Gum chewing while walking increases fat oxidation and energy expenditure.

[Purpose] Although gum chewing while walking has been reported to increase walking speed and heart rate, its effect on energy expenditure remains unclear. The purpose of the present study was to investigate the effects of gum chewing while walking on fat oxidation, energy expenditure, and different walking parameters. [Participants and Methods] This randomized crossover study included 10 males and 5 females who walked for 15 min at their own pace while chewing 2 pieces of gum in the gum trial or while eating 2 tablets in the control trial. A wearable metabolic system, heart rate monitor, and pedometer measured fat oxidation, energy expenditure, heart rate, step count, and walking distance. Walking speed and stride length were also calculated. [Results] The energy expenditure, fat oxidation and heart rate were significantly higher during the gum trial than during the control trial. Significant increases were observed in the step count, walking distance, and walking speed but not in the stride length. [Conclusion] Our results suggest that gum chewing affects sympathetic nervous system activity and walking rhythm with a consequent improvement in the health-related effects of walking, which in turn helps to maintain weight. These findings may play a role in preventing the gradual age-related weight gain that predisposes to obesity.

The effects of gum chewing while walking on physical and physiological functions.

[Purpose] This study examined the effects of gum chewing while walking on physical and physiological functions. [Subjects and Methods] This study enrolled 46 male and female participants aged 21-69 years. In the experimental trial, participants walked at natural paces for 15 minutes while chewing two gum pellets after a 1-hour rest period. In the control trial, participants walked at natural paces for 15 minutes after ingesting powder containing the same ingredient, except the gum base, as the chewing gum. Heart rates, walking distances, walking speeds, steps, and energy expenditure were measured. [Results] Heart rates during walking and heart rate changes (i.e., from at rest to during walking) significantly increased during the gum trial compared with the control trial. Walking distance, walking speed, walking heart rate, and heart rate changes in male participants and walking heart rate and heart rate changes in female participants were significantly higher during the gum trial than the control trial. In middle-aged and elderly male participants aged ≥40 years, walking distance, walking speed, steps, and energy expenditure significantly increased during the gum trial than the control trial. [Conclusion] Gum chewing while walking measurably affects physical and physiological functions.

The Effects of Chewing Gum in Preventing Eyestrain.

PURPOSE: To investigate the effects of chewing gum and tablet candy to reduce eyestrain in healthy individuals. MATERIALS AND METHODS: A double-blinded crossover trial was conducted. Forty-six healthy individuals (23 men, 23 women) between 20 and 59 years old, feeling eyestrain, were enrolled. Each 10-year age group included 12 individuals except the 30s group, which included 10 individuals. A visual task was performed on reading material displayed on a computer screen at a fixed distance for 60 min. Gum or tablet candy of two pieces were chewed for two 15-min periods starting 15 and 45 min after starting to read. Subjects chewed gum on Day 1 and tablet candy on Day 2, and vice versa. Primary outcome is as follows: subjective eye fatigue (eye tiredness, eye heaviness, blurred vision, double vision, and eye dryness) using a visual analog scale (VAS). Secondary outcomes are as follows: subjective accommodation from near and far points of accommodation measured with a D'ACOMO, spherical equivalent refraction, and eye dryness by analyzing ring break-up time (RBUT) measured with the RT-7000 Auto Ref-Topographer. RESULTS: The VAS scores of subjective eye fatigue were not significantly changed between chewing gum and tablet candy (P = 0.397 - P = 0.909). Those scores of eye tiredness and eye heaviness were significantly longer before and after the visual task with tablet candy (P = 0.013 and P = 0.025, respectively) but not with chewing gum. The changes of subjective accommodation were significantly lower after the visual task between chewing gum and candy (P = 0.043). There were significant differences among each age group (20 s vs. 30 s, P = 0.594; 20 s vs. 40 s, P = 0.002; 20 s vs. 50 s, P = 0.002). After reading, the changes of spherical equivalent refraction did not indicate a shift toward myopia (P = 0.267). In the RBUT, there were no significant differences between the samples (P = 0.680). CONCLUSIONS: Chewing gum helps improve the ability of the eye to focus, especially in young adults.

A new family of D-2-hydroxyacid dehydrogenases that comprises D-mandelate dehydrogenases and 2-ketopantoate reductases.

The gene for the D-mandelate dehydrogenase (D-ManDH) of Enterococcus faecalis IAM10071 was isolated by means of an activity staining procedure and PCR and expressed in Escherichia coli cells. The recombinant enzyme exhibited high catalytic activity toward various 2-ketoacid substrates with bulky hydrophobic side chains, particularly C3-branched substrates such as benzoylformate and 2-ketoisovalerate, and strict coenzyme specificity for NADH and NAD(+). It showed marked sequence similarity with known NADP-dependent 2-ketopantoate reductases (KPR). These results indicate that together with KPR, D-ManDH constitutes a new family of D-2-hydroxyacid dehydrogenases that act on C3-branched 2-ketoacid substrates with various specificities for coenzymes and substrates.

A novel method using cyanobacteria for ecotoxicity test of veterinary antimicrobial agents.

The effect of antimicrobial agents for veterinary use on the growth of cyanobacteria was investigated by measuring minimum inhibitory concentration, medium effective concentration (EC50), and no-observed-effect concentration of seven antimicrobial agents for eight cyanobacteria. The results demonstrated that the seven antimicrobial agents, even at low concentrations, inhibited the growth of cyanobacteria. Microcystis aeruginosa and Synechococcus sp. had the highest sensitivity to the antimicrobial agents used in the present study. It is considered that the utilization of cyanobacteria would enable easy and highly sensitive assessment of the toxicity of such chemicals as antimicrobial agents. We suggest that cyanobacteria be used for ecotoxicity test in addition to the hitherto established method that uses green algae.