Dietary supplementation with New Zealand blackcurrant extract enhances fat oxidation during submaximal exercise in the heat

Objectives. This study investigated the effect of 7 days’ supplementation with New Zealand blackcurrant extract on thermoregulation and substrate metabolism during running in the heat. Design. Randomized, double-blind, cross-over study. Methods. Twelve men and six women (mean ± SD: Age 27 ± 6 years, height 1.76 ± 0.10 m, mass 74 ± 12 kg, V˙ O2max 53.4 ± 7.0 mL kg−1 min−1) completed one assessment of maximal aerobic capacity and one familiarisation trial (18 ◦C, 40% relative humidity, RH), before ingesting 2 × 300 mg day−1 capsules of CurraNZTM (each containing 105 mg anthocyanin) or a visually matched placebo (2 × 300 mg microcrystalline cellulose M102) for 7days (washout 14 days). On day 7 of each supplementation period, participants completed 60 min of fasted running at 65% V˙ O2max in hot ambient conditions (34 ◦C and 40% relative humidity). Results: Carbohydrate oxidation was decreased in the NZBC trial [by 0.24 g min−1 (95% CI: 0.21–0.27 g min-1)] compared to placebo (p = 0.014, d = 0.46), and fat oxidation was increased in the NZBC trial [by 0.12 g min−1 (95% CI: 0.10 to 0.15 g min−1)], compared to placebo (p = 0.008, d = 0.57). NZBC did not influence heart rate (p = 0.963), rectal temperature (p = 0.380), skin temperature (p = 0.955), body temperature (p = 0.214) or physiological strain index (p = 0.705) during exercise. Conclusions. Seven-days intake of 600 mg NZBC extract increased fat oxidation without influencing cardiorespiratory or thermoregulatory variables during prolonged moderate intensity running in hot conditions

Anthocyanin-Rich Blackcurrant Extract Preserves Gastrointestinal Barrier Permeability and Reduces Enterocyte Damage but Has No Effect on Microbial Translocation and Inflammation After Exertional Heat Stress

This study investigated the effects of 7 days of 600 mg/day anthocyanin-rich blackcurrant extract intake on small intestinal permeability, enterocyte damage, microbial translocation and inflammation following exertional heat stress. Twelve recreationally active men (maximal aerobic capacity = 55.6 ± 6.0 mL.kg-1.min-1) ran (70% VO2max) for 60 minutes in an environmental chamber (34°C, 40% relative humidity) on two occasions (Placebo/Blackcurrant, randomized double-blind cross over). Permeability was assessed from a 4-hour urinary excretion of lactulose (L) and rhamnose (R) and expressed as a ratio of L/R. Venous blood samples were taken at rest and 20, 60 and 240 min after exercise to measure enterocyte damage (intestinal fatty acid binding protein, I-FABP), microbial translocation (sCD14; lipopolysaccharide binding protein, LBP), and interleukins 6 (IL-6), 10 (IL-10) and 1 receptor antagonist (IL-1RA). Exercise increased rectal temperature (by ~2.8 °C) and heart rate (by ~123 beats.min-1) in each condition. Blackcurrant supplementation led to a) ~12% reduction in L/R ratio (p<0.0034) and enterocyte damage (~40% reduction in I-FABP area under the curve, AUC; p<0.0001) relative to placebo. No between condition differences were observed immediately after exercise for LBP (+80%, +61 to +99%; mean, 95% confidence interval), sCD14 (+37%, +22 to +51%), IL-6 (+494%, +394 to +690%), IL-10 (+288%, +105 to +470%) or IL-1RA (+47%, +13 to +80; all time main effects). No between-condition differences for these markers were observed after 60 or 240 min of recovery. Blackcurrant extract preserves the GI barrier, however at sub-clinical levels this had no effect on microbial translocation and downstream inflammatory processes