Short-term effects of chewing gum on snack intake and appetite

Chewing Gum Is Associated with Better Diet Quality but Not Oral Health Measures in U.S. Adults

OBJECTIVE

Chewing gum (especially sugar-free gum) has been linked to improved oral health, however there is an absence of observational research using nationally-representative data in the United States. We sought to examine the factors associated with chewing gum and its relationship with the oral health status of U.S. adults.

METHODS

Cross-sectional data from the U.S. National Health and Nutrition Examination Survey (NHANES) 2013-2018 cycles were used in these analyses. Primary outcomes were the odds of having gum disease, treatment for gum disease, ever being told of bone loss around teeth, root caries, caries, and restoration. Unadjusted and multivariate logistic regression models were used to investigate the relationship of chewing gum use with demographic/lifestyle factors and the oral health status of participants.

RESULTS

2.40% (n = 365) of adults were users of chewing gum and the average among users was 5.20 ± 0.40 g/d. Users of chewing gum were more likely to be female, younger in age, and non-Hispanic Black or Hispanic. Self-reported chewing gum use did not affect the oral health status of U.S. adults (OR: 1.10, 95% CI: 0.42-2.88 for gum disease; OR: 1.34, 95% CI: 0.64-2.81 for treatment for gum disease; OR: 0.56, 95% CI: 0.27-1.17 for bone loss around teeth; OR: 1.01, 95% CI: 0.32-3.12 for root caries; OR: 0.96, 95% CI: 0.54-1.69 for caries), except for restoration (OR: 3.54, 95% CI: 1.78-7.06), but was associated with improved diet quality (OR: 1.86, 95% CI: 1.11-3.12 for a healthy eating index (HEI) of 51-59; OR: 1.96, 95% CI: 1.08-3.56 for HEI of 60-93); and decreased intakes of snacks (OR: 1.64, 1.01-2.69), and added sugars.

CONCLUSION

Future observational studies that more accurately capture chewing gum usage are needed, as these analyses have several limitations.

A concise review of chewing gum as an anti-cariogenic agent

Chewing gum has been endorsed as a caries preventive agent by the FDI World Dental Federation, the American Dental Association, and the European Food Safety Authority. This review discusses the mechanism and provides an update of the use of chewing gum for caries prevention. Chewing gum typically consists of a water-insoluble gum base, water-soluble added ingredients, and active ingredients. It can be classified as sugar-containing or sugar-free, as well as nonmedicated or medicated. Chewing gum prevents dental caries through a range of mechanisms, including the clearance of the oral cavity, neutralization of oral acidity, inhibition of cariogenic bacterial growth, remineralization of enamel, and reduction of appetite. Recent clinical studies have evaluated the efficacy of sugar-free chewing gum for caries prevention, with most demonstrating positive results, although some studies have reported contradictory outcomes. To achieve optimal caries prevention, it is generally recommended that individuals chew sugar-free gum for five minutes after meals, three times daily.

The Efficacy of Gum Arabic in Managing Diseases: A Systematic Review of Evidence-Based Clinical Trials

Gum arabic (GA) is a natural product commonly used as a household remedy for treating various diseases in the Sub-Saharan Africa region. Despite its claimed benefits, there has been a lack of research on the findings of current clinical trials (CTs) that investigated its efficacy in the treatment of various medical diseases. The aim of this systematic review was to study CTs which focused on GA and its possible use in the management of various medical diseases. A search of the extant literature was performed in the PubMed, Scopus, and Cochrane databases to retrieve CTs focusing on evidence-based clinical indications. The databases were searched using the keywords ("Gum Arabic" OR "Acacia senegal" OR "Acacia seyal" OR "Gum Acacia" OR "Acacia Arabica") AND ("Clinical Trial" OR "Randomized Controlled Trial" OR "Randomized Clinical Trial"). While performing the systematic review, data were obtained on the following parameters: title, authors, date of publication, study design, study aim, sample size, type of intervention used, targeted medical diseases, and main findings. Twenty-nine papers were included in this systematic review. The results showed that ingestion of GA altered lipid profiles, renal profiles, plaque, gingival scores, biochemical parameters, blood pressure, inflammatory markers, and adiposity. GA exhibited anti-inflammatory, prebiotic, and antibacterial properties. GA has been successfully used to treat sickle cell anemia, rheumatoid arthritis, metabolic disorders, periodontitis, gastrointestinal conditions, and kidney diseases. Herein, we discuss GA with respect to the underlying mechanisms involved in each medical disease, thereby justifying GA's future role as a therapeutic agent.

Effects of stress on chewing and food intake in patients with anorexia nervosa

OBJECTIVE

The present study investigates the impact of psychosocial stress on chewing and eating behavior in patients with anorexia nervosa (P_AN ).

METHOD

The eating and chewing behavior of P_AN were examined in a standardized setting by means of a chewing sensor. These procedures encompassed n = 19 P_AN , age, and gender matched to n = 19 healthy controls (HC). Food intake and chewing frequency were assessed in two experimental conditions: rest versus stress (via Trier Social Stress Test). To verify stress induction, two appraisal scales were employed. In addition, chronic stress, psychological distress and eating disorder symptoms were assessed.

RESULTS

In terms of food intake and chewing frequency, the results of the 2x2 ANOVA demonstrated a significant effect of condition and group. During stress, all participants demonstrated a higher chewing frequency and a decreased ingestion. In general, patients ate less at a lower chewing frequency (vs. HC). However, sample specific analyses demonstrated that the eating and chewing behavior of P_AN remained unchanged regardless of the condition, except for their drinking. Food choices were comparable between the groups, but appetite values significantly differed.

DISCUSSION

The increase in chewing frequency in all participants during stress suggests that chewing might impact affect regulation, however, not specifically in P_AN . Future research should clarify to what extent the normalization of chewing behavior could ameliorate ED-symptoms (incl. food intake) in P_AN . The application of a chewing sensor could support this aim and future interventions.

Gum chewing while walking increases walking distance and energy expenditure: A randomized, single-blind, controlled, cross-over study

Background/objective

Gum chewing while walking increases walking distance and energy expenditure in middle-aged male and female individuals. This study aimed to examine the effects of gum chewing while walking on walking distance and energy metabolism in male and female individuals of various age groups.

Methods

Fifty participants (25 male and 25 female individuals) aged 22-69 years completed two trials in a random order. In the gum trial, participants walked at a natural pace for 15 min while chewing two gum pellets (1.5 g, 3 kcal per pellet) following a 50-min rest period. In the tablet trial, participants rested for 50 min before walking, and the participants then walked at a natural pace for 15 min after ingesting two pellets of tablet containing the same ingredients with the exception of the gum base. The walking distance, step count, walking speed, stride, heart rate, energy expenditure, and respiratory exchange ratio were measured.

Results

Walking distance, step count, walking speed, heart rate, and energy expenditure during walking were significantly higher in the gum trial than in the tablet trial. In participants aged ≥40 years, walking distance, walking speed, stride, heart rate, and energy expenditure during walking were significantly increased during the gum trial compared with those during the tablet trial.

Conclusion

The study findings demonstrated that gum chewing while walking increased walking distance and energy expenditure in both male and female individuals.

How oro-sensory exposure and eating rate affect satiation and associated endocrine responses-a randomized trial

BACKGROUND

Longer oral processing decreases food intake. This can be attributed to greater oro-sensory exposure (OSE) and a lower eating rate (ER). How these factors contribute to food intake, and the underlying physiological mechanisms, remain unclear.

OBJECTIVES

We aimed to determine the independent and simultaneous effects of OSE and ER on satiation and associated endocrine responses.

METHODS

Forty participants in study 1 [mean ± SD age: 24 ± 4 y; BMI (in kg/m2): 22 ± 2] and 20 in study 2 (mean ± SD age: 23 ± 3 y; BMI: 23 ± 2) participated in a 2 × 2 randomized trial. In both studies, participants ate chocolate custard with added caramel sauce (low OSE) or caramel fudge (high OSE) and with short (fast ER) or long breaks (slow ER) in between bites, until fullness. In study 2, endocrine responses were measured during the meal.

RESULTS

In study 1, participants ate (mean ± SEM) 42 ± 15 g less in the slow- than in the fast-ER condition, only within the high-OSE condition (P = 0.04). In study 2, participants ate 66 ± 21 g less in the high- than in the low-OSE condition and there were no intake differences between slow and fast ER (P = 0.35). Eight minutes after starting to eat, insulin concentrations increased by 42%-65% in all treatments compared with the control. At the end of the meal, insulin concentrations were 81% higher in the high-OSE, slow-ER than in the low-OSE, fast-ER condition (P = 0.049). Pancreatic polypeptide (PP) increased by 62%, 5 min after meal onset in the low-OSE, fast-ER condition (P = 0.005). Ghrelin concentrations did not change.

CONCLUSIONS

Greater OSE increases insulin responsiveness. In contrast, PP responses are stronger when OSE is reduced and ER is fast. Insulin and PP responses may mediate the independent effects of OSE and ER on food intake. These may be beneficial eating strategies, particularly for type 2 diabetic patients, to control food intake and maintain glucose homeostasis.This trial was registered at trialregister.nl as NL6544.

Effects of gum chewing on glycaemic control in women with gestational diabetes mellitus: A randomized controlled trial. Impact of chewing on hyperglycaemia in women with GDM

BACKGROUND

The amount of chewing might be relevant in reducing hyperglycaemia in diabetic patients. The study assessed the impact of enhanced chewing on glycaemic control in women with gestational diabetes mellitus (GDM).

METHODS

As an open-label, mono-centre randomized controlled trial, 59 women with recent diagnosis of GDM were included. They received either routine care or additional chewing gum intervention. SMBG was performed for five days.

RESULTS

No significant impact on mean values of postprandial glucose levels were observed. The estimated mean differences (intervention vs. control group) were: 4.9 mg/dl, 98.4 %CI -7.2-17.1 (breakfast); -4.5 mg/dl, 98.4 %CI -15.1-6.0 (lunch); -3.8 mg/dl, 98.4 %CI -15.9 to 8.4 (dinner). OGTT levels at 60 and 120 min. were associated with glucose levels after breakfast.

CONCLUSION

In conclusion, no significant differences in blood glucose levels were observed between the groups and therefore major effects of chewing on hyperglycaemia in women with GDM could be excluded.

TRIAL REGISTRATION

ClinicalTrials.gov; NCT03961542, Date of registration: 20.01.2019. Retrospectively registered.

Morning Mastication Enhances Postprandial Glucose Metabolism in Healthy Young Subjects

Postprandial glucose concentration is dependent on the time of day and its concentration in the morning is lower than in the evening. However, whether it is dependent on mastication at different times of the day has not been studied before. We hypothesized that mastication affects insulin-mediated glucose metabolism differently in the morning and evening in healthy individuals. Firstly, nine healthy male volunteers (22.0 ± 0.7 SEM years, body mass index 22.0 ± 1.0 kg/m²) performed a 75-g oral glucose tolerance test (OGTT). One week after the OGTT, they participated in a high-carbohydrate food (rice) consumption test with 10 or 40 chews per mouthful. Each experiment was conducted in the morning (0800 h) and evening (2000 h) on the same day. Blood samples were collected before and at 30-min intervals for 120 min after glucose or rice consumption. The incremental area under the curve (iAUC) for glucose in the OGTT was significantly lower in the morning than in the evening, whereas the iAUC for insulin was similar at both times. In participants who chewed 40 times, the iAUC for glucose after rice consumption was significantly lower in the morning than in the evening but was similar at both times in individuals who chewed 10 times. Chewing 40 times in the morning (but not the evening) significantly increased insulin secretion at 30 min. This suggests that morning mastication improves early-phase insulin secretion after rice consumption. This novel finding may aid in reducing the incidence of obesity and type 2 diabetes mellitus.

Relationship between bite size per mouthful and dental arch size in healthy subjects

Although multiple factors influence food bite size, the relationship between food bite size per mouthful and mandible or tongue size remains poorly understood. Here, we examined the correlations between food bite size and the lower dental arch size (an indicator of tongue size) in human subjects with good oral and general health, using fish sausage and bread as test foods. Notably, bite size of both foods was significantly positively correlated with the lower dental arch size, whereas masticatory performance (measured in terms of glucose extraction from a gummy jelly) showed no dependence on bite size. Further, bite size was significantly positively correlated with the body mass index. Our findings suggest that larger bite size is associated with larger tongue size, which might be a contributory factor to obesity.

Exacting Responses: Lack of Endocrine Cephalic Phase Responses Upon Oro-Sensory Exposure

Oro-sensory exposure (OSE) to food plays an important role in the regulation of food intake. One proposed underlying mechanism is the occurrence of cephalic phase responses (CPRs). CPRs include the pre-digestive endocrine responses induced by food-related sensory input. Yet, whether OSE duration or sweetness intensity affects CPRs is unknown. The objective of this study was to determine the independent and interactive effects of oro-sensory duration (chewing) and stimulation intensity (sweetness) on endocrine CPRs and satiation. Eighteen males (22 ± 2 years, BMI 22 ± 2 kg/m2) participated in a 2 × 2 randomized study with a control condition. Each session participants performed modified sham feeding (MSF) with one of the four gel-based model foods. During the control session no MSF was performed. Model foods differed in chewing duration (hard or soft texture) and sweetness (low or high intensity). During each session, eight blood samples were collected up till 25 min after MSF onset. Subsequently, food intake from an ad libitum lunch was measured. No typical CPR was found for insulin, pancreatic polypeptide (PP), and ghrelin. However, the overall PP response was 1.1 times greater for the hard sweet MSF condition compared to control (p = 0.02). Overall ghrelin responses were 1.1 times greater for the hard model food compared to the soft model food conditions (p = 0.003). These differences in endocrine response were not associated with differences in food intake at the subsequent meal. Exploratory sub-analysis of the responsive insulin curves showed that after 2.5 min of MSF the hard texture model foods insulin concentrations were 1.2 greater compared to the soft texture. These findings indicate that texture hardness and sweetness increase the overall PP response and that MSF on hard texture increases the overall ghrelin response compared to soft texture model foods. However, MSF on model foods does not lead to a typical CPR. This study, among others, shows that there are major dissimilarities in the endocrine responses to food stimulation between individuals. This emphasizes the importance of considering cephalic responders and non-responders. More research is needed to understand CPRs in relation to food texture and taste properties.

Chewing Stimulation Reduces Appetite Ratings and Attentional Bias toward Visual Food Stimuli in Healthy-Weight Individuals

Based on the theory of incentive sensitization, the exposure to food stimuli sensitizes the brain’s reward circuits and enhances attentional bias toward food. Therefore, reducing attentional bias to food could possibly be beneficial in preventing impulsive eating. The importance of chewing has been increasingly implicated as one of the methods for reducing appetite, however, no studies to investigate the effect of chewing on attentional bias to food. In this study, we investigated whether chewing stimulation (i.e., chewing tasteless gum) reduces attentional bias to food as well as an actual feeding (i.e., ingesting a standardized meal) does. We measured reaction time, gaze direction and gaze duration to assess attentional bias toward food images in pairs of food and non-food images that were presented in a visual probe task (Experiment 1, n = 21) and/or eye-tracking task (Experiment 2, n = 20). We also measured appetite ratings using visual analog scale. In addition, we conducted a control study in which the same number of participants performed the identical tasks to Experiments 1 and 2, but the participants did not perform sham feeding with gum-chewing/actual feeding between tasks and they took a rest. Two-way ANOVA revealed that after actual feeding, subjective ratings of hunger, preoccupation with food, and desire to eat significantly decreased, whereas fullness significantly increased. Sham feeding showed the same trends, but to a lesser degree. Results of the visual probe task in Experiment 1 showed that both sham feeding and actual feeding reduced reaction time bias significantly. Eye-tracking data showed that both sham and actual feeding resulted in significant reduction in gaze direction bias, indexing initial attentional orientation. Gaze duration bias was unaffected. In both control experiments, one-way ANOVAs showed no significant differences between immediately before and after the resting state for any of the appetite ratings, reaction time bias, gaze direction bias, or gaze duration bias. In conclusion, chewing stimulation reduced subjective appetite and attentional bias to food, particularly initial attentional orientation to food. These findings suggest that chewing stimulation, even without taste, odor, or ingestion, may affect reward circuits and help prevent impulsive eating.

Chewing gum decreases energy intake at lunch following a controlled breakfast

The impact of chewing gum on fasting appetite or meal intake has not been studied. We tested the hypothesis that chewing gum would decrease lunch intake after a controlled breakfast, and reduce hunger in fasting and fed states. Seventeen males and sixteen females (21.4 ± 6.3y, BMI 23.8 ± 2.7 kg/m²) participated in a randomized crossover study in which subjects chewed sugar-free gum a total of 1 h on the test day (GC), and did not chew gum on a control day (NG). The 1 h of gum chewing included 20 min while fasting, and two 20-min sessions between breakfast and lunch. Subjects rated their appetite and mood on visual analog scales. After completing the fasting measures, subjects consumed a breakfast shake containing 30% of their measured resting energy expenditure. Three hours later they consumed an ad libitum lunch with water. Fasting ratings of hunger were lower in GC than NG (t = 2.66, p = 0.01). Subjects consumed significantly less pasta (41 g, 68 kcals, t = 2.32, p = 0.03) during GC than NG. In conclusion, gum chewing decreased fasting hunger ratings and lunch energy consumed. Chewing gum may be a useful tool impacting energy balance in this population. Longer studies, especially in other populations, will be required.

The effect of gum chewing on blood GLP-1 concentration in fasted, healthy, non-obese men

We evaluated the effect of chewing on blood GLP-1 concentration by having volunteers to chew sugarless gum. Our intention was to explore the neural mechanisms regulating the secretion of glucagon-like peptide-1(GLP-1). After fasting for 12 h, 12 healthy male, non-obese volunteers (18 < BMI < 30), were asked to chew sugarless gum at a frequency of 80 times every 2 min for a total of 30 min. Blood samples were collected before the start of chewing and 5, 10, 15, 20, 25, and 30 min after the start of chewing. Satiety and hunger were evaluated on a scale from 0 to 100 at each time point. Compared with the control group, the test group's satiety was increased at 15, 25, and 30 min (p = 0.043, p = 0.014 and p = 0.018, respectively) after they began chewing sugarless gum 80 times every 2 min. The blood GLP-1 level of the test group at 30 min was 49.6 ± 20.3 pmol/l, significantly higher than that of the control group (38.9 ± 20.9 pmol/l; p = 0.031). There was no significant difference in the test group's GLP-1 concentration at each time point. In the control group, compared to baseline, the GLP-1 concentrations at 15, 25, and 30 min were significantly decreased (p = 0.042, p = 0.0214 and p = 0.012, respectively). No significant differences in the blood concentration of glucose, insulin and GIP or hunger were observed between groups. Our study suggests that fasting sugarless gum chewing can increase satiety and reduce the decrease in GLP-1 concentration.

Chewing gum increases energy expenditure before and after controlled breakfasts

Chewing has been associated with improved satiation and satiety, but little is known about the metabolic impact of gum chewing. We tested the hypothesis that gum chewing would increase energy expenditure (EE) and reduce respiratory exchange ratio (RER) before and after a controlled test meal. Seventeen males and 13 females (age 21.5 ± 6.6 years, body mass index 23.9 ± 2.8 kg/m(2)) participated in a randomized crossover study in which subjects chewed sugar-free gum for a total of 1 h (3 sessions of 20 min) on the test day (GC) and did not chew gum on a control day (NG). EE and RER were measured by indirect calorimetry after an overnight fast. Subjects consumed a breakfast shake containing 30% of their measured energy needs, and then postprandial EE and RER were measured for 3 h. Blood glucose (GLC) was measured in the fasting and postprandial states at regular intervals. Fasting EE was higher during GC (1.23 ± 0.04 kcal/min; 1 kcal = 4.2 kJ) than during NG (1.17 ± 0.04 kcal/min; p = 0.016). Postprandial EE was also higher during GC (1.46 ± 0.05 kcal/min) than during NG (1.42 ± 0.05 kcal/min; p = 0.037). Fasting and postprandial RER and GLC did not differ between GC and NG. The findings demonstrate that GC is associated with higher fasting and postprandial EE without altering blood glucose or substrate oxidation as measured by RER. These data suggest that gum chewing potentially could influence short-term energy balance in this population; however, longer-term research is needed.

Candy consumption patterns, effects on health, and behavioral strategies to promote moderation: summary report of a roundtable discussion

Nearly all Americans (97%) report eating candy at least once per year; yet, on a given day, only approximately one-fourth of the US population aged ≥2 y consumes candy. Among all Americans, candy contributes a relatively small proportion of calories, added sugars, and saturated fat to the total diet, and recent research suggests that current levels of candy consumption are not associated with risk of weight gain and cardiovascular disease in children and adults. Providing guidance for the consumption of candy in moderation requires an understanding of various behavioral health-related factors that influence candy consumption. A roundtable of behavioral nutrition experts, researchers, and nutrition educators met to discuss recent data on intakes of candy, health outcomes associated with usual candy intake, and the impact of behavioral strategies, including restriction, education, and environmental awareness, on modifying eating behaviors to achieve moderate intakes of candy. Restricting access to palatable foods, whether self-imposed or by parental control, may have potentially negative consequences. Techniques and insight into how to adopt "moderation" in candy consumption, from effective parental practices to environmental strategies that facilitate behavior change without a high degree of effort, were identified as important next steps toward sustainable dietary guidance related to the role of candy and other treats in a healthy lifestyle.

Sensory-specific appetite is affected by actively smelled food odors and remains stable over time in normal-weight women

Understanding overconsumption starts with knowledge of how separate factors influence our eating behavior. Food cues such as food odors are known for their effect on general appetite and sensory-specific appetite (SSA). Active sniffing rather than passive exposure may induce satiation over time. The objective of this study was to investigate how actively sniffing banana odors affects general appetite, SSA, and subsequent food intake. In a crossover study, 61 women actively smelled cups containing natural banana, artificial banana odor, or water (no odor) for 10 min. Treatment order was randomly assigned as much as possible. General appetite and SSA were monitored by using 100-mm visual analog scales during the 10 min of active sniffing, followed by ad libitum intake of banana milkshake. Results showed that SSA was consistently high (+12 mm) during actively sniffing natural or artificial banana odors, with no decrease in SSA over time. Sniffing both banana odors increased the appetite for banana (+11 mm) and other sweet products (+4 mm), whereas the appetite for savory products decreased by 7 mm (all P < 0.01) compared with no odor. Actively sniffing banana odor did not significantly influence food intake (P = 0.68) or general appetite scores (P = 0.06). In conclusion, SSA scores during active sniffing were identical to the SSA found in a similar study that used passive smelling, suggesting that SSA is independent of the manner of sniffing and exposure time. Moreover, sweet/savory categorization may suggest that food odors communicate information about the nutrient composition of their associated foods. These data clearly show the appetizing effects of food odors.

A Mediterranean-like breakfast affects energy intake and appetite-related feelings

Energy intake and appetite feelings after the consumption of two different types of breakfast, a high-fiber, traditional, Mediterranean-type breakfast and a low-fiber, Western-type breakfast were compared. Sixteen non-obese young men received the two treatments on separate days: the Mediterranean- and the Western-type breakfasts were isocaloric, similar in volume and macronutrient content, but different in fiber content. Following a 4-hour fast, subjects offered an ad libitum lunch. Food consumed and subjective feelings of hunger, fullness, and desire to eat were evaluated. Energy intake in the ad libitum lunch was significantly lower after the Mediterranean-type, compared to the Western-type breakfast, adjusting for previous day's energy intake (1488 ± 468 versus 1674 ± 416 kcal, respectively), whereas no energy compensation was made throughout the day. Furthermore, those who had the Mediterranean-type breakfast reported lower values in the desire to eat during study's course. These findings propose a fulfilling effect of a traditional, Mediterranean, high in fiber breakfast.

Aroma exposure time and aroma concentration in relation to satiation

The present study investigated the effect of aroma exposure time and aroma concentration on ad libitum intake and subjective satiation. In a within-subject study, thirty-eight unrestrained, healthy female participants (age: 18-39 years; BMI: 18·5-26·0 kg/m²) were asked to consume tomato soup during lunchtime, until they felt comfortably full. Every 30 s, the participants consumed 10 g of a bland soup base while tomato soup aroma was delivered separately through the nose via a retronasal tube that was attached to an olfactometer. This gave the impression of consuming real tomato soup. For each sip, the aroma varied in exposure time (3 and 18 s) and concentration (5 × ), resulting in four different test conditions. Ad libitum food intake and appetite profile parameters were measured. A 9% lower food intake was observed when the participants were exposed to the condition with 18 s exposure time and a high concentration than when exposed to the other three conditions. These results indicate that changing the retronasal aroma release by aroma concentration and aroma exposure time affects food intake.

Oral processing effort, appetite and acute energy intake in lean and obese adults

Chewing reportedly contributes to satiation and satiety signals. Attempts to document and quantify this have led to small and inconsistent effects. The present trial manipulated oral processing effort though required chewing of gums of different hardness and measured appetitive sensations, energy intake, gastric emptying, GI transit time, and concentrations of glucose, insulin, GLP-1, ghrelin and pancreatic polypeptide. Sixty adults classified by sex and BMI (15 each of lean females, obese females, lean males and obese males) were tested in a randomized, controlled, cross-over trial with three arms. They chewed nothing, soft gum or hard gum for 15 min while sipping grape juice (10% of individual energy needs) containing acetaminophen and lactulose on one day each separated by 7 days. Electromyographic recordings and self-reports were obtained during and after chewing to quantify oral processing effort. Blood was sampled through an indwelling catheter and appetite ratings were obtained at baseline and at 0, 15, 30, 45, 60, 90, 120, 180 and 240 min after chewing initiation. Breath samples were collected at 10 min intervals for the first 2h and at 30 min intervals for the next 2h. No effects of chewing were observed for appetitive sensations or gut peptide concentrations. Energy intake tended to decline in lean and increase in obese participants so that daily energy intake differed significantly between the two groups when chewing either gum, while no difference was observed on the non-chewing day. Serum glucose and insulin were significantly lower at selected time points 90-240 min after chewing compared to baseline and the non-chewing day. These data indicate chewing effort does not affect appetitive sensations or gut peptide secretion, but may exert a small differential effect on acute energy intake in lean and obese individuals and lead to greater post-prandial declines of serum glucose and insulin. The efficacy of gum chewing as a substitute for eating for weight management remains uncertain.

Acute and chronic effects of gum chewing on food reinforcement and energy intake

Although chewing gum has been considered a potential method for reducing energy intake, little empirical data exist to support this idea. The purpose of this study was to test the hypothesis that chewing gum before eating reduces motivation to eat, hunger, and energy intake. In order to test this hypothesis, we conducted two experiments in which participants chewed gum prior to completing a food reinforcement task or before all eating occasions for two of three weeks. In Experiment 1, we found that chewing gum had no influence on the reinforcing value of food, but chewing mint gum reduced liking of and energy intake from fruit. In addition, chewing gum reduced self-reported hunger immediately after gum chewing and after eating compared with the no gum condition. In Experiment 2, gum chewing had no significant effect on total energy intake, but participants consumed fewer meals, consumed more energy per meal, and had a lower nutrient adequacy ratio during the gum chewing weeks. These studies provide no evidence that acute or chronic gum chewing reduces hunger or energy intake. In fact, chewing mint-flavored gum may deter consumption of fruit and reduce diet quality.

Randomized controlled trial of chewing gum for weight loss

The possible effects on body weight of chewing gum on a regular schedule have not been tested in a randomized controlled trial (RCT). We conducted an 8-week RCT in 201 overweight and obese adults to test the hypothesis that receiving printed material on good nutrition and chewing gum for a minimum of 90 min/day (n = 102) would lead to greater weight loss than receiving printed nutrition information only (n = 99). Changes in BMI, waist circumference, and blood pressure were secondary outcomes. Adherence to the gum-chewing protocol in the intervention group was >95%. In the intention-to-treat analysis, there were virtually no changes in weight or BMI in either group between baseline and the end of the intervention at 8 weeks. Waist circumference decreased significantly in the intervention group between baseline and 8 weeks (mean ± SD change = -1.4 ± 5.3 cm; P = 0.0128); however, there was no significant difference in change in waist circumference comparing the groups. Similarly, systolic and diastolic blood pressure decreased significantly in the intervention group between baseline and 8 weeks (-3.0 ± 9.9 mm Hg; P = 0.0032 and -3.2 ± 7.3 mm Hg; P = 0.0001, respectively); however, there were no significant differences in the changes in systolic or diastolic blood pressure between the groups. Analyses including completers only produced essentially the same results. We conclude that chewing gum on a regular schedule for 8 weeks did not facilitate weight loss in these overweight and obese adults.

Improvement in chewing activity reduces energy intake in one meal and modulates plasma gut hormone concentrations in obese and lean young Chinese men

BACKGROUND

Mastication is the first step in ingesting food, but the effects of mastication on energy intake and gut hormones in both obese and lean subjects have not been extensively evaluated.

OBJECTIVE

The current study aimed to compare the differences in chewing activities between obese and lean subjects and to examine the effects of chewing on energy intake and gut hormone concentrations in both obese and lean subjects.

DESIGN

Sixteen lean and 14 obese young men participated in the current research. In study 1, we investigated whether the chewing factors of obese subjects were different from those of lean subjects. In study 2, we explored the effects of chewing on energy intake. A test meal consisting of 2200 kJ (68% of energy as carbohydrate, 21% of energy as fat, and 11% of energy as protein) was then consumed on 2 different sessions (15 chews and 40 chews per bite of 10 g of food) by each subject to assess the effects of chewing on plasma gut hormone concentrations.

RESULTS

Compared with lean participants, obese participants had a higher ingestion rate and a lower number of chews per 1 g of food. However, obese participants had a bite size similar to that of lean subjects. Regardless of status, the subjects ingested 11.9% less after 40 chews than after 15 chews. Compared with 15 chews, 40 chews resulted in lower energy intake and postprandial ghrelin concentration and higher postprandial glucagon-like peptide 1 and cholecystokinin concentrations in both lean and obese subjects.

CONCLUSION

Interventions aimed at improving chewing activity could become a useful tool for combating obesity. This trial was registered at chictr.org as ChiCTR-OCC-10001181.

Effects of chewing gum on short-term appetite regulation in moderately restrained eaters

Orosensory stimulation is an important contributing factor to the development of satiation. Providing orosensory stimulation with few calories may satisfy appetite and help to suppress cravings for high energy snacks. This may be a useful strategy for those motivated to lose or maintain weight. The present study tested the hypothesis that chewing sweetened gum will reduce subjective appetite and subsequent snack intake in moderately restrained eaters. Within-subjects, repeated measures study, sixty healthy participants (53 women; body mass index, in kg/m(2): 26.2±4.5) came to the laboratory 4 times for a standard lunch. Immediately after this meal, participants rated hunger, appetite and cravings for sweet and salty snacks every hour until they returned to the laboratory 3 h later for snack. On two occasions during this 3 h period participants chewed gum for at least 15 min at hourly intervals (45 min) and on two occasions no gum was chewed. On two occasions salty snacks were offered and on two occasions sweet snacks were provided. A small but significant reduction in snack intake was observed, chewing gum reduced weight of snack consumed by 10% compared to no gum (p<0.05). Overall, chewing gum for at least 45 min significantly suppressed rated hunger, appetite and cravings for snacks and promoted fullness (p<0.05). This study demonstrated some benefit of chewing gum which could be of utility to those seeking an aid to appetite control.

Chewing gum and context-dependent memory: The independent roles of chewing gum and mint flavour

Two experiments independently investigated the basis of the chewing gum induced context-dependent memory effect. At learning and/or recall, participants either chewed flavourless gum (Experiment 1) or received mint-flavoured strips (Experiment 2). No context-dependent memory effect was found with either flavourless gum or mint-flavoured strips, indicating that independently the contexts were insufficiently salient to induce the effect. This is found despite participants' subjective ratings indicating a perceived change in state following administration of flavourless gum or mint-flavoured strips. Additionally, some preliminary evidence for a non-additive facilitative effect of receiving gum or flavour at either learning and/or recall is reported. The findings raise further concerns regarding the robustness of the previously reported context-dependent memory effect with chewing gum.

Three months of regular gum chewing neither alleviates xerostomia nor reduces overhydration in chronic hemodialysis patients

INTRODUCTION AND AIMS

Gum chewing has been known to be a part of adjunctive medical therapy for cancer-related xerostomia. Nonadherence to fluid restriction in hemodialysis (HD) patients brought about by unrestricted thirst and xerostomia leads to excessive interdialytic weight gain (IWG). The effectiveness of gum chewing in reducing thirst in HD patients has till recently been evaluated by only a single study with short 2-week intervention period. The aim of the present study was to assess the effect of 3 months of regular use of sugar-free chewing gum on xerostomia, thirst, and hydration and nutritional status in HD patients.

METHODS

A prospective pre/post (3 + 1 month[s]) study including 38 chronic HD patients (14 women, 17 men; mean age, 59 ± 10 years; time on dialysis, 48 ± 45 months) with mean mid-week IWG of >1 kg, persistent xerostomia, and/or thirst was conducted. Seven patients did not complete the study including 3 because of suspected side effects of gum chewing (diarrhea or paradoxically increased thirst). After a 2-week run-in period, the subjects received a specified number of packs of low-tack, sugar-free chewing gum and specially designed diaries. Basic biochemistry and multifrequency electric bioimpedance were performed a total of 8 times, that is, at baseline and after each month of the intervention period, both before and after dialysis. Questionnaires related to xerostomia and thirst were filled in by the patients at baseline, at the end of the intervention period, and 1 month later. Body weight (for IWG assessment) and blood pressure were measured at the start of each dialysis for the whole duration of the study.

RESULTS

The mean number of chewing gum pellets used during the first and the third month of the study was 137 ± 56 and 139 ± 59, respectively. The patients did not report experiencing any changes in the intensity of xerostomia and thirst during the study. Total body water content assessed with bioimpedance did not decrease (41.9 ± 8.9 kg at baseline vs. 42.7 ± 9.1 kg at the end of the intervention period). Moreover, no changes in extracellular mass (31.9 ± 6.4 kg vs. 32.6 ± 6.6 kg), extracellular water (18.0 ± 5.2 kg vs. 18.3 ± 5.0 kg), and phase angle (4.6 ± 0.8 vs. 4.6 ± 0.8) were observed. Mean IWG between 2 mid-weekly HD sessions also did not change (2.3 ± 0.8 kg at baseline vs. 2.3 ± 0.9 kg at the end of the intervention period). No significant changes in thirst and xerostomia were observed 4 weeks after the end of the intervention period; however, mean IWG between 2 mid-weekly HD sessions increased to 2.8 ± 1.0 kg (P < .001).

CONCLUSIONS

Regular gum chewing is known to be well tolerated by most HD patients; however, it does not lead to the alleviation of xerostomia or excessive thirst and does not reduce IWG or improve hydration status.

Effects of bite size and duration of oral processing on retro-nasal aroma release - features contributing to meal termination

The brain response to a retro-nasally sensed food odour signals the perception of food and it is suggested to be related to satiation. It is hypothesised that consuming food either in multiple small bite sizes or with a longer durations of oral processing may evoke substantial oral processing per gram consumed and an increase in transit time in the oral cavity. This is expected to result in a higher cumulative retro-nasal aroma stimulation, which in turn may lead to increased feelings of satiation and decreased food intake. Using real-time atmospheric pressure chemical ionisation-MS, in vivo retro-nasal aroma release was assessed for twenty-one young, healthy and normal-weight subjects consuming dark chocolate-flavoured custard. Subjects were exposed to both free or fixed bite size (5 and 15 g) and durations of oral processing before swallowing (3 and 9 s) in a cross-over design. For a fixed amount of dark chocolate-flavoured custard, consumption in multiple small bite sizes resulted in a significantly higher cumulative extent of retro-nasal aroma release per gram consumed compared with a smaller amount of large bite sizes. In addition, a longer duration of oral processing tended to result in a higher cumulative extent of retro-nasal aroma release per gram consumed compared with a short duration of oral processing. An interaction effect of bite size and duration of oral processing was not observed. In conclusion, decreasing bite size or increasing duration of oral processing led to a higher cumulative retro-nasal aroma stimulation per gram consumed. Hence, adapting bite size or duration of oral processing indicates that meal termination can be accelerated by increasing the extent of retro-nasal aroma release and, subsequently, the satiation.

Systematic review and meta-analysis of chewing-gum therapy in the reduction of postoperative paralytic ileus following gastrointestinal surgery

BACKGROUND

Postoperative ileus has long been considered an inevitable consequence of gastrointestinal surgery. It prolongs hospital stay, increases morbidity, and adds to treatment costs. Chewing is a form of sham feeding reported to stimulate bowel motility. This analysis examines the value of chewing-gum therapy in treatment of postoperative ileus.

METHODS

A search for randomized, controlled trials studying elective gastrointestinal surgery was undertaken using MEDLINE, Embase, Cochrane Controlled Trials Register, and reference lists. Outcomes were extracted including time to first flatus and bowel motion, length of stay, and complications. Statistical analysis was undertaken using the weighted mean difference (WMD) and random-effects model with 95% confidence intervals (CI).

RESULTS

Seven studies with 272 patients were included. For time to first flatus the analysis favored treatment with a WMD of 12.6 h (17%) reduction (95% CI -21.49 to -3.72; P = 0.005). For time to first bowel motion, treatment was favored with a WMD of 23.11 h (22%) reduction (95% CI -34.32 to -11.91; P < 0.001). For length of stay, the analysis showed a nonsignificant trend toward treatment with WMD of 23.88 h (12%) reduction (95% CI -53.29 to +5.53; P = 0.11). There were no significant differences in complication rates.

CONCLUSIONS

Chewing-gum therapy following open gastrointestinal surgery is beneficial in reducing the period of postoperative ileus, although without a significant reduction in length of hospital stay. These outcomes are not significant for laparoscopic gastrointestinal surgery.

Impact of gum chewing on stress levels: online self-perception research study

OBJECTIVE

To investigate whether gum chewing affects perceived levels of everyday stress among persons who (1) regularly chew gum or (2) do not chew gum on a regular basis.

RESEARCH DESIGN AND METHODS

Two Internet-based studies were conducted. Study 1 enrolled participants who chewed gum > or =4 days per week, chewed > or =11 pieces of gum per week, and chewed gum during the previous week (frequent or heavy chewers, n = 280). Study 2 enrolled participants who had chewed gum previously but did so infrequently and had not chewed during at least the 7 days before recruitment (n = 212). Both studies used a randomized, crossover design: each participant either chewed gum or abstained from chewing for a number of sequential days, then switched to the opposite behavior for the same number of days. Stress levels were assessed by means of self-reported responses to the State-Trait Anxiety Inventory (STAI) at screening and after each test sequence.

RESULTS

More participants (54% in study 1 [p < or = 0.10] and 57% in study 2 [p < or = 0.05]) reported that chewing gum reduced their stress level at least a little, compared with those who reported no effect on or an increase in stress. In both studies, mean STAI state scores increased significantly after the abstaining period, indicating an increase in the perceived level of stress, and decreased significantly after the gum-chewing period. Particular stress-specific emotions (e.g., not feeling relaxed, feeling tense) were reported to have significantly increased when participants abstained from chewing gum and to have decreased when they chewed. More severe levels of stress (e.g., being upset or frightened) were not affected by chewing or abstaining from chewing gum. The studies had several potential limitations, including self-reporting, a large initial recruitment, and the need for habit alteration.

CONCLUSIONS

The findings point to a relationship between decreased stress and gum chewing and suggest chewing gum may help reduce perceived levels of everyday stress.

Sip size of orangeade: effects on intake and sensory-specific satiation

Sensory-specific satiation (SSS) drives food selection and contributes to meal termination. We hypothesised that smaller sips would increase SSS due to increased oro-sensory exposure, irrespective of energy content. The objective was to determine the effects of sip size and energy content on ad libitum intake of orangeade and subjective SSS for orangeade. Orangeade intake and ratings of wanting and liking were measured before and after ad libitum orangeade consumption in a 2 × 2 cross-over design (n 53). Conditions differed in energy content (no-energy v. regular-energy orangeade) and in sip size (large, 20 g/sip v. small, 5 g/sip). The mean intake of both orangeades was lower when consumed with small sips than when consumed with large sips (regular-energy, 352 v. 493 g; no-energy, 338 v. 405 g; both P < 0·001). When consumed with large sips, the mean intake of no-energy orangeade was lower than that of regular-energy orangeade (P = 0·02). When consumed with small sips, subjective SSS (based on the desire to drink) was higher for no-energy orangeade than for regular-energy orangeade (P = 0·01), while mean intake was comparable. We concluded that smaller sip size, i.e. increased oro-sensory exposure per unit of consumption, can lower intake of sweet drinks. Only with low oro-sensory exposure (large sip size) was intake higher for an energy-containing sweet drink than for a no-energy sweet drink. This suggests that intake of sweet drinks is stimulated by (metabolic) reward value and inhibited by sensory satiation. This underpins the importance of SSS for meal termination.

Retro-nasal aroma release depends on both subject and product differences: a link to food intake regulation?

It is hypothesized that differences in the extent of retro-nasal aroma release during consumption may be 1 of the reasons that people vary in their satiation characteristics. Using real-time atmospheric pressure chemical ionization mass spectrometry (APcI-MS), in vivo retro-nasal aroma release was determined for 30 subjects consuming 9 different food products, varying in physical structure (i.e., [semi]liquid and solid food products). Additionally, for a subset of the subjects ad libitum food intake was measured. Retro-nasal aroma release intensity and profile morphology appeared to be subject specific and relatively independent of the type of food product subjects consumed. A subject who was observed as having a relatively high retro-nasal aroma release intensity for a (semi)liquid food product also appeared to have a relatively high retro-nasal aroma release intensity for a solid food product. However, for all subjects, there were absolute differences between food products in the extent of retro-nasal aroma release comparing (semi)liquid and solid food products. This implies that the extent of retro-nasal aroma release is a valid physiological feature that characterizes any individual. Interestingly, a negative trend was observed between extent of retro-nasal aroma release and amount of ad libitum food intake (P = 0.07). This may have implications for the regulation of food intake.