JUL 29, 2019 03:25 PM PDT

Does Diet Shape Our Microbiome More than Genetics?

WRITTEN BY: Annie Lennon

Recent findings from mouse studies have concluded that genetics may have a more important role than environmental factors in the composition of the microbiome (Lennon: 2019). Yet, although it is true that humans and mice share certain genetic loci, researchers warn that their findings may not be completely relevant to humans. Thus, are genetics really more significant in the make-up of the microbiome?

A study conducted in Israel analyzing blood and stool samples of 1,046 Israeli adults of mixed origins demonstrated that their ancestry had little impact on the composition of their microbiomes (Rothschild: 2018). Comparing host genetic profiles and the diversity between microbiome samples, they found that environmental factors instead played a larger role in the make-up of each person’s microbiome. 

The same researchers also investigated the impact of the environment on the microbiome by looking at the microbial compositions of related individuals who did not live together alongside those of unrelated couples who did. They found that the microbiomes of relatives who did not live together had few similarities, whereas those of unrelated couples who lived together bore many (Daley: 2018). 

These findings are consistent with other studies too. For example, a study on the microbiome composition of 1,126 pairs of twins in the UK found that heritable bacterial taxa are only temporarily stable (Goodrich: 2016). Analysing their data, they also found that only between 5.3%and 8.8% of gut taxa is inherited. According to Emily Davenport, one of the study’s coauthors: “Certain bacteria are heritable, but it’s a very small portion of the microbiome, and even if we do identify them as heritable, it’s very moderate. (Daley: 2018)”

But how much can environmental factors shape microbiota composition over generations? A 2016 study researched the reasons behind reduced biodiversity in gut microbiota in Western populations, leading to a higher risk for inflammatory diseases, compared to those with more traditional diets and lifestyles. They found that microbiota-accessible carbohydrates (MACs) found in dietary fibre play a fundamental role in producing a healthy microbiome, and that these are significantly reduced in Western diets, where they are substituted by more fats and simple carbohydrates (Sonnenburg: 2016). 

They then conducted experiments on several generations of mice to understand how reversible these changes in the microbiota are. Feeding the mice a low-MAC diet, they found that if changes in the microbiota were only experienced over one generation, they are largely reversible by dietary changes alone. However, if a low-MAC diet is maintained over several generations, certain taxa are driven to low abundance, meaning that they are less efficiently transmitted between generations, and thus become extinct. The only way to regain more healthy microbiota in such cases, is via both the reintroduction of dietary MACs and the administration of certain taxa (ibid.). 

To conclude, although genetics certainly seem to play some role in shaping the human microbiome, to insist that they are mostly responsible for its composition would be to discount other research that expresses otherwise. Thus, even if genetics provide a baseline for the microbiome, its operational composition is otherwise open for modification by diet and/ or administration of certain taxa.

 

Sources 

 

Lennon, Annie: LabRoots 

Rothschild, Daphna, Nature

Goodrich, Julia K., Science Direct 

Daley, Jim: The Scientist 

Sonnenburg, Erica D. et al. : Nature 

 

About the Author
  • Annie graduated from University College London and began traveling the world. She is currently a writer with keen interests in genetics, psychology and neuroscience; her current focus on the interplay between these fields to understand how to create meaningful interactions and environments.
You May Also Like
JAN 18, 2020
Genetics & Genomics
JAN 18, 2020
Identifying the Origins of Modern Humans
New research reported in Nature has suggested that modern humans come from Southern Africa, where they lived for approximately 70,000 years....
JAN 18, 2020
Microbiology
JAN 18, 2020
A New Strain of HIV is Identified
For the first time since 2000, researchers have identified a new subtype of HIV....
JAN 18, 2020
Genetics & Genomics
JAN 18, 2020
The Sequence of the Devil Worm Genome is Revealed
The 'Devil Worm' was found in an aquifer and is the deepest animal that's been found living beneath the surface of the Earth....
JAN 18, 2020
Genetics & Genomics
JAN 18, 2020
Fertility Treatments May Cause Epigenetic Disorders
Epigenetic diseases are still relatively rare, but when women use fertility treatments, the risk of epigenetic disease in their children rises....
JAN 18, 2020
Genetics & Genomics
JAN 18, 2020
Functional Mini-Livers Made With New Bioprinting Technique
This technique, could be useful in the production of complete organs that can be transplanted into patients....
JAN 18, 2020
Neuroscience
JAN 18, 2020
Why Do you Have a Higher IQ than your Grandparents?
In the 1980’s James Flynn found that on average, human intelligence quotients (IQ) increase by 3 points every 10 years. Known as the “Flynn eff...
Loading Comments...