Trusting our Gut (Microbiome) in Nutrition-Focused Healthcare

By Sheri Vettel MPH, RD, LDN
Emtiro Health

We have all experienced a “gut feeling” about something or someone in our lives. These strong, intuitive instincts have likely lead us to act one way or another, perhaps even serving to protect. In a similar way, research is revealing that the beneficial microbes found in our gut may be influencing our mental state (via the gut-brain axis) and protecting us from a host of diseases and illnesses. 

The human gut flora contains over 100 trillion bacteria, the largest number of bacteria in our body. The composition of one’s gut flora is established quite early in life, around 1-2 years-old, and although the bacteria continue to change, it occurs much less rapidly after childhood. The composition of the gut microbiome is determined by many factors including delivery mode (vaginal verses caesarean birth), environmental exposures, hygiene, antibiotic use, and nutritional composition of one’s diet. 

Research is unveiling the important role that healthy gut microbes play in overall health and disease prevention. Dysbiosis, or microbial imbalance in the body, may unfortunately cause normally-dominant microbes to become outcompeted with new species associated with illness. To date, this microbial imbalance has been linked with mental health disorders, autoimmune disease, cancer, obesity, metabolic syndrome, and cardiovascular disease to name a few. 

When painting a comprehensive picture of the clients we work with, assessing the integrity of one’s gut microbiome is paramount. Medical nutrition therapy can support the proliferation of healthy gut flora, while mitigating dysbiosis, with the addition of prebiotics, probiotics, and anti-inflammatory foods. An integrative nutrition practice may also serve to educate clients about other gut-health related factors too—including the use of plastics on food, residual antibiotics and preservatives in food, artificial sweeteners, contact with biodiversity in nature, and the role of chronic stress.

Dysbiosis and Disease

The gut microbiome may influence the host’s eating behavior. This factor alone may help explain the links between the nutritional quality of diet and risk of disease. It is hypothesized that a microbiome thriving on nutrient-poor foods (such as those high in sugar) may lead to selecting and craving similar foods leading to poor health outcomes such as obesity, cardiovascular disease, and metabolic syndrome. This cycle likely leads to reduced inclusion of food choices that protect health outcomes, such as antioxidant and anti-inflammatory-rich foods.

This link has been investigated in the field of mental health too. For example, when one is underfed, as seen in anorexia nervosa, increases in depression and anxiety associated with the disease may be related to a gut microbiota change in which production of the neurotransmitter serotonin (made in the gut)is reduced. While research continues to emerge, it appears some associations have been made between dysbiosis and risk of depression and anxiety in other populations as well. 

Medical Nutrition Therapy

Using an individualized approach to shifting food choices may protect health outcomes related to dysbiosis. 

Prebiotics, including leeks, asparagus, and dandelion greens, serve as a rich food source for probiotics. Probiotics, beneficial bacteria, are found naturally in many foods such as fermented vegetables and sour-milk products. Dietary supplements for a variety of probiotics are available as well.

Probiotic consumption has been associated with a reduction in systolic and diastolic blood pressure and improved glucose stability in Type II Diabetics. It has also been linked to a reduction in antibiotic-associated diarrhea. 

Even with the addition of prebiotics and probiotics into one’s diet, an overall dietary pattern that promotes disease and maintains gut integrity cannot be ignored. Even if you place a one-million-dollar fish (your probiotic supplement) in a fancy aquarium, it will still die unless you feed it properly! Working with a Registered Dietitian to develop a dietary pattern inclusive of nutrient-dense and anti-inflammatory foods will further assist gut integrity likely enhancing health outcomes. 

As Hippocrates famously said, “all disease begins in the gut.”Whether this is 100% accurate or not, I believe research in this direction is quite promising and warrants consideration of assessing the gut microbiome in healthcare. 


Academy of Nutrition and Dietetics. (2016). Integrative and Function Nutrition Digestive Health Module. 

Institute for Natural Resources. (2017). Probiotics, Food, & the Immune System. 

Prescott, S., Millstein, R., Katzman, A., & Logan, A. (2016). Biodiversity, the Human Microbiome and Mental Health: Moving toward a New Clinical Ecology for the 21stCentury? Int J Biodiversity, 1-18. 

Wolfram, T. (January/ February 2018). Exploring the Gut-Brain Axis. Food & Nutrition, 16-17. 

Sarah Dohl