Mix of bacteria in gut may depend more on diet than genes

Mix of bacteria in gut may depend more on diet than genes

Genes are important, but diet may be even more important in determining the relative abundance of the hundreds of health-shaping bacterial species comprising an individual's gut microbiota, according to UC San Francisco scientists whose latest mouse experiments to probe this nature-versus-nurture balance were published online December 18, 2014 in Cell Host and Microbe.

Gut bacteria vastly outnumber our own cells, and the microbial species normally dwelling within us throughout our lives can affect our health by influencing our metabolism and perhaps even our behavior.

But the makeup of the gut microbiota varies tremendously among individuals, and can vary over time. Until now it has been unclear whether variation is driven more by differences in people's unchangeable genetic backgrounds, or by different diets and other environmental influences.

"In a healthy adult, the same microbial strains and species can colonize the gut for years, while the relative abundance of each member – in other words, community structure – is highly dynamic," said Peter Turnbaugh, PhD, an assistant professor of microbiology and immunology at UCSF, and the leader of the study.

Plastic Microbiome

"These new results emphasize that, unlike a mammalian genome – which is relatively constant – the microbial genomes that comprise the gut microbiome are relatively plastic," Turnbaugh said.

This raises hopes for treating individuals whose gut microbiomes are unhealthy, according to Turnbaugh.

"It may someday be possible to design diets that shape the in a way that is therapeutically beneficial," Turnbaugh said. "The good news is that the microbial response to a given diet may be similar for many people's microbial communities, suggesting that we might not need to tailor interventions differently for every single person."

Turnbaugh's team found that switching mice to a high-sugar, high-fat diet reshaped the abundance of the community of microbes in the gut to a new, stable makeup within three days, in a reproducible manner that was largely independent of genetic differences among individual mice.

The findings are in agreement with a recent human study by Turnbaugh and colleagues, in which were rapidly and reproducibly altered when 10 participants were fed a vegan or animal-based diet. That study demonstrated that dietary perturbations can exert strong effects on the gut microbiota for a few days. But the new research—based on data from hundreds of mice with well-defined genetic backgrounds—demonstrates that diet can trump host genetic variation over days to months.

Microbiota Changes Quickly with Dietary Changes

Turnbaugh began to strongly suspect diet might be of paramount importance in altering the gut microbiota while conducting his graduate work with Jeffrey Gordon, MD, at Washington University in Saint Louis. Turnbaugh observed that genetically identical human twins had gut microbiotas that were no more similar than those of fraternal twins, who share only half of their genes.

In the new study Turnbaugh's lab team included mice from five different inbred strains of mice, in which all members of a strain are genetically identical. In addition, they studied four lines of mice deficient for key genes involved in immunity and obesity. Also added to the mix were more than 200 "outbred" mice—bred to yield offspring with an abundance of easy-to-trace genetic diversity.

The researchers fed the mice two different diets, altering between a high-fat, high-sugar diet comprised of 14.8 percent protein, 44.6 percent fat, and 40.6 percent carbohydrate; and a low-fat, plant-based diet consisting of 22.2 percent protein, 16.0 percent fat, and 61.7 percent carbohydrate.

Regardless of the genetic backgrounds the mice, fecal analysis revealed that the high-fat, high-sugar diet increased the abundance of members of the Firmicutes phylum and decreased the abundance of members of the Bacteroidetes phylum.

"We have shown in the past that alterations to the gut microbiota in response to a high-fat, high-sugar diet contribute to adiposity, and we have been very interested in how the metabolic activity of these organisms is affected by diet," Turnbaugh said.

"Whether changes in the microbial community arise directly from the altered nutrient environment in the gastrointestinal tract, or indirectly due to effects of altered diets on host physiology that are consistent across genotypes, remains a fascinating area for future inquiry."

Another surprising finding was that when the researchers returned the mice to their original diets, changes in microbial abundance were largely reversed—but not entirely. The microbiota was influenced by the imprint of past diets as well as by present .

"Repeated dietary shifts demonstrated that most changes to the are reversible," Turnbaugh said. "But we also identified bacterial species whose abundance depends on prior consumption."


Explore further

Researchers find evidence of a link between high fat diets, gut bacteria, and bowel cancer

More information: "Diet rapidly and reproducibly alters the human gut microbiome." Nature 505, 559–563 (23 January 2014) DOI: 10.1038/nature12820

"Diet Dominates Host Genotype in Shaping the Murine Gut Microbiota." Cell Host and Microbe. DOI: dx.doi.org/10.1016/j.chom.2014.11.010

Journal information: Nature , Cell Host and Microbe

Citation: Mix of bacteria in gut may depend more on diet than genes (2014, December 19) retrieved 16 July 2019 from https://medicalxpress.com/news/2014-12-bacteria-gut-diet-genes.html
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Dec 19, 2014
But the new research—based on data from hundreds of mice with well-defined genetic backgrounds—demonstrates that diet can trump host genetic variation over days to months.

Does the 50% nature / 50% nurture rule apply here? Because here it looks more like 40/60 or maybe even 30/70. Regardless, the endless "terror, terror, terror" stimuli can't be healthy...

Dec 19, 2014
its not genetic because the microbiota is not human. How is this news?

Dec 19, 2014
I have always assumed that if I eat meat, my gut will be full of microbes that are evolved to eat meat. That seemed fine until I realized that I am made of meat.

JVK
Dec 20, 2014
Nutrient-dependent/pheromone-controlled adaptive evolution: a model.
http://www.ncbi.n...24693353

Excerpt: Nutrients are metabolized to pheromones that condition behavior in the same way that food odors condition behavior associated with food preferences. The epigenetic effects of olfactory/pheromonal input calibrate and standardize molecular mechanisms for genetically predisposed receptor-mediated changes in intracellular signaling and stochastic gene expression in GnRH neurosecretory neurons of brain tissue. For example, glucose and pheromones alter the hypothalamic secretion of GnRH and LH. A form of GnRH associated with sexual orientation in yeasts links control of the feedback loops and developmental processes required for nutrient acquisition, movement, reproduction, and the diversification of species from microbes to man.

Dec 21, 2014
Nutrient-dependent/pheromone-controlled adaptive evolution: a model

Criticisms of the nutrient-dependent pheromone-controlled evolutionary model

Did you think no one would read it?

JVK
Dec 21, 2014
Did you think no one would read it?


I thought most people understood the difference between an amino acid substitution and a mutation.

A 3D Map of the Human Genome at Kilobase Resolution Reveals Principles of Chromatin Looping http://www.cell.c...)01497-4
"More and more, we're realizing that folding is regulation..."

Thanks for the reminder that biologically uninformed science idiots will continue to tout their pseudoscientific nonsense if only one other person claims that mutations lead to the evolution of biodiversity, which is obviously nutrient-dependent.

Dec 21, 2014
biologically uninformed science idiots

Nice to meet you too. So your response is deflection and ad hominem, then? I understand.

JVK
Dec 21, 2014
So your response is deflection and ad hominem, then?


Thanks for asking.

Of course not! I'm not a science idiot. I cited the published work that supports my model, which you inferred was invalidated by the criticisms of Andrew Jones, who is a science idiot.

Dec 22, 2014
So your response is deflection and ad hominem, then?


Thanks for asking.

Of course not! I'm not a science idiot. I cited the published work that supports my model, which you inferred was invalidated by the criticisms of Andrew Jones, who is a science idiot.


Keep it up James Kohl. Every time to post you expose yourself as a deluded fool.

Dec 22, 2014
I thought most people understood the difference between an amino acid substitution and a mutation.


So, explain to us uninformed idiots what the difference is?

Dec 22, 2014
So, from your blog entry at perfumingthemind.com/are-evolutionary-theorists-nob-ends/ :

Supposedly, that's how mutations in viruses enable changes in virulence, which actually arise via amino acid substitutions and changes in hydrogen bonds that link atoms to ecosystems.


Are you able to give a detailed description on the molecular level how the amino acids become substituted while the nucleic acid sequence, in your opinion, is not altered?

We can further read in your blog entry:

They adapt! Viruses do not mutate and evolve.


Isn't this just semantics? Aren't the viruses adapting to their environment in order to increase their chances of survival and reproduction? In other words, aren't they evolving?

Dec 30, 2014
I thought most people understood the difference between an amino acid substitution and a mutation
you don't even comprehend the definition of the term "mutation" and that is why you keep confusing everyone with stupidity as you continually vilify mutations while your own model causes mutations
remember when i asked
DOES your model make any changes to the nucleotide sequence of the genome of an organism, virus, or extrachromosomal genetic element?
This is a yes or no answer
(this is the DEFINITION of mutation) to which you answered
YES!
--Thanks for asking
and now you are being educated about epigenetics and transcription because you really messed those up here: http://phys.org/n...firstCmt

instead of arguing and looking stupid, You really should start learning from Anonymous9001 and Dr_ Rock, you might actually begin to understand why your creationist religious beliefs are fallacious and delusional

Dec 30, 2014
biologically uninformed science idiots will continue to tout their pseudoscientific nonsense if only one other person claims that mutations lead to the evolution of biodiversity
if you are choosing to define a science idiot as someone who doesn't comprehend mutations

something like this...
DOES your model make any changes to the nucleotide sequence of the genome of an organism, virus, or extrachromosomal genetic element?
This is a yes or no answer
(this is the DEFINITION of mutation) to which you answered
YES!
--Thanks for asking
because you state here that your own model causes mutations
YOUR WORDS, not mine

then, per your own words
and per your own definition
i guess that means that you ARE a science idiot after all

JVK
Dec 30, 2014
The Pharmacology of Regenerative Medicine
http://www.ncbi.n...3698935/

"Collagen (RGD), fibrin (RGD), laminin (YIGSR), and keratin (LDV) all contain three to five amino acid sequences that promote cell binding through integrin or other interactions (Fig. 7Aiii)."

If mutations did not always perturb protein folding, they could be beneficial.

Dec 30, 2014
If mutations did not always perturb protein folding, they could be beneficial

and if you weren't a complete "science idiot" (using your own words)

you would realise that YOUR OWN MODEL is evidence that MUTATIONS can be beneficial

but even ignoring THAT...

there is EXPERIMENTAL EVIDENCE showing that Mutations CAN BE BENEFICIAL

http://myxo.css.m...dex.html
http://www.oeb.ha...oeb.html

you've never:
-been able to prove that either Lenski OR Extavour are wrong
-been able to refute their experiments
-been able to refute evolution

you STILL completely avoid answering Anon with detail regarding his questions showing you are even slightly conversant with genetics vs epigenetics
You still have yet to show any indication that you understand the difference between changing when or how often genes are expressed and the base sequence of a gene
http://phys.org/news/2014-12-eukaryotic-cell-ii-cytoskeleton.html

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