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York scientists investigate the fibre of our being

Posted on 20 January 2014

We are all aware of the health benefits of "dietary fibre". But what is dietary fibre and how do we metabolise it?

Research at the University of York's Structural Biology Laboratory, in collaboration with groups in Canada, the USA and Sweden, has begun to uncover how our gut bacteria metabolise the complex dietary carbohydrates found in fruits and vegetables.


3D structure of a key enzyme used by gut bacteria to digest fruit and vegetables
Trillions of bacteria live in human intestines - there are about ten times more bacterial cells in the average person's body than human ones.  Known as “microbiota”, these bacteria have a vital role to play in human health: they are central to our metabolism and well-being. 

The research team has uncovered how one group of gut bacteria, known as Bacteroidetes, digest complex sugars known as xyloglucans. These make up to 25  per cent of the dry weight of dietary fruit and vegetables including lettuce, onion, aubergine and tomatoes. 

Understanding how these bacteria digest complex carbohydrates informs studies on a wide range of nutritional issues. These include prebiotics (the consumption of 'beneficial' micro-organisms as a food supplement) and probiotics (the consumption of foods or supplements intended to stimulate the production of healthy bacteria in the gut). 

Researchers from the York Structural Biology Laboratory in the University’s Department of Chemistry, and international collaborators have carried out detailed structural and mechanistic studies into the precise functioning of specific enzymes.  This work has shed further light on which organisms can and cannot digest certain fruits and vegetables, and how and why the "good bacteria" do what they do.

Professor Gideon Davies, who led the research at York, said: “Despite our omnivorous diet, humans aren't well equipped to eat complex plant matter; for this we rely on our gut bacteria.  This work is helping us to understand the science of that process.

“The possible implications for commerce and industry extend beyond the realm of human nutrition, however.  The study of how enzymes break down plant matter is also of direct relevance to the development of processes for environmentally-friendly energy solutions such as biofuels.”

The research at York was funded by the Biotechnology and Biological Sciences Research Council (BBSRC)

Notes to editors:

  • The paper ‘A discrete genetic locus confers xyloglucan metabolism in select human gut Bacteroidetes’ is published in Nature this week 
    http://dx.doi.org/10.1038/nature12907
  • BBSRC invests in world-class bioscience research and training on behalf of the UK public. Our aim is to further scientific knowledge, to promote economic growth, wealth and job creation and to improve quality of life in the UK and beyond.
    Funded by Government, and with an annual budget of around £467m (2012-2013), we support research and training in universities and strategically funded institutes. BBSRC research and the people we fund are helping society to meet major challenges, including food security, green energy and healthier, longer lives. Our investments underpin important UK economic sectors, such as farming, food, industrial biotechnology and pharmaceuticals. For more information about BBSRC, please visit www.bbsrc.ac.uk
  • For more information about the York Structural Biology Laboratory, please visit www.york.ac.uk/chemistry/research/ysbl

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