Excerpt from New Book “Our Fermented Lives: A History of How Fermented Foods Have Shaped Cultures & Communities”

The Microbiome Today

Microbes, both beneficial and not, are our oldest teachers, and as our plan- et’s earliest life-forms, they are our ancestors as well. Eventually, the earliest microbes began living inside other microbes, functioning as organelles for them and creating the framework for multicellular life. We see, then, how the very shape and function of our bodies was in part determined by the relationships of microorganisms to each other. As our bodies continued to develop specialized organs and cells, we developed another relationship with all the microorganisms that live within and on our bodies: what we today call the microbiome. The number of microorganisms that make up our microbiome is vast, far outnumbering our own cells by a ratio of 10 to 1. The majority of them live in our gastrointestinal (GI) tract, and in total these microbes contain 100 times as many genes as our genome.

Our modern bodies are the way they are in part because of the microbes with whom we share our world. In some cases, our bodies, populations, and societies have been profoundly shaped by the impact of pathogenic microbes, and not always in a positive way (for example, the loss of life from the COVID-19 pandemic). But in others, beneficial microorganisms have taught our bodies about the delicate art of immunity, forming an ancient symbiotic relationship in which we serve as host and they serve as a critical part of our immune system. Today, our microbiome helps keep us healthy in the face of unwanted microbial intruders, and we’re just now learning about some of its other benefits to our physical and mental health, such as better digestion, changes in mood and reduction of depression and anxiety, decreased inflammation, and more.

Each time I think of how central these tiny beings are to the web of life, I think of something my mom used to tell me as a child: Magic (or faith) and science do not have to be opposite ends of a spectrum. For her, as for me, the more I learn about the evolution of microbes and the intersection of microbes and our physical bodies, the more I believe in the existence of magic in the world.

Ferments for Flavor and Nutrition

Taste is one of the most important ways in which our body communicates to us the nutritive value of our food. Our senses of taste and smell actually developed to guide us toward foods that are beneficial to our bodies. We are born with aversions to certain tastes and smells (for example, the smell of rotting meat) because it was evolutionarily advantageous for us to avoid those objects, just as we are drawn toward flavors that indicate the presence of nutrition (for instance, the sweetness of calorie-rich ripe fruit).

Fermentation has a role in that dynamic. Through fermentation, for example, the starches in grains are broken down from long chains of linked glucose molecules into simple sugars, and the proteins in soybeans and meat are transformed into free amino acids. In the process, the flavors we associate with nutrient-dense food (umami in protein-rich foods, for example) develop. This is an excellent example of how the concepts we cover in this book have overlapped throughout our history: We often make fermented foods for flavor, but the flavors we choose and enjoy, and the ingredients we pick, are based on a long evolutionary history of valuing what was most nutritious.

As human communities transitioned toward agriculture and away from hunter-gatherer lifestyles, we started to grow the nourishing foods that we found in the wild. And fermentation played a big role in allowing us to grow more and keep it longer so we could continue to nourish ourselves through- out the year. Milk, for example, could be turned into more shelf-stable cheeses, and vegetables turned into any manner of pickles. Both could be combined with grains and legumes to make tarhana, the Turkish dried soup mix from Chapter 1. Fermentation, in tandem with a variety of plant and animal crops, thus became a cornerstone of human nutrition, helping to keep people fed and healthy.

The Nutrition Of Early Ferments

Fermentation was an important part of keeping our ancestors healthy on diets that were limited both geographically and seasonally.

MILK AND DAIRY PRODUCTS, for example, are rich sources of calcium, protein, carbohydrates, and other nutrients, but these benefits can- not be accessed by anyone who is lactose intolerant. Lactose intolerance is common throughout many global populations, though it seems to be least common among those with northern European heritage for numerous reasons, including the development of mixed farming (crops and livestock) with dairy production. If the people in a community could not consume fresh milk but it was one of their available food sources, their health would depend on making that food digestible. Fermentation was often the answer. When milk is fermented, lactose is converted into lactic acid, which the body can tolerate.

BEANS AND SEEDS were relatively simple to grow and are among our earliest crops, present in all the great agricultural societies. As Ken Albala says, “Beans are perhaps the one food common and indispensable to us all.” Beans are filling and nutritious, and even more so with fermentation. Fermentation “predigests” legumes, breaking down nutrient-blocking compounds (such as rigid cellulose compounds) and making proteins more digestible to our bodies. Raw soybeans, for example, contain slight toxins that are eliminated when the beans are cooked or fermented. When fermented, the B vitamins (except for thiamine) are increased, and the protein is hydrolyzed to amino acids, making it more bioavailable. When legumes are fermented together with grains, as in Indian idli and dosa, they become a complete protein, containing all the amino acids our bodies need to thrive.

To read about the nutrition of other early ferments like grains, beer and more, read Skinner’s book, “Our Fermented Lives.” Following is a favorite fermented dairy recipe of hers from the book, for cultured butter.