We can thank Elie Metchnikoff for the existence of probiotic supplements. Probiotic supplements are various strains of bacteria that are thought to be beneficial to health because of their favorable effect on the balance of bacteria that exist in the intestinal microbiome. The intestinal microbiome is a massive population of bacteria, fungi, even viruses that exist in the colon or large intestine. The number of these organisms is in the trillions; indeed, it's estimated that there are over 10-times as many organisms living in our colons as there are cells in our bodies. Three pounds of your body weight consists of these resident organisms. For the most part, they are not only benign but highly beneficial. In the past, intestinal bacteria were thought to provide minor health effects, such as synthesizing nutrients such as vitamin K and others. But more recently, the full extent of the activity of the intestinal microbiome has become apparent.In fact, there is no aspect of human health that isn't affected by the microbiome. Besides producing vitamins and other nutrients, the microbiome is deeply involved in immune response, with some researchers suggesting that 99% of immune response is dependent on communication between the microbiome and the immune system. The microbiome encodes over 5 million genes. Humans are born sterile; that is without any organisms in their colons, but the microbial colonization begins shortly after birth. Over 1,000 species of bacteria reside in the colon, and recent studies show that the particular balance of these resident bacteria can determine nutrient uptake, such as how many carbohydrates and fats you are able to absorb. This, in turn, affects body composition and some preliminary research even suggests that consuming some types of probiotic strains can help you lose body fat and even increase testosterone levels. For example, having an intestinal bacteria population that is dominated by Firmicutes bacteria favors increased body fat levels. On the other hand, when the bacteroroidetes strain is dominant, you tend to be leaner because of the lower absorption of both calories and carbohydrates. This area of research, or the relationship of the microbiome to obesity and body composition, is still in its infancy, but evidence emerges weekly that seems to concur with the notion that if you can manipulate the microbiome you can not only favorably affect overall health, but also longevity.
Indeed, that's what attracted Metchnickoff to study the contents of the colon. He believed that the human colon was just a "vestigial cesspool" that functions as not much more than a reservoir for a waste matter that is acted upon by resident microbes who produce fermentation and putrefaction that are harmful to people. He also was prescient in his belief that the production of noxious substances by the bacteria residing in the colon was amplified by the typical western diet. He stated that people should avoid alcohol and meats that are . . .