Effects of appetite, BMI, food form and flavor on mastication: almonds as a test food

Consuming almonds with chocolate or lettuce influences oral processing behaviour, bolus properties and consequently predicted lipid release from almonds

Lipids in almonds are naturally encapsulated by cell walls which may reduce the actual metabolizable energy content of almonds. Oral processing increases the accessibility of lipids to digestive enzymes by grinding the almond matrix. This study aimed to investigate the effect of adding accompanying foods (chocolate and iceberg lettuce) to almonds on oral processing behaviour, bolus properties and predicted lipid release. Natural chewing times of four almond model foods including one almond (1.3 g), four almonds (4.6 g), one almond with chocolate (4.3 g) and one almond with iceberg lettuce (4.3 g) were collected from n = 59 participants in duplicate. Expectorated boli at the moment of swallowing were characterized for number and mean area of almond bolus particles. Predicted lipid bioaccessibility was estimated using a previously validated model. At similar bite size (4.3-4.6 g), the addition of chocolate and iceberg lettuce to almonds significantly decreased (p < 0.05) chewing time and significantly increased (p < 0.05) eating rate compared to consumption of almonds alone. Almond bolus particle sizes were similar for almonds consumed alone (one and four almonds) and with chocolate, while consuming almonds with lettuce generated significantly fewer and larger almond bolus particles (p < 0.05). Predicted lipid bioaccessibility of almonds consumed with iceberg lettuce was significantly lower (p < 0.05) than for almonds consumed alone (one and four almonds) and almonds consumed with chocolate. Eating rate correlated significantly and positively with the mean area of bolus particles and significantly and negatively with predicted lipid release. In conclusion, combining almonds with other foods such as chocolate and lettuce influences oral processing behaviour and bolus properties and consequently predicted lipid bioaccessibility of almonds, highlighting the impact of food matrix and consumption context on these aspects.

Effect of Obesity on Masticatory Muscle Activity and Rhythmic Jaw Movements Evoked by Electrical Stimulation of Different Cortical Masticatory Areas

This study investigates rhythmic jaw movement (RJM) patterns and masticatory muscle activities during electrical stimulation in two cortical masticatory areas in obese male Zucker rats (OZRs), compared to their counterparts-lean male Zucker rats (LZRs) (seven each). At the age of 10 weeks, electromyographic (EMG) activity of the right anterior digastric muscle (RAD) and masseter muscles, and RJMs were recorded during repetitive intracortical micro-stimulation in the left anterior and posterior parts of the cortical masticatory area (A-area and P-area, respectively). Only P-area-elicited RJMs, which showed a more lateral shift and slower jaw-opening pattern than A-area-elicited RJMs, were affected by obesity. During P-area stimulation, the jaw-opening duration was significantly shorter (p < 0.01) in OZRs (24.3 ms) than LZRs (27.9 ms), the jaw-opening speed was significantly faster (p < 0.05) in OZRs (67.5 mm/s) than LZRs (50.8 mm/s), and the RAD EMG duration was significantly shorter (p < 0.01) in OZRs (5.2 ms) than LZR (6.9 ms). The two groups had no significant difference in the EMG peak-to-peak amplitude and EMG frequency parameters. This study shows that obesity affects the coordinated movement of masticatory components during cortical stimulation. While other factors may be involved, functional change in digastric muscle is partly involved in the mechanism.

Comparing the effects of consuming almonds or biscuits on body weight in habitual snackers: A one-year randomized controlled trial

PURPOSE

Almonds are nutrient-rich, providing a healthier alternative to many snack foods. Studies report health benefits with regular almond consumption without adverse weight gain. However, most interventions have been relatively short or have included additional dietary advice. Taking a pragmatic approach, we compared consumption of almonds versus biscuits on body weight and other health outcomes in a population of regular snackers of discretionary foods, hypothesizing the almonds will displace some of the less healthful snacks in their current diets.

METHODS

We randomly assigned 136 non-obese habitual discretionary snack consumers to receive almonds or biscuits daily for one-year. These isocaloric snacks provided either 10% of participants' total energy (TE) requirements or 1030 kJ (equivalent to 42.5 g almonds), whichever was greater. Anthropometry, blood biomarkers, diet, appetite, sleep, and, physical activity, were assessed at baseline, 3, 6, and 12 months, and body composition and resting metabolic rate at baseline and 12 months.

RESULTS

The difference in changes for body weight from baseline to 12 months was not statistically significant (geometric means 67.1 kg and 69.5 kg for almonds and 66.3 kg and 66.3 kg for biscuits, P = 0.275). There were no statistically significant differences in changes for body composition or other non-dietary outcomes (all P ≥ 0.112). Absolute intakes of protein; total, polyunsaturated, and monosaturated fat; fibre; vitamin E; calcium; copper; magnesium; phosphorous; and zinc, and % TE from total monounsaturated, and polyunsaturated fat statistically significantly increased from baseline (all P ≤ 0.033), while % TE from carbohydrate and sugar statistically significantly (both P ≤ 0.014) decreased from baseline, in the almond compared to the biscuit group.

CONCLUSIONS

Almonds can be incorporated into the diets of habitual snackers to improve diet quality, without evidence for changes in body weight, compared to a popular discretionary snack food.

TRIAL REGISTRATION

ACTRN12618001758291 https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=375610&isReview=true.

A Conceptual Model for Mobile Health-enabled Slow Eating Strategies

Ingestive behaviors (IBs) (eg, bites, chews, oral processing, swallows, pauses) have meaningful roles in enhancing satiety, promoting fullness, and decreasing food consumption, and thus may be an underused strategy for obesity prevention and treatment. Limited IB monitoring research has been conducted because of a lack of accurate automated measurement capabilities outside laboratory settings. Self-report methods are used, but they have questionable validity and reliability. This paper aimed to present a conceptual model in which IB, specifically slow eating, supported by technological advancements, contributes to controlling hedonic and homeostatic processes, providing an opportunity to reduce energy intake, and improve health outcomes.

Particle Size Distribution and Predicted Lipid Bioaccessibility of Almonds and the Effect of Almond Processing: A Randomised Mastication Study in Healthy Adults

Almonds are rich in unsaturated lipids, which play a role in some of the reported benefits of almond consumption for human health. Almond lipids are poorly bioaccessible due to almonds' unique physicochemical properties that influence particle size distribution (PSD) following mastication, allowing much intracellular lipid to escape digestion in the upper gastrointestinal tract. To investigate the impact of commercial processing (grinding almonds into flour), on PSD and predicted lipid bioaccessibility following mastication, a randomised cross-over design mastication study was conducted in healthy adults. The PSDs of masticated whole and ground almonds was assessed using two laboratory methods (mechanical sieving and laser diffraction). PSD from mechanical sieving was used to calculate lipid bioaccessibility using a theoretical mathematical model. Thirty-one healthy adults (18-45 years) completed both mastication sessions. Following mastication, ground almonds had a PSD with significantly fewer larger particles and more smaller particles, compared with whole almonds. Predicted lipid bioaccessibility of masticated ground almonds (10.4%, SD 1.8) was marginally but significantly greater than the predicted lipid bioaccessibility of masticated whole almonds (9.3%, SD 2.0; p = 0.017). Commercial grinding of almonds significantly influences the PSD of almonds following mastication, which results in a modest but significant increase in predicted lipid bioaccessibility.

The role of dietary fibers in regulating appetite, an overview of mechanisms and weight consequences

Dietary fibers prevent obesity through reduction of hunger and prolongation of satiety. A number of mechanical and endocrine signals from gastrointestinal tract are stimulated by fibers and their fermentation products, reach regions of brain involved in the regulation of appetite, and ultimately reduce food intake. Gastric distention, delayed gastric emptying, prevention of hypoglycemic, increased amounts of unabsorbed nutrients reaching to the ileum, and stimulation of enteroendocrine cells for secretion of cholecystokinin, glucagon-like peptide-1 (GLP-1), and peptide YY are among mechanisms of fibers in decreasing hunger and prolongation of satiety. Fermentation of fibers produces short-chain fatty acids that also stimulates enteroendocrine cells to secrete GLP-1 and PYY. Randomized controlled trials have shown reductions in energy intake and body weight along with increased satiation and reduced hunger following consumption of fibers. Prospective cohort studies have confirmed these results but the extent of weight loss in some studies has been small. Controversies exist between studies particularly for the effect of fibers on the gastrointestinal hormones, subsequent food intake, and the resultant weight loss. More studies are needed before a clear conclusion can be drawn especially for the effect of fibers on appetite-related hormones and weight loss.

Eating habit patterns may predict maximum occlusal force: A preliminary study

Masticatory function is thought to be related to various eating habits, but it is difficult to evaluate overall masticatory function by assessing complex eating habits. Maximum occlusal force is an important indicator of masticatory function that is affected by age and sex. This preliminary study focused on the maximum occlusal force of young women and their eating habits, excluding food and nutritional factors, and investigated whether individual eating habits and eating habit patterns predict maximum occlusal force. We measured the maximum occlusal force for the whole dentition of 53 healthy young women before they ate lunch. The participants also completed a 12-item questionnaire about their eating habits. Scores were determined from the relationship between each item and increased maximum occlusal force. We found a significant but weak relationship between maximum occlusal force and some questions. The total questionnaire scores for the participants’ eating habits showed an almost normal distribution (mean ± standard deviation: 22.7 ± 2.6, median: 23.0, mode: 23.0, range of total scores: 17–28). The accuracy of the linear regression between the total scores for eating habits and maximum occlusal force was high but not perfect (β: standardized regression coefficient = 0.527, P < 0.001). Although further research is needed, our findings confirm that eating habit patterns are significantly associated with maximum occlusal force and may help predict occlusal force. Our results provide important information about eating patterns in humans.

A randomised crossover clinical trial of masticatory function in complete denture wearers with conventional and lingualised balanced occlusion

OBJECTIVES

The purposes of the present study were as follows: (1) to conduct a randomised crossover clinical trial to evaluate masticatory performance in wearers of conventional complete dentures in both arcs with conventional balanced occlusion (CBO) and lingualised balanced occlusion (LBO), using almonds as natural test food chewed for (a) 30 chewing cycles, (b) 40 chewing cycles and (c) until the subject felt ready to swallow and (2) to perform a randomised crossover clinical trial of oral health self-perception through the Geriatric Oral Health Assessment Index (GOHAI) questionnaire.

BACKGROUND

During rehabilitation with full dentures, achieving stability and retention is essential for masticatory performance. A factor that can act is the appropriate occlusal scheme to be used, although the literature is full of discussions as to the most suitable occlusal scheme to be used, being CBO and LBO the most used in complete dentures.

MATERIALS AND METHODS

The clinical trial was conducted with 30 participants (14 males and 16 females; average age 65.8 years). A base of interchangeable posterior teeth in the lower dentures was used, thereby changing the occlusal schemes without needing to make another complete denture. The masticatory tests and GOHAI application were conducted in two sessions: first with each occlusal scheme, and second only after participants did not report discomfort with dentures. The analysis of variance for the mixed repeated-measures test (ANOVA) was used to verify the results (α = 0.05).

RESULTS

The results showed no difference in masticatory performance according to the occlusal scheme (P = .519). The masticatory performance increased with the number of cycles (P < .001) tested, regardless of the type of occlusion scheme, and oral health self-perception was higher after the second masticatory evaluation session (P = .027).

CONCLUSION

The masticatory performance was similar between the two occlusal schemes, increasing according to the number of chewing cycles. The adaptive period is relevant, regardless of the occlusion scheme, because the time factor was decisive for the improvements noted in the oral health self-perception of the participants (according to the GOHAI results).

Snacking on Almonds Lowers Glycaemia and Energy Intake Compared to a Popular High-Carbohydrate Snack Food: An Acute Randomised Crossover Study

Consuming nuts may have advantages over other snack foods for health and body-weight regulation. Suggested mechanisms include increased satiety and lower glycaemia. We used an acute randomised crossover trial to assess glycaemic and appetite responses to consuming two isocaloric snacks (providing 10% of participants’ total energy requirements or 1030 kJ (equivalent to 42.5 g almonds), whichever provided greater energy): raw almonds and sweet biscuits among 100 participants with available data (25 males and 75 females) following 106 being randomised. Two hours after consuming a standardised breakfast, participants consumed the snack food. Finger-prick blood samples measuring blood glucose and subjective appetite ratings using visual analogue scales were taken at baseline and at 15 or 30 min intervals after consumption. Two hours after snack consumption, an ad libitum lunch was offered to participants and consumption was recorded. Participants also recorded food intake for the remainder of the day. The mean area under the blood glucose response curve was statistically and practically significantly lower for almonds than biscuits (mean (95% CI) difference: 53 mmol/L.min (45, 61), p < 0.001). Only the composite appetite score at 90 min was higher in the almond treatment compared to the biscuit treatment (45.7 mm vs. 42.4 mm, p = 0.035 without adjustment for multiple comparisons). There was no evidence of differences between the snacks for all other appetite ratings or for energy intake at the ad libitum lunch. However, mean energy intakes following snack consumption were significantly lower, both statistically and in practical terms, for the almond treatment compared to the biscuit (mean (95% CI) diff: 638 kJ (44, 1233), p = 0.035). Replacing popular snacks with almonds may have advantages in terms of glycaemia and energy balance.

Higher Activity and Quality of Life Correlates with Swallowing Function in Older Adults with Low Activities of Daily Living

INTRODUCTION

The aim of this study was to clarify the relationship among swallowing function, activity, and quality of life (QOL) in older adults with low activities of daily living (ADL).

MATERIALS AND METHODS

We conducted a cross-sectional study. In total, 271 Japanese adults aged over 65 years who underwent medical intervention at their residence (male: n = 107; female: n = 164; mean age = 84.6 ± 8.3 years) participated. We collected data regarding age, sex, body mass index (BMI), residence (their house/nursing home), activity status, consciousness level (eye response), history of aspiration pneumonia, other medical history, number of medication types, frequency of going out, and time spent away from bed. We judged consciousness level (eye response) using the Glasgow Coma Scale (GCS), calculated the Charlson comorbidity index, measured QOL using the short version of the Quality of Life Questionnaire for Dementia (short QOL-D), and assessed swallowing function using the Functional Oral Intake Scale (FOIS). To examine the relationship between scores for the FOIS and the other variables, we used the Spearman rank correlation coefficient and ordinal logistic regression analysis.

RESULTS

The FOIS was strongly correlated with BMI (ρ = 0.47), activity status (ρ = -0.60), GCS (ρ = -0.41), time spent away from bed (ρ = 0.56), scores for the short QOL-D (ρ = 0.40), weakly correlated with history of aspiration pneumonia (ρ = -0.27), and frequency of going out (ρ = 0.39). Results for the ordinal logistic regression analysis showed that the FOIS was associated with activity status, frequency of going out, time spent away from bed, and scores for the short QOL-D.

CONCLUSION

The swallowing function of older adults with low ADL was related to their QOL and activities, such as time spent away from bed and home. Thus, in rehabilitation programs for swallowing function in older adults, not only functional but also psychological approaches may prove effective.

Ease of mastication index-Quantification of mastication effort using quality function deployment

An effort required to masticate a bite of food seems important for a broad group of consumers considering many foodstuffs. Consumers with specific needs (elderly, people with impaired oral functioning) are also interested in ease of mastication. Besides understanding the relationships between mastication and sensory perception, a better insight into foodstuffs' mastication effort is needed to gain vital information when choosing the food and judging its quality. However, there is not much work describing the quantification of mastication effort as a quality grade. Within this research, we: (a) analyzed consumers' demands toward mastication attributes, (b) examined mastication, mechanical, and sensory parameters for nine foodstuffs (meat and dairy products), and (c) developed a quality function deployment model that connects consumers' demands with a multidimensional technical scale, enabling mastication effort quantification through a novel "ease of mastication index" (EMI). As a single-value quality score, EMI answers how much effort must be applied to masticate certain foodstuff. It is a left-sided index (it can have only positive values up to EMI = 1), having the maximal value for creamy cheese (0.96) and minimal (0.40) for fermented sausage in the present study, meaning the latter was the most difficult case study product for mastication. This study's practical application may be seen in the proposed model usage for foodstuffs research and development, bearing in mind ease of mastication. EMI may play an essential role as a novel quality indicator that can be considered crucial for broad and specific consumer groups.

Virtual Reality as a Tool to Study the Influence of the Eating Environment on Eating Behavior: A Feasibility Study

In this manuscript, we describe a new approach to study the effect of the eating environment on food intake and eating behavior using virtual reality technology. Fifteen adults consumed pizza rolls in two virtual reality (VR) environments: a restaurant and a table in an empty room. The participants' food intake, eating parameters (e.g., masticatory parameters and eating rate), and their sensory evaluation of the test food was measured. The participants' sense of presence (the feeling of being in the virtual environment) and markers of arousal were also measured. There was no statistical significant difference in food intake or the sensory evaluation of the test food. In the restaurant condition, participants used fewer masticatory cycles before swallowing but there was no effect on eating rate or maximum bite force. Participants experienced a greater sense of presence when they were in the pizza restaurant scene. Moreover, their heart rate and skin temperature were higher in the restaurant condition. This study suggests that VR could be developed as a new tool to study the effect of the eating environment on food intake and eating behavior.

Evaluation of the Influence of Raw Almonds on Appetite Control: Satiation, Satiety, Hedonics and Consumer Perceptions

Snack foods can be substantial contributors to daily energy intake, with different types of snacks exerting potentially different effects on satiety per calorie consumed. The present research compared the effect of consuming almonds as a mid-morning snack compared to an energy and weight-matched comparator snack (savoury crackers) or the equivalent weight of water (zero energy control). In a crossover design, 42 female participants (age: 26.0 ± 7.9, BMI: 22.0 ± 2.0) consumed a fixed breakfast then a mid-morning snack. Appetite, 24-h energy intake, food hedonics, and consumer perceptions of the snack foods were assessed under laboratory conditions. AUC analyses revealed a lower overall hunger drive after consuming almonds compared to crackers or water. There was no difference in 24-h energy intake in the almond compared to the cracker or the zero-energy control condition, however participants consumed more energy in the cracker condition compared to the zero-energy control condition. In addition, almonds suppressed hedonic preference (implicit wanting) for consuming high-fat foods and demonstrated a higher satiety quotient (SQ) than crackers. Almonds were perceived to have a more favourable consumer profile aligned with successful weight management. In conclusion, these findings demonstrate that in the context of a 24-h period of objectively measured energy intake, raw almonds are effective for controlling appetite compared to an energy matched alternative snack. This trial was registered at clinicaltrials.gov [NCT02480582].

Smartphone use while eating increases caloric ingestion

The use of smartphones during meals may possibly influence the number of ingested calories. We evaluated the influence of smartphones' distraction during eating on caloric intake. Physical (masticatory parameters, sex and body mass index - BMI); environmental (with or without distraction) and psychological (stress levels) variables were evaluated as confounding factors. Sixty-two adults were recruited for experimental snack tests performed on four different days. At baseline, we evaluated masticatory performance, swallowing threshold, masticatory frequency and body mass index (BMI). In the following three sessions, volunteers were presented a snack test in which participants ate under three experimental conditions: no distraction, using their smartphones, or reading a printed text. At the end of each session, total and nutritional compound stratified caloric intake was measured. Three-way mixed model ANOVA was used to test the effect of experimental condition on the total, carbohydrate and lipid caloric intakes. Hierarchical multiple linear regression models were used to estimate the influence of confounding factors on the total caloric intake. We found an effect of the condition (no distraction, smartphone or reading) on the total caloric (p = .007) and lipid intake (p = .002). When eating without distraction, the mean caloric intake was 535 (±164) kcal, in comparison to 591 (±203) kcal using smartphone (p = .05) and 622 (±226) kcal (p = .002) reading a text (no significant difference between distracters). Eating with distracters increased approximately 15% caloric ingestion. An interaction condition*sex effect was observed on lipid intake (p = .020). Energy intake was found to be dependent on sex and age, in which older men ingested more calories. Smartphone use during a meal increased caloric and lipid intake, depending on sex and age in young adults with complete dentition.

Can Nuts Mitigate Malnutrition in Older Adults? A Conceptual Framework

The proportion of adults aged over 60 years in the world is expected to reach 20% by the year 2050. Ageing is associated with several physiological changes that increase the risk of malnutrition among this population. Malnutrition is characterized by deficiencies or insufficiencies of macro- and micronutrients. Malnutrition has detrimental effects on the health, wellbeing, and quality of life in older adults. Nuts are rich in energy, unsaturated fats, and protein, as well as other nutrients that provide a range of health benefits. While the effects of nuts on overnutrition have been studied extensively, very few studies have been specifically designed to understand the role of nuts in mitigating undernutrition in the elderly. Therefore, this review explores the potential role of nuts in improving the nutritional status of older adults who are at risk of undernutrition. Several properties of whole nuts, some of which appear important for addressing overnutrition, (e.g., hardness, lower-than-expected nutrient availability, satiety-enhancing effects) may limit their effectiveness as a food to combat undernutrition. However, we propose that modifications such as transforming the physical form of nuts, addressing the timing of nut ingestion, and introducing variety may overcome these barriers. This review also discusses the feasibility of using nuts to prevent and reverse undernutrition among older adults. We conclude with a recommendation to conduct clinical studies in the future to test this conceptual framework.

Mastication of Nuts under Realistic Eating Conditions: Implications for Energy Balance

The low digestibility and high satiety effects of nuts have been partly attributed to mastication. This work examines chewing forces and the bolus particle size of nuts (walnuts, almonds, pistachios) varying in physical properties under different conditions (with and without water, juice, sweetened yogurt and plain yogurt) along with satiety sensations and gut hormone concentrations following walnut consumption (whole or butter). In a randomized, cross-over design with 50 adults (25 males, 25 females; Body Mass Index (BMI) 24.7 ± 3.4 kg/m²; age: 18⁻52 years old (y/o), the chewing forces and particle size distribution of chewed nuts were measured under different chewing conditions. Appetite sensations were measured at regular intervals for 3 h after nut intake, and plasma samples were collected for the measurement of glucose, insulin and Glucagon-like peptide-1 (GLP-1). The three nuts displayed different particle sizes at swallowing though no differences in chewing forces were observed. Walnuts with yogurt yielded larger particle sizes than the other treatments. Particle size was not correlated with either food palatability or flavor. Fullness sensations were higher after whole nut than nut butter consumption though there were no significant changes in glucose, insulin, or GLP-1 concentrations under any condition. Changing the conditions at swallowing might influence the release of energy from nuts.

Association of mastication and factors affecting masticatory function with obesity in adults: a systematic review

Background

A substantial number of adults suffer from obesity, that is caused by the risk factor, masticatory dysfunction. The association between mastication and obesity, however, is inconclusive. This systematic review aims to provide literature regarding the association between mastication and factors affecting masticatory function, and obesity in adults.

Methods

Four electronic databases (PubMed, EMBASE, Cochrane Library, and Web of Science) were used to search for publications that met the following criteria: published between 2007 and 2016, written in English, and assessed the associations between mastication and obesity among the population aged ≥18 years. The included publications were analyzed based on the study design, main conclusions, and strength of evidence identified by the two authors who screened all the abstracts and full-text articles and, abstracted data, and performed quality assessments by using a critical appraisal tool, the Critical Appraisal Skills Programme Cohort Studies Checklists.

Results

A total of 18 articles (16 cross-sectional, 1 cohort studies, and 1 randomized controlled trial [RCT]) met our inclusion criteria and were evaluated. Poorer mastication was associated with obesity in 12 out of 16 cross-sectional studies. One cohort study showed that the obesity group displayed higher tooth loss than the normal weight group. One RCT demonstrated that gum-chewing intervention for 8 weeks significantly decreased waist circumference.

Conclusions

Most studies revealed a positive association between mastication and obesity among adults. Nonetheless, most of them are cross-sectional studies, which are insufficient to demonstrate a causal relation. Further advancement requires RCT, especially an intervention of improvement of mastication and obesity needed to confirm this association.

Electronic supplementary material

The online version of this article (10.1186/s12903-018-0525-3) contains supplementary material, which is available to authorized users.

The effect of mastication on food intake, satiety and body weight

As mastication is the major component of the oral processing of solid foods a better understanding of its influence on ingestion, digestion and metabolism may lead to new approaches to improve health. A growing number of studies provide evidence that mastication may influence energy balance through several routes: activation of histaminergic neurons, reducing eating rate, altered digestion kinetics, and changes in macronutrient availability. Indeed, accumulating evidence indicates that increasing the number of masticatory cycles before swallowing reduces food intake and increases satiety. However, while slowing eating rate has been shown to limit weight gain in children and adolescents it is not clear that slowing eating rate by increasing the number of masticatory cycles or slowing mastication rate is a viable method to aid weight management ([10], [15]). Further research is required to determine the influence of mastication on energy balance and how it could be manipulated to aid weight management. This narrative review will provide a brief overview of the effect of mastication on food intake, satiety and body weight.

Current nut recommendation practices differ between health professionals in New Zealand

OBJECTIVE

Despite evidence linking regular nut consumption with reduced chronic disease risk, population-level intakes remain low. Research suggests nut-promoting advice from doctors facilitates regular nut consumption. However, there is no information on current nut recommendation practices of health professionals. The aim of the present study was to examine the advice provided by health professionals regarding nut consumption.

DESIGN

In this cross-sectional study, participants were invited to complete a survey including questions about their nut recommendation practices.

SETTING

New Zealand (NZ).

SUBJECTS

The NZ Electoral Roll was used to identify dietitians, general practitioners and practice nurses.

RESULTS

In total 318 dietitians, 292 general practitioners and 149 practice nurses responded. Dietitians were more likely (82·7 %) to recommend patients increase consumption of nuts than general practitioners (55·5 %) and practice nurses (63·1 %; both P<0·001). The most popular nuts recommended were almonds, Brazil nuts and walnuts, with most health professionals recommending raw nuts. The most common recommendation for frequency of consumption by dietitians and practice nurses was to eat nuts every day, while general practitioners most frequently recommended 2-4 times weekly, although not statistically significantly different between professions. Dietitians recommended a significantly greater amount of nuts (median 30 g/d) than both general practitioners and practice nurses (20 g/d; both P<0·001).

CONCLUSIONS

Dietitians were most likely to recommend consumption of nuts in accordance with current guidelines, but there are opportunities to improve the adoption of nut consumption recommendations for all professions. This may be a viable strategy for increasing population-level nut intakes to reduce chronic disease.

Benefits of Nut Consumption on Insulin Resistance and Cardiovascular Risk Factors: Multiple Potential Mechanisms of Actions

Epidemiological and clinical studies have indicated that nut consumption could be a healthy dietary strategy to prevent and treat type 2 diabetes (T2DM) and related cardiovascular disease (CVD). The objective of this review is to examine the potential mechanisms of action of nuts addressing effects on glycemic control, weight management, energy balance, appetite, gut microbiota modification, lipid metabolism, oxidative stress, inflammation, endothelial function and blood pressure with a focus on data from both animal and human studies. The favourable effects of nuts could be explained by the unique nutrient composition and bioactive compounds in nuts. Unsaturated fatty acids (monounsaturated fatty acids and polyunsaturated fatty acids) present in nuts may play a role in glucose control and appetite suppression. Fiber and polyphenols in nuts may also have an anti-diabetic effect by altering gut microbiota. Nuts lower serum cholesterol by reduced cholesterol absorption, inhibition of HMG-CoA reductase and increased bile acid production by stimulation of 7-α hydroxylase. Arginine and magnesium improve inflammation, oxidative stress, endothelial function and blood pressure. In conclusion, nuts contain compounds that favourably influence glucose homeostasis, weight control and vascular health. Further investigations are required to identify the most important mechanisms by which nuts decrease the risk of T2DM and CVD.

Do dry roasting, lightly salting nuts affect their cardioprotective properties and acceptability?

PURPOSE

Previous studies have reported improvements in cardiovascular disease (CVD) risk factors with the consumption of raw nuts. However, around one-third of nuts consumed are roasted and salted. Thus, it is important to determine whether roasting and salting nuts affect the health benefits observed with raw nuts. This study aimed to compare the effects of consuming two different forms of hazelnuts on cardiovascular risk factors and acceptance.

METHODS

Using a randomised crossover design, 72 participants were asked to consume 30 g/day of either raw or dry roasted, lightly salted hazelnuts for 28 days each. CVD risk factors were measured at the beginning and end of each treatment period. "Desire to consume" and "overall liking" for both forms of hazelnuts were assessed daily using a 150-mm visual analogue scale.

RESULTS

Body composition, blood pressure, plasma total and low-density lipoprotein-cholesterol, apolipoprotein A1 and B100, glucose and α-tocopherol concentrations did not differ between forms of hazelnuts (all P ≥ 0.054). High-density lipoprotein (HDL)-cholesterol (P = 0.037) and triacylglycerol (P < 0.001) concentrations were significantly lower following the consumption of dry roasted, lightly salted hazelnuts when compared to the raw hazelnuts. Compared with baseline, consuming both forms of hazelnuts significantly improved HDL-cholesterol and apolipoprotein A1 concentrations, total-C/HDL-C ratio, and systolic blood pressure without significantly changing body composition. Acceptance ratings did not differ between forms of hazelnuts and remained high throughout the study.

CONCLUSION

Dry roasting and lightly salting nuts do not appear to negate the cardioprotective effects observed with raw nut consumption, and both forms of nuts are resistant to monotony. Public health messages could be extended to include dry roasted and lightly salted nuts as part of a heart healthy diet.

Manipulation of starch bioaccessibility in wheat endosperm to regulate starch digestion, postprandial glycemia, insulinemia, and gut hormone responses: a randomized controlled trial in healthy ileostomy participants

BACKGROUND

Cereal crops, particularly wheat, are a major dietary source of starch, and the bioaccessibility of starch has implications for postprandial glycemia. The structure and properties of plant foods have been identified as critical factors in influencing nutrient bioaccessibility; however, the physical and biochemical disassembly of cereal food during digestion has not been widely studied.

OBJECTIVES

The aims of this study were to compare the effects of 2 porridge meals prepared from wheat endosperm with different degrees of starch bioaccessibility on postprandial metabolism (e.g., glycemia) and to gain insight into the structural and biochemical breakdown of the test meals during gastroileal transit.

DESIGN

A randomized crossover trial in 9 healthy ileostomy participants was designed to compare the effects of 55 g starch, provided as coarse (2-mm particles) or smooth (<0.2-mm particles) wheat porridge, on postprandial changes in blood glucose, insulin, C-peptide, lipids, and gut hormones and on the resistant starch (RS) content of ileal effluent. Undigested food in the ileal output was examined microscopically to identify cell walls and encapsulated starch.

RESULTS

Blood glucose, insulin, C-peptide, and glucose-dependent insulinotropic polypeptide concentrations were significantly lower (i.e., 33%, 43%, 40%, and 50% lower 120-min incremental AUC, respectively) after consumption of the coarse porridge than after the smooth porridge (P < 0.01). In vitro, starch digestion was slower in the coarse porridge than in the smooth porridge (33% less starch digested at 90 min, P < 0.05, paired t test). In vivo, the structural integrity of coarse particles (∼2 mm) of wheat endosperm was retained during gastroileal transit. Microscopic examination revealed a progressive loss of starch from the periphery toward the particle core. The structure of the test meal had no effect on the amount or pattern of RS output.

CONCLUSION

The structural integrity of wheat endosperm is largely retained during gastroileal digestion and has a primary role in influencing the rate of starch amylolysis and, consequently, postprandial metabolism. This trial was registered at isrctn.org as ISRCTN40517475.

Comparisons of chewing rhythm, craniomandibular morphology, body mass and height between mothers and their biological daughters

OBJECTIVE

To study and compare the relationships between mean chewing cycle duration, selected cephalometric variables representing mandibular length, face height, etc., measured in women and in their teenage or young-adult biological daughters.

DESIGN

Daughters were recruited from local high schools and the University of Michigan School of Dentistry. Selection criteria included healthy females with full dentition, 1st molar occlusion, no active orthodontics, no medical conditions nor medication use that could interfere with normal masticatory motor function. Mothers had to be biologically related to their daughters. All data were obtained in the School of Dentistry. Measurements obtained from lateral cephalograms included: two "jaw length" measures, condylion-gnathion and gonion-gnathion, and four measures of facial profile including lower anterior face height, and angles sella-nasion-A point (SNA), sella-nasion-B point (SNB) and A point-nasion-B point (ANB). Mean cycle duration was calculated from 60 continuous chewing cycles, where a cycle was defined as the time between two successive maximum jaw openings in the vertical dimension. Other variables included subject height and weight. Linear and logistic regression analyses were used to evaluate the mother-daughter relationships and to study the relationships between cephalometric variables and chewing cycle duration.

RESULTS

Height, weight, Co-Gn and Go-Gn were significantly correlated between mother-daughter pairs; however, mean cycle duration was not (r(2)=0.015). Mean cycle duration was positively correlated with ANB and height in mothers, but negatively correlated with Co-Gn in daughters.

CONCLUSIONS

Chewing rate is not correlated between mothers and daughters in humans.

Modelling of nutrient bioaccessibility in almond seeds based on the fracture properties of their cell walls

The cell walls (dietary fibre) of edible plants, which consist of mainly non-starch polysaccharides, play an important role in regulating nutrient bioaccessibility (release) during digestion in the upper gastrointestinal tract. Recent studies have shown that structurally-intact cell walls hinder lipid release from the parenchyma cells of almond seeds. A theoretical model was developed to predict the bioaccessibility of lipid using simple geometry and data on cell dimensions and particle size for calculating the number of ruptured cells in cut almond cubes. Cubes (2 mm) and finely-ground flour of low and high lipid bioaccessibility, respectively, were prepared from almond cotyledons. The model predictions were compared with data from in vitro gastric and duodenal digestion of almond cubes and flour. The model showed that lipid bioaccessibility is highly dependent on particle size and cell diameter. Only a modified version of the model (the Extended Theoretical Model, ETM), in which the cells at the edges and corners were counted once only, was acceptable for the full range of particle sizes. Lipid release values predicted from the ETM were 5.7% for almond cubes and 42% for almond flour. In vitro digestion of cubes and flour showed that lipid released from ruptured cells was available for hydrolysis and resulted in lipid losses of 9.9 and 39.3%, respectively. The ETM shows considerable potential for predicting lipid release in the upper gastrointestinal tract. Further work is warranted to evaluate the efficacy of this model to accurately predict nutrient bioaccessibility in a broad range of edible plants.

Effect of mastication on lipid bioaccessibility of almonds in a randomized human study and its implications for digestion kinetics, metabolizable energy, and postprandial lipemia

BACKGROUND

The particle size and structure of masticated almonds have a significant impact on nutrient release (bioaccessibility) and digestion kinetics.

OBJECTIVES

The goals of this study were to quantify the effects of mastication on the bioaccessibility of intracellular lipid of almond tissue and examine microstructural characteristics of masticated almonds.

DESIGN

In a randomized, subject-blind, crossover trial, 17 healthy subjects chewed natural almonds (NAs) or roasted almonds (RAs) in 4 separate mastication sessions. Particle size distributions (PSDs) of the expectorated boluses were measured by using mechanical sieving and laser diffraction (primary outcome). The microstructure of masticated almonds, including the structural integrity of the cell walls (i.e., dietary fiber), was examined with microscopy. Lipid bioaccessibility was predicted by using a theoretical model, based on almond particle size and cell dimensions, and then compared with empirically derived release data.

RESULTS

Intersubject variations (n = 15; 2 subjects withdrew) in PSDs of both NA and RA samples were small (e.g., laser diffraction; CV: 12% and 9%, respectively). Significant differences in PSDs were found between these 2 almond forms (P < 0.05). A small proportion of lipid was released from ruptured cells on fractured surfaces of masticated particles, as predicted by using the mathematical model (8.5% and 11.3% for NAs and RAs, respectively). This low percentage of lipid bioaccessibility is attributable to the high proportion (35-40%) of large particles (>500 μm) in masticated almonds. Microstructural examination of the almonds indicated that most intracellular lipid remained undisturbed in intact cells after mastication. No adverse events were recorded.

CONCLUSIONS

Following mastication, most of the almond cells remained intact with lipid encapsulated by cell walls. Thus, most of the lipid in masticated almonds is not immediately bioaccessible and remains unavailable for early stages of digestion. The lipid encapsulation mechanism provides a convincing explanation for why almonds have a low metabolizable energy content and an attenuated impact on postprandial lipemia.

A shift toward a new holistic paradigm will help to preserve and better process grain products’ food structure for improving their health effects

A holistic approach to grain products will help preserve their food structure and nutrient density and thus their health potential.

The effects of processing and mastication on almond lipid bioaccessibility using novel methods of in vitro digestion modelling and micro-structural analysis

A number of studies have demonstrated that consuming almonds increases satiety but does not result in weight gain, despite their high energy and lipid content. To understand the mechanism of almond digestion, in the present study, we investigated the bioaccessibility of lipids from masticated almonds during in vitro simulated human digestion, and determined the associated changes in cell-wall composition and cellular microstructure. The influence of processing on lipid release was assessed by using natural raw almonds (NA) and roasted almonds (RA). Masticated samples from four healthy adults (two females, two males) were exposed to a dynamic gastric model of digestion followed by simulated duodenal digestion. Between 7·8 and 11·1 % of the total lipid was released as a result of mastication, with no significant differences between the NA and RA samples. Significant digestion occurred during the in vitro gastric phase (16·4 and 15·9 %) and the in vitro duodenal phase (32·2 and 32·7 %) for the NA and RA samples, respectively. Roasting produced a smaller average particle size distribution post-mastication; however, this was not significant in terms of lipid release. Light microscopy showed major changes that occurred in the distribution of lipid in all cells after the roasting process. Further changes were observed in the surface cells of almond fragments and in fractured cells after exposure to the duodenal environment. Almond cell walls prevented lipid release from intact cells, providing a mechanism for incomplete nutrient absorption in the gut. The composition of almond cell walls was not affected by processing or simulated digestion.

A review of the effects of nuts on appetite, food intake, metabolism, and body weight

Tree nuts and peanuts are good sources of many nutrients and antioxidants, but they are also energy dense. The latter often limits intake because of concerns about their possible contribution to positive energy balance. However, evidence to date suggests that nuts are not associated with predicted weight gain. This is largely due to their high satiety value, leading to strong compensatory dietary responses, inefficiency in absorption of the energy they contain, a possible increment in resting energy expenditure, and an augmentation of fat oxidation. Preliminary evidence suggests that these properties are especially evident when they are consumed as snacks.

The relationship between nut consumption and lipid profile among the Iranian adult population; Isfahan Healthy Heart Program

BACKGROUND/OBJECTIVE

The study was carried out to assess the relationship between nut consumption and lipid profile among Iranian adults.

SUBJECT/METHODS

The study was based on data from the Isfahan Healthy Heart Program across three counties in central Iran in 2007. A cross-sectional survey of 9660 randomly selected adults aged ≥ 19 years were chosen based on sex, age and settlement distributions in each community. Nutritional behaviors were assessed by validated qualitative 48-item food frequency questionnaires, which covered regular intakes of four types of nuts: walnuts, almonds, pistachios and hazelnuts. Analysis of covariance and logistic regression tests were utilized to determine odds ratio (OR) 95% confidence interval of hyperlipidemia according to nut consumption patterns in unadjusted and three-adjusted models.

RESULTS

The results showed a significant link between high nut consumption and lower total cholesterol, triglyceride (TG), low-density lipoprotein cholesterol (LDL-C) levels and apo B/apo A ratio (P<0.05) in female subjects and lower TG, LDL-C and apoB/apoA ratio in male subjects (P<0.05). The frequency of nut consumption was inversely associated with dyslipidemia, especially for those who had consumed nuts ≥ 4 times weekly (0.67 (0.57-0.79)). After adjusting for sex, age and other potential confounders, ORs increased enormously. Except for low apo A and high LDL-C, more frequent nut consumption (4 ≤ times per week) had a significant inverse effect on other dyslipidemia risk factors in all four models.

CONCLUSIONS

We concluded that frequent consumption of nuts, particularly ≥ 4 times a week, may result in lower dyslipidemia occurrences and may exert cardioprotective effects.

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.

Reduced masticatory function in non-elderly obese Japanese adults

SUMMARY

OBJECTIVES

Abnormal eating behaviors such as compulsive overeating, eating fast, chewing less, palatable soft food preferences and avoiding hard food are often observed in obese individuals, and these behaviors may affect their masticatory function, but little information of masticatory function in obese subjects are available at present. The present study investigated masticatory function in non-elderly obese Japanese adults and explored the relationships between obesity and masticatory function.

METHODS

Seventy-five obese subjects (BMI ≥ 25; male: 34, female: 41) and 98 subjects with normal weight (BMI 18.5-25; male: 63, female: 35) aged 25-40 years old were enrolled in the present study. The status of masticatory function was determined using a chewing gum mixing method, a direct method of examining masticatory function, and the numbers of present teeth, untreated decayed teeth, missing teeth, and filled teeth were also examined.

RESULTS

Masticatory function was significantly lower in the obese subjects both in male and female, whereas the numbers of present teeth, decayed teeth, missing teeth and filled teeth did not differ significantly between the obese subjects and the controls both in male and female. Multiple regression analysis revealed a significant correlation between obesity and reduced masticatory function after adjustment for gender, age, and numbers of decayed teeth, missing teeth, and filled teeth.

CONCLUSIONS

Significantly reduced masticatory function was found in male and female non-elderly obese adults based on direct measurement of masticatory function. Multiple regression analysis suggested that obesity might induce reduced masticatory function.

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.

Nuts improve diet quality compared to other energy-dense snacks while maintaining body weight

Previous studies have reported that regular nut consumption reduces cardiovascular disease (CVD) risk and does not promote weight gain despite the fact that nuts are energy-dense. However, no studies have investigated the body composition of those regularly consuming nuts compared to similar intakes of other snacks of equal energy density. This parallel study (n = 118) examined the effects of providing daily portions (~1100 kJ/d) of hazelnuts, chocolate, or potato crisps compared to a control group receiving no snacks for twelve weeks. Effects on body weight and composition, blood lipids and lipoproteins, resting metabolic rate (RMR), appetite indices, and dietary quality were compared. At week 12, there was no significant difference in any of the outcome measurements between the groups except for dietary quality, which improved significantly in the nut group. Nuts can be incorporated into the diet without adversely affecting body weight and can improve diet quality.

Effects of Peanut Processing on Masticatory Performance during Variable Appetitive States

Background. Current evidence indicates that peanut consumption reduces cardiovascular disease risk, while posing little threat to positive energy balance. However, questions have been raised as to whether inter- and intraindividual variability in mastication in response to peanut form and processing properties may influence these health effects, since mastication has the potential to alter the bioaccessibility of nutrients within the nut matrix. Objective. To explore the relationship between peanut form and processing and masticatory function. Subjects/Methods. Thirty nine adults (16 M, 23 F; BMI: 30.4 ± 4.0 kg/m²; age: 27 ± 8 y) with healthy dentition chewed four different forms of peanuts until they would normally swallow and then expectorated the bolus. Surface electromyograms (EMGs) were obtained from the masseter and temporalis muscles during chewing of the four test foods. The maximum and mean bite forces, duration of chewing sequence, number of chews, and total muscle work for the complete chewing cycle were measured on the integrated EMG in fasted and sated states. Results. While no significant differences were noted in response to appetitive state, peanut form and processing had a significant influence on masticatory efficiency, as measured by proportional particle size distributions. The processed peanuts (honey roasted, roasted salted, and roasted unsalted) were chewed significantly fewer times compared to the unprocessed form (raw). Further, the proportional particle sizes within the swallowing bolus were significantly larger for the processed forms compared to the unprocessed form. Conclusion. These observations may have implications for bioaccessibility of energy and cardioprotective nutrients as well as endocrine responses, following peanut consumption.