The research question discussed by the Weizmann Institute of Science, in a new research paper, is “Genetics or lifestyle: What is it that shapes our microbiome?” The majority of human microbiome researchers lean towards the variation, in terms of our different microbial communities, as beginning with differences in our genes. However, a new, large-scale study from Weizmann now challenges this idea. The researchers also provide further evidence of the importance of the connection between a microbiome and health.
Microbiome
The human microbiome is composed of bacteria, archaea, viruses and eukaryotic microbes that reside in and on our bodies. A microbiome resides on the surface and in deep layers of skin, in the saliva and oral mucosa, in the conjunctiva and in the gastrointestinal tracts. Most of the microbes associated with humans appear to be harmless and instead assist in maintaining processes necessary for a healthy body. It has also been shown, at specific sites on the body, that a different set of microbes may perform the same function for different people.
Microbiome and health
As an example of the microbiome’s connection to health, there are hundreds of different bacterial species that live in the human gut, helping us to digest our food. The metabolic processes of these bacteria have been shown to be tremendously important to our health, as well as being tremendously complex. The microorganisms located in the gut contribute metabolic functions, protect against pathogens, educate the immune system and, through these basic processes, they affect most of our physiologic functions.
It therefore stands that an imbalance of the normal gut microbiota can cause adverse health affects. An imbalance has been been linked with gastrointestinal conditions such as inflammatory bowel disease and irritable bowel syndrome, plus wider systemic manifestations of disease like obesity, type 2 diabetes and atopy.
Environment shapes the microbiome
The new research indicates that a person’s genetics plays only a minor role in determining microbiome composition, perhaps only accounting for just two percent of the variation between populations. The research indicates that most of our microbiome is influenced by out external environment.
The focus of the research is on the gut microbiome and it was based on analysis of a database of some 1,000 Israelis; each subject had agreed to participate in a longitudinal study of personalized nutrition. The data, in addition to microorganisms and genetic material, included an assessment of dietary habits, lifestyle, medications and additional measurements. Microbial identification was performed primarily by the sequencing of the 16S rRNA-encoding gene. This is a highly conserved region of the bacterial genome, unaffected by environmental factors.
There was also a link with microbial populations and individual health, in terms of levels of cholesterol, an individual’s weight, their blood glucose levels and other clinical parameters. This carries an important medical implication: factors which influence our microbiomes are probably key to understanding and subsequently treating many common health problems.
The new research has been published in the journal Nature, with the paper titled “Environment dominates over host genetics in shaping human gut microbiota.”
Essential Science
This article is part of Digital Journal’s regular Essential Science columns. Each week Tim Sandle explores a topical and important scientific issue. Last week we examined a new nanoparticle, at the cellular level, which can reveal how cancer cells move to different locations in the human body. This process involved co-opting the human body’s intercellular delivery service
The week before the association between household cleaning chemicals and respiratory problems was examined in light of a new study from the University of Bergen in Norway, which raises concerns about the longer-term health impact.
