Bacteria have recently wiggled their way into health and nutrition. Normally perceived as hallmarks of illness, people have started to look for ways to introduce them into the human body through everyday products such as yogurt. Researchers from University College Cork followed 22 men for 4 weeks looking at the effects of a pill packed with bacteria that was ingested daily. When interviewed, these men reported that their stress levels decreased and that they had improved memory.

Bacteria may do more than just synthesize needed nutrients; they may also impact our minds. In a different study conducted by researchers from the University of Missouri, mice were treated with microbes from people with a history of depression; these mice eventually developed symptoms of the illness. Although this research is preliminary, these results suggest that the right microbes when consumed can help produce chemicals responsible for happiness.

The drawback of both of these studies is the lack of a control. Even though gut microbiome research seems promising, if there is no normalization factor, then the results of the study can only be taken with a grain of salt.