Writing in the journal BioFactors, researchers investigated the effects of fructooligosaccharides (FOS) on the development of obesity, using two experiments in rats and mice. They found that body weight and percent body fat were lower in mice fed FOS than in controls, whilst rats receiving an oral dose of FOS were reported to have suppressed elevation of plasma triglycerides.
“We have shown that a low dose of dietary FOS suppressed weight gain, accumulation of visceral adipose [fat] tissue, and the increase in liver triglycerides resulting from feeding a high-fat ‘western’ diet ... while fat excretion increased,” reported the authors, led by Yuko Nakamura from the Food and Health R&D Laboratories at the Japanese pharmaceutical company Meiji Seika Kaisha.
“These results suggest that FOS may prevent fat accumulation by inhibiting intestinal absorption of dietary fat in a high-fat ‘western’ diet,” added the researchers.
The authors noted that with the prevalence of overweight and obesity increasing worldwide, there is an associated risk of insulin resistance, type 2 diabetes mellitus, dyslipidemia, hypertension, and cardiovascular disease.
“Obesity is caused by various environmental and genetic factors. One major obesogenic environmental factor is intake of a high-fat ‘western’ diet,” said the researchers, noting that many animal models that simulate human obesity have been developed in order to search for effective anti-obesity regimes.
They added that previous research has reported that FOS intake “can prevent certain lipid disorders in rats”, but noted that “the effects of FOS on obesity remain unclear.”
“The purpose of this study was to evaluate the effects of FOS ... added to a high-fat ‘western’ diet that induces obesity, on body weight and composition in mice, and to assess whether FOS can reduce the accumulation of visceral adipose tissue associated with obesity, and hyperlipidemia induced by a high-fat diet,” explained Nakamura and his team.
In the first experiment, Wistar rats were orally administered a 2.5 g/kg body weight lipid emulsion containing FOS (provided by Meiji Seika Kaisha Ltd), and the subsequent elevation of plasma triglycerides was significantly suppressed compared with that in rats receiving lipid emulsion alone. The authors reported that between two and four hours after lipid emulsion administration, the change in plasma triglycerides was significantly smaller in FOS-treated rats than in controls.
In the second experiment, mice were fed a high-fat ‘western’ diet with or without 2.5% FOS supplementation ad libitum for 12 weeks. Nakamura and his team reported that “body weight gain after 8 weeks was significantly suppressed by the addition of FOS to the high-fat diet.”
They added that total body mass (weight) and calculated percent body fat were significantly significantly lower in the high-fat plus FOS group than in the high-fat group. “Furthermore, the weight of the visceral adipose tissue, and the weight and triglyceride content of the liver were significantly lower in the high-fat + FOS group,” added the research team.
Fecal excretion of lipids was also reported to be “markedly enhanced by FOS consumption,” leading to the suggestion that FOS may prevent fat accumulation by inhibiting intestinal absorption of dietary fat.
"To clarify the mechanism of the effects of FOS on obesity, our future studies will focus on hepatic lipid metabolism-related gene expression," concluded Nakamura and his colleagues.
Published online ahead of print, doi: 10.1002/biof.147
“Fructooligosaccharides suppress high-fat diet-induced fat accumulation in C57BL/6J mice”
Authors: Y. Nakamura, M. Natsume, A. Yasuda, M. Ishizaka, K. Kawahata, J. Koga