Article Review: Stress, depression, diet, and the gut microbiota

The field of gut microbiome research is still new with many studies still looking at evidence from rodents, however more human studies are becoming available and supporting the beginning research with rodents. This article focused on the emerging evidence supported by human subject research.

Gut bacteria have a wide variety of roles within the body, including reward pathways, food metabolism, appetite control, taste receptors, sleep, and mood changes through the release of neurotransmitters like serotonin and norepinephrine.

The general definition of a healthy gut microbiome is diversity in bacteria and balance among the bacteria. Imbalances and lack of diversity result in what is called dysbiosis. Dysbiosis leads to a vicious cycle where negative factors impact the gut bacteria and the bacteria then supports high stress, variant moods, cravings, and high appetites, which worsens diet, stress, and other factors further worsening the dysbiosis of gut bacteria.

It has been found that proton-pump inhibitors such as Omeprazole, widely used to treat GERD, reduce gut microbiome diversity and affect by 20%, which is more negative impact than most antibiotics. However, medication use is not the only thing negatively impacting the Western societies gut microbiome health. High stress and diet are some of the biggest factors in dysbiosis.

"Stress and depression can increase gut barrier permeability. The result, a ‘leaky gut,’ allows bacteria to seep into circulation, producing an inflammatory response. Indeed, both depression and stress can provoke heightened inflammation and gut leakiness."

It is noted that long-term diets form the base of the gut microbiome, but diet modifications can cause shifts in some bacterial specials in as little as 24 hours. Studies have found that high quality diets, like the Mediterranean diet with anti-inflammatory emphasis, reduce the risk of depression overtime. Studies also support that this anti-inflammatory response is facilitated by the gut microbiome, high fiber and low saturated fats encourage the good gut bacteria to create a sturdy barrier in the gut, preventing leaky gut and inflammation.

Broadly speaking, plant protein, unsaturated fats, and fiber support a pro-health gut microbiota — in contrast to excessive consumption of animal protein, saturated fats, and simple or artificial sugars.

There is still much to be learned about the gut microbiome, however what we do know already is that a healthy lifestyle with decreased stress and a diet high in plant proteins, fiber, and unsaturated fats helps the biome flourish. A healthy, balanced, and diverse gut microbiome helps to support health by decreasing inflammation and disease risk and supporting sleep, the immune system, appetite regulation, craving regulation, and stress levels. The cycle of gut microbiome health can either work for you or against your depending on diet and lifestyle choices.

Resources:

Madison A, Kiecolt-Glaser JK. Stress, depression, diet, and the gut microbiota: human-bacteria interactions at the core of psychoneuroimmunology and nutrition. Curr Opin Behav Sci. 2019 Aug;28:105-110. doi: 10.1016/j.cobeha.2019.01.011. Epub 2019 Mar 25.

Written By: Meghan Hawley, RD Ellen Byron & Associates