Calcium supplementation for the management of primary hypertension in adults.
ABSTRACT Metabolic studies suggest calcium may have a role in the regulation of blood pressure. Some epidemiological studies have reported that people with a higher intake of calcium tend to have lower blood pressure. Previous systematic reviews and meta-analyses have reached conflicting conclusions about whether oral calcium supplementation can reduce blood pressure.
To evaluate the effects of oral calcium supplementation as a treatment for primary hypertension in adults.
We searched the Cochrane Library, MEDLINE, EMBASE, Science Citation Index, ISI Proceedings, ClinicalTrials.gov, Current Controlled Trials, CAB abstracts, and reference lists of systematic reviews, meta-analyses and randomised controlled trials (RCTs) included in the review.
Inclusion criteria were: 1) RCTs comparing oral calcium supplementation with placebo, no treatment, or usual care; 2) treatment and follow-up >/=8 weeks; 3) participants over 18 years old, with raised systolic blood pressure (SBP) >/=140 mmHg or diastolic blood pressure (DBP) >/=85 mmHg; 4) SBP and DBP reported at end of follow-up. We excluded trials where: participants were pregnant; received antihypertensive medication which changed during the study; or calcium supplementation was combined with other interventions.
Two reviewers independently abstracted data and assessed trial quality. Disagreements were resolved by discussion or a third reviewer. Random effects meta-analyses and sensitivity analyses were conducted.
We included 13 RCTs (n=485), with between eight and 15 weeks follow-up. The results of the individual trials were heterogeneous. Combining all trials, participants receiving calcium supplementation as compared to control had a statistically significant reduction in SBP (mean difference: -2.5 mmHg, 95% CI: -4.5 to -0.6, I(2 )= 42%), but not DBP (mean difference: -0.8 mmHg, 95% CI: -2.1 to 0.4, I(2) = 48%). Sub-group analyses indicated that heterogeneity between trials could not be explained by dose of calcium or baseline blood pressure. Heterogeneity was reduced when poor quality trials were excluded. The one trial reporting adequate concealment of allocation and the one trial reporting adequate blinding yielded results consistent with the primary meta-analysis.
In view of the poor quality of included trials and the heterogeneity between trials, the evidence in favour of causal association between calcium supplementation and blood pressure reduction is weak and is probably due to bias. This is because poor quality studies generally tend to over-estimate the effects of treatment. Larger, longer duration and better quality double-blind placebo controlled trials are needed to assess the effect of calcium supplementation on blood pressure and cardiovascular outcomes.
SourceAvailable from: teaching-resources.nottingham.ac.uk[Show abstract] [Hide abstract]
ABSTRACT: Cardiovascular Disease and Hypertension Cardiovascular disease (CVD) encompasses many conditions including coronary heart disease, heart attack (myocardial infarction), stroke and hypertension. In 2003, CVD accounted for 16.7 million premature deaths worldwide (World Health Organisation (WHO), 2003), 238000 of which occurred in the UK (Sproston and Primatesta, 2003). In addition to this, CVD seriously affects physical fitness and impacts upon lifestyle resulting in restrictions upon diet, employment, recreation and travel. Hypertension refers to blood pressures above those typical for an adult. Blood pressure is measured indirectly as the highest and lowest pressures in the large artery of the arm, via a pressurised cuff. Blood pressure is presented in the non-SI., units of millimetres of mercury (mmHg). Typically normal blood pressures are below 130 mmHg (the systolic or maximum value occurring when the heart beats) and 90 mmHg (the diastolic or minimum value occurring between heart beats) and are written as 130/90 mmHg. Values of 140/90 mmHg or more are considered hypertensive. Optimal blood pressure (one pertaining to good health) is classified as <120/80mmHg (see table 1). The USA has defined a separate blood pressure category called prehypertension which reflects those at risk of developing hypertension and is classified as 120-139/80-89mmHg.
[Show abstract] [Hide abstract]
ABSTRACT: Magnesium fulfils important roles in multiple physiological processes. Accordingly, a tight regulation of magnesium homeostasis is essential. Dysregulated magnesium serum levels, in particular hypomagnesaemia, are common in patients with chronic kidney disease (CKD) and have been associated with poor clinical outcomes. In cell culture studies as well as in clinical situations magnesium levels were associated with vascular calcification, cardiovascular disease and altered bone-mineral metabolism. Magnesium has also been linked to diseases such as metabolic syndrome, diabetes, hypertension, fatigue and depression, all of which are common in CKD. The present review summarizes and discusses the latest clinical data on the impact of magnesium and possible effects of higher levels on the health status of patients with CKD, including an outlook on the use of magnesium-based phosphate-binding agents in this context.Journal of nephrology 09/2014; DOI:10.1007/s40620-014-0140-6 · 2.00 Impact Factor
[Show abstract] [Hide abstract]
ABSTRACT: A DASH (dietary approaches to stop hypertension) dietary pattern rich in fruits and vegetables and low-fat dairy products with increased dietary protein provided primarily from plant protein sources decreases blood pressure. No studies, however, have evaluated the effects of a DASH-like diet with increased dietary protein from lean beef on blood pressure and vascular health. The aim of this study was to study the effect of DASH-like diets that provided different amounts of protein from lean beef (DASH 28 g beef per day; beef in an optimal lean diet (BOLD) 113 g beef per day; beef in an optimal lean diet plus additional protein (BOLD+) 153 g beef per day) on blood pressure, endothelial function and vascular reactivity versus a healthy American diet (HAD). Using a randomized, crossover study design, 36 normotensive participants (systolic blood pressure (SBP), 116±3.6 mm Hg) were fed four isocaloric diets,: HAD (33% total fat, 12% saturated fatty acids (SFA), 17% protein (PRO), 20 g beef per day), DASH (27% total fat, 6% SFA, 18% PRO, 28 g beef per day), BOLD (28% total fat, 6% SFA, 19% PRO, 113 g beef per day) and BOLD+ (28% total fat, 6% SFA, 27% PRO, 153 g beef per day), for 5 weeks. SBP decreased (P<0.05) in subjects on the BOLD+ diet (111.4±1.9 mm Hg) versus HAD (115.7±1.9). There were no significant effects of the DASH and BOLD diets on SBP. Augmentation index (AI) was significantly reduced in participants on the BOLD diet (-4.1%). There were no significant effects of the dietary treatments on diastolic blood pressure or endothelial function (as measured by peripheral arterial tonometry). A moderate protein DASH-like diet including lean beef decreased SBP in normotensive individuals. The inclusion of lean beef in a heart healthy diet also reduced peripheral vascular constriction.Journal of Human Hypertension advance online publication, 19 June 2014; doi:10.1038/jhh.2014.34.Journal of Human Hypertension 06/2014; 28(10). DOI:10.1038/jhh.2014.34 · 2.69 Impact Factor