The Chocolate Study 2.0

Assessment of Dopaminergic Neurotransmission in Response to Tasting Chocolate (The Chocolate Study 2.0)

The purpose of this study is to test how the brain responds when enjoyable foods such as chocolate are consumed. The investigators know that eating certain types of foods can make an individual want to keep eating even when he or she is full. The chemical in the brain that causes this is called dopamine. The investigators can measure this response by looking at changes to how an individual's eye responds to light.

Study Overview

• Status: Completed
• Conditions: Normal Weight
• Intervention / Treatment: Other: Chocolate

Detailed Description

The overall objective of this study is to determine dopamine (DA) neuromodulation (changes in b-wave amplitude as measured by electroretinography (ERG)) in response to consuming a highly reinforcing food (chocolate). The investigators hypothesize that orosensory stimulation with chocolates with increasing sugar content will increase the beta wave (b-wave) amplitude and the increase in the b-wave amplitude will correlate with score changes on the Psychophysical Effects Questionnaire (PEQ). This will be accomplished by testing different chocolates (extreme dark (90% cocoa), dark (70% cocoa), milk (38% cocoa), and white (0% cocoa)) on different days using 1.0 cd∙s/m2 flash luminance energy.

• Study Type: Observational
• Enrollment (Actual): 20

Contacts and Locations

Study Locations

• United States
  • North Dakota
    • Grand Forks, North Dakota, United States, 58203
      • USDA Grand Forks Human Nutrition Research Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 30 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Community sample

Description

Inclusion Criteria:

• BMI 20-24.9 kg/m2
• ability to understand and sign the consent form
• availability of transportation (i.e., participants must be able to provide their own transportation to the Grand Forks Human Nutrition Research Center)
• be free of any major illness/disease

Exclusion Criteria:

• food allergies
• participation in a weight loss diet/exercise program
• pregnancy
• lactation
• metabolic illness/disease (diabetes, renal failure, thyroid illness, hypertension)
• eye illness/disease (narrow angle glaucoma, macular degeneration, retinal detachment, cataracts)
• psychiatric, neurological or eating disorders (schizophrenia, depression, Parkinson's Disease, Huntington's Disease, cerebral palsy, stroke, epilepsy, anorexia nervosa or bulimia nervosa)
• taking any type of prescription medication with the exception of oral contraceptives and antihyperlipidemia agents

Study Plan

How is the study designed?

Design Details

• Observational Models: Cohort
• Time Perspectives: Other

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Chocolate; Participants will be asked to taste commercially available chocolate varying in sugar, fat and percent cocoa.	Other: Chocolate; Participants will be asked to taste commercially available chocolate varying in sugar, fat and percent cocoa (extreme dark (90%), dark (70%), milk (38%), and white (0%)).

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Retinal dopamine response to oral stimuli	Electroretinograph b-wave amplitude will increase in response to increases in the amount of sugar in the chocolate.	30 minutes

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Correlation between b-wave amplitude and PEQ scores	The change in b-wave amplitude will positively correlate to Psychophysical Effects Questionnaire (PEQ) score changes.	30 minutes
Correlation between b-wave amplitude and habitual dietary intake	A preference for dark chocolate and/or a greater habitual fat intake will positively correlate with the retinal dopamine-mediated response to the dark chocolates (90% and 70% cocoa) and a preference for milk chocolate and/or a greater habitual added sugar will positively correlate with the retinal dopamine-mediated response to the milk and white chocolates. Higher amounts of artificial sweetener intake will will positively correlate with the retinal dopamine-mediated response to the milk and white chocolates. Greater habitual chocolate intake will positively correlate to changes in b-wave amplitude.	30 minutes

Collaborators and Investigators

• Sponsor: USDA Grand Forks Human Nutrition Research Center

Study record dates

Study Major Dates

• Study Start (Actual): July 25, 2019
• Primary Completion (Actual): September 5, 2019
• Study Completion (Actual): September 5, 2019

Study Registration Dates

• First Submitted: July 25, 2019
• First Submitted That Met QC Criteria: July 25, 2019
• First Posted (Actual): July 30, 2019

Study Record Updates

• Last Update Posted (Actual): February 2, 2022
• Last Update Submitted That Met QC Criteria: January 18, 2022
• Last Verified: January 1, 2022

More Information

Terms related to this study

• Other Study ID Numbers: GFHNRC218

Drug and device information, study documents

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