Consumption of yacon flour improves body composition and intestinal function in overweight adults: A randomized, double-blind, placebo-controlled clinical trial

Summary Background & aims Yacon root is a natural source of fructooligosaccharides (FOS), and it has been studied for its potential effect as a functional food. However, FOS in the in natura root are rapidly hydrolyzed. Thus, the use of dehydrated products such as flour ensures stability of FOS. The effect of chronic consumption of yacon flour on body composition, food intake and of biochemical variables concentration has not yet been evaluated in humans. Thus, we evaluated the effects of yacon flour consumption on these variables associated with excess body weight. Methods Twenty-six adults (31.3 ± 8.5 years) with excess weight (30.4 ± 2.4 kg/m2 , 40.16 ± 6.7% body fat) participated in this randomized, double-blind, six-week study. Subjects were randomly allocated to one of the experimental groups (control (n = 13) or yacon flour (n = 13)), received the prescription of energy-restricted diets (- 500 kcal/day) and daily consumed a breakfast drink not containing or containing 25 g of yacon flour (0.1 g of FOS/kg body weight). At the beginning and at the end of the study, biochemical analyses (glycemia, insulinemia, lipid profile and liver function markers), anthropometrics (weight, waist, hip and neck circumference and sagittal abdominal diameter), body composition (lean mass, total body fat, trunk fat, android fat and gynoid fat), blood pressure, intestinal function, and food intake were assessed. Results Daily yacon flour consumption was well tolerated, did not cause adverse gastrointestinal effects, increased dietary fiber consumption, promoted greater body weight, waist circumference, waist to height index, sagittal abdominal diameter, and body fat reduction, besides improving bowel function in comparison to the control group. Conclusions Yacon flour served as a natural fiber supplement and proved to be an effective adjuvant to be used in nutritional strategies to control excess body weight.