Can broccoli sprouts enhance adaptations to high-intensity interval training? Original paper

In this randomized controlled study, supplementing with broccoli sprouts reduced markers of oxidative stress during a period of high-intensity interval training and improved submaximal and maximal exercise performance after training.

Whether glucosinolate-rich broccoli sprouts can protect against oxidative stress and enhance adaptations to high-intensity interval training (HIIT).

A total of 9 adults without any known health conditions.

In this randomized controlled crossover study, the participants completed two 9-day interventions, one in which they received glucosinolate-rich broccoli sprout juice and another in which they received alfalfa sprout juice (very low glucosinolate content). A 1-month washout period separated each intervention.

The participants consumed 1 bottle of sprout juice twice daily. Each bottle contained 75 grams of sprouts (the broccoli sprout juice contained 1.15 mmol of glucosinolates per bottle, and the alfalfa sprout juice contained 0.015 mmol of glucosinolates).

During each intervention, the participants completed a total of 7 HIIT sessions: 5 sessions comprised 5 intervals of 4 minutes each at 90%–95% of the participants’ VO₂max plus 2 to 3 maximal 3-second sprints, and 2 of the sessions comprised 5 intervals of 8 minutes each at 85%–90% of the participants’ VO₂max.

Before and after the intervention, submaximal and maximal (i.e., VO₂max) exercise tests were performed. A muscle biopsy was taken to assess mitochondrial function and muscle glycogen content, oxidative stress biomarkers (i.e., malondialdehyde or MDA and carbonyls), and protein content of nuclear factor erythroid 2-related factor 2 (Nrf2). Levels of myeloperoxidase (another oxidative stress biomarker) and insulin were assessed in plasma. The participants also wore a continuous glucose monitor throughout the study to assess interstitial glucose levels.

Carbonyl content and myeloperoxidase were lower (better) after broccoli sprout supplementation compared to the placebo.

Blood lactate levels during submaximal exercise were lower (better) following broccoli sprout supplementation compared to the placebo. Although VO₂ max was no different between conditions, time-to-exhaustion during the VO₂max test improved by approximately 20 seconds after broccoli sprout supplementation compared the placebo. Interestingly, maximal heart rate declined by 3 beats per minute in the placebo group but was unchanged after broccoli sprout supplementation.

During the broccoli sprout intervention, the participants spent less time in hypoglycemia (interstitial glucose levels below 4 mM or 72 mg/dL) and had a higher average blood glucose (5.02 mM or 90 mg/dL vs. 4.67 mM or 84.1 mg/dL) compared to the placebo.

Oddly, this study provided no demographic information on the participants — we know nothing of their age, gender, or other characteristics.

Two of the authors hold a patent related to the use of isothiocyanates to enhance athletic performance. Isothiocyanates are produced when glucosinolates from sprouts are hydrolyzed during chewing or mechanical processing.