An Old Asthma Cure from 1860
Conor P. Kerley, Kathleen Cahill, Kenneth Bolger, Aisling McGowan, Conor Burke, John Faul, Liam Cormican, Dietary nitrate supplementation in COPD: An acute, double-blind, randomized, placebo-controlled, crossover trial☆, Nitric Oxide, Volume 44, 30 January 2015, Pages 105-111, ISSN 1089-8603, http://dx.doi.org/10.1016/j.niox.2014.12.010.
Abstract: AbstractBackground The acute consumption of dietary nitrate has been shown to improve exercise capacity in athletes, healthy adults and subjects with peripheral vascular disease. Many COPD patients have reduced exercise capacity. We hypothesized that acute nitrate consumption might increase incremental shuttle walk test (ISWT) distance in COPD subjects. Methods Eleven COPD subjects were randomly assigned to consume either a high nitrate or a matched, low nitrate beverage in a double-blind, randomized, placebo-controlled, crossover design. ISWT distance was measured both before and 3 h after the beverage and change was recorded. After a 7-day washout, ISWT distances were re-measured before and 3 h after the alternate beverage and changes were recorded. Results We observed an increase in ISWT distance after consuming the high nitrate juice (25 m) compared with a reduction after the low nitrate juice (14 m) (p < 0.01). This improvement in exercise capacity was associated with significant increases in serum nitrate (p < 0.000005) and nitrite (p < 0.01) levels and a significant lowering of resting blood pressure (<0.05). Conclusions In patients with stable COPD, the acute consumption of dietary nitrate increased serum nitrate/nitrite levels and exercise capacity and was associated with a decrease in resting blood pressure. Nitrate consumption might alter exercise capacity in COPD patients. Keywords: Dietary nitrate; Nitrite; Nitric oxide; COPD; Beetroot; Exercise tolerance
Alex H. Liu, Catherine P. Bondonno, Kevin D. Croft, Ian B. Puddey, Richard J. Woodman, Lisa Rich, Natalie C. Ward, Joseph A. Vita, Jonathan M. Hodgson, Effects of a nitrate-rich meal on arterial stiffness and blood pressure in healthy volunteers, Nitric Oxide, Volume 35, 30 November 2013, Pages 123-130, ISSN 1089-8603, http://dx.doi.org/10.1016/j.niox.2013.10.001.
Abstract: Abstract An increase in nitrate intake can augment circulating nitrite and nitric oxide. This may lead to lower blood pressure and improved vascular function. Green leafy vegetables, such as spinach, are rich sources of nitrate. We aimed to assess the acute effects of a nitrate-rich meal containing spinach on arterial stiffness and blood pressure in healthy men and women. Twenty-six participants aged 38–69 years were recruited to a randomized controlled cross-over trial. The acute effects of two energy-matched (2000 kJ) meals, administered in random order, were compared. The meals were either high nitrate (220 mg of nitrate derived from spinach [spinach]) or low nitrate [control]. Outcome measurements were performed pre-meal and at specific time points up to 210 min post meal. Spinach resulted in an eightfold increase in salivary nitrite and a sevenfold increase in salivary nitrate concentrations from pre-meal (P < 0.001) to 120 min post meal. Spinach compared with control resulted in higher large artery elasticity index (P < 0.001), and lower pulse pressure (P < 0.001) and systolic blood pressure (P < 0.001). Post meal carotid–femoral pulse wave velocity (P = 0.07), augmentation index (P = 0.63), small artery elasticity index (P = 0.98) and diastolic blood pressure (P = 0.13) were not significantly altered by spinach relative to control. Therefore, consumption of a nitrate-rich meal can lower systolic blood pressure and pulse pressure and increase large artery compliance acutely in healthy men and women. If sustained, these effects could contribute to better cardiovascular health. Keywords: Dietary nitrate; Nitric oxide; Arterial stiffness; Blood pressure