Gut Microbiota and Depression

So... how does this relate to depression?

• Association between diet quality and depression is most likely mediated by the gut microbiota
• Study at Oregon University- found that a high sugar diet caused changes in the gut microbiota of mice, impairing their ability to adjust to surroundings
• Affected mood and physical function as well
• Monosaccharides- disrupt normal microbial balance because digested very quickly without help from microbes (microorganisms)
• So, gut bugs start nibbling on the mucus of our intestines, leading to inflammation

Video on how probiotics help to alleviate depressive symptoms

Microbiota and diet

Sources

• Study conducted between two groups
• African children consuming a plant based diet
• European children consuming a Western diet
• African children had more microbial diversity and anti inflammatory bacteria
• European children had less microbial diversity and lacked anti inflammatory bacteria
• Microbial diversity- leads to a clearer, more positive mind

http://www.medicalnewstoday.com/articles/307998.php

http://www.psychologicalscience.org/index.php/publications/observer/2013/september-13/the-link-between-personality-and-immunity.html

http://www.cell.com/cell/abstract/S0092-8674(12)00104-3?_returnURL=http%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0092867412001043%3Fshowall%3Dtrue&cc=y=

https://www.sciencedaily.com/releases/2015/07/150728110734.htm

https://www.sciencenews.org/article/microbes-can-play-games-mind

http://www.medscape.com/viewarticle/836260_6

http://www.everydayhealth.com/columns/therese-borchard-sanity-break/ways-cultivate-good-gut-bacteria-reduce-depression/

https://www.ncbi.nlm.nih.gov/pubmed/25550456

What is Gut Microbiota?

Source: T.G. Dinan et al/J. Psych. Res. 2015

Gut Microbiota and Depression

Also called "gut flora", these trillions of cells (4 lbs of biomass!!!) live in our gastrointestinal tract. The population can include bacteria, eukaryotes, fungi, and viruses. Each person has their own "special blend".

Kristen Neal Jonassie Zamor Lamiyah Mussaji Heather Chandler

Serotonin

Why is it important?

• Gut microbiota are important for nutrition, immunity, and effects on the brain.
• Can be linked to numerous diseases when delicate balance of microbiata is disturbed, such as allergies, austism, obesity, Crohn's, Depression, and more.

Link to Depression

-90% of the body's serotonin, or 5HT, is produced in the gut in enterochromaffin, or EC, cells and synthesized by tryptophan hydroxylase.

-According to a recent study, gut microbiota promote tryptophan expression and 5-HT production on EC cells through the use of short chain fatty acids, which are provided by these gut microbiota.

A study was performed in mice, in which newborns were separated from their mothers for three hours a day.

• The group with complex microbiota showed anxiety, depression-like behavior, heightened levels of stress hormone corticosterone, and increased release of acetylcholine (which caused gut dysfunction).
• In a germ free environment, the mice still had increases in corticosterone and acetylcholine, but no anxiety or depression.

So what does this mean?

-Imbalance of important microbiota that produce short chain fatty acids could cause a decrease in a large amount of serotonin synthesis.

-One of the several things serotonin affects is mood and a deficiency in it is thought to cause depression.

When they put the two groups together, both groups would show signs of depression and anxiety.

However, if they just transfered the bacteria from the complex microbiota to the germ-free group, nothing happened. So the researchers concluded that in order for the behavioral changes to occur, then the host and microbial factors must be involved.