“We are not alone” is often said to indicate that extraterrestrials are out “there.” This also conjures up the thought they’re intent on dominating humans. The notion that other life forms are obsessed with controlling humans has been a common theme in science fiction. Evolving research argues that another organism controlling humans and their behavior isn’t such a fantastic notion and is already here. Have you considered “intra-terrestrials?”
Bacteria that live in us and on us already exert much influence on humans. Bacteria and fungi outnumber our own cells by more than 100 times. This diverse community of organisms is our microbiome. The microbiome provides many benefits as an important source of nutrients, as well as providing the first line of defense against invading disease-causing microbes. Alterations in the microbiome can lead to health issues and is associated with obesity, irritable bowel syndrome, skin diseases, urogenital infections, allergy, and can even affect our brains by affecting emotion and behavior.
An intriguing area of current research is exploring connections between the microbiome in our guts and the health of our brain, the so-called gut microbiota — brain axis. Communication between the microbes and the brain is bidirectional. The nerve structure in the intestinal track is an important source of this communication. The intestinal track is the source of the highest concentration of neurons outside the brain. In addition, the immune system contributes with small molecules called cytokines and chemokines that are messengers between the gut and the brain. Neuropeptides and microbial products also transmit messages and complete this communication system. It has been established that the communication between these systems lead to normal functioning of the immune system and the gut.
Alterations in these systems can lead to inappropriate brain-gut communication and neurological disorders such as attention deficient hyperactivity disorder, depression, anxiety, and autism spectrum disorder. There’s accumulating evidence that some probiotics that can alter brain-gut communication and disease states. Probiotics are live microbes when given in appropriate levels confer a health benefit. A subclass of probiotics is called psychobiotics, which can affect cognitive functions. Recent studies suggest that certain bacteria can reduce anti-inflammatory effects in the brain and make the brain more resistant to stress. In animals, the bacterium Mycobacterium vaccae, reduces brain anti-inflammatory activity associated with mood disorders such as anxiety and depression.
When this bacterium was administered to rats higher levels of an anti-inflammatory molecule called interleukin-4 was found in the brain’s hippocampus which controls cognitive function, anxiety, and fear. Also, bacterial treated animals had higher levels of brain proteins that reduced brain inflammation and stress levels.
If similar effects can be demonstrated in people, this bacterium could be used as a probiotic to treat soldiers for post-traumatic stress disorder or immunize those in stressful jobs from stress related disorders. We’re only beginning to realize the many profound effects of our relationship with our microbiome — these microbes we live with.