James H. Hollis

The Impact of Food Viscosity on Eating Rate, Subjective Appetite, Glycemic Response and Gastric Emptying Rate

Understanding the impact of rheological properties of food on postprandial appetite and glycemic response helps to design novel functional products. It has been shown that solid foods have a stronger satiating effect than their liquid equivalent. However, whether a subtle change in viscosity of a semi-solid food would have a similar effect on appetite is unknown. Fifteen healthy males participated in the randomized cross-over study. Each participant consumed a 1690 kJ portion of a standard viscosity (SV) and a high viscosity (HV) semi-solid meal with 1000 mg acetaminophen in two separate sessions. At regular intervals during the three hours following the meal, subjective appetite ratings were measured and blood samples collected. The plasma samples were assayed for insulin, glucose-dependent insulinotropic peptide (GIP), glucose and acetaminophen. After three hours, the participants were provided with an ad libitum pasta meal. Compared with the SV meal, HV was consumed at a slower eating rate (P = 0.020), with postprandial hunger and desire to eat being lower (P = 0.019 and P<0.001 respectively) while fullness was higher (P<0.001). In addition, consuming the HV resulted in lower plasma concentration of GIP (P<0.001), higher plasma concentration of glucose (P<0.001) and delayed gastric emptying as revealed by the acetaminophen absorption test (P<0.001). However, there was no effect of food viscosity on insulin or food intake at the subsequent meal. In conclusion, increasing the viscosity of a semi-solid food modulates glycemic response and suppresses postprandial satiety, although the effect may be short-lived. A slower eating rate and a delayed gastric emptying rate can partly explain for the stronger satiating properties of high viscous semi-solid foods.

Dietary oil composition differentially modulates intestinal endotoxin transport and postprandial endotoxemia

BackgroundIntestinal derived endotoxin and the subsequent endotoxemia can be considered major predisposing factors for diseases such as atherosclerosis, sepsis, obesity and diabetes. Dietary fat has been shown to increase postprandial endotoxemia. Therefore, the aim of this study was to assess the effects of different dietary oils on intestinal endotoxin transport and postprandial endotoxemia using swine as a model. We hypothesized that oils rich in saturated fatty acids (SFA) would augment, while oils rich in n-3 polyunsaturated fatty acids (PUFA) would attenuate intestinal endotoxin transport and circulating concentrations.MethodsPostprandial endotoxemia was measured in twenty four pigs following a porridge meal made with either water (Control), fish oil (FO), vegetable oil (VO) or coconut oil (CO). Blood was collected at 0, 1, 2, 3 and 5 hours postprandial and measured for endotoxin. Furthermore, ex vivo ileum endotoxin transport was assessed using modified Ussing chambers and intestines were treated with either no oil or 12.5% (v/v) VO, FO, cod liver oil (CLO), CO or olive oil (OO). Ex vivo mucosal to serosal endotoxin transport permeability (Papp) was then measured by the addition of fluorescent labeled-lipopolysaccharide.ResultsPostprandial serum endotoxin concentrations were increased after a meal rich in saturated fatty acids and decreased with higher n-3 PUFA intake. Compared to the no oil control, fish oil and CLO which are rich in n-3 fatty acids reduced ex vivo endotoxin Papp by 50% (P < 0.05). Contrarily, saturated fatty acids increased the Papp by 60% (P = 0.008). Olive and vegetable oils did not alter intestinal endotoxin Papp.ConclusionOverall, these results indicate that saturated and n-3 PUFA differentially regulate intestinal epithelial endotoxin transport. This may be associated with fatty acid regulation of intestinal membrane lipid raft mediated permeability.

Increasing the number of masticatory cycles is associated with reduced appetite and altered postprandial plasma concentrations of gut hormones, insulin and glucose

To determine the influence of masticatory efficiency on postprandial satiety and glycaemic response, twenty-one healthy males were recruited for this randomised cross-over trial. The participants consumed a fixed amount of pizza provided in equal-sized portions by chewing each portion either fifteen or forty times before swallowing. Subjective appetite was measured by appetite questionnaires at regular intervals for 3 h after the meal and plasma samples were collected for the measurement of selected satiety-related hormones, glucose, insulin and glucose-dependent insulinotropic peptide (GIP) concentrations. An ad libitum meal was provided shortly after the last blood sample was drawn and the amount eaten recorded. Compared with fifteen chews, chewing forty times per portion resulted in lower hunger (P= 0·009), preoccupation with food (P= 0·005) and desire to eat (P= 0·002). Meanwhile, plasma concentrations of glucose (P= 0·024), insulin (P< 0·001) and GIP (P< 0·001) were higher following the forty-chews meal. Chewing forty times before swallowing also resulted in a higher plasma cholecystokinin concentration (P= 0·045) and a trend towards a lower ghrelin concentration (P= 0·051). However, food intake at the subsequent test meal did not differ (P= 0·851). The results suggest that a higher number of masticatory cycles before swallowing may provide beneficial effects on satiety and facilitate glucose absorption.

Short-term exposure to heat stress attenuates appetite and intestinal integrity in growing pigs

Acute heat stress (HS) and heat stroke can be detrimental to the health, well-being, and performance of mammals such as swine. Therefore, our objective was to chronologically characterize how a growing pig perceives and initially copes with a severe heat load. Crossbred gilts (n=32; 63.8±2.9 kg) were subjected to HS conditions (37°C and 40% humidity) with ad libitum intake for 0, 2, 4, or 6 h (n=8/time point). Rectal temperature (Tr), respiration rates (RR), and feed intake were determined every 2 h. Pigs were euthanized at each time point and fresh ileum and colon samples were mounted into modified Ussing chambers to assess ex vivo intestinal integrity and function. Transepithelial electrical resistance (TER) and fluorescein isothiocyanate-labeled dextran (FD4) permeability were assessed. As expected, Tr increased linearly over time (P<0.001) with the highest temperature observed at 6 h of HS. Compared to the 0-h thermal-neutral (TN) pigs, RR increased (230%; P<0.001) in the first 2 h and remained elevated over the 6 h of HS (P<0.05). Feed intake was dramatically reduced due to HS and this corresponded with significant changes in plasma glucose, ghrelin, and glucose-dependent insulinotropic peptide (P<0.050). At as early as 2 h of HS, ileum TER linearly decreased (P<0.01), while FD4 linearly increased with time (P<0.05). Colon TER and FD4 changed due to HS in quadratic responses over time (P=0.050) similar to the ileum but were less pronounced. In response to HS, ileum and colon heat shock protein (HSP) 70 mRNA and protein abundance increased linearly over time (P<0.050). Altogether, these data indicated that a short duration of HS (2-6 h) compromised feed intake and intestinal integrity in growing pigs.

Associations between the number of natural teeth and metabolic syndrome in adults

AIM To explore associations between the number of natural teeth and metabolic syndrome in adults. MATERIAL AND METHODS Cross-sectional data from the National Health and Nutrition Examination Survey 2005-2008 were used. Eligible adults (n = 5511) were classified into four groups by their number of natural teeth (excluding third molars): full dentition, 21-27 teeth, 1-20 teeth, or edentulous. Metabolic syndrome was defined by diagnostic guidelines from the American Heart Association and National Heart, Lung, and Blood Institute. Associations were analysed by survey logistic regression. Biometric and metabolic parameters in different dentition groups were compared. RESULTS Adjusting for age, gender, race/ethnicity, ratio of family income to poverty, physical activity, smoking, and energy intake, tooth loss was significantly associated with metabolic syndrome (p = 0.002). Compared to participants with full dentition, the odds were 32% higher in those with 21-27 teeth, 55% higher in those with 1-20 teeth and 79% higher in edentulous participants. The number of natural teeth was inversely associated with body mass index, waist circumference, blood pressure, fasting plasma glucose and insulin concentrations (p < 0.01 for all); it was positively associated with serum HDL cholesterol concentration (p = 0.003). CONCLUSIONS The number of natural teeth is inversely associated with the presence of metabolic syndrome in adults.

Tooth loss and its association with dietary intake and diet quality in American adults

OBJECTIVES To investigate associations between the number of natural teeth and energy intake, nutrient intake, and diet quality in adults. METHODS Eligible adults who participated in the National Health and Nutrition Examination Survey during 2005-2008 were included in the present study (n=9140). Participants were classified into three groups depending on the total number of natural teeth (excluding third molars): full dentition (28 teeth), moderate dentition (21-27 teeth), and poor dentition (20 teeth or less). Dietary intake and diet quality were estimated from the first 24-h dietary recall data. RESULTS Participants in the poor dentition group had significantly lower energy intake than those with moderate dentition (P<0.05), however, both groups did not significantly differ from those who had full dentition. Adjusting for sociodemographic characteristics, physical activity, smoking status, and energy intake, the intake of protein as well as most vitamins and minerals were positively associated with the total number of natural teeth (P<0.05); an inverse association was observed for carbohydrate intake (P<0.001). Diet quality, as measured by the Healthy Eating Index 2005, was inversely associated with tooth loss (P<0.001). CONCLUSIONS Tooth loss in adults is associated with lower diet quality and reduced intake of most nutrients; this may partly explain for the higher risk of chronic diseases in this population. CLINICAL SIGNIFICANCE People with missing teeth are recommended to monitor their dietary intake to avoid nutrient deficiency and to improve their diet quality for better health.

Modified sham feeding of foods with different macronutrient compositions differentially influences cephalic change of insulin, ghrelin, and NMR-based metabolomic profiles.

Little is known about the effect of the macronutrient composition of foods on cephalic phase response of gastrointestinal hormones. In addition, the metabolomics of cephalic phase response has not been studied before. The objective of the present study was to assess cephalic phase endocrinological and metabolomic responses following modified sham feeding (MSF) of foods with different macronutrient compositions. Ten healthy males attended four separate test sessions after overnight fasting, for a 3-min MSF of water, high-fat, high-carbohydrate or high-protein food, respectively, in a randomized order. Blood samples were collected at baseline and at regular time points for 10min following the completion of MSF and assayed for plasma glucose, insulin, ghrelin and glucose-dependent insulinotropic peptide. (1)H nuclear magnetic resonance was used to acquire metabolomic profiles of the plasma samples. Plasma glucose increased after MSF of all test foods, but there were no differences due to the macronutrient composition of the test foods. MSF of the high-carbohydrate food elicited significantly higher insulin, and the high-protein food resulted in higher ghrelin compared to other test sessions. No significant change in glucose-dependent insulinotropic peptide was found. Analysis of plasma metabolomic profiles revealed concentrations of lipids were lower after MSF while plasma glucose increased after MSF. There was also a macronutrient-dependent change in certain amino acids. In conclusion, short-term oral exposure to foods with different macronutrient compositions can induce a macronutrient-specific cephalic change in insulin and ghrelin, as well as metabolomic profiles.

The effect of food form on satiety.

To understand the influence of food form on satiety, 19 male participants attended two separate test sessions to consume either a liquid–solid meal (LS), which consisted of whole pieces of vegetable in a broth, or a liquid version of the same ingredients [liquid meal (LM)]. Following this meal, appetite questionnaires and blood samples were collected at regular intervals over 3 h. An ad libitum meal was then served and the amount eaten recorded. Fullness and preoccupation with food were higher following the LM compared with the LS (p = 0.001 and p = 0.031, respectively). Postprandial plasma concentration of cholecystokinin (p < 0.001) and insulin (p < 0.001) was higher and plasma glucose concentration was lower (p = 0.003) following the LM compared with the LS. However, there was no difference in the food intake at the subsequent meal. These results suggest that food form has a limited effect on satiety; however, the influence of the postprandial insulin response warrants further attention.

Chewing thoroughly reduces eating rate and postprandial food palatability but does not influence meal size in older adults.

Recent studies have shown that increasing the number of chews before swallowing reduces meal size in young adults. However, whether this ingestive behavior influences meal size in older adults is unknown. Eighteen older adults (4 males and 14 females, age 72±1years, body mass index 25.9±1.2kg/m(2)) participated in this randomized cross-over trial. A preliminary session was conducted to assess their habitual number of chews (HNC) using pizza rolls as the test food. Participants then attended three test sessions at their habitual lunch time. In each test session, participants were asked to eat pizza rolls until comfortably full, by chewing each pizza roll for 100%, 150% and 200% of HNC before swallowing. Subjective appetite was measured at regular time points for 60min after meal initiation. There was no difference in meal duration and meal induced change in appetite at meal termination between test sessions. However, eating rate at the 150% and 200% of HNC sessions (16.4±1.0g/s and 13.7±0.8g/s, respectively) was significantly reduced, compared with eating rate at the 100% of HNC condition (22.5±1.8g/s). Moreover, thorough chewing significantly reduced postprandial ratings on palatability of the test food. There was no significant difference in food intake between test sessions (177.8±43.0g, 164.0±41.7g, and 166.6±33.0g for 100%, 150% and 200% of HNC, respectively). These results suggest that increasing the number of chews does not affect meal size in older adults. Aging-related appetite dysregulation may partly account for the difference in results from studies in young and older adults.

Relationship between chewing behavior and body weight status in fully dentate healthy adults.

Abstract Recent research indicates that chewing behavior may influence energy intake and energy expenditure. However, little is known about the relationship between chewing behavior and body weight status. In the present study, 64 fully dentate normal-weight or overweight/obese adults were asked to consume five portions of a test food and the number of chewing cycles, chewing duration before swallowing and chewing rate were measured. Adjusting for age and gender, normal-weight participants used a higher number of chewing cycles (p = 0.003) and a longer chewing duration (p < 0.001) to consume each portion of the food, compared to overweight/obese participants. However, there was no significant difference in their chewing rate (p = 0.597). A statistically significant negative correlation between body mass index and the number of chewing cycles (r = −0.296, p = 0.020) and chewing duration (r = −0.354, p = 0.005) was observed. In conclusion, these results suggest that chewing behavior is associated with body weight status in fully dentate healthy adults.