Made in Munster: Harvesting power of gut bacteria

Clodagh Finn visits UCC’s world-leading microbiome centre, where researchers are exploring new ways to use intestinal bacteria to improve our mental and physical health, including the possibility of developing a probiotic capsule to help control weight

Dr Cormac Gahan: “Diet is the single most important factor in shaping good bacteria in the gut.”
Dr Cormac Gahan: “Diet is the single most important factor in shaping good bacteria in the gut.”

True, one laboratory looks very much like another but you get the sense that you are stepping into the future when you visit the APC Microbiome Ireland, SFI Research Centre at University College Cork.

The scientists at work are global research leaders who are showing the importance of the microbes that live in our gut.

We know, for instance, that these “little critters”, as Prof John Cryan once called them, play a role in digestion and educating our immune systems. They can also influence mood and mental health.

Now these Cork-based researchers are finding that they also play a role in so much more – sleep, appetite, fighting infections and lowering cholesterol, to mention a few.

The central importance of bacteria should not really come as a surprise when you consider that more than half of the cells in the human body are not, well, human, but bacteria.

“We have more bacterial cells than human cells. The ratio is about 1.3 to 1,” says Dr Sally Cudmore, general manager of the centre.

Later, over lunch, she’ll tell me how poo transplants could help form the basis of a new generation of therapeutics, but more on that anon.

For now, let’s try to get a handle on the microscopic colonists in our colons. They weigh about one to two kilos (the equivalent of one to two bags of sugar) and the human body has more of them than there are stars in the Milky Way.

Fight against obesity

Just as everyone has a unique fingerprint, everybody’s microbiome is personal to them.

It’s a point that Dr Harriët Schellekens, an investigator at the Institute, makes when she explains that some people’s microbiome is better at harvesting energy from food compared to others and this can influence our metabolism.

So perhaps our gut microbes control our appetite — we are, after all, not only feeding ourselves but our microbes.

Those differences in gut bacteria may also explain people’s different food preferences, she says, turning to her own children for an everyday example. Her youngest child Ellie (17 months), for instance, loves sugar — “she throws broccoli across the table” — but son Callum (almost three) likes raw vegetables while Aidan (six) prefers his cooked.

Appetite is immensely complex but new research from Dr Schellekens and her team is shedding more light on the subject and could, in time, play a role in the fight against obesity.

She and her colleagues have found that a particular strain of bacteria (B. longum) in the gut can decrease appetite by reducing the hunger hormone ghrelin.

Now, they are investigating how this translates to humans. If it behaves in the same way, it means the APC (Alimentary Pharmabiotic Centre) could potentially, in the future, develop a probiotic capsule to help manage weight.

APC Cork
APC Cork

It wouldn’t be a magic bullet, of course, Dr Schellekens says. At the moment, people are advised to control their weight through diet and exercise but a new probiotic could offer extra support to those struggling with obesity, a condition that has nearly tripled worldwide since 1975, according to the World Health Organisation.

Feed your gut

In the meantime, though, the best and most effective way to promote the growth of good bacteria is through diet. So what should we be eating?

“Think caveman with a lot of fruit, vegetables and fibre, but not as much meat,” Dr Schellekens tells Feelgood.

I love my roast dinner once in a while, but not too often. Maybe have meat once a week. And bread is not the enemy, especially if wholewheat.

The key, she adds, is increasing our fibre intake, which means eating more fruit, vegetables, wholegrains, nuts and legumes. Fermented foods are having something of a renaissance and they have been shown to help gut health.

Dr Cormac Gahan, senior lecturer in microbiology and pharmacy, takes up the story: “Diet is the single most important factor in shaping good bacteria in the gut. Eating a diverse diet will feed a diverse microbiome and there is good evidence linking microbiome diversity to health.”

Dr Gahan, also a principal investigator, has been involved with APC Microbiome Ireland since the very beginning some 16 years ago.

Anaerobic chamber which is used for research on gut bacteria where the environment is similar to that inside the colon where oxygen is excluded. APC Cork
Anaerobic chamber which is used for research on gut bacteria where the environment is similar to that inside the colon where oxygen is excluded. APC Cork

When a group of clinicians and microbiologists in Cork applied for Science Foundation Ireland funding in 2003 to study the microbiome, they were true pioneers.

The first research papers, in an area that is now much more well-known, were still three years away. Looking back, Dr Gahan says they could see the potential in the field and had all the elements and expertise in place.

The multidisciplinary APC was founded and, put simply, its aim was to link science, industry and society together to investigate how gut bacteria influence health and disease. Or to quote one of its snappier slogans: it set about “mining microbes for mankind”.

New interventions

Ask Dr Gahan about the achievements to date and he says the APC is getting closer to developing new interventions that could make a big difference in people’s lives.

It has already partnered with Alimentary Health, a Cork biotechnology company, to bring two products, Alflorex and Zenflore, to market that ease the symptoms of IBS and stress. Looking ahead, APC, in cooperation with other industry partners, may be able to develop a natural way of reducing cholesterol. Dr Gahan and his team looked at a particular enzyme produced by bacteria in the gut that is involved in the metabolism of bile acid. There is good evidence that this enzyme helps to lower cholesterol which could bring far-reaching health benefits down the road.

If you’d prefer a more tangible explanation of all that is going on at the APC, you can drop in to see an exhibition on circadian rhythms which runs at the Glucksman Gallery, UCC, until November 3. It won’t just cast light on the 24-hour cycle; it will reinforce gallery director Fiona Kearney’s point that art and science are not in opposition. “They have shared values. Experimentation, discovery, and observation of the world are part of how both scientists and artists operate,” she says.

And of course there is an important link to the gut too. In a study on mice, other researchers found that antibiotics upset the body’s 24-hour cycle, while gut bacteria play a role in keeping our body clock ticking.

Dr Gahan and his team are looking at how those findings might apply to humans. Eventually, it may be possible to use bacteria to regulate the human body clock and, in turn, potentially ease jet lag and help those on shift work.

Stool transplants

All of that seemed pie-in-the-sky just two short decades ago, but APC Microbiome Ireland has not only made sci-fi a reality, it has also introduced the concept of the microbiome to the general public.

As Dr Sally Cudmore says:

Ten years ago, if you had said to someone that you have billions of bacteria in your gut that can affect your mood, they may not have believed you. Or if you said, you have a bacterial infection in your gut, I’m going to treat you with poo, they would have laughed at you.

And there you have it: we’re back to poo — at lunchtime.

Treating people with stool transplants (or faecal microbiota transplants) might not be ideal mealtime conversation but the treatment is nothing new. Thousands of years ago, the Chinese spoke of a yellow soup made from stool that was used to cure patients, Dr Cudmore explains.

Microbiota transplants are a particularly effective treatment for very debilitating Clostridium difficile infections.

Harriet Schellekens, APC Cork
Harriet Schellekens, APC Cork

More recently, APC scientists Colin Hill and Paul Ross “mined the microbiota” for new antibiotics that can kill pathogens, and isolated thuricin, a potent antimicrobial that is highly effective against Clostridium difficile.

They continue their search for a new generation of more natural antibiotics that will be easier on the normal bacterial residents in the gut that are so important for our health, so called narrow-spectrum antibiotics.

That is yet to come but, thanks to the expertise of the APC family (300-plus) and Science Foundation Ireland funding, the future is getting nearer every day.

A lunchtime talk on the circadian rhythms of plants, human and bacteria takes place at the Glucksman Gallery on Tuesday, October 22

APC in numbers

  • It is ranked number one globally in the fields of anti-microbial research and probiotics
  • Ten APC scientists are ranked in the top 1% of researchers worldwide
  • It helps to support 526 jobs in Ireland
  • It helps to generate €1.2m for the Irish economy every week
  • It has won more than €200m in funding
  • It has produced over 2,500 publications and has been cited more than 81,000 times

Call for volunteers

Do you want to take part in some ground-breaking research that can contribute greatly to our health?

Researchers at APC Microbiome Ireland are looking for volunteers to get involved in their research on the microbiome — the community of microbes (bacteria, viruses and fungi) which live in and on us.

Dr Cormac Gahan: “Diet is the single most important factor in shaping good bacteria in the gut.”
Dr Cormac Gahan: “Diet is the single most important factor in shaping good bacteria in the gut.”

The volunteers will be part of a study investigating the role of diet in stress and anxiety. They should be non-smokers aged between 18 and 59, who currently have a poor diet, but who are willing to follow dietary advice to improve their diet for four weeks.

“Many people don’t realise how incredibly important the microbiome is for our health,” Dr Kirsten Berding-Harold tells Feelgood.

“In fact, most of the diseases of modern civilisation are due, in part, to a reduction in the diversity of microbes in and on our body, or a complete loss of many species. There are links between these changes in the microbes and the increased incidence of obesity, diabetes, allergies and chronic inflammatory diseases.”

The study takes place over six weeks and involves three visits to University College Cork. Any expenses incurred will be covered at the end of the study.

- To sign up, email Dr Kirsten Berding-Harold at Kirsten.berdingharold@ucc.ie

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