A whiz kid in youth—and a Nobel Prize-winning scientist in his later years—this legendary health superstar named Elie Metchnikoff finished a four-year university program in only two years. He then went on to gain his doctorate in zoology and—with a personal invitation from Louis Pasteur—to use his research skills in microbiology to work at the Pasteur Institute alongside the brightest scientists of his day.
For example, Metchnikoff’s work on immunity from infectious diseases, together with Paul Ehrlich, got him awarded the Nobel Prize for Physiology and Medicine in 1908. Metchnikoff was in his early 60s when he was catapulted to fame for winning the Nobel Prize, and like anyone getting up there in years, he contemplated his mortality. His informed opinion was that the aging process was largely abnormal in modern man. He didn’t understand why normal life expectancy in humans wasn’t 120 years.
Metchnikoff speculated that old age might be due to unhealth caused by an abnormal ratio of intestinal bacteria, which, in turn, were caused by toxins from a poor diet. The Russian researcher laid all the blame on the large intestine, which was “the reservoir or garbage dump of the digestive processes, and the waste stagnating long enough would rot or putrefy,” he said. “The products of putrefaction are harmful.”
As Metchnikoff continued his investigation into aging, someone told him to check into the Bulgarian peasants living in the Caucasus Mountains, who tended to live to an average ripe old age of 87 years. This was double the average life expectancy of Europeans in the early 1900s, which was about mid-40s. For the Bulgarian peasants, however, living to be 100 years old was not uncommon.
You might say that this microbiologist was driven to find out what made this group of geezers keep on ticking! He narrowed it down to an ultra-healthy food filled with healthy probiotics the Bulgarians called “sour milk.”
Here's what happened: The Bulgarian peasants didn’t have any refrigerators, of course, so they would take fresh raw cow’s milk to the family cellar. The peasants drank the raw milk, but they left the extra raw milk behind to culture and thicken over the next several days. The result was the tangy thick beverage they called “sour milk”—which is the equivalent to our modern day probiotic- and enzyme-rich yogurt and kefir.
According to Metchnikoff’s empirical observations, consuming this sour milk caused the Bulgarian bowels to become acidic and thereby support the beneficial microflora of the digestive system. Metchnikoff isolated and identified a healthy bacterium in the peasants’ cultured dairy and named it Lactobacillus bulgaricus in honor of the Bulgarians. Lactobacillus bulgaricus is an example of live lactic acid bacteria that is commonly referred to as a probiotic, which is very important for your digestive system.
Metchnikoff believed that consumption of this sour milk would “seed” the intestines with harmless lactic acid bacteria and suppress the process of putrefaction in the gut. In short, this led to Metchnikoff’s theory of longevity which indicated that duration of life may be prolonged by measures directed against intestinal putrefaction.
Based on this theory—and probably his own calculated gut reaction—Metchnikoff reportedly drank sour milk every day from that time forward.