How Stress Impacts IBS and Your Gut Microbiome

Have you ever felt super stressed and then decided you needed your favorite comfort food?

My comfort food is ice cream- specifically a milkshake from a chain called Cookout. 

There is a science to suggest that stress affects food choices, which can ultimately influence your gut health and the gut microbiome. It’s also suggested that this can be reversed- your gut microbiome can send signals to your brain and influence stress/depression leading to poor food choices. The gut-brain axis is a hot topic right now and there is a lot of research surrounding it about IBS and anxiety and depression. Now it’s all making sense to me- full circle.

As mentioned before IBS is correlated with mood disorders and stress- this can ultimately impact the gut microbiome leading to gut dysbiosis and dysfunction further causing issues with metabolism and immune function. Let's break this down a little further:

Gut dysbiosis facilitated by psychological stress and depression:

o Distress signals are sent to the gut via the autonomic and circulatory systems. Immune cells are also messengers that send signals of stress to the gut.

o Chronic and acute stress has been shown to attenuate the gut microbiome- pathogenic bacteria can grow leading to more inflammation in the GI tract.

o Stress or depression can lead to increased gut permeability (leaky gut)- leading to a systemic inflammatory response. Elevated cortisol and mast cells weaken the mucosal gut barrier in stressed people.

Psychological stress and depression can promote unhealthy food choices leading to poor metabolic response:

o Neuroimaging suggests that our bodies may crave comfort foods in response to stress and completely ignore normal hunger and satiety cues- so even if you are not hungry your first instinct may be to eat your favorite comfort food.

o “Stress eating” has been shown in research to be related to increased cortisol levels, impaired fat oxidation, higher insulin, and lower energy expenditure.

Diet – a powerful predictor of the gut microbiome:

o The diversity of bacteria is determined by diet- Do you eat a western-style diet (saturated fats, added sugars)? Do you eat more whole foods (fruits, vegetables, whole grains)?

o An imbalance of macronutrients in the diet can also lead to gut dysbiosis- low-fiber diets may dysregulate immune function due to lower production of short-chain fatty acids.

Gut bacteria influences diet:

o Certain molecules that are byproducts from the gut bacteria can interfere with or act as appetite-regulating peptides and hormones.

o Gut bacteria can influence the modification of reward pathways and the vagus nerve which controls appetite and digestion.

o Gut bacteria also modulate food choices through mood changes and behavior changes through the release of neurotransmitters.

Diet influences stress and depression:

o Western/high-fat diets may encourage inflammation and stress vs the Mediterranean diet has been shown to reduce stress and inflammation in the body. This could be linked back to a whole foods diet increasing healthy gut bacteria.

Gut microbiome influences stress:

o Neurotransmitters like serotonin, acetylcholine, and norepinephrine send messages to the brain which may affect mood changes.

o The vagus nerve controls appetite and gut bacteria can control appetite-stimulating hormones affecting the vagus nerve.

All this together shows that there is a relationship between the gut microbiome, diet, and stress- they all possibly modulate and influence one another. So in regards to IBS- think about how you eat in reaction to stress. Does stress affect your diet? Does your diet affect your stress?

Stress management could help control IBS. Consider talking with your healthcare provider if you are interested in more information on how to manage stress or check out these articles for tips on making manageable lifestyle changes to help decrease IBS symptoms: Lifestyle Changes for IBS Management Part One and Part Two.

_{Madison A, Kiecolt-Glaser JK. Stress, depression, diet, and the gut microbiota: Human–bacteria interactions at the core of psychoneuroimmunology and Nutrition. Current Opinion in Behavioral Sciences. 2019;28:105-110. doi:10.1016/j.cobeha.2019.01.011}