ABSTRACT
Free glutamate, a key substance underlying the umami taste of foods, fulfills a number of physiological functions related to energy balance. Previous experimental studies have shown that intake of a broth or soup supplemented with monosodium glutamate (MSG) prior to a meal can decrease appetite and food intake, particularly in women with propensity to overeat and gain weight. In this study, we examined potential neurocognitive mechanisms underlying this effect. We evaluated changes after intake of a chicken broth with or without MSG added (MSG+/MSG-) in a sample of healthy young women. Subjects were assessed with a food-modified computerized inhibitory control task, a buffet meal test with eye-tracking, and brain responses during a food choice paradigm evaluated with functional neuroimaging. We found evidence for improvement in key parameters related to inhibitory control following intake of the MSG+ broth, particularly in subjects with high levels of eating disinhibition, who also showed lower intake of saturated fat during the meal. Additionally, consumption of the MSG+ broth led to a reduction of the rate of fixation switches between plates at the meal, and increased engagement of a brain region in the left dorsolateral prefrontal cortex previously associated with successful self-control during dietary decisions. Altogether, these results, while preliminary, suggest potential facilitating effects of glutamate (MSG) on cognitive executive processes that are relevant for the support of healthy eating behaviors and food choice.
Subject(s)
Feeding Behavior/physiology , Food Preferences/physiology , Taste/physiology , Adolescent , Adult , Brain/diagnostic imaging , Choice Behavior , Dietary Fats/pharmacology , Eating , Female , Food Additives , Healthy Volunteers , Humans , Inhibition, Psychological , Magnetic Resonance Imaging , Reaction Time/drug effects , Sodium Glutamate/pharmacology , Young AdultABSTRACT
There are limited data on successful weight management approaches among adolescents from underserved communities. The primary aim of this study was to obtain preliminary data on the efficacy, safety, and acceptability of a lifestyle intervention with milk-based supplements among adolescents from underserved communities. The secondary aims of this study were to assess change in adiposity indices and metabolic indices and to measure compliance. The authors conducted a 12-week open-labeled lifestyle intervention. Adolescents were taught a structured meal plan, including the use of 2 milk-based supplements daily, and participated in weekly lifestyle counseling. Overweight was defined as a body mass index >85th percentile. Percent total body fat was estimated using bioelectric impedance. Fasting blood samples were used to measure insulin indices and other biochemical safety tests. The sample consisted of 40 adolescents (70% girls, 83% minority). Although there was no significant change in body mass index (median [Q1, Q3]; -0.10 [-0.91, 0.61] kg/m(2), P = .26), participants showed a decrease in body mass index z score (-0.03 [-0.08, 0.01] SD, P = .01]), weight z score (-0.04 [-0.11, 0.02] SD, P = .001), and percent total body fat (-1.20 [-2.55, -0.12]%, P = .0001). No new onset of type 2 diabetes mellitus was reported, and plasma vitamin D increased (P < .01). Consumption of milk-based drinks increased from a median of 4.5 to 13.5 servings per week, whereas sugary beverages decreased from 8.0 to 3.8 servings per week. A lifestyle intervention that includes milk-based supplements may safely improve some adiposity indices and decrease intake of sugary beverages among overweight adolescents from underserved areas.
