Common Ground Hypothesis- The Link Between the Gut and Disease

Is there any coincidence that bowel habits/health changes coincide with inflammatory diseases?

Over the past 20-ish years, researchers have been studying the gut and how it could play a role in disease development.

We’ve already addressed the development of childhood disease but what about other inflammatory diseases?

Yu 2018 describes the “common ground hypothesis” which places microbiota dysbiosis (pathogenic changes in the gut microbiome) and gut permeability (leaky gut) at the forefront as possible mechanisms for the development of a variety of diseases.

First, let us start with what we already know –

1. Western-style diet (high fat, high added sugars, processed foods) is linked to increased inflammation (oxidative stress) and the development of chronic disease 
2. Oxidative stress/inflammation (increase in pro-inflammatory cytokines, reactive oxygen species, decrease in antioxidant activity) is linked to the development of disease
3. Western diet is also a contributing factor for gut dysbiosis and increased gut permeability
4. Dysbiosis and gut permeability can lead to inflammation in the gut and systemically (throughout the whole body)

So is there a link between inflammation caused in the gut and the development of disease?

YES! Increased inflammation secondary to gut dysbiosis and gut permeability has been suggested as a link to disease development in a few of the following diseases (research has also suggested links with more diseases):

•         Atherosclerotic cardiovascular disease 
•         Neurodegenerative diseases (Parkinson’s and Alzheimer’s) 
•         Diabetes 
•         Chronic kidney disease 
•         Psoriasis 
•         Rheumatoid arthritis 
•         Multiple sclerosis 

The mechanisms by which some of these diseases are linked to dysbiosis are not fully understood. There is a very complex relationship between gut flora-derived inflammation and inflammation independent of the gut. To keep it simple, it is suggested that a high-fat diet/westernized diet can lead to a decrease in healthy gut bacteria (bacteria that produce short-chain fatty acids) and an increase in pathogenic bacteria. 

The decrease in short-chain fatty acid production within the gut aids in gut permeability and local inflammation. Increased amounts of pathogenic bacteria release toxic substances (endotoxins like lipopolysaccharide). As a result of this, in addition to non-gut-derived inflammation, there is systemic inflammation which could create the perfect environment for disease to develop.

What should you do to decrease inflammation, and prevent gut dysbiosis and gut permeability?

1.       Eat a plant-based diet
2.       Consume prebiotic-rich foods as tolerated (helps promote healthy gut bacteria)
3.       Reduce saturated fat intake (red meat, fried foods, processed meats)
4.       Reduce added sugars (beverages, candy, processed foods)
5.       Avoid alcohol and smoking
6.       Be physically active
7.       Maintain adequate Vitamin D

Talk with a Registered Dietitian to learn more! This all points back to diet and emphasizes its importance in fueling our health.

1. _{Li, M., & Wang, F. (2021). Role of intestinal microbiota on gut homeostasis and rheumatoid arthritis. Journal of Immunology Research, 2021, 1–9.}
2. _{Malesza, I. J., Malesza, M., Walkowiak, J., Mussin, N., Walkowiak, D., Aringazina, R., Bartkowiak-Wieczorek, J., & Mądry, E. (2021). High-fat, western-style diet, systemic inflammation, and gut microbiota: A narrative review. Cells, 10(11), 3164.}
3. _{Salguero, M., Al Obaide, M., Singh, R., Siepmann, T., & Vasylyeva, T. (2019). Dysbiosis of gram negative gut microbiota and the associated serum lipopolysaccharide exacerbates inflammation in type 2 diabetic patients with chronic kidney disease. Experimental and Therapeutic Medicine.}
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6. _{Tan, L. Y., Yeo, X. Y., Bae, H.-G., Lee, D. P., Ho, R. C., Kim, J. E., Jo, D.-G., & Jung, S. (2021). Association of gut microbiome dysbiosis with neurodegeneration: Can gut microbe-modifying diet prevent or alleviate the symptoms of neurodegenerative diseases? Life, 11(7), 698.}
7. _{Yoo, J. Y., Sniffen, S., McGill Percy, K. C., Pallaval, V. B., & Chidipi, B. (2022). Gut dysbiosis and immune system in atherosclerotic cardiovascular disease (ACVD). Microorganisms, 10(1), 108.}
8. _{Yu, L. C.-H. (2018). Microbiota dysbiosis and barrier dysfunction in inflammatory bowel disease and colorectal cancers: Exploring a common ground hypothesis. Journal of Biomedical Science, 25(1).}