Gone are the days of simply identifying a gut pathogen, prescribing an antibiotic and moving onto the next biological system. Although the identification and eradication of pathogens remains important, it is no longer sufficient. Recent advancements, most notably DNA technology and culturomics, allow us to identify the details of vast microbial communities held within our human biology. We have discovered that many seemingly disparate conditions ranging from anorexia nervosa, neurotransmitter imbalance, extroverted behavior, major depressive disorder, sleep physiology and aging have all been linked to the gut microbiome.^1-6 Abundance and diversity are the foundation of the gut microbiome and intricately connected to various health outcomes. Diversity of species is an important component of health for any ecosystem, and the gastrointestinal (GI) microbiome is no exception.  Even colic in infancy is associated with decreased gut microbial diversity.⁷ Chronic preventable lifestyle diseases, those categorized as potentially more difficult to treat, also have a link to microbiome abundance and diversity.⁸ As the father of medicine Hippocrates predicted, “all disease begins in the gut.”¹ The key to understanding this sage adage may lie in testing and addressing gut microbial abundance and diversity.

To fully understand the human GI microbiome, we may begin with our past. The Hadza tribe of Tanzania are the closest living approximation to our ancestry as they have remained largely unchanged for thousands of years. They do not store any food yet subsist by hunting with hand-made bows and arrows and foraging for edible plants, especially tubers, akin to our modern-day potato.⁹ Today, proponents of paleo and carnivore diets would lead one to believe the hunter-gather diet consists primarily of meat. Contrary to pop culture belief, nearly all warm climate hunter-gather diets consist of a mixture of plants and meats, actually approximating 50/50.¹⁰ The fact remains that hunting is an endeavor ending in failure more often than not, hence the gathering of carbohydrates account for a sizeable portion of pre-agrarian diets. The most frequently consumed food of the Hadza, is also their least favorite, tubers.⁹ These tubers contribute to their notable daily fiber intake of approximately 100-150 g QD.¹⁰ In contrast the standard American diet contains approximately 15 grams of fiber QD, while the current Dietary Guidelines recommend approximately 30 grams QD.¹¹ This is relevant as fiber, specifically soluble fiber, is linked to gut microbial abundance and diversity, which is in turn associated with a wide variety of health outcomes. Generally speaking for produce, one-third of the fiber will be soluble and two-thirds of the total is insoluble.