Influence of Pre-meal Inulin Consumption on Energy Intake in Overweight and Obese Middle-aged and Older Adults: A Pilot Study

Seventy-six percent of men and 71% of women over the age of 55 in the United States are considered overweight or obese, and the numbers are expected to rise especially since the population is aging. Aside from various metabolic comorbidities, such as hypertension, dyslipidemia, and coronary artery disease, overweight and obesity are also linked to decreased mobility and increased rate of falls in elderly, all of which may lead to premature death. Furthermore, adults over the age of 65 have 339% greater obesity-related medical expenses compared to younger adults (18-30 years old), thus strategies to promote weight management are needed. Belonging to the group of fiber, prebiotics are selectively fermented non-digestible food ingredients that have a favorable impact on the composition and activity of the gut microbiota. Specifically, inulin-type fructans (ITF) including inulin, oligosaccharides, and fructooligosaccharides have been generating interest in the prebiotic area in the past two decades. A lot of attention has been directed at weight management, since ITFs are known to stimulate the excretion of anorectic gut hormones glucagon like peptide-1 and peptide YY upon fermentation in the colon. Research done to date has included samples with wide age and BMI ranges, various doses of inulin, as well as different study designs. More investigations are needed in specific populations, such as older adults who might have age-related alterations in gastric emptying. This pilot research study investigated the effects of short-term pre-meal inulin consumption (10 g, mixed into 500 ml water) on energy intake (EI) and appetite sensations over a 24-hour period, in overweight and obese middle-aged and older adults (n=7, 55-67 years old), in order to determine the potential role of prebiotics in weight loss and weight management. A randomized crossover design was used, with participants completing both pre-meal inulin and control (500 ml water alone) conditions. There were no differences in EI, gram weight, nor energy density of foods consumed between the inulin and control conditions. However, observed subgroup differences suggest variances in response to the inulin preload related to gender, habitual fiber consumption, cognitive dietary restraint, and BMI status. Influence of pre-meal Inulin consumption on Energy Intake in overweight and obese middleaged and Older Adults: a pilot study Katarina Smiljanec GENERAL AUDIENCE ABSTRACT The United States population is expected to grow older during next few decades. Three fourths of adults in the United States over 60 years of age are considered overweight or obese, which is not only associated with conditions, such as hypertension, dyslipidemia, and coronary artery disease, but also with decreased mobility and increased rate of falls in elderly, all of which increase medical costs and can lead to premature death. These statistics call for weight loss strategies applicable to middle-aged and older adult population. Recently, prebiotics, and specifically inulin, have been introduced as a potential aid in weight management. Inulin is found in foods such as bananas, garlic, onions, wheat, oat, leek, and asparagus, and is usually extracted from chicory root or Jerusalem artichokes for supplemental use. Upon ingestion, inulin passes undigested through gastrointestinal tract and is fermented in the colon. Compounds resulting from fermentation may stimulate the release of hormones glucagon like peptide-1 and peptide YY, which may influence food consumption. Research on the role of inulin in eating behavior has been scarce and needs more focus on specific populations, such as middle-aged and older adults, who may have altered gastrointestinal processes due to aging. Hence, this research study investigated the influence of short-term inulin consumption on food intake and appetite sensations over a 24-hour period, with the goal of exploring a possible weight management strategy in overweight and obese middle-aged and older adults. There were no differences observed in food intake between the inulin and the control condition, however, mixed results among subgroups suggest differences in response to inulin consumption related to gender, usual dietary fiber consumption, dietary restraint, and weight status.