Polysulphide-enriched garlic supplementation: dose-response relationships and physiological responses to high intensity intermittent exercise / Ahmad Safwanudin Nordin

A new emerging study shows that moderately boiled garlic enriched polysulphide-derived hydrogen sulphide (H2S). However, the dose-response effect of polysulphide-enriched garlic (PEG) on endogenous H2S production, and the therapeutic, ergogenic and physiological responses has yet to be explored. In a randomized, double-blind, placebo–controlled crossover design trial, 12 healthy men ingested 2 g, 4 g and 6 g of PEG or placebo (PLA) to establish the effects of PEG on systolic BP, diastolic BP and eH2S over 24-hr. Subsequently, 15 collegiate-level male completed high-intensity intermittent exercise tests, with optimal timing and dose of PEG informed from the preceding trial. Compared to PLA, systolic BP was lowered in a dose-dependent manner in 4 g and 6 PEG (p < 0.01), but not diastolic BP (p > 0.05). Similarly, eH2S was significantly elevated in the two of the highest dosages of PEG compared to PLA, with no additional increase in eH2S after ingesting 6 g compared with 4 g PEG (both p < 0.001) with peak changes (Δ) at 3 to 5 hours relative to baseline (p < 0.05). In the subsequent phase, following 5-day supplementation of 4 g PEG and PLA prior to 3 hours preceding the completion of a YYIRTL1. Resting eH2S was ~42% greater, while systolic BP and mean arterial pressure (MAP) was lower by ~2.6% in PEG compared to PLA (p < 0.05). Performance in the cognitive function test was ~3.81% and ~2.66% faster at rest and during YYIRTL1, respectively, with performance in YYIRTL1 only tended to increase in PEG compared to PLA (p = 0.08). Blood [glucose] and mean heart rate was lower during YYIRTL1 (p < 0.05), but no changes in blood [lactate]. Taken together, the present study suggests that PEG supplementation dose-dependently lower resting BP and may enhance cognitive function during high-intensity intermittent performance.