28 September 2017
Chances are you don’t give much thought to what’s going on in your gut, unless you have an upset tummy. But the gut – and the population of bacteria that live there – is the new frontier in health research. The microbiome, as it’s known, is something that’s getting scientists excited – and it could hold the key to preventing one of our most serious health problems: type 2 diabetes.
Bacteria and our health
What’s the microbiome? Each of us has a unique, individual population of bacteria which lives in and on us. This individual population is known as the microbiota. The term microbiome describes the genetic material of the microbiota; it’s our bacterial ‘fingerprint’ – and it’s different in everyone.
Scientists now know our bacteria perform vital functions in our bodies. And it’s the bacteria in the gut that are the subject of most attention. Emerging research suggests that our gut bacteria can affect many aspects of our health, from our likelihood of developing diseases to our mental health.
This opens up huge possibilities in potential treatments and interventions to solve some of our most pressing health problems. And it’s this potential which got endocrinologist Jeremy Krebs, Associate Professor at the University of Otago, Wellington, started on a fascinating research project as part of the Healthier Lives National Science Challenge, and jointly funded by the Ministry of Health and the Health Research Council of NZ.*
Energy metabolism and obesity
“It’s become increasingly evident in recent years that the gut microbiome has a specific role to play in energy metabolism,” he says. And there’s a growing exploration and understanding of what’s cause and what’s effect.
“In other words, does a fat person’s microbiome look different from a skinny person’s microbiome because they are fat? Or has their particular gut microbiome contributed to their becoming obese in the first place? That question still remains unanswered to some extent, although there is growing evidence that it may be the latter – a particular microbiome pattern may predispose you to gaining weight.”
Mouse studies have found that when the microbiome from fat mice is transplanted into mice with no gut bacteria, the mice develop obesity. When the microbiome from skinny mice is transplanted, the mice stay skinny.
There’s evidence in humans of the reverse concept, too. Associate Professor Krebs points to research on people who’ve had bariatric surgery for obesity, who have lost large amounts of weight and stayed slim afterwards. “Their gut microbiome changes fundamentally from before surgery to after surgery. That would suggest that there’s a very tight and close relationship there.”
The question for Krebs and his team is: can the gut bacteria be altered in other ways?
This is where probiotics come in.
Treating diabetes with probiotics
Evidence has emerged of potential in the use of probiotics to treat diabetes. Research from Finland using a probiotic to treat pregnant women showed a reduction in the development of gestational diabetes in subjects. And NZ research looking at the prevention of asthma and allergy also found an accompanying decreased incidence of gestational diabetes.
This sparked the idea of conducting a trial on patients with prediabetes.
“I thought ‘there’s something real here’,” says Krebs. “This is potentially a very simple intervention for one of our biggest problems.”
Krebs and his team’s trial will look at whether adults with prediabetes who take a probiotic supplement can improve the glucose and fat levels in their blood.
How the study will investigate the effectiveness of probiotics
This study is a blinded randomised placebo-controlled trial on 152 patients. It’s what’s known as a two-by-two factorial study, meaning participants will randomly receive either a probiotic or a placebo, and one of two different cereals. Cereals are included in the study because of their potential to act as a prebiotic with the potential to ‘boost’ the effect of the probiotic.
The study will be conducted over six months, with a follow-up at 12 months to determine whether the effects, if any, are sustained over time.
If the trial shows benefits, the potential for a simple treatment to prevent type 2 diabetes developing is huge.
“It’s a simple treatment. It could be added to a meal,” suggests Krebs. “It could be rolled out straight away, and it doesn’t demand any real behavioural change.”
The significance of prediabetes in New Zealand
With 25% of New Zealand adults having pre-diabetes, and a 70% lifetime risk of them progressing to develop type 2 diabetes, it’s one of the most serious health issues facing New Zealand. Probiotics could be a new way of addressing the issue, and that’s what appeals to Krebs.
“If there’s a chance to turn that around with something other than a drug, it’s really worth looking at.”
* This research is jointly funded by the Healthier Lives National Science Challenge, the Ministry of Health, and the Health Research Council of New Zealand (HRC) as part of the Long Term Conditions Partnership.
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