Saliva Insulin as Biomarker of Risk Factors for Metabolic Dysregulation and Caries

Saliva Insulin as Biomarker of Risk Factors for Metabolic Dysregulation and Caries Which Can be Limited by Drinking Water Intervention in Elementary School Age Children

Saliva insulin shows promise as a non-invasive biomarker of high carbohydrate intake and/or insulin resistance, key risk factors for metabolic dysregulation and caries.

Saliva insulin monitoring could potentially inform the planning and evaluation of interventions to prevent child obesity, diabetes and caries, without relying on self-reported measures from children, parents, child care providers or teachers.

School-based public health screening programs, which have staff and data collection infrastructure in place to regularly and systematically collect saliva during oral health screening, have opportunity to monitor saliva insulin.

This randomized controlled trial explores if saliva insulin is responsive to the kinds of obesity and caries intervention currently in progress in schools, namely drinking water intervention. Public health programs may justify adding saliva collection to protocol already in place if saliva insulin data are found to be actionable, i.e. sensitive to risk and intervention.

Study Overview

• Status: Completed
• Conditions: Caries; Metabolomic Profile
• Intervention / Treatment: Other: Drinking water; Other: Apple juice

Detailed Description

This randomized controlled trial explores if saliva insulin is responsive to the kinds of obesity and caries intervention currently in progress in schools, namely drinking water intervention.

The specific aims of this randomized controlled trial are to:

Determine if the standard serving (500 ml) of drinking water normalizes saliva insulin to a greater extent, within 60 min, than no beverage or a standard serving (200 ml) apple juice in elementary school age children.

Determine if, in line with lower saliva insulin, 500 ml drinking water significantly alters macronutrient metabolism, within 60 min, relative to no beverage or 200 ml apple juice.

Determine if 500 ml drinking water reduces caries risk factors, improves saliva osmolality, pH, buffering capacity and immune response to a greater extent, within 60 min, than no beverage or 200 ml apple juice.

• Study Type: Interventional
• Enrollment (Actual): 105
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • California
    • San Francisco, California, United States, 94143
      • UCSF Pediatric Dentistry

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 5 years to 10 years (Child)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

UCSF Pediatric Dental Clinic patients New patient exam or recall exams Caregiver and child speak English, Spanish or Chinese Ages 5-10 years San Francisco residents Non-acutely ill (healthy enough to attend school, no fever and no systemic conditions)

Exclusion Criteria:

Child and caregiver do not speak English, Spanish or Chinese Not a San Francisco resident Under age 5 years Over age 10 years Child unwilling to accept randomized drink assignment Child unable or unwilling to drink water or apple juice Child unable or unwilling to give saliva Child is presenting to the dental clinic for an operative procedure Acute illness, fever, infection or condition that would prevent the child from attending school No remaining space in study group (weight-specific recruitment is complete).

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
No Intervention: No drink; Control; Participants will receive no drink
Experimental: Drinking water; Intervention drink; Participants will receive 500 ml drinking water from the San Francisco tap (i.e. fluoridated tap water). 500 ml is the standard bottle size.	Other: Drinking water; The intervention will compare the effects of a usual serving of drinking water with the effects of a usual serving of apple juice. Both beverages will also be assessed relative to the effects of not drinking anything at all.
Active Comparator: Apple juice; Intervention drink; Participants will receive 200 ml box of apple juice. 200 ml is the standard serving usually available to this study population in the school setting	Other: Apple juice; apple juice

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Lower saliva insulin after drinking water compared to juice; compared to no drink	Lower mean saliva insulin; Greater relative odds of saliva insulin below 5mU/I	1 hour

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Different untargeted metabolomic profile after drinking water compared to juice; and after drinking water compared to no drink	The metabolomic profile will be measured by Untargeted Profiling of Primary Metabolism by mass spectrometry at the University of California Davis West Coast Metabolomics Center. Metabolomic data analyses will be done on data normalized by creatinine, log transformed, and mean centered using metaboanalyst software. The metabolomic profiles will be evaluated using Orthogonal Partial Least Squares Discriminant Analysis 2-D score plots and Principal Components Analysis score plots. Both types of analyses are required because each has limitations. This study hypothesizes that in both types of analysis, the 95% confidence ellipse for the saliva metabolomic profile after drinking water does not overlap the 95% confidence ellipse for the metabolomic profile after apple juice; nor does it overlap the 95% confidence ellipse after no drink.	1 hour
Higher saliva pH (potential of hydrogen) after drinking water than after apple juice or no drink	Mean change in saliva pH from baseline to 1 hour after drinking water is significantly more positive than the mean change in saliva pH after apple juice (anticipating a decrease in saliva pH following the apple juice drink)	1 hour
Higher saliva buffering capacity after drinking water than after apple juice or no drink	Greater relative odds of not having 'low' saliva buffering capacity after drinking water compared to apple juice, with 'low' as defined by the CRT buffer capacity test (Ivoclar, Vivadent, Schaan, Liechtenstein); similarly greater odds of not having 'low' buffering capacity after drinking water vs no drink; Greater odds of an improvement in buffering capacity classification (change from baseline to 1 hour after drink treatment) after drinking water compared to apple juice or no drink	1 hour
Significantly higher saliva secretory immunoglobin a (IgA) after drinking water than after apple juice or no drink	Mean change in saliva IgA concentration from baseline to 1 hour after drinking water	1 hour

Collaborators and Investigators

• Sponsor: Jodi Stookey
• Investigators: Principal Investigator: Thomas Tanbonliong, DDS, University of California, San Francisco; Principal Investigator: Mimansa Cholera, DDS, University of California, San Francisco; Principal Investigator: Jodi Stookey, PhD, San Francisco Department of Public Health

Study record dates

Study Major Dates

• Study Start (Actual): October 12, 2022
• Primary Completion (Actual): December 31, 2023
• Study Completion (Actual): January 29, 2024

Study Registration Dates

• First Submitted: December 17, 2021
• First Submitted That Met QC Criteria: January 14, 2022
• First Posted (Actual): January 27, 2022

Study Record Updates

• Last Update Posted (Actual): February 25, 2026
• Last Update Submitted That Met QC Criteria: February 24, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Diet, Food, and Nutrition; Physiological Phenomena; Food and Beverages; Inorganic Chemicals; Beverages; Anions; Ions; Electrolytes; Hydroxides; Alkalies; Oxides; Oxygen Compounds; Water; Drinking Water
• Other Study ID Numbers: Saliva insulin biomarker

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No