Effects of a glucosinolate-rich beverage on blood lactate concentrations during submaximal exercise

Glucosinolate-rich red kale sprouts (GRS) combined with intense exercise training for 7 days reduce blood lactate during exercise, attenuate hypoglycemic events, improve performance, and reduce markers of oxidative stress. This study aimed to investigate the acute, dose-dependent effects of GRS on blood lactate and blood glucose after ingestion of two different doses. In the study, healthy participants (n = 15) consumed 37.5 or 75 g of GRS or an isocaloric placebo blended into a beverage on three occasions. They cycled on an ergometer at three submaximal work rates (~100, ~120, ~140 W, respectively) before and 3 h after ingestion of GRS. Oxygen uptake, substrate-level oxidation, blood lactate, blood glucose, and ratings of perceived exertion were taken before and after each interval. GRS intake acutely decreased blood lactate during submaximal cycling and increased resting blood glucose. The largest lactate reduction occurred at 37.5 g compared to placebo, with concentrations 0.4 ± 0.6 mM lower at the highest work rate (p = 0.00175). For 75 g, the reduction was 0.3 ± 0.5 mM (p = 0.0484). No significant effects appeared at the lowest work rate. Resting blood glucose averaged 3.9 ± 0.3 mM after placebo compared to 4.3 ± 0.4 mM after 37.5 g and 4.3 ± 0.4 mM after 75 g GRS (p < 0.0001, respectively). In conclusion, these findings suggest that acute intake of a glucosinolate-rich beverage may influence lactate and glucose metabolism, with lower blood lactate concentrations observed at two submaximal work rates and altered blood glucose concentrations at rest.