A Nutritional Anthropology of the Human Gut Microbiota

The feeding strategy of Homo sapiens appears to be characterized by an extraordinary omnivorism, which has no equal among mammals with the exception to some extent of the Suidae and the brown bear. This strategy allows him to have a diet that is able to capture all substances and nutrients necessary for its energy and structural needs, according to the best sources, such as foods, available in the ecosystem of origin and from a certain point in its evolution, adapted to remote ecosystems. We can therefore say that diet is one of the main factors that differentiates and drives evolution of human populations. Dietary differences originated from cultural evolution and geographic differences in availability of crops and cultivation and animal husbandry. It is widely recognized that a varied and balanced diet is essential to an individual's health. The adverse effects of nutrient deficiency are numerous and well documented.1 4 Because nutritionally related problems continue to be the cause behind many diseases that hinder progress towards universally adequate health, all countries should be actively pursuing the improvement of their people's nutritional status. Recently we witnessed an explosion of food consumption studies in both urban and rural areas of developing countries.5 7 These types of studies are vital to our understanding of more "transitional" and/or "traditional" diets vs. the modern-day Western-style diet. Furthermore, food-consumption in rural communities in particu- lar generally involves a large proportion of the food coming from home-production or gathering or, at the very least, having been grown, produced and purchased locally. Therefore, diets are usually monotonous and simple because they are dependent on the availability of foods in the home or local markets as well as the prices of those foods. However, the foods themselves, often consumed with little processing or using traditional fermentation technologies, represent complex mixtures of non-digestible carbohydrates and fibers, polyphenols and live fermentative microorganisms, thereby representing both complex nutritional support for the gut microbiota and an important source of passenger microorganisms with immune-modulatory and metabolic potential. The relative invariability of these traditional diets may potentially be reflected in gut colonization by relatively homogeneous and characteristic microbiomes. Recent discoveries highlighting the importance of gut microbiota have demonstrated how the availability of the nutrients present in the foods comprising everyone's diet is highly dependent on the human gut microbiota. The question then becomes, to what extent is the human gut microbiota dependent on changes in diet and how robust is the human micro- biota from birth to death? To propose potential answers to these questions first of all we have to understand what is the human microbiota.