The Acute Effects of Cocoa Flavanols Intake on Overt and Covert Attention

The Acute Effects of Cocoa Flavanols Intake on Overt and Covert Attention: a Randomized, Double-blind Crossover Trial

The present study aimed to examine whether a cocoa beverage containing 710 mg of flavanols enhances both overt and covert attention in healthy young adults, using a randomized, double-blind, baseline- and placebo-controlled crossover design.

Study Overview

• Status: Completed
• Conditions: Healthy Young Adults
• Intervention / Treatment: Dietary supplement: Flavanol; Dietary supplement: Placebo; Other: Sugar water

Detailed Description

Cocoa flavanols (CF) have various physiological effects that may directly or indirectly enhance cognitive functions. Following CF intake, a series of biochemical processes within vascular smooth muscle cells lead to the relaxation of smooth muscles, the dilation of blood vessels, and an increase in cerebral blood flow. For the brain to function optimally, cerebral blood flow must be maintained at a level that ensures a constant supply of oxygen and glucose to neurons. During periods of intense neuronal activity, neurons require more oxygen and nutrients, which is met by an increase in blood flow. Given that CF has been shown to enhance blood flow and perfusion in brain regions associated with attention (e.g., the parietal cortex, anterior cingulate cortex, and dorsolateral prefrontal cortex), it was hypothesized that CF intake could acutely improve both overt and covert attention.

• Study Type: Interventional
• Enrollment (Actual): 48
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Turkey
  • Konya, Turkey, 42090
    • Konya Necmettin Erbakan University Cognitive Psychology Laboratuary

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Normal or corrected-to-normal visual acuity

Exclusion Criteria:

• History of neurological, psychiatric, cardiovascular or metabolic disorders
• Following a medically restricted diet
• Taking antidepressant, anxiolytic, and antipsychotic drugs in the past three months
• Currently taking anticoagulant
• Taking herbal supplements in the past week
• Allergic or intolerant to cocoa, caffeine, sucrose, or fructose
• Color blindness

Study Plan

How is the study designed?

Design Details

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

Number of Arms

6

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Baseline/Placebo/Flavanol; Participants consumed sugar water, an alkalized cocoa beverage, and a natural cocoa beverage containing 710 mg of flavanols, with a one-week washout period between interventions.	Dietary supplement: Flavanol; Natural cocoa powder containing 710 mg of flavanols was dissolved in 250 mL of hot water and sweetened with 6 g of sugar.; Dietary supplement: Placebo; Alkalized cocoa powder containing no flavanols was dissolved in 250 mL of hot water and sweetened with 6 g of sugar.; Other: Sugar water; 250 mL of hot water with 6 g of sugar
Experimental: Baseline/Flavanol/Placebo; Participants consumed sugar water, a natural cocoa beverage containing 710 mg of flavanols, and an alkalized cocoa beverage, with a one-week washout period between interventions.	Dietary supplement: Flavanol; Natural cocoa powder containing 710 mg of flavanols was dissolved in 250 mL of hot water and sweetened with 6 g of sugar.; Dietary supplement: Placebo; Alkalized cocoa powder containing no flavanols was dissolved in 250 mL of hot water and sweetened with 6 g of sugar.; Other: Sugar water; 250 mL of hot water with 6 g of sugar
Experimental: Placebo/Baseline/Flavanol; Participants consumed an alkalized cocoa beverage, sugar water, and a natural cocoa beverage containing 710 mg of flavanols, with a one-week washout period between interventions.	Dietary supplement: Flavanol; Natural cocoa powder containing 710 mg of flavanols was dissolved in 250 mL of hot water and sweetened with 6 g of sugar.; Dietary supplement: Placebo; Alkalized cocoa powder containing no flavanols was dissolved in 250 mL of hot water and sweetened with 6 g of sugar.; Other: Sugar water; 250 mL of hot water with 6 g of sugar
Experimental: Placebo/Flavanol/Baseline; Participants consumed an alkalized cocoa beverage, a natural cocoa beverage containing 710 mg of flavanols, and sugar water, with a one-week washout period between interventions.	Dietary supplement: Flavanol; Natural cocoa powder containing 710 mg of flavanols was dissolved in 250 mL of hot water and sweetened with 6 g of sugar.; Dietary supplement: Placebo; Alkalized cocoa powder containing no flavanols was dissolved in 250 mL of hot water and sweetened with 6 g of sugar.; Other: Sugar water; 250 mL of hot water with 6 g of sugar
Experimental: Flavanol/Baseline/Placebo; Participants consumed a natural cocoa beverage containing 710 mg of flavanols, sugar water, and an alkalized cocoa beverage, with a one-week washout period between interventions.	Dietary supplement: Flavanol; Natural cocoa powder containing 710 mg of flavanols was dissolved in 250 mL of hot water and sweetened with 6 g of sugar.; Dietary supplement: Placebo; Alkalized cocoa powder containing no flavanols was dissolved in 250 mL of hot water and sweetened with 6 g of sugar.; Other: Sugar water; 250 mL of hot water with 6 g of sugar
Experimental: Flavanol/Placebo/Baseline; Participants consumed a natural cocoa beverage containing 710 mg of flavanols, an alkalized cocoa beverage, and sugar water, with a one-week washout period between interventions.	Dietary supplement: Flavanol; Natural cocoa powder containing 710 mg of flavanols was dissolved in 250 mL of hot water and sweetened with 6 g of sugar.; Dietary supplement: Placebo; Alkalized cocoa powder containing no flavanols was dissolved in 250 mL of hot water and sweetened with 6 g of sugar.; Other: Sugar water; 250 mL of hot water with 6 g of sugar

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Spatial cueing task - accuracy	Difference in the total accuracy (%)	1 hour 40 minutes post-ingestion
Spatial cueing task - reaction time	Difference in the reaction time (ms) for correct responses	1 hour 40 minutes post-ingestion
Visual search task - accuracy	Difference in the total accuracy (%)	1 hour 40 minutes post-ingestion
Visual search task - reaction time	Difference in the reaction time (ms) for correct responses	1 hour 40 minutes post-ingestion

Collaborators and Investigators

• Sponsor: Konya Necmettin Erbakan Üniversitesi
• Collaborators: The Scientific and Technological Research Council of Turkey
• Investigators: Principal Investigator: Oğuz Karataş, Ph.D., Konya Necmettin Erbakan University

Publications and helpful links

General Publications

• Karataş O, Karabay A, Alıcı T. Uzun süreli kakao flavanolleri alımının bilişsel işlevlere ve duygudurumuna etkileri ve bu etkilerin altındaki fizyolojik mekanizmalar: Bir derleme çalışması. Türk Psikoloji Yazıları. 2022;25(49):1-26. http://dx.doi.org/10.31828/tpy1301996120211203m000043
• Lamport DJ, Pal D, Moutsiana C, Field DT, Williams CM, Spencer JP, Butler LT. The effect of flavanol-rich cocoa on cerebral perfusion in healthy older adults during conscious resting state: a placebo controlled, crossover, acute trial. Psychopharmacology (Berl). 2015 Sep;232(17):3227-34. doi: 10.1007/s00213-015-3972-4. Epub 2015 Jun 7.
• Francis ST, Head K, Morris PG, Macdonald IA. The effect of flavanol-rich cocoa on the fMRI response to a cognitive task in healthy young people. J Cardiovasc Pharmacol. 2006;47 Suppl 2:S215-20. doi: 10.1097/00005344-200606001-00018.

Study record dates

Study Major Dates

• Study Start (Actual): November 26, 2022
• Primary Completion (Actual): January 20, 2023
• Study Completion (Actual): January 20, 2023

Study Registration Dates

• First Submitted: February 1, 2025
• First Submitted That Met QC Criteria: February 1, 2025
• First Posted (Actual): March 25, 2025

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: February 13, 2025
• Last Verified: February 1, 2025

More Information

Terms related to this study

• Keywords: cocoa flavanols; overt attention; covert attention
• Other Study ID Numbers: 122K636

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: All IPD collected throughout the trial
• IPD Sharing Time Frame: Beginning 3 months after publication with no end date.
• IPD Sharing Access Criteria: A proposal that describes planned analyses must be submitted
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No