Effects of a glucosinolate-rich beverage on blood lactate concentrations during submaximal exercise
Study Details
This single-blind, randomised crossover study examined the acute effects of glucosinolate-rich red kale sprouts on lactate and glucose metabolism during submaximal cycling in 15 healthy adults 🔍
Participants consumed placebo, 37.5 g or 75 g red kale sprouts, then repeated three cycling stages 3 h later 🥤
37.5 g dose provided ~606 mg glucosinolates / 8 mg sulforaphane, while the 75 g provided ~1212 mg and 16 mg 🧪
Key Findings
🚴 Blood lactate was significantly lower after 37.5 g at the two higher work rates
📉 At the highest work rate, lactate was ~0.4 mmol/L lower with 37.5 g versus placebo
📉 The 75 g dose also reduced lactate at the highest work rate by ~0.3 mmol/L
↔️ Neither dose significantly changed lactate at the lowest exercise intensity
📊 The response appeared U-shaped rather than dose-dependent, with modelling estimating ~44 g as the dose producing the lowest lactate
🩸 Resting blood glucose was higher after both doses: ~4.3 mmol/L versus 3.9 mmol/L with placebo
⚠️ Ten of 15 participants had glucose <4 mmol/L after placebo, compared with 4 after 37.5 g and 2 after 75 g
🧬 Myeloperoxidase, a marker associated with oxidative stress, was modestly lower after both red kale doses
🫁 Oxygen uptake and CO₂ production were unchanged across exercise intensities
😮💨 Ratings of perceived exertion were also unaffected
🫀 Resting heart rate and blood pressure did not differ between conditions
Conclusion
The mechanism remains uncertain, but altered lactate transport, pyruvate dehydrogenase activity or Nrf2 signalling are proposed possibilities 🧐
This study did not test whether lower lactate translated into better exercise performance ☝️
Acute glucosinolate-rich red kale intake may alter lactate and glucose metabolism during submaximal exercise, but performance benefits remain unproven ✅
Reference
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