Correlation between the median particle size of chewed frankfurter sausage and almonds during masticatory performance test

Interplay between particle size and microbial ecology in the gut microbiome

Physical particles can serve as critical abiotic factors that structure the ecology of microbial communities. For non-human vertebrate gut microbiomes, fecal particle size (FPS) has been known to be shaped by chewing efficiency and diet. However, little is known about what drives FPS in the human gut. Here, we analyzed FPS by laser diffraction across a total of 76 individuals and found FPS to be strongly individualized. Surprisingly, a behavioral intervention with 41 volunteers designed to increase chewing efficiency did not impact FPS. Dietary patterns could also not be associated with FPS. Instead, we found evidence that mammalian and human gut microbiomes shaped FPS. Fecal samples from germ-free and antibiotic-treated mice exhibited increased FPS relative to colonized mice. In humans, markers of longer transit time were correlated with smaller FPS. Gut microbiota diversity and composition were also associated with FPS. Finally, ex vivo culture experiments using human fecal microbiota from distinct donors showed that differences in microbiota community composition can drive variation in particle size. Together, our results support an ecological model in which the human gut microbiome plays a key role in reducing the size of food particles during digestion, and that the microbiomes of individuals vary in this capacity. These new insights also suggest FPS in humans to be governed by processes beyond those found in other mammals and emphasize the importance of gut microbiota in shaping their own abiotic environment.

Chewing and its influence on swallowing, gastrointestinal and nutrition-related factors: a systematic review

The study aimed to evaluate the hypothesis that chewing is a mechanical and physiological contributor to swallowing, physiologic/pathologic processes of the gastrointestinal tract (GIT), and nutrition-related factors. A search strategy was applied to three different databases to investigate if chewing function in adults affects the swallowing, physiologic/pathologic processes of the GIT, and nutrition-related factors compared to controls with no exposure. The included studies were evaluated for methodological quality and risk of bias and certainty of evidence. The results showed 71 eligible studies. Overall, the results showed that 46 studies supported the hypothesis while 25 refuted it. However, the GRADE analysis showed low to very low certainty of the evidence to support the hypothesis that chewing is an important contributor in the swallowing process, and physiologic/pathologic processes in the GIT. The GRADE analysis also showed a moderate to very low certainty of the evidence to suggest that chewing function contributes to nutrition-related parameters. The overall results of the current study showed that a majority (64.7%) of the studies (46 out of 71) supported the hypothesis. However, robust studies with proper design, adequate sample size, and well-defined outcome parameters are needed to establish conclusive evidence.

Inter-measurement variation of masticatory performance test using gummy jelly

The purpose of this study was to clarify the inter-measurement variation of the masticatory performance test. Forty healthy adults were divided into group A (10 males and 10 females), who did not chew the test food before experiment, and group B (10 males and 10 females) who chewed the test food before the experiment. Subjects were asked to chew a gummy jelly for 20 s on the habitual chewing side, and the amount of glucose extraction was measured. The test was repeated three times with an interval of 1 min in both groups (Group A: A1, A2, A3; Group B: B1, B2, B3). In both groups A and B, the difference between the measured values was compared and the reliability between measurements was investigated. In group A, the value of A1 was small, and a statistically significant difference was observed between A1 and other measured values. In group B, the three measured values were similar and no significant difference was observed among the measured values. The intraclass correlation coefficient (ICC) values for determining inter-measurement reliability in group A were 0.758 for A1-A2-A3, 0.708 for A1-A2, and 0.901 for A2-A3. The ICCs in group B were 0.924 for B1-B2-B3, 0.945 for B1-B2, and 0.926 for B2-B3. Based on these results, it can be suggested that high reliability between the measurements can be obtained if the subjects are accustomed to chewing the test food before the experiment, and that the measured values were similar whether it was performed two or three times. Consequently, one measurement was sufficient if subjects were accustomed to chewing the test food before the experiment.

Masticatory Force in Relation with Age in Subjects with Full Permanent Dentition: A Cross-Sectional Study

Masticatory performance is directly correlated with masticatory muscle work to grind and cut the food. Chewing efficacy is decisive to eating a variety of foods needed maintain general health status at all ages. Older people have oral problems that get worse with age. Elders have more pathologies such as periodontal diseases, caries, tooth loss and inadequate dental prostheses than younger subjects. Objectives: to investigate the correlation between masticatory bite force (MBF) and body mass index (BMI) vs. aging and sex. Methods: This study was performed on 426 subjects (213 females plus 213 male) assigned into five different groups by age. Group “A” aged from 20 to 35 years; group “B” aged 45–59 years; group “C” aged 60–69 years; group “D” aged 70–79 years; and group “E” aged more than 79 years. Results: There were not statistically significant differences in right-side MBF versus left-side MBF. The differences between sex were statistically significant with a stronger bite in males than females (p < 0.05). At the same time, younger subjects had a stronger bite than elders (p < 0.05). In group “E”, more corpulent subjects (BMI > 25) had an MBF higher than less corpulent subjects (BMI < 25, p < 0.05). The analysis of mean MBF showed a statistically significant difference within all groups stratified by BMI with mean values inversely proportional with age (p < 0.001). Conclusion: The results in our study confirm data from many scientific papers. The importance of the present paper was to correlate data between and within a large sample with a wide range of ages. Our sample subjects had a 31%–33% decrease in MBF from group “A” to group “E” group, but they all had full permanent dentation and they preserved a valid MBF.

Masticatory performance is influenced by masticatory muscle activity balance and the cumulative occlusal contact area

OBJECTIVE

To investigate the influence of masticatory muscle activity balance, occlusal contact area balance and the area of occlusal contact on masticatory performance in healthy dentate adults.

DESIGN

This cross-sectional study included ninety-three healthy subjects with complete dentition. Surface electromyography (sEMG) was used to record bilateral anterior temporalis activity and masseter muscle activity during maximum voluntary clenching and while chewing a test food. Seven levels of area of occlusal contact and near contact (ACNC) were registered and calculated cumulatively. The percentage overlapping coefficients were calculated for both muscle groups at maximum voluntary clenching and chewing and all levels of ACNC. Masticatory performance was measured by determining the median particle size of frankfurter sausage after 15 chewing cycles. Pearson's correlation and stepwise multiple linear regression analyses were used to assess the correlations between variables and the influence of the variables on masticatory performance, respectively, at the 0.05 level of significance.

RESULTS

Muscle balance during clenching and chewing, all near contact levels of cumulative ACNC and ACNC balance correlated negatively with median particle size (P <  0.05). The model based on stepwise multiple linear regression analysis showed muscle balance during clenching and cumulative ACNC at < 250 μm influenced median particle size.

CONCLUSION

Masticatory muscle activity balance during maximum voluntary clenching and the cumulative amount of near contact area were associated with masticatory performance, suggesting the amount of occlusal contact area-as well the balance of masticatory muscle activity-play a role in masticatory performance.

Destructuring and restructuring of foods during gastric digestion

All foods harbor unique length scale-dependent structural features that can influence the release, transport, and utilization of macro- or micronutrients in the human gastrointestinal tract. In this regard, food destructuring and restructuring processes during gastric passage significantly influence downstream nutrient assimilation and feelings of satiety. This review begins with a synopsis of the effects of oral processing on food structure. Then, stomach-centric factors that contribute to the efficacy of gastric digestion are discussed, and exemplified by comparing the intragastric de- and restructuring of a number of common foods. The mechanisms of how intragastric structuring influences gastric emptying and its relationship to human satiety are then discussed. Finally, recently developed, non-destructive instrumental approaches used to quantitively and qualitatively characterize food behavior during gastric destructuring and restructuring are described.

Assessment of the relationship between masticatory performance, occlusal contact area, chewing time and cycles, and gastric emptying scintigraphy in dentate subjects

BACKGROUND

Good mastication is thought to help digestion in the stomach, hence promoting the health of the gastrointestinal system. However, the correlation between masticatory and gastric function has been controversial. This is partly explained by different food types used to assess the performance of the two organs. Recently, frankfurter sausage has been proposed to be suitable for both masticatory performance and gastric emptying tests.

OBJECTIVES

To examine the relationship between masticatory performance, occlusal contact area, chewing time and cycles, and gastric emptying scintigraphy parameters in healthy dentate adults.

MATERIALS AND METHODS

Forty healthy subjects (15 men: 25 women, age 23.9 ± 3.8 years) underwent masticatory performance tests and gastric emptying scintigraphy using frankfurter sausage as a test food. Masticatory performance was calculated as the median particle size (MPS) of chewed frankfurter sausage cubes after 30 chewing cycles. Gastric emptying scintigraphy was performed using frankfurter sausage mixed with technetium-99 m-labelled microwaved egg meal. Cumulative occlusal areas of contact-near contact (cACNC) were determined by silicone bite registration and image-analysed. Chewing time and cycles before swallowing were also recorded.

RESULTS

No significant differences in MPS, cACNC, chewing time and cycles, or gastric emptying parameters were observed between gender. Bivariate correlation showed masticatory performance, occlusal contact area, chewing time and cycles were not correlated with gastric emptying parameters (P > 0.05).

CONCLUSION

Using the same test food to assess the masticatory and gastric function in dentate subjects, the present study showed that masticatory performance, occlusal contacts, chewing time and cycles did not affect gastric emptying.