Biology / Medicine / Neuroscience / Psychology

How microbes affect you from brain to bowel

From Cosmos Magazine, September 5-9, 2016. (Photo: Lactobacillus casei by AJC1 via Flickr)

Not a day goes by without some new study proclaiming the importance of our microbes to our health. It’s hard to keep up, and hard to sort the wheat from the chaff, the mildly interesting association from the water-tight causal link. I recently wrote a five part series that looks at the current state of microbiota research – what evidence is solid, and what needs further investigation.

Microbes and you: a partnership millions of years old

We are not alone. Our bodies are teeming metropolises of microscopic life – and the microbes that call us home influence everything from bowel to brain.

Over the past decade, technological advances in the lab have allowed us to take a census of our microbial entourage – known as the microbiota – like never before. Instead of seeing only the small fraction of microbes from our skin or poo that blossom on a petri dish, we can now blend, extract and read the genetic essence – the DNA – of all microbes, called the microbiome, to get a better idea of who’s there.

The picture that has emerged is one of staggering complexity. Read more…

How bugs in your gut can make you fat (or thin)

Tinkering with gut microbes causes more than a tummy ache. They can wring more calories from food and boost fat cell production – all from day one.

By far the majority of our companion microbes, weighing an impressive 1.5 kilograms and containing more than 1,000 species, reside in our gut, mostly in the large intestine.

As soon as a baby is born – and perhaps even before – microbes move in. Many are seeded from bacteria in the mother’s birth canal if it’s a vaginal birth or from her skin if it’s a caesarean birth. Read more…

Microbe tenants help – and hinder – your immune system

Obesity isn’t the only condition linked to imbalanced gut microflora. A host of autoimmune and inflammatory conditions – inflammatory bowel disease, coeliac disease, multiple sclerosis, rheumatoid arthritis and lupus – are also associated with changes to gut microbial ecosystems.

(Indeed, obesity is often described as an inflammatory condition for the widespread immune reaction that accompanies excess weight.)

Connecting the dots between altered gut microbes and disease is a lively area of research. Scientists are working on the ‘chicken or egg’ problem: does disrupting the gut microflora cause the disease, or does having the disease lead to changes in gut microflora?

In many cases, it is likely that a complex interplay between genetics and environmental triggers – including the microbes in our guts – is involved. Read more…

Mood, mind and memory – can gut bacteria meddle with the brain?

The microbes in your gut may be tiny, but their influence appears to extend as far as the brain, affecting mental health, stress levels, memory and cognitive abilities. Yet many of the most compelling results illustrating the microbiota-gut-brain axis, as it has become known, have only been seen in animals.

The potential for gut microbes to affect mood is probably best illustrated by an experiment conducted at McMaster University in Canada. Mice devoid of a microbiota were effectively given ‘personality make-overs’ via poo transplants. Timid mice became more brazen, and once daring mice retreated into shyness, taking on the anxiety profiles of their donors.

Human-to-rodent poo transplants also work. Read more…

Bugs as drugs – medicine’s next frontier

Microbiome research is providing tantalising clues about how we might change our microbiota to improve our health. But translating findings from the lab into clinical treatments is a slow and arduous process.

The most dramatic illustration of how our microbiota can be used in the clinic is the case of the poo transplant, also known as faecal microbiota transplantation. Read more…

 

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