The influence of polysulphide-enhanced garlic intake on gasotransmitters profiles and selected physiological responses to high-intensity constant load exercise / Muhammad Alif Nazrin Jumat

A new study has shown that moderately boiled garlic can enhance polysulphides, a known potent donor of essential gasotransmitters (hydrogen sulphide, H2S and nitric oxide, NO) in humans. However, the dose response relationship of polysulphide-enhanced garlic (PEG) on exhaled gasotransmitter profiles as well as the physiological responses to high-intensity constant load exercise tolerance have yet to be investigated. In a randomised, double-blinded, 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 eH2S, FeNO and MAP over a 24-hour period. Subsequently, 12 collegiate-level male athletes completed high-intensity constant load exercise 3-hour after orally consuming 4 g of either PEG or PLA with a washout period of 14 days separating each trial. Compared to PLA, eH2S was significantly elevated during two of the highest dosages of PEG, with no additional increase after 6 g PEG ingestion compared to 4 g (both p < 0.001), however no changes in FeNO (p > 0.05). Additionally, MAP decreased in a dose-dependent manner for the highest dosage of 6 g PEG (p < 0.001), with peak changes (Δ) in MAP and eH2S occurred at 3 to 5 hours relative to the baseline (p < 0.05). A negative correlation has been observed between the changes in MAP and the changes in eH2S for PEG and PLA (r = -0.37, p < 0.001). In the subsequent phase, resting eH2S was ~49% greater, while the systolic BP and MAP were lower by ~3% and ~2% in PEG compared to PLA (p < 0.05), respectively. Although PEG did not significantly alter time-to-exhaustion in intense constant load exercise (p = 0.06), the results indicate substantial improvements (~6%) in 8 out of 12 participants. Blood [glucose] was lower during constant load exercise (p < 0.05) but no changes in blood [lactate]. The current study suggests that the dose-dependent PEG supplementation could lower several BP indices likely via enhanced bioavailability of H2S, but not NO. This study further demonstrates that short-term PEG supplementation (i.e., 4 g) could enhance high-intensity exercise tolerance, with the effects were highly variable between participants.