Effect of Flavored, Carbonated Drinks on Salivary Flow, Salivary Composition, and Taste Perceptions

June 26, 2026 updated by: PepsiCo Global R&D
To determine the effect of flavored, carbonated drinks on salivary flow rate, saliva composition, and taste perceptions compared with control drinks (water, carbonated water, non-carbonated)

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Previous studies have shown that drinking a beverage can stimulate the production of saliva and alter its composition. These effects could impact oral processing and taste perceptions. Various ingredients in beverages such as carbonation may affect saliva and oral processing. The objective of this study is to determine the effect of flavored carbonated beverages on salivary flow rate, saliva composition (pH, mucins, carbonic anhydrase, and total protein), and taste perceptions compared with unflavored and non-carbonated control drinks.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
13

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • United States
    • New York
      • Valhalla, New York, United States, 10595
        • Gatorade Sports Science Institute

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Subject is male or female
  • If female, subject is not pregnant or nursing (based on self-report)
  • Subject is 18-45 years of age, inclusive
  • Subject is a regular consumer of carbonated drinks (questionnaire)
  • Subject is willing to avoid alcohol consumption 24 hours prior to visits
  • Subject is willing to fast (no food or gum) for 2 hours prior to study sessions
  • Able to speak, write, and read English
  • Provision of written consent to participate

Exclusion Criteria:

  • Subject smokes, vapes, or uses any nicotine/tobacco products (or has quit for less than 6 months)
  • Subject currently has or recently had an illness (cold, flu, COVID) within the past month
  • Subject has a condition affecting the oral cavity such as Xerostomia (dry mouth), Sores/lesions, Untreated dental caries, Major dental implants/appliances (including dentures)
  • Subject has a reduced sense of taste (dysgeusia) or smell (parosmia)
  • Subject has a health condition that would interfere with the study as indicated on the general health questionnaire (GHQ) (including cardiovascular, renal, or metabolic diseases)
  • Subject has participated in a clinical trial within the past 30 days
  • Subject has participated in any PepsiCo trial within past 6 months
  • Subject has a condition or is taking medication that the investigator believes would interfere with his/her ability to provide informed consent, comply with the study protocol, which might confound the interpretation of the study results, or put the person at undue risk
  • Subject is employed by, or has a parent, guardian, or other immediate family member employed by a company that manufactures any products that compete with any PepsiCo product. If subject is unsure if a company would be considered a competitor to PepsiCo, they will be asked to please let the study investigator know the name of the other company and the nature of their relationship to that company before they sign the informed consent.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Flavored carbonated drink 1
Flavored carbonated beverage with nutritive sweeteners
Other: Beverage
15 milliliter aliquot interspersed with tastants with a 3 minute break between tastants
Experimental: Flavored carbonated drink 2
Flavored carbonated beverage with non-nutritive sweeteners
Other: Beverage
15 milliliter aliquot interspersed with tastants with a 3 minute break between tastants
Experimental: Flavored drink
Flavored non-carbonated beverage with nutritive sweeteners
Other: Beverage
15 milliliter aliquot interspersed with tastants with a 3 minute break between tastants
Experimental: Flavored non-carbonated drink
Flavored non-carbonated beverage with non-nutritive sweeteners
Other: Beverage
15 milliliter aliquot interspersed with tastants with a 3 minute break between tastants
Experimental: Carbonated Water
Unflavored carbonated water
Other: Beverage
15 milliliter aliquot interspersed with tastants with a 3 minute break between tastants
Experimental: Water
Plain, unflavored, non-carbonated water
Other: Beverage
15 milliliter aliquot interspersed with tastants with a 3 minute break between tastants

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Salivary flow rate
Time Frame: At each of six 2 hour test sessions 2-8 days apart at same time of day
5 minute passive drool saliva and 10 minute filter paper saliva (one sample each from tongue and palate) collected in a fixed sequence of tastant flavors (same for each session) and the assigned test beverage intervention (different for each session)
At each of six 2 hour test sessions 2-8 days apart at same time of day

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Salivary pH
Time Frame: Sequence of repeated sampling over 2 hours on each of 6 test days with a different beverage and the same tastants each test day
Lab test
Sequence of repeated sampling over 2 hours on each of 6 test days with a different beverage and the same tastants each test day
Saliva carbonic anhydrase concentration
Time Frame: Sequence of repeated sampling over 2 hours on each of 6 test days with a different beverage and the same tastants each test day
Lab test, unit mg/L
Sequence of repeated sampling over 2 hours on each of 6 test days with a different beverage and the same tastants each test day
Saliva total protein concentration
Time Frame: Sequence of repeated sampling over 2 hours on each of 6 test days with a different beverage and the same tastants each test day
Lab test, unit mg/ml
Sequence of repeated sampling over 2 hours on each of 6 test days with a different beverage and the same tastants each test day
Saliva mucin 5B concentration Saliva mucin 5B concentration
Time Frame: Sequence of repeated sampling over 2 hours on each of 6 test days with a different beverage and the same tastants each test day
Lab test, unit micrograms/ml
Sequence of repeated sampling over 2 hours on each of 6 test days with a different beverage and the same tastants each test day
Saliva mucin 7 concentration
Time Frame: Sequence of repeated sampling over 2 hours on each of 6 test days with a different beverage and the same tastants each test day
Lab test, unit micrograms/ml
Sequence of repeated sampling over 2 hours on each of 6 test days with a different beverage and the same tastants each test day
Taste perceptions
Time Frame: Sequence of repeated sampling over 2 hours on each of 6 test days with a different beverage and the same tastants each test day.
Labeled Magnitude Scale (LMS)) of intensity of perception rated from barely detectable to strongest imaginable (tastants such as sweet, sour, salty, bitter, umami).
Sequence of repeated sampling over 2 hours on each of 6 test days with a different beverage and the same tastants each test day.
Beverage liking
Time Frame: Sequence of repeated sampling over 2 hours on each of 6 test days with a different beverage and the same tastants each test day
9-point hedonic scale rating from 1=Dislike extremely to 9= Like extremely
Sequence of repeated sampling over 2 hours on each of 6 test days with a different beverage and the same tastants each test day
Adverse Events
Time Frame: Symptoms reported at each test day and between visits from Screening to test day six
Safety
Symptoms reported at each test day and between visits from Screening to test day six

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
PepsiCo Global R&D

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Lindsay Baker, PhD, PepsiCo, Inc. Sports Science

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
March 24, 2025

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
May 22, 2025

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
May 22, 2025

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
April 1, 2025

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 15, 2025

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
April 18, 2025

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
June 30, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 26, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • PEP-2423

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

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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