Up to 90% of all diseases appear to be either indirectly or directly linked to the microbiome.
Micro-organisms populating the gut have a considerable influence on our health. A balanced and diverse intestinal microbiota strengthens the immune system, improves metabolism and helps to regulate food intake and weight.
Conversely, an ill-balanced and poor microbiota can lead to a higher risk of developing inflammation and diseases. This is because a community poor in number and diversity leaves space for other opportunistic microbes that may have the ability to lead to diseases.
In an ill-balanced microbiota there might also be bacteria that trigger inflammatory responses and consequently raise the risk of wrong answers from our immune system – which is one of the causes of autoimmune diseases. Chronic inflammation also increases cancer risk.
Dr. Daniela Weiler, an oncologist at the Lucerne Hospital and specialist of nutritional medicine, described in a Curaden Academy webinar on Microbiomes and nutrition how, in fact, up to 90% of all diseases appear to be either indirectly or directly linked to the microbiome. Among them are cardiovascular diseases, inflammatory bowel disease, allergies, diabetes, Alzheimer’s disease, cancer, autism and psychiatric disorders such as depression.
Here, we explore how microbes are linked to three of these.
A poor microbiome has a negative impact on the stability of the immune system
Our immune system is composed of different types of cells. Some of them have a regulatory function and prevent the over-reaction of our immune system. Other cells trigger inflammation, which is a normal physiological defense against pathogen infection or tissue damage and, under normal circumstances, ends quickly. Both kinds of cells are important, and usually they are well balanced in the system.
Scientists at the University of California observed that certain bacteria living in our gut have an impact on the cells of the immune system, and on its balance. For example, Bifidobacteria – bacteria linked to a fibre-rich diet – are known to foster the creation of regulatory cells while limiting the increase of pro-inflammatory cells.
A poor microbiome with less good bacteria has a negative impact on the stability of our immune system, triggering more inflammatory responses and thus increasing the risk of getting a higher rate of wrong responses. That abnormal inflammatory response is closely associated with many chronic diseases and with the insurgence of autoimmune diseases.
Oral health is the key to personal well-being and overall health. Various studies show that the microbiome of the mouth is of vital importance to the intestinal bacteria and there are many other links between the mouth and the rest of the body. Part of Curaden’s vision and mission is a commitment to improving overall health through improved oral health, and spreading the message of this important and deep connection.
Obese people have a less diverse microbial community
Lean people and obese people tend to have different types of microbes living in their guts – Dr. Daniela Weiler explained in the Curaden Academy webinar that, for example, in lean people a large presence of a bacteria called Christensenella minuta has been observed, whereas obese people have a less diverse microbial community.
When obese people lose weight, their microbiota change accordingly. Obesity is a multifactorial disease, however, in recent years scientists have uncovered the role that microbiome plays in this kind of metabolic disease.
According to research outputs from the Seoul National University College of Medicine, part of the influence may be linked to butyrate, a short chain fatty acid manufactured by gut bacteria through the fermentation of fibres. This element can regulate the appetite signals that our stomach sends to our brain, thus helping to control food intake and metabolism.
TMAO increases the risk of cardiovascular diseases
Byproducts generated by the fermentation of food by microbes in our gut can have a positive or negative impact on our health. While products like the short chain fatty acids are associated with several benefits, there is one – Trimethylamine N-oxide (TMAO) – that can be particularly dangerous.
As described by Stanley Hazen, Vice Chair of Translational Research at the Lerner Research Institute, “The higher someone’s level of TMAO is, the more susceptible that person is to an accumulation of cholesterol in the artery wall. This increases the risk of a heart attack or stroke.”
Trimethylamine N-oxide is manufactured when particular gut microbes digest choline, a nutrient particularly found in animal proteins including eggs, red meat, poultry and seafood. “The more of this food that is eaten,” explains Dr. JoAnn E. Manson, professor of Women’s Health at Harvard Medical School, “the more the body grows microbes that can metabolise it – thus producing more TMAO”.
This article is part of a series about microbiota and its connection to all aspects of the human body, including oral health. If you would like to learn more about this topic, have a look at other articles from the series:
- The Microbiome and Disease
- The Gut Microbiome and its Role in Cardiovascular Diseases
- Influence of diet on the gut microbiome and implications for human health
- Red meat, TMAO, and your heart
- TMAO Testing: A New Way To Assess Heart Attack And Stroke Risk