollan summarized his advice for eating well in seven words: Eat food, not too much, mostly plants.[i] He arrived at that advice without considering the microbiome. But if we have to think about eating in terms of feeding the microbiome, then what? In my opinion, nothing. Pollan’s advice about feeding the human body is probably the perfect advice for feeding the microbiome too.
In his view, “eating food” means eating food that resembles the original organism, which is to say not highly processed and still possessing most of the original qualities in terms of vitamins, minerals, fiber, and so on. In other words, the food should be as natural as possible and not be covered by the fingerprints (read: enhancements) of technology. And Pollan insisted that plants should be the basis of the diet and those plants should be as fresh and natural as possible.
Let’s go back to the tomato. I suggested that the tomato fruit is the expression of the tomato genome and that the garden tomato is the fullest expression of that genetic potential. The garden tomato contains everything that a tomato plant is capable of having because it has been challenged by the garden environment to express all of those attributes it has collected over evolutionary time in response to all manner of environmental stresses. In much the same way, our microbiome has incredible potential hidden in the thousands of species represented by trillions of bacteria possessing an estimated five million genes. What does it take to unlock that potential and to take advantage of the incredible ability of bacteria to produce new mutations rapidly?
The key to microbiome health is the partnership with bacteria and the realization that they are not alien hitchhikers, but digestive partners. They belong in our colon. We literally invited them in. The colon is an odd organ, but close examination reveals that it is an ideal housing complex for bacteria and quite possibly we have a backwards opinion of it.
The indigestible parts of the food we eat pass quickly through the small intestine to the colon. The colon is sealed from the oxygenated environment and ideal for fermentation. The appendix is situated where it can influence the composition of the colon quickly. Food passage is slow and deliberate, and the conditions change from one end to the other which creates varying habitats for supporting community diversity. The colon is an ideal bacterial environment.
Importantly, absorption of nutrients is not the primary function of the colon, which is in stark contrast to the small intestine where absorption is definitely the primary function. The environment of the colon is not designed for food digestion in the same way that chemical secretion in the small intestine denatures carbs, fats, and proteins. No, the colon is a place where our digestive enzymes don’t even serve a purpose.
As humans, we have a limited chemical arsenal when it comes to digesting food material, but the colon is a place where the biochemical arsenal is almost limitless and the toughest materials and chemical compounds in our food can be degraded. The structure of the colon is ideal for that task, but only if the attacking hordes are bacteria. It has to be bacteria.
The omnivore diet of humans can literally contain any kind of food material and the plant components will vary on an almost monthly basis if one eats what is naturally available. Hunter and gatherer humans were mobile and moved frequently to follow the seasonal food supply, and pastoralist and agricultural cultures also cultivated and ate a wide variety of plant foods. Spicy, aromatic and even toxic plants were incorporated into regional cuisines which added more chemical complexity. Plants are everywhere, which means food is everywhere, but only if it can be digested. How to handle the digestive chores faced by omnivorous humans? It has to be bacteria.
So, we must feed our partners. We must eat for an ecosystem. That’s the rub: if we think of ourselves as individuals, our approach to eating is simple, but if we think of ourselves as ecosystems, our approach to eating should be very different. The simple approach is to think that for nutrition we need carbs, fats, and proteins in some kind of proportion and for health we avoid the overconsumption of calories. And fiber is indigestible, but it keeps everything moving. Simple, right?
Most of us just worry about the proportions of carbs, fats, and proteins. At different times in recent history, carbs, fats, and proteins have all been considered good or bad, and to the point today that we aren’t sure who to listen to. And as we try to decide, we also are told that the quality of the foods we eat has changed. Wheat is now laden with gluten, cows are fed exclusive corn, flavor is disappearing, chicken has antibiotics, produce is grown under sterile condition in hothouses, and so on. What to do? What to eat? Eating as an individual used to be easy! Now we’re fat and tired and allergic and stressed, and exercise doesn’t seem to help. Perhaps it’s not so simple anymore.
Or maybe it is. If we eat to feed an ecosystem, we change the focus from feeding ourselves to eating what supports “them”. “They” need plants, fiber, and diversity, and not carbs, fats, and proteins. The microbiome needs us to eat food that can make it through the small intestine to their anaerobic home in the colon. This needs to be our new normal everyday diet and it needs to vary constantly in composition.
Our diet should be a flow of food information from the outside world. The food we eat should not be a single favorite plant that favors the dominance of only certain bacteria; it should be a buffet. It should be fruits and vegetables, leaves and roots, seeds and flowers, nuts and berries. It should not be peeled, canned, mechanically processed, or cooked unto death in oil. Flavors should not have to be added except to enhance the natural flavors of the plant and added flavors should be plant-based. Our plant-based diet should be full of strong flavors. Remember, eating isn’t about you personally, eating is about you collectively.
[i] Michael Pollan. 2008. In Defense of Food. Penguin Press.