By now, many of you are aware of the important implications that the critters that live in and on our bodies have on our health. Thankfully, we have influence in the population of bugs and creepy crawlers that will live in our cavities. This is through our lifestyle choices. In fact, a few recent studies have reported on these amazing interactions between our non-human inhabitants and our health, what we eat, and the resultant messages they send to our genes!!
In other words, our “buggies in our bellies” influence how our internal and external environment shape our genetic expression and, furthermore, we can impact which buggy friends we live with. This is what I call the study of microbiome (the genetics of the population of our own microbe population) epigenetics (epi= “above”, genetics-“genes”).
Here’s some of these exciting research studies for you to ponder:
Food, Bugs, and You
As mentioned, studies have indicated that diet is one thing that can rapidly change the composition of belly bugs and this can modulate our wellness in many ways- in humans and animals. For this reason, many integrative doctors have changed the phrase, “You are what you eat” to “You are what your gut bugs eat.”
Eurekalert just recently reviewed a study indicating how this may be so. Researchers were able to determine a dietary link to what mice ate and the metabolites produced by their gut microbes. These belly bug byproducts resulted in changes in gene expression throughout their body:
You are what you eat, the old saying goes, but why is that so? Researchers have known for some time that diet affects the balance of microbes in our bodies, but how that translates into an effect on the host has not been understood. Now, research in mice is showing that microbes communicate with their hosts by sending out metabolites that act on histones–thus influencing gene transcription not only in the colon but also in tissues in other parts of the body. The findings publish November 23 in Molecular Cell.
As you may expect, the quality of the food counted:
Furthermore, they found that mice given a Western diet didn’t produce certain metabolites at the same levels as mice who ate the healthier diet. “We thought that those metabolites–the short-chain fatty acids acetate, propionate, and butyrate, which are mostly produced by microbial fermentation of fiber–may be important for driving some of the epigenetic effects that we observed in mouse tissues,” Denu says.
The next step was to connect changes in metabolite production to epigenetic changes. When they looked at tissues in the mice, they found differences in global histone acetylation and methylation based on which diet the mice consumed. “Our findings suggest a fairly profound effect on the host at the level of chromatin alteration,” Denu explains. “This mechanism affects host health through differential gene expression.”
Another recent study looked at the macronutrient content using a model of 25 different diets in rodent experiments. The researchers then determined the potential effect of each component on their microbiome. These results could provide further clues on additional ways that dietary choices modulate our own microbe community.
From a series of three related papers, Science Daily reported on other specific environmental, genetic, and microbe factors that impacted immune response in humans. This gene-microbiome-immune connection was summarized as follows:
A study led by investigators at Massachusetts General Hospital (MGH), the Broad Institute of MIT and Harvard, and two academic medical centers in the Netherlands has begun to elucidate how differences in the gut microbiome — the microbial population of the gastrointestinal tract — affect the immune response in healthy individuals. The study is one of three related papers published in this week’s issue of Cell, the other two looking at genetic and environmental influences, as part of the Human Functional Genomics Project (HFGP).
“The underlying premise of the HFGP is that the immune system is a perfect target for studying human variation and the intersection of genes and the environment,” says Ramnik Xavier, MD, PhD, chief of the MGH Gastrointestinal Unit, an institute member at the Broad and a principal investigator of the HFGP. “We know that some people are more susceptible to infections than others; some develop autoimmune diseases while most don’t. In these studies we wanted to see how genes affect the immune system, how environmental factors affect susceptibility and in this investigation, whether and how the gut microbiome influences the immune system’s response to various pathogens.”
Summary and Conclusion
We are host to many critters that live inside and on our bodies. These little guys interact with our cells and modulate responses that impact our health in many ways. New studies are showing that what we feed them effects the signals they give to our cells and can potentially alter the response of our genes. Furthermore, the more researchers study gut bugs, the more evidence we have that what we generally consider to be part of a healthy diet- fibers, veggies, and whole, unprocessed foods- creates healthy bodies. However, now we are learning this may be related to the responses of our non-human inhabitants and their signaling to all the body’s systems.
For more information and to learn some quick tips on how to treat your critters well, click here.
I have another blog on my homepage that you can read here. This week: The connection of smell and pain.