Timing of Broccoli Sprout Intake to Improve Exercise Performance

Effects of Acute and Subacute Intake of Broccoli Sprouts Intake on Exercise Performance and Recovery

This study examines how the timing of intake of a broccoli sprout-based drink (a natural source of isothiocyanates, ITCs) affects physiological responses, recovery, and performance after a standardized endurance cycling session. Healthy, endurance-trained adults (18-64 years) will complete four laboratory visits at the Swedish School of Sport and Health Sciences (GIH): one screening/physiology test visit and three intervention visits in a randomized, double-blind, placebo-controlled cross-over design. On intervention visits, participants will ingest either an active broccoli sprout drink (50 g sprouts) or a placebo drink based on alfalfa sprouts (50 g sprouts) according to randomization. The drink will be consumed either approximately 16 hours before exercise (the evening before) or approximately 3 hours before exercise (the morning of the test), enabling comparison of timing in relation to a standardized ~2-hour cycling protocol (individualized intensity) followed by a 10 km cycling time trial. Outcomes include measures of performance, heart rate, perceived exertion and recovery, blood glucose and lactate, and metabolic responses. Venous blood samples are collected at multiple time points before and after exercise and during the subsequent laboratory recovery period, and muscle biopsies are obtained at defined time points to assess muscle metabolism and recovery-related markers. Participants return ~24 hours after exercise for follow-up sampling after an overnight fast, including a glucose tolerance test

Study Overview

• Status: Not yet recruiting
• Conditions: Glycogen Metabolism; Glucose; Lactate; Physical Performance; Broccoli Sprout; Isothiocyanate
• Intervention / Treatment: Dietary supplement: Placebo drink; Dietary supplement: Broccoli sprout drink (isothiocyanate-rich

Detailed Description

This is a randomized, double-blind, placebo-controlled cross-over study conducted at the Swedish School of Sport and Health Sciences (GIH), Stockholm, designed to isolate the effect of timing of isothiocyanate (ITC) intake from broccoli sprouts on exercise responses, recovery, and cycling performance. Each participant completes four laboratory visits: one screening/physiology visit and three intervention visits. The screening visit includes a health check and an incremental cycle test to determine maximal oxygen uptake and to individualize exercise intensities for subsequent visits; oxygen uptake is assessed by indirect calorimetry, and capillary fingertip samples are used to measure blood lactate and glucose during the test. A venous blood sample is collected at the screening visit.

Intervention visits (three separate occasions) follow the same standardized test-day structure with different drink assignments according to randomization. The active drink consists of 50 g broccoli sprouts (ITC source) and the placebo drink consists of 50 g alfalfa sprouts. Drinks are administered to compare "subacute" intake (approximately 16 hours before exercise, the evening prior) versus "acute" intake (approximately 3 hours before exercise, the morning of the test day). The three intervention conditions are: (1) placebo at ~16 h plus placebo at ~3 h before the cycling protocol (control), (2) active at ~16 h plus placebo at ~3 h (subacute condition), and (3) placebo at ~16 h plus active at ~3 h (acute condition). Participants and investigators/test staff are blinded to drink identity at each visit.

On each intervention test day, participants arrive to the laboratory (approximately 08:30) and compliance with pre-visit instructions is checked. Baseline samples are collected, including a muscle biopsy from vastus lateralis, venous blood, and saliva. Participants then complete a standardized, strenuous cycling protocol on an ergometer with individualized intensity based on the screening test (approximately 80% of VO2max). An example structure is repeated intervals around lactate threshold (e.g., 8 × 5 min work with short recovery), with physiological monitoring throughout. Heart rate is recorded continuously (smartwatch), and capillary blood lactate and glucose are measured at predefined time points during exercise. Oxygen uptake/energy metabolism may be monitored during portions of the protocol using indirect calorimetry.

The exercise protocol includes a 10 km cycling performance test on the ergometer. In addition, approximately 4 hours after completion of the initial cycling bout (and following the relevant sampling time point), participants perform a second 10 km ergometer time trial in which they are instructed to perform as well as possible. Perceived exertion is recorded during exercise, and perceived recovery is assessed during the recovery period (e.g., Perceived Recovery Status Scale).

Biological sampling is extensive to characterize acute and post-exercise recovery processes. At each intervention visit, venous blood is collected at 10 time points: pre-exercise, immediately post-exercise, and then once per hour during the subsequent 8-hour laboratory recovery period (approximately 4 mL per draw; ~40 mL per intervention visit). Muscle biopsies from vastus lateralis are collected at four time points per intervention visit: pre-exercise, immediately post-exercise, approximately 4 hours post-exercise, and approximately 24 hours post-exercise (separate incision sites; predetermined/randomized leg). Saliva sampling is also performed (including at baseline and at the end of the ~8-hour laboratory recovery period). During the 0-8 hour recovery period in the laboratory, standardized meals are provided.

After approximately 8 hours in the laboratory, participants leave and return the next day (~24 hours after exercise) for final sampling, including the last muscle biopsy. For the 24-hour visit, participants fast for at least 10 hours. A glucose tolerance test is performed at the 24-hour follow-up to assess post-exercise glucose regulation.

• Study Type: Interventional
• Enrollment (Estimated): 30
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Filip J Larsen, PhD; Phone Number: 08-120 53 700; Email: filip.larsen@gih.se

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

Healthy, endurance-trained adults aged 18-64 years.

Regular endurance training (e.g., cycling/running) and ability to complete a standardized 2-hour high-intensity cycling session on an ergometer.

Approved health declaration and screening assessment by study staff (including that ergometer testing can be performed safely).

Willing and able to follow the study protocol (diet/fasting instructions, standardized training before visits, attendance at all four laboratory visits).

No known allergy/hypersensitivity to ingredients in the broccoli sprout drink or placebo drink.

Exclusion Criteria:

Does not meet inclusion criteria at screening (e.g., abnormal health declaration or medical findings making intense endurance exercise or muscle biopsy inappropriate).

Known allergy/hypersensitivity to ingredients in the intervention or placebo drink (broccoli/cruciferous vegetables or alfalfa) or other relevant food allergy.

Ongoing illness, fever, or infection at any test occasion, or other acute medical event judged to affect safety or data quality.

Ongoing treatment with medications/supplements judged to affect primary outcomes or increase risk (e.g., anti-inflammatory medication close to test days per study instructions).

Pregnancy (if women are included) or breastfeeding.

Inability to comply with the study protocol (e.g., failure to standardize diet/fasting, deviating training/alcohol intake despite instructions, or repeated missed visits).

Participant withdraws consent or investigator judges continued participation to pose risk.

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Study Plan

How is the study designed?

Design Details

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

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Placebo Comparator: placebo; Participants ingest placebo drink prepared from alfalfa sprouts (50 g) ~16 hours before exercise (evening prior) and placebo drink (50 g) ~3 hours before exercise (test day morning). Exercise protocol and sampling are identical to other conditions.	Dietary supplement: Placebo drink; The placebo intervention is a drink prepared from alfalfa sprouts (50g per dose) as a placebo. Participants ingest the drink at both ~16 hours before the exercise session (evening prior) and ~3 hours before the exercise session (test day morning). The study compares the timing of ITC intake versus placebo, with identical procedures across conditions.
Experimental: active, ~16 hours pre exercise; Participants ingest broccoli sprout drink (isothiocyanate-rich; 50 g sprouts) ~16 hours before exercise and placebo alfalfa sprout drink (50 g) ~3 hours before exercise. Exercise protocol and sampling are identical to other conditions.	Dietary supplement: Broccoli sprout drink (isothiocyanate-rich; Active intervention is a drink prepared from broccoli sprouts (50 g per dose) as a natural source of glucosinolates/isothiocyanates (ITCs). Participants ingest the drink either ~16 hours before the exercise session (evening prior) or ~3 hours before the exercise session (test day morning), depending on randomized condition. The study compares the timing of ITC intake versus placebo, with identical procedures across conditions.
Experimental: active, ~3 hours pre exercise; Participants ingest placebo alfalfa sprout drink (50 g) ~16 hours before exercise and broccoli sprout drink (isothiocyanate-rich; 50 g sprouts) ~3 hours before exercise. Exercise protocol and sampling are identical to other conditions.	Dietary supplement: Broccoli sprout drink (isothiocyanate-rich; Active intervention is a drink prepared from broccoli sprouts (50 g per dose) as a natural source of glucosinolates/isothiocyanates (ITCs). Participants ingest the drink either ~16 hours before the exercise session (evening prior) or ~3 hours before the exercise session (test day morning), depending on randomized condition. The study compares the timing of ITC intake versus placebo, with identical procedures across conditions.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Lactate	blood lactate (mmol/L) at predefined time points during exercise; venous sampling schedule as per protocol.	During exercise and across the 0 to 8 hours recovery period (hourly venous samples), and at the follow-up, approximately 24 hours post-exercise.
Glucose	Blood glucose (mmol/L) at predefined time points during exercise; venous sampling schedule as per protocol.	During exercise and across the 0 to 8 hours recovery period (hourly venous samples), and at the follow-up, approximately 24 hours post-exercise.
Glycogen	Muscle glycogen content in the vastus lateralis obtained from biopsies at pre-exercise, immediately post-exercise, 8 hours post-exercise, and 24 hours post-exercise to quantify glycogen depletion during exercise and repletion during recovery	Before exercise, immediately post-exercise, 8 hours post-exercise, and 24 hours post-exercise

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Physical performance	Time to complete the approximately 10-kilometer cycling time trial on an ergometer	Twice per visit. First, immediately following the standardized cycling protocol, and second, 4 hours post-exercise during the same intervention visit.

Collaborators and Investigators

• Sponsor: The Swedish School of Sport and Health Sciences

Study record dates

Study Major Dates

• Study Start (Estimated): March 31, 2026
• Primary Completion (Estimated): December 15, 2027
• Study Completion (Estimated): September 1, 2028

Study Registration Dates

• First Submitted: February 25, 2026
• First Submitted That Met QC Criteria: March 4, 2026
• First Posted (Actual): March 10, 2026

Study Record Updates

• Last Update Posted (Actual): March 10, 2026
• Last Update Submitted That Met QC Criteria: March 4, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: Exercise; Lactate; Glycogen; Broccoli Sprouts; Isothiocyanate
• Additional Relevant MeSH Terms: Behavior; Motor Activity
• Other Study ID Numbers: ITC-2026-001

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: De-identified individual participant data (IPD) underlying the primary and secondary outcomes (and associated data dictionary/codebook) will be made available to qualified researchers upon reasonable request after publication of the primary results. Data will be shared in a de-identified form in accordance with Swedish/EU data protection regulations and the approved ethics application. Requests will be reviewed by the study investigators; data sharing may require a data use agreement and proof of ethical approval where applicable

Drug and device information, study documents

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