The human microbiome – the new frontier

The human microbiome – the new frontier in our fight against obesity

Is obesity the result of a complex interplay between the human brain and a range of biological processes?

That’s the question Massey University researchers at the School of Food and Nutrition are investigating as obesity rates continue to rise in New Zealand, despite many other unsuccessful interventions to halt the epidemic.

Current studies to combat obesity focus on food and nutrition policies, making healthier food more readily available along with community-based initiatives fostering healthy eating habits.

But Massey researchers say the conventional wisdom that obesity is solely caused by consuming more energy than we expend does not explain the substantial increase in obesity around the world. Nor is obesity due to a lack of willpower or the wrong lifestyle choices. Instead, scientists now believe that obesity is the result of a complex interplay between the brain and a series of intricate biological processes.

Researchers at Massey University are building on knowledge that in a healthy human body, microbial cells outnumber human cells by about ten to one. This, they believe, could ultimately change the outcome for millions of obese people.

New research to fight obesity
A new study, The gut microbiome: a new pathway to obesity prevention and metabolic health, with researchers from Massey University and the University of Otago, has been funded by the Health Research Council of New Zealand. It is looking for new ways to fight the increase in obesity by exploring how the microbial populations in our gut and their genetic endowment alter how our bodies extract energy from food and influence energy metabolism and fat storage in our body.

Lead researcher Professor Bernhard Breier from Massey University’s School of Food and Nutrition hopes to untangle the hidden role of billions of microbes in the human bowel.

“Microbial communities in our intestines change how we balance glucose levels in our blood, how we store fat, and how we respond to hormones that make us feel full or hungry. The wrong combination of members of the microbial community can set the stage for obesity and metabolic disease.

“Advances in DNA sequencing technology lets us analyse genetic material harvested directly from these microbial communities [microbiome] in our intestines, providing unprecedented insights into how the gut microbiome and the human host interact to support a healthy bodyweight or trigger obesity and disease,” says Professor Breier.

What can modify the gut microbiome?
Researchers will test whether taste perception, food choice and dietary intake, eating behaviour, sleep and physical activity modify the gut microbiome and its impact on obesity.

“The outcomes will help us to understand how to combat obesity –and they will guide future intervention studies involving specific microbiota-based strategies to design foods that offer health benefits through changes of the gut microbiome. Our theory is that the more diverse the microbial communities and their genetic makeup are, the better we are equipped to withstand the pressures of our Western environment. We are particularly interested in identifying which dietary patterns are most protective,” he says.

Professor Breier says this new knowledge will help us understand the development of obesity and how best to prevent it. “Although the causes of obesity are complex, key drivers include the over-consumption of highly palatable energy-dense and nutrient-poor foods, such as Western dietary patterns with high intakes of processed foods. These dietary changes have had a profound impact on our gut microbiome. New evidence suggests the microbial communities in the gut may play a crucial role in obesity.”

New study participants needed
This research, a first for New Zealand, will study the gut microbiome in two populations with markedly different metabolic disease risk — Pacific and European women — who have different body weight profiles.

“We are focusing on women because trends in obesity show a significant rise in women with major weight gains between the ages of 20 and 40. The long-term health impact is alarming. Increased obesity in women of child-bearing age is associated with acute and chronic adverse health outcomes, including increased obesity risk for their children,” Professor Breier says.

Who can apply for this study?
Two groups of women (140 Pacific women and 140 New Zealand European women) between 20 and 40 years of age will be recruited. Half in each group will have a normal Body Mass Index (BMI) and the other half will have an obese BMI.

The study requirements
Study participants will make two visits to the Human Nutrition Research Unit at Massey University’s Auckland campus, two weeks apart. They will provide a fasting blood sample (they will receive breakfast after this), and undergo testing in a sensory booth to test their taste perception. They will provide information regarding their dietary intake and habits, and keep food and sleep records, and wear an accelerometer and a sleep monitor for seven days. They will also provide a blood, faecal and urine sample. Several body composition measurements will be taken to determine body weight and body fat status (including a DXA scan). Blood pressure will also be measured.

Who cannot participate?
Women who are pregnant or breast feeding, smokers, those with food allergies or those who have taken antibiotics in the past month will not be eligible for this study.

How long will the study run?
The study launched in June and will continue until December 2016. Women aged between 20 and 40 years are invited to contact the study team at the Human Nutrition Research Unit at Massey University’s Auckland campus directly:Phone: 09 212 7013

Email: promise@massey.ac.nz

Study website: www.massey.ac.nz/promise

© Scoop Media