In recent years, the microbiome has become one of the hottest topics in the world of science and many studies have been conducted on the subject. Most of the studies were performed on laboratory mice. Sterile mice are grown without bacteria from birth and, in doing so, can receive a microbiome sample from another animal.
These studies have unraveled some fascinating findings:
- In a study performed in the US and published in the scientific journal “Nature”(2006), mice were fed a fat-rich diet in order to make them gain excessive weight. Once the mice fattened up, samples of their stool were taken and administered into the intestines of sterile mice. After a period of time, the sterile mice that were given the stool were compared to a control group of sterile mice. The mice that received a fecal transfer became fat themselves due to their new microbiome alone.
- In a study from 2013 published in the scientific journal “Science”, the same procedure was performed on sterile mice, this time with human stool samples from overweight individuals. In this case, as well, the sterile mice that underwent a fecal transfer became overweight much faster than the sterile mice in the control group.
- It is possible that the microbiome has a “memory” or a “fingerprint” that is yet to be defined. In a study performed in Israel and published in the scientific journal “Nature”(2016), normal mice were fed a fat-rich diet in order to make them overweight. After the mice gained weight, they were put on a weight-loss diet and returned to normal weight. In the third stage of the study, the mice were once again put on a fat-rich diet. These mice were then compared to a group of regular mice on a fat-rich diet that did not experience the weight gain and loss process. Researchers discovered that the mice that did not experience the weight loss and weight gain procedure stayed around the same weight and did not gain more weight while the ones who did go through this process gained weight once again. After the two groups were compared with different parameters such as fat levels, kidney function, glucose variance, etc., researchers noted that the only truly significant distinction between the two groups was their microbiome composition.