The Second Brain?
David Wiss, MS RDN, has been obsessed with microorganisms for the past year. Could they be the second brain? He has had so many burning questions as a registered dietitian nutritionist working with addictions and eating disorders. These include:
- Why are so many of us drawn to foods that can compromise our quality of life?
- Why do some of us reject foods that can heal us?
- Why are educational efforts often insufficient to produce sustainable behavior change?
- Why is it so challenging to develop a new relationship with food?
Is it a lack of willpower? Food addiction? Restrained eating and dieting? In search of answers to the questions, Mr. Wiss has had to investigate new insights into gut microbiota and behavioral health.
New Insights
Gut microbiota can significantly impact disease development, brain health, attenuation, memory, and learning (Matsumoto et al., 2013). Dysbiosis of the gut is associated with a reduction in the diversity of the microorganisms, whereas healthy guts have higher diversity (Belizario & Napolitano, 2015). Highly diverse microbial communities are more likely to expend energy and resources in competition, whereas less diverse microbial communities have more resources for host manipulation (Alcock, Maley, & Aktipis, 2014). So, how does the gut microbiota impact human behavior? Is it possible that they have much more influence than we ever imagined?
In 2014 Alcock and colleagues stated:
“We hypothesize that there has been a genomic arms race in which microbes have evolved genes to manipulate their hosts (particularly analogs of human signaling molecules such as neuropeptides and hormones) and corresponding host genes have evolved to prevent that manipulation where it conflicts with the host’s future interests.”
Authors proposed that gastrointestinal microbes could generate cravings for foods they specialize in, and induce dysphoria until the host eats foods that enhance their fitness, acting as “microscopic puppetmasters.” Diagram from their publication below:
These authors concluded:
- Microorganisms are competing for nutritional resources
- Evolutionary conflict between host & microbiota may lead to cravings and cognitive conflict regarding food choice
- Exercising self-control over eating may be partly a matter of suppressing microbial signals that originate in the gut
- Acquired taste may be due to acquisitions of microbes that benefit from that food
- One way to change eating behavior is by intervening on the microbiota: FOCUS ON INCREASING MICROBIAL DIVERSITY
This information blew David’s mind and led him to researching this fascinating topic in great detail.
References:
Alcock, J., Maley, C. C., & Aktipis, C. A. (2014). Is eating behavior manipulated by the gastrointestinal microbiota? Evolutionary pressures and potential mechanisms. Bioessays, 36, 940-949.
Belizario, J. E., & Napolitano, M. (2015). Human microbiomes and their roles in dysbiosis, common diseases, and novel therapeutic approaches. Frontiers in Microbiology, 6(1050).
Matsumoto, M., Kibe, R., Ooga, T., Aiba, Y., Sawaki, E., Koga, Y., & Benno, Y. (2013). Cerebral low-molecular metabolites influenced by intestinal microbiota: A pilot study. Frontiers in Systems Neuroscience, 7(9).
