The Human As Host Microbe Supraorganism Analysis

The human as host–microbe supraorganism. A win-win situation?

At the dawn of microscopy, the 17th century Dutch scientist Antony van Leeuwenhoek used his crudely built microscope to view magnified scrapings of his own dental plaque: “I then most always saw, with great wonder, that in the said matter there were many very little living animalcules, very prettily a-moving. The biggest sort… had a very strong and swift motion, and shot through the water (or spittle) like a pike does through the water…”, he wrote in an illustrated letter to the Royal Society of London in 1683. Trillions of these “animalcules” or microbes inhabit us, numbering more than 10,000 different species with 150-fold more genes than the 20,500 human genes in our human genome.
How careful should we be with these numbers? At the Max Planck Institute (MPI) for Biology of Ageing in Cologne, Germany, Managing Director Adam Antebi suggests that “… cell number is not as important as the diversity of bacterial flora, which drives the possibilities of “genome expansion" and the mass. I would guess the flora make up less than 5% of our mass…” As hosts, we can think of ourselves as superorganisms, with our own eukaryotic cells joined with trillions of microbes as a “commensal” microbiome. Commensalism is defined as non-harmful coexistence between two organisms, where food or some other benefit is received by one party, without causing damage to the other. To their benefit, bacteria obtain energy to ensure their own survival, and to ours, they help us break down fats and carbohydrates, produce vitamins and hormones, train our immunity, and protect us from a hegemony of pathogenic microbes. Commensalism or mutualism? Both can be used to describe the fascinating relationship between bacteria and human
Eating an animal-based diet results in more bile-tolerant microorganisms and fewer microbes specialized at digesting complex carbohydrates. Dietary change also rapidly alters the numbers of carbohydrate- (plant-based) and protein-fermenting (meat-based) microbes in our microbiome. According to Valenzano, “there are huge possibilities to manipulate the host metabolism and physiology through pre- and pro-biotics and microbial transplantations … we are just at the beginning of a transformative era for biology and medicine, where the potential of commensal bacteria in treating and preventing human conditions will be explored.” Antebi agrees, “…In the future, we may have probiotic shakes tailored to our individual health needs, together with dietary changes that would facilitate a healthy microbiome. … by studying nature, we would see how other organisms have taken advantage of “probiotics” in their food cycle to maximize reproductive success.” The relationship between our microbiome and our health or lack thereof, is only beginning to be understood. Ideally, future probiotics will play a role in manipulating the diversity of our microbial companions in a targeted way to our own advantage, without creating an imbalance in the health-promoting microbial communities that help protect our health. Individuals have a unique microbiome depending on genetic heritage and a multitude of environmental factors. To treat this complexity at