Five gut stories for World Microbiome Day

Today, 27 June, marks World Microbiome Day. Microbes are deeply important for global environmental health, but they’re also vital to your personal health.

According to researcher Phil Hugenholtz, who we chatted to last week, “the most intensively studied ecosystem on the planet is our own gut”. Here are five of our favourite pieces of human microbiome research.

How many genes in the human microbiome?

Microbiologists and bio-informaticians from Harvard Medical School and Joslin Diabetes Centre gathered all the publicly available sequencing data on human oral and gut microbiomes and analysed the DNA from around 1400 mouths and 2100 guts.

In all, there were nearly 46 million bacterial genes – 24 million in the oral microbiome and 22 million in the gut.

Healthy bacteria thrive in gut before birth

Micro-organisms in the gut microbiome begin growing in foetuses as early as five months.

201020 microbiome
Credit: Gene Drendel, La Trobe University

An Australian-led team published a study in the journal Scientific Reports, examining bacteria in the intestinal tract of calf embryos.

“Our findings confirm, without doubt, that bacteria colonise in the gut before birth, changing the future of foetal research and our understanding of how the microbiome influences our developing immune system, gut and brain,” says Ashley Franks, pro vice-chancellor at La Trobe University.

How the gut protects the brain

Antibodies that defend the perimeter of the brain are normally found in, and trained by, our gut.

“This finding opens a new area of neuro-immunology, showing that gut-educated antibody-producing cells inhabit and defend regions that surround the central nervous system,” says Dorian McGavern from the National Institutes of Health, US, co-author of a study in the journal Nature, which described antibodies found in mouse and human brain cells that were previously only found in the gut.

Gut bacteria could shape your persona

The diversity of your gut bacteria may have an effect on your personality, according to one study.

US researchers examined faecal samples from 600 people, mostly North Americans, and found that more sociable people had greater gut microbiome diversity, while those with higher anxiety or stress had less.

We would love to know how the researchers encouraged people to volunteer for this study.

Yet more potential in viruses from poo

Faecal transplants may help people suffering from obesity and type 2 diabetes.

In trials at the University of Copenhagen, obese mice with unhealthy lifestyles given viruses transplanted from the stool of lean mice put on significantly less weight and appeared to be protected against developing glucose intolerance, a hallmark of diabetes.

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