Scientific papers and research data cited in our articles
E01 🧠 Brain & Mental 2015
Chewing Maintains Hippocampus-Dependent Cognitive Function
Kubo KY, Iinuma M, Chen H.
PMC / International Journal of Medical Sciences
📝 Summary
Peripheral sensory input from chewing projects through the trigeminal nerve to the brainstem reticular formation, thalamus, cerebral cortex, and hippocampus. Animal studies confirmed that reducing masticatory function leads to hippocampal neuron loss and severe spatial memory deficits. Chewing under stress conditions was shown to restore hippocampal neurogenesis and suppress HPA axis overactivity.
🔑 Key Findings
▸Trigeminal-hippocampal neural circuits support cognition
Effects of Mastication Dynamics on GLP-1 Secretion in Mice
菅 他 (北海道医療大学)
北海道医療大学学術リポジトリ
📝 Summary
Mice forced to chew solid feed showed significantly increased active GLP-1 secretion compared to those given identical liquid feed. Mechanical and gustatory stimulation from chewing enhances vagal efferent activity, triggering GLP-1 release from intestinal L-cells. Long-term chewing habits may promote pancreatic β-cell differentiation and proliferation.
Comparing three liquid food intake conditions—normal drinking, savoring, and chewing while savoring—chewing produced the highest postprandial DIT increase. Oral chewing stimulation activates the sympathetic nervous system and enhances thermogenesis in brown adipose tissue.
🔑 Key Findings
▸Chewing significantly increased postprandial energy expenditure
▸Effect mediated via sympathetic→brown fat pathway
▸Physiological basis for "chew more to lose weight"
The Suita Study follow-up of 599 middle-aged men showed that low masticatory ability is an independent risk factor for metabolic syndrome, hypertension, and fasting hyperglycemia.
Mastication of Nuts under Realistic Eating Conditions: Energy Balance
Grundy MM et al.
Nutrients (MDPI)
📝 Summary
Examined walnut intake forms (whole nuts vs. butter) and pre-swallowing particle size. Physical properties and chewing effort affect gut hormone dynamics and satiety. Thorough chewing increases enzyme contact area and stabilizes blood glucose.
🔑 Key Findings
▸Food particle reduction from chewing stabilizes blood glucose
Chewing and Its Influence on Swallowing, GI, and Nutrition: A Systematic Review
Various (Taylor & Francis)
Critical Reviews in Food Science and Nutrition
📝 Summary
Large food boluses swallowed without sufficient chewing alter digestive dynamics and increase postprandial blood glucose spikes. Reduced masticatory function leads to dietary changes, nutritional imbalances, and gut microbiome shifts.
Improved Masticatory Function Reduces Hypertension Risk by 18%
NHANES 2005-2018 Data Analysis
CareNet Academia / NHANES
📝 Summary
Large-scale NHANES analysis showed optimal masticatory function (10-12 FTUs) reduced hypertension risk by 18% (adjusted OR 0.82). Mediation analysis revealed 18% of this effect was mediated through HbA1c metabolic pathways.
🔑 Key Findings
▸Significant inverse correlation between chewing and hypertension
Autonomic Nervous System Balance and Erectile Dysfunction
Various (Frontiers / PMC)
Frontiers in Endocrinology / PMC
📝 Summary
Comparison of 75 psychogenic ED patients vs. 75 controls showed significantly higher stress scores and elevated LF/HF ratio (sympathetic activity), with reduced HF and pNN50 (parasympathetic markers). Rhythmic chewing may suppress HPA axis overactivity and restore parasympathetic tone.
🔑 Key Findings
▸Psychogenic ED caused by sympathetic overactivity
▸HRV analysis confirmed elevated LF/HF ratio
▸Chewing anti-stress effects restore parasympathetic tone
Erectile Dysfunction: Definition and Pathophysiology
Johns Hopkins Medicine
Johns Hopkins Medicine
📝 Summary
ED is defined as the inability to achieve or maintain sufficient erection. It is recognized as a sentinel marker for cardiovascular disease and metabolic disorders.
🔑 Key Findings
▸ED is an early marker for cardiovascular disease
▸Obesity, diabetes, hypertension are risk factors
▸Physical activity and BMI maintenance are protective
Erection initiation and maintenance require parasympathetic dominance and NO-mediated vascular smooth muscle relaxation. Sympathetic activation inhibits erection. Nocturnal erections during REM sleep occur when sympathetic activity is switched off.
Comprehensive report on gum chewing effects on cerebral blood flow, arousal, stress relief, and scalp circulation. One-month intervention with middle school students showed improvements in math scores and 10m sprint times alongside bite force.
🔑 Key Findings
▸Gum chewing improves cerebral blood flow and arousal
▸Student academic and athletic performance improved
▸Arousal mechanism via reticular activating system
Integrative Approach to Hair Growth Cycle and Hair Loss
Various (MDPI)
Journal of Clinical Medicine (MDPI)
📝 Summary
Adequate blood supply to the deep dermis is essential for angiogenesis and cell division during hair growth. The temporal muscle pump from chewing improves microcirculation in the gravitationally challenged scalp vertex.
🔑 Key Findings
▸Scalp blood flow essential for hair matrix cell division
Mastication and Obesity in Adults: A Systematic Review
PMC (Various)
PMC / Systematic Review
📝 Summary
Systematic review on the association between masticatory function and obesity. Reduced chewing leads to dietary changes, nutritional imbalances, and increased metabolic syndrome risk. Increased chewing frequency effectively suppresses appetite and aids weight management.
🔑 Key Findings
▸Systematic link between reduced chewing and obesity
Large cohort study of 31,742 men over 50. High physical activity and normal BMI strongly associated with maintained erectile function. Improved masticatory function reduces metabolic and vascular risks through GLP-1 and HbA1c pathways.
🔑 Key Findings
▸Large dataset of 31,742 men
▸Physical activity and normal BMI maintain erectile function
▸Metabolic improvement through chewing provides indirect protection
Cerebral Blood Flow During Chewing and Cognition in Prognathism Patients
東北大学研究グループ
東北大学プレスリリース
📝 Summary
Prognathism patients showed cerebral blood flow during chewing at approximately half of healthy controls. While cognitive scores were maintained in young patients through compensatory mechanisms, a clear positive correlation was found between chewing-related cerebral blood flow and cognitive scores within the patient group.
🔑 Key Findings
▸Prognathism halves cerebral blood flow during chewing
▸Positive correlation between chewing blood flow and cognition
▸Long-term chewing inefficiency may accumulate dementia risk