University of Calgary study has found that rats fed a fibre supplement while on a high-fat and high-sugar diet show a much lower weight gain than those who did not eat the fibre. A team of researchers from the university’s Cumming School of Medicine and the Faculty of Kinesiology says the study helps scientists better understand the mechanisms of weight control and energy balance. “Our data shows that a simple dietary intervention, with a prebiotic oligofructose fibre, reduced weight gain, and this may also lead to the long-term maintenance of a lower body weight in the face of continued dietary challenge,” says Keith Sharkey, PhD, senior author of the study and deputy director of the Cumming School of Medicine’s Hotchkiss Brain Institute (HBI).
Funded by the Canadian Institutes of Health Research, along with
Alberta Innovates-Health Solutions, the study was published in the April
edition of the journal, Obesity.
Despite having constant access to food high in fat and sugar, rats
given supplemental oligofructose fibre gained about one third less
weight than the control group.
The effect was seen regardless of the animals’ genetic predisposition
to obesity, with rats prone to obesity and those that were more
resistant and relatively leaner showing similar results. “The striking
finding was they both gained far less weight than controls,” says the
study’s lead author, Nina Cluny, PhD, a postdoctoral fellow in the HBI
and the Department of Physiology and Pharmacology.
Feeding the bacteria that live in our guts
Oligofructose is a naturally occurring dietary fibre found in
vegetables such as onions and other foods such as bananas. “It’s a
prebiotic fibre — a food, if you like, for the bacteria that live in our
guts,” says Sharkey, who is also a Crohn’s and Colitis Foundation of
Canada Chair in Inflammatory Bowel Disease Research, as well as a member
of the university’s Snyder Institute for Chronic Diseases.
Trillions of bacteria live in the human gut, collectively forming
what is known as our microbiota. They help with everything from
digesting food to warding off harmful micro-organisms. Oligofructose is
suspected to decrease weight gain by affecting the composition of
microbiota and some of the gut hormones that control food intake.
Cluny says the study showed microbiota in obese rats given
oligofructose were changed to be more similar to those of lean animals.
Gut hormones were also affected by the oligofructose, including an
increase of a hormone that helps control the sensation of satiety — the
feeling of being full.
Raylene Reimer, PhD, RD, a co-author of the study, has published
studies looking at the relationship between oligofructose and weight
management in humans, and has identified a dose that helps adults and
children eat less and reduce their body fat.
Not a 'magic bullet'
“It is not a ‘magic bullet’,” says Reimer, who is a professor in the
Faculty of Kinesiology, a member of the Department of Biochemistry and
Molecular Biology and a member of the university’s Alberta Children’s
Hospital Research Institute. “If you take prebiotic fibre, it doesn’t
cause you to lose 100 pounds in six months.”
In a 2009 human study that she led, adults receiving supplements of
oligofructose lost on average one kilogram over a 12 week period — and,
perhaps more importantly, didn’t continue to gain weight, which is what
occurred among the participants who took the placebo. In the most recent
study published this month, researchers used an animal model to
investigate the mechanisms of how the fibre interacted with the gut to
reduce weight gain.
Oligofructose shouldn’t be seen as a potential alternative to
exercise and diet, which have many other health benefits besides
lowering weight, says Sharkey. He, Cluny and Reimer instead view the
fibre as one of many possible tools in the fight against the growing
problem of obesity. Visit YouTube to see a video about their study.
Led by the HBI, Brain and Mental Health is one of six strategic research themes guiding the University of Calgary toward its Eyes High goals