title: Relationships Between Gum-Chewing and Stress.
abstract: Studies have shown that chewing is thought to affect stress modification in humans. Also, studies in animals have demonstrated that active chewing of a wooden stick during immobilization stress ameliorates the stress-impaired synaptic plasticity and prevents stress-induced noradrenaline release in the amygdala. On the other hand, studies have suggested that the right prefrontal cortex (PFC) dominates the regulation of the stress response system, including the hypothalamic-pituitary-adrenal (HPA) axis. The International Affective Digitized Sounds-2 (IADS) is widely used in the study of emotions and neuropsychological research. Therefore, in this study, the effects of gum-chewing on physiological and psychological (including PFC activity measured by NIRS) responses to a negative stimulus selected from the IADS were measured and analyzed. The study design was approved by the Ethics Committee of Tokyo Dental College (No. 436). We studied 11 normal adults using: cerebral blood oxygenation in the right medial PFC by multi-channel NIRS; alpha wave intensity by EEG; autonomic nervous function by heart rate; and emotional conditions by the State-Trait Anxiety Inventory (STAI) test and the 100-mm visual analogue scale (VAS). Auditory stimuli selected were fewer than 3.00 in Pleasure value. Sounds were recorded in 3 s and reproduced at random using software. Every task session was designed in a block manner; seven rests: Brown Noise (30 s) and six task blocks: auditory stimuli or auditory stimuli with gum-chewing (30 s). During the test, the participants' eyes were closed. Paired Student's t-test was used for the comparison (P<0.05). Gum-chewing showed a significantly greater activation in the PFC, alpha wave appearance rate and HR. Gum-chewing also showed a significantly higher VAS score and a smaller STAI level indicating 'pleasant'. Gum-chewing affected physiological and psychological responses including PFC activity. This PFC activation change might influence the HPA axis and ANS activities. In summary, within the limitations of this study, the findings suggest that gum-chewing reduced stress-related responses. Gum-chewing might have a possible effect on stress coping.
authors.affiliation: Department of Oral Health and Clinical Science, Division of Sports Dentistry, Tokyo Dental College, 2-9-18, Misaki, Chiyoda, 101-0061, Japan. mkonno@tdc.ac.jp.
authors.forename: Michiyo
authors.initials: M
authors.lastname: Konno
authors.affiliation: Department of Oral Health and Clinical Science, Division of Sports Dentistry, Tokyo Dental College, 2-9-18, Misaki, Chiyoda, 101-0061, Japan.
authors.forename: Tomotaka
authors.initials: T
authors.lastname: Takeda
authors.affiliation: Department of Oral Health and Clinical Science, Division of Sports Dentistry, Tokyo Dental College, 2-9-18, Misaki, Chiyoda, 101-0061, Japan.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Kawakami
authors.affiliation: Department of Oral Health and Clinical Science, Division of Sports Dentistry, Tokyo Dental College, 2-9-18, Misaki, Chiyoda, 101-0061, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Suzuki
authors.affiliation: Department of Oral Health and Clinical Science, Division of Sports Dentistry, Tokyo Dental College, 2-9-18, Misaki, Chiyoda, 101-0061, Japan.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Kawano
authors.affiliation: Department of Oral Health and Clinical Science, Division of Sports Dentistry, Tokyo Dental College, 2-9-18, Misaki, Chiyoda, 101-0061, Japan.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Nakajima
authors.affiliation: Department of Oral Health and Clinical Science, Division of Sports Dentistry, Tokyo Dental College, 2-9-18, Misaki, Chiyoda, 101-0061, Japan.
authors.forename: Takamitsu
authors.initials: T
authors.lastname: Ozawa
authors.affiliation: Department of Oral Health and Clinical Science, Division of Sports Dentistry, Tokyo Dental College, 2-9-18, Misaki, Chiyoda, 101-0061, Japan.
authors.forename: Keiichi
authors.initials: K
authors.lastname: Ishigami
authors.affiliation: Department of Electrical and Electronics Engineering, Nihon University, NEWCAT Institute, College of Engineering, Fukushima, Japan.
authors.forename: Naohiro
authors.initials: N
authors.lastname: Takemura
authors.affiliation: Department of Electrical and Electronics Engineering, Nihon University, NEWCAT Institute, College of Engineering, Fukushima, Japan.|Department of Neurological Surgery, School of Medicine, Nihon University, Tokyo, Japan.
authors.forename: Kaoru
authors.initials: K
authors.lastname: Sakatani
mesh_terms: D000223:Adaptation, Psychological; D000328:Adult; D002638:Chewing Gum; D005260:Female; D006339:Heart Rate; D006801:Humans; D007030:Hypothalamo-Hypophyseal System / Q000502:physiology; D008297:Male; D010913:Pituitary-Adrenal System / Q000502:physiology; D017397:Prefrontal Cortex / Q000502:physiology; D013315:Stress, Psychological; D064232:Visual Analog Scale
chemical_list: D002638:Chewing Gum
keywords: Electroencephalogram; Gum-chewing; International Affective Digitized Sounds-2; Near-infrared spectroscopy; Prefrontal cortex