Inorganic nitrate and beetroot juice supplementation reduces blood pressure in adults: a systematic review and meta-analysis.

Diets including food products rich in inorganic nitrate are associated with lower blood pressure (BP). The evidence for the BP-lowering effects of inorganic nitrate and beetroot in randomized clinical trials has not been systematically assessed. The objective was to conduct a systematic review and meta-analysis of randomized clinical trials that examined the effects of inorganic nitrate and beetroot supplementation on BP. Medline, EMBASE, and Scopus databases were searched from inception to February 2013. The specific inclusion criteria were: 1) randomized clinical trials; 2) trials reporting effects on systolic or diastolic BP or both; and 3) trials comparing inorganic nitrate or beetroot juice supplementation with placebo control groups. Random-effects models were used to assess the pooled BP effect sizes. Sixteen trials met the eligibility criteria for the systematic review. All studies had a crossover study design. The trials were conducted between 2006 and 2012 and included a total of 254 participants with 7-30 participants/study. The duration of each intervention ranged from 2 h to 15 d. Inorganic nitrate and beetroot juice consumption were associated with greater changes in systolic BP [-4.4 mm Hg (95% CI: -5.9, -2.8); P < 0.001] than diastolic BP [-1.1 mm Hg (95% CI: -2.2, 0.1); P = 0.06]. The meta-regression showed an association between daily dose of inorganic nitrate and changes in systolic BP (P < 0.05). Inorganic nitrate and beetroot juice supplementation was associated with a significant reduction in systolic BP. These findings need to be tested in long-term trials and in individuals at greater cardiovascular risk.

New lower-limb gait biomechanical characteristics in individuals with Achilles tendinopathy: A systematic review update.

BACKGROUND: Variations in lower-limb biomechanics have recurrently been associated as aetiological factors for Achilles tendinopathy. OBJECTIVE: To update a previous systematic review examining lower-limb gait biomechanics in Achilles tendinopathy. DESIGN: Systematic Review. DATA SOURCES: MEDLINE, EMBASE, CINAHL PLUS, SPORTDiscus and PUBMED databases searched from inception to May 2016. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Studies investigating adults with Achilles tendinopathy and lower-limb gait biomechanics including kinematics, kinetics, dynamic plantar-pressures, temporospatial parameters and muscle activity. RESULTS: Fourteen studies were identified, involving 836 participants. Three were prospective studies and 11 were case-control designs. Selection and performance bias were high for all studies except the prospective studies, reporting bias was unclear for all studies. Significant effect size reductions in gait speed (d = -0.80), stride length (d = -0.84) and step length (d = -0.80) were calculated in runners with Achilles tendinopathy. Increased effect sizes for ankle eversion (d = 1.08), time to maximum pronation (d = -1.72), calcaneal inversion (d = -1.82) and ankle and hip joint moments were also established. Significant differences in plantar pressures and timing of ground reaction forces were calculated. Individuals with Achilles tendinopathy demonstrated differences in amplitude and timing of several lower-limb muscles, notably reductions in the onset of activity (d = 2.02) and duration of activation (d = 2.11) in the Gluteus Medius of subjects with Achilles tendinopathy. CONCLUSION: Eighteen new biomechanical characteristics in individuals with Achilles tendinopathy have been established. This review highlights a topic rich in quantity, but generally weak in quality, consequently results should be interpreted cautiously. High powered prospective studies are required to determine causality.

Effects of handgrip exercise or inorganic nitrate supplementation on 24-h ambulatory blood pressure and peripheral arterial function in overweight and obese middle age and older adults: A pilot RCT.

INTRODUCTION: Hypertension is a major contributor to the global burden of cardiovascular diseases and its prevalence increases progressively with ageing. Therefore the identification of effective, age-friendly exercise and nutritional interventions which lower blood pressure (BP) is a research priority. OBJECTIVE: To undertake a pilot RCT examining the efficacy of isometric handgrip exercise (IHGE) and beetroot juice (a rich source of inorganic nitrate) consumption in modifying clinic and 24-h ambulatory BP (24-h ABP), peripheral arterial function and plasma asymmetric dimethylarginine (ADMA) in older overweight and obese adults. DESIGN: Thirty middle age and older adults (62±5 years) were randomised to: (a) bilateral IHGE at 50% of maximal voluntary contraction (8 min/day), (b) 140 ml/day of concentrated beetroot juice, or (c) no-intervention (control group), for 7 days. All groups followed a standardised diet to control nitrate intake. Clinic and 24-h ABP, peripheral arterial function quantified by pulse wave velocity (PWV) and arterial volume distensibility were assessed before and after intervention. SETTING: Clinical ageing research unit, Newcastle University. RESULTS: At baseline, there were no between-group differences in age, handgrip strength, clinic or 24-h ABP, BMI, waist circumference, fat mass, physical activity level, energy intake or urinary and plasma nitrate concentrations. After intervention, there were no significant effects on clinic systolic and diastolic BP or 24-h ABP, PWV (p=0.54), arterial volume distensibility (p=0.89), or ADMA (p=0.45). CONCLUSIONS: IHGE or beetroot juice consumption for 7 days did not affect BP or peripheral arterial function in overweight and obese middle age and older adults. Ageing may reduce the effects of these interventions on vascular function and studies are needed to test this hypothesis.