HEALTHY GUT SERIES by Godfrey Grech
Gut health is central to various conditions that can lead to disease. An average individual consumes 35 tonnes of food in a lifetime. The quality and composition of the food affects drastically the health of the digestive system of our body. The digestive tract has multiple functions and the main output is to convert the food into essential nutrients that can be absorbed to provide energy to the body. Digestion is a very complex process, and humans are not capable to digest every substance. Therefore, the intestinal lining harbours more than 40 trillion beneficial microbes that are capable to provide us with health promoting nutrients. Taking care of the microbiota (microbes) is crucial for our health.
The beneficial microbes in our gut (gut microbiota) have various functions. They convert dietary components into protective compounds, maintain the gut lining structure and interact with inflammatory and immune responses. The composition and correct abundance also suppress the multiplication of dangerous (pathogenic) microbes. To ensure that the microbiota composition is healthy, the unnecessary use of antibiotics avoided, and a balanced diet is highly recommended. For example, a high fat diet (HFD) and low fibre diet results in defects in the intestinal barrier, leading to penetration of microbes, food antigens and other harmful substances into the blood system. The resulting sustained (chronic) inflammatory response is exemplified by irritable bowel syndrome (IBS) and metabolic syndromes. Obesity and/or diabetes are a result of this “leaky gut syndrome”, due to increased fat deposition and insulin resistance.
Suppressing the symptoms using medication is important, but does not target the cause of the chronic inflammation. Hence, strategies to restore microbiota composition and abundance should accompany or replace medicines. Restoring butyrate-producing bacteria is important for gut lining integrity. Human trails with daily oral supplementation of butyrate-producing microbes showed a significant improvement of insulin sensitivity and cholesterol levels in obese insulin-resistant individuals [1]. This result anticipates a major impact in functional medicine whereby treatment is targeted to the causative effect and not used to suppress the symptoms. So what can be done to prevent disease? Various studies are ongoing to study the composition of microbiota in the gut through measurement of a representation of the microbiota in fecal material. Based on these results the microbes are identified, and the necessary supplementation (probiotics) and diet formulations (prebiotics) are initiated to regenerate beneficial microbes that are lacking. Cultivation of our gut microbial composition is a means to protect ourselves from metabolic syndromes and inflammatory bowel disease. Perturbed metabolism and inflammation are key to the development of colorectal cancer and further studies on the association between gut microbiota and cancer are ongoing. Specific microbes were shown to adhere to the cells in the colon and activate signals that are known to be oncogenic [2]. What is imperative is the need to nurture our gut health and maintain the right composition and abundance of the microbiota in our gut to prevent multiple diseases with major social and personal impact.
[1] Depommier, C., Everard, A., Druart, C. et al. Supplementation with Akkermansia muciniphila in overweight and obese human volunteers: a proof-of-concept exploratory study. Nat Med 25, 1096–1103 (2019). https://doi.org/10.1038/s41591-019-0495-2
[2] Rubinstein, MR., Wang, X., Liu, W., et al. Fusobacterium nucleatum Promotes Colorectal Carcinogenesis by Modulating E-Cadherin/β-Catenin Signaling via its FadA Adhesin. Cell Host & Microbe, 14 (2), 195-206 (2013). https://doi.org/10.1016/j.chom.2013.07.012.