Trusting Your Gut (And Why I Don't Just Drink Beer)

I consume a lot of fermented food—and I am not talking just beer. Homemade kefir plays a starring role in my diet. I drink milk kefir straight up and in three-ingredient smoothies (with frozen strawberries and agave syrup), and add a lot of it when I make frozen yogurt. Naturally carbonated water kefir, which I make with various fruit juices, is my healthful soda substitute. Then there are sourdough bread, cheese, pickles, kimchi, and sauerkraut. I am fortunate because I actually like sour-tasting food. But I would eat or drink them even if I didn’t.

It is obvious to me that humans need to eat fermented food because we evolved to do so. As soon as you pick a fruit, it starts to change. The same thing happens to milk as soon as it leaves the cow, and to fresh bread once it cools down sufficiently. In our hyper-sterile modern world, we look at this natural breakdown and call it spoiling. But real fermentation is actually nature's original defense strategy—a microbial turf war. When beneficial bacteria move in and ferment a food, they create a clean, acidic environment that keeps the bad, pathogenic "spoiling" bugs from taking over. Refrigeration and preservatives can slow this process down to a crawl, but those are modern interventions. Our ancestors did not have those available, so they relied on techniques such as salting and smoking. But they also regularly ate live, active foods that we would reject as spoiled.

Assuming that I am correct about this, why does it matter? Well, I believe strongly that people need healthy gut biomes. I also believe that humans evolved in tandem with our gut bacteria. That means that a sudden change in which bacteria live in your gut will affect your health. My evidence for this is all the mental and physical ailments that are common among Americans today but that were much less prevalent a few decades ago and unheard of in traditional societies. If, like me, you think humans evolved to be healthy by default, then how can you explain this sudden susceptibility to health problems like depression, anxiety, obesity, diabetes, and asthma? You won’t be surprised that my answer is that unhealthy gut biomes are largely to blame. While human evolution is a very slow process, changing which strains of bacteria colonize your gut can happen very quickly.

It is widely accepted that overuse of antibiotics is harmful. The gut biomes of both children and seniors are particularly fragile. Researchers have also theorized other reasons why certain gut bacterial strains that used to be common are disappearing, from the increasing incidence of Caesarean births to the widespread use of emulsifiers in processed food. Those may all play a part. I haven’t taken antibiotics in a long time, and I make my own salad dressing to keep corporate additives out of my engine. But most importantly, I eat a lot of fermented food.