The influence of dietary and nondietary calcium supplementation on blood pressure: an updated metaanalysis of randomized controlled trials

Association between Daily Dietary Calcium Intake and the Risk of Cardiovascular Disease (CVD) in Postmenopausal Korean Women

We aimed to evaluate the association between daily dietary calcium intake and the risk of cardiovascular disease (CVD) in postmenopausal women using data from the Korean National Health and Nutrition Examination Survey (KNHANES). This cross-sectional study included 12,348 women aged 45-70 years who had reached natural menopause. They were classified into three groups according to daily dietary calcium intake: <400 mg, 400-800 mg, and >800 mg. The risks of CVD, stroke, angina, and myocardial infarction were assessed in each group. Further, we performed subgroup analysis according to the post-menopause duration (≤10 vs. >10 postmenopausal years). We performed logistic regression analysis with adjustment for age, menopausal age, income, urban area, education, insulin use, body mass index, hypertension, diabetes mellitus, dyslipidemia, high alcohol intake, smoking, exercise, oral contraceptive use, and hormonal therapy use. Calcium intake level was not significantly associated with the risk of CVD in the total population and the ≤10 postmenopausal years subgroup. However, in the >10 postmenopausal years subgroup, daily calcium intake >800 mg was associated with significantly decreased risks of all CVD (odds ratio [OR], 0.27; 95% confidence interval [CI], 0.11-0.64), stroke (OR, 0.06; 95% CI, 0.01-0.42), and myocardial infarction (OR, 0.27; 95% CI, 0.11-0.64). Our findings suggest that a dietary calcium intake of >800 mg/day decreases the risk of CVD events in women who have been menopausal for >10 years.

Review Article on Molecular Mechanism of Regulation of Hypertension by Macro-elements (Na, K, Ca and Mg), Micro-elements/Trace Metals (Zn and Cu) and Toxic Elements (Pb and As)

Hypertension (HT) is a medical condition arising due to increase in blood pressure (BP) prevalent worldwide. The balanced dietary intakes of macro-elements and micro-elements including Na, K, Ca, Mg, Zn, and Cu have been described to maintain BP in humans by regulating the osmolarity of blood, cells/tissues, prevention of generation of oxidative and nitrosative stress (OANS), and endothelial damage through their functioning as important components of renin-angiotensin-aldosterone system (RAAS), antioxidant enzyme defense system, and maintenance of blood vascular-endothelial and vascular smooth muscle cell (VSMC) functions. However, inadequate/excess dietary intakes of Na/K, Ca/Mg, and Zn/Cu along with higher Pb and As exposures recognized to induce HT through common mechanisms including the followings: endothelial dysfunctions due to impairment of vasodilatation, increased vasoconstriction and arterial stiffness, blood clotting, inflammation, modification of sympathetic activity and higher catecholamine release, increased peripheral vascular resistance, and cardiac output; increased OANS due to reduced and elevated activities of extracellular superoxide dismutase and NAD(P)H oxidase, less nitric oxide bioavailability, decrease in cGMP and guanylate cyclase activity, increase in intracellular Ca2+ ions in VSMCs, and higher pro-inflammatory cytokines; higher parathyroid and calcitriol hormones; activation/suppression of RAAS resulting imbalance in blood Na+, K+, and water regulated by renin, angiotensin II, and aldosterone through affecting natriuresis/kaliuresis/diuresis; elevation in serum cholesterol and LDL cholesterol, decrease in HDL cholesterol due to defect in lipoprotein metabolism. The present study recommends the need to review simple dietary mineral intervention studies/supplementation trials before keeping their individual dietary excess intakes/exposures in consideration because their interactions lead to elevation and fall of their concentrations in body affecting onset of HT.

Evaluating adherence, tolerability and safety of oral calcium citrate in elderly osteopenic subjects: a real-life non-interventional, prospective, multicenter study

BACKGROUND

Osteoporosis is a common concern in the elderly that leads to fragile bones. Calcium supplementation plays a crucial role in improving bone health, reducing fracture risk, and supporting overall skeletal strength in this vulnerable population. However, there is conflicting evidence on the safety of calcium supplements in elderly individuals.

AIM

The aim of this study was to evaluate the adherence, safety and tolerability of calcium citrate supplementation in elderly osteopenic subjects.

METHODS

In this non-interventional, prospective, multicenter study, subjects received daily 500 mg calcium citrate supplementation for up to one year. Adherence was calculated based on compliance and persistence. Safety was assessed through adverse reactions (ARs), deaths, and clinical laboratory evaluations.

RESULTS

A total of 268 Caucasian subjects (91.4% female, mean age 70 ± 4.5 years) participated in the study. Mean adherence to treatment was 76.6 ± 29.5% and half of subjects had an adherence of 91% and ~ 33% of participants achieved complete (100%) adherence. ARs were reported by nine (3.9%) subjects, primarily gastrointestinal disorders, with no serious ARs. The frequency of all adverse events (including ARs) was significantly higher in subjects with adherence of < 80% (41.6%; 32/77) vs. those with adherence ≥ 80% (11%; 16/145, p < 0.0001). Both systolic and diastolic blood pressure decreased from baseline to follow-up visit (change of -2.8 ± 13.9 mmHg, p = 0.0102 and -2.1 ± 10.4 mmHg, p = 0.0116, respectively).

CONCLUSION

This study demonstrated favorable adherence to calcium citrate supplementation in elderly osteopenic subjects. The occurrence of ARs, though generally mild, were associated with lower adherence to calcium supplementation.

The Role of Diet in the Prevention of Hypertension and Management of Blood Pressure: An Umbrella Review of Meta-Analyses of Interventional and Observational Studies

High blood pressure (BP) is a major pathological risk factor for the development of several cardiovascular diseases. Diet is a key modifier of BP, but the underlying relationships are not clearly demonstrated. This is an umbrella review of published meta-analyses to critically evaluate the wide range of dietary evidence from bioactive compounds to dietary patterns on BP and risk of hypertension. PubMed, Embase, Web of Science, and Cochrane Central Register of Controlled Trials were searched from inception until October 31, 2021, for relevant meta-analyses of randomized controlled trials or meta-analyses of observational studies. A total of 175 publications reporting 341 meta-analyses of randomized controlled trials (145 publications) and 70 meta-analyses of observational studies (30 publications) were included in the review. The methodological quality of the included publications was assessed using Assessment of Multiple Systematic Reviews 2 and the evidence quality of each selected meta-analysis was assessed using NutriGrade. This umbrella review supports recommended public health guidelines for prevention and control of hypertension. Dietary patterns including the Dietary Approaches to Stop Hypertension and the Mediterranean-type diets that further restrict sodium, and moderate alcohol intake are advised. To produce high-quality evidence and substantiate strong recommendations, future research should address areas where the low quality of evidence was observed (for example, intake of dietary fiber, fish, egg, meat, dairy products, fruit juice, and nuts) and emphasize focus on dietary factors not yet conclusively investigated.

Cardiovascular Impact of Calcium and Vitamin D Supplements: A Narrative Review

Calcium and vitamin D play an important role in mineral homeostasis and the maintenance of skeletal health. Calcium and vitamin D supplements have been widely used for fracture prevention in elderly populations. Many trials have studied the effectiveness and cardiovascular safety of calcium and vitamin D supplementation, with disparate results. In this review, we summarize the most important trials and systematic reviews. There is significant heterogeneity in clinical trial design, differences in the nature of trial outcomes (self-reported vs. verified), prior calcium intake, and trial size. Inconsistent results have been reported concerning the effects of calcium and vitamin D supplementation on cardiovascular outcomes. Most current guidelines recommend calcium intake of up to 1,200 mg daily, preferably from the diet, without concern for cardiovascular risk. Recommendations regarding vitamin D supplementation vary widely. There is compelling evidence from well-conducted randomized trials that modest vitamin D supplementation is safe but does not confer cardiovascular benefit or cardiovascular harm.

Cardiovascular benefits and risks associated with calcium, vitamin D, and antiresorptive therapy in the management of skeletal fragility

Osteoporosis affects one in every five women over the age of 50 worldwide. With a rapidly ageing population, the prevalence of fragility fractures, considered a largely preventable consequence of osteoporosis, is expected to increase. Age is also a major risk for cardiovascular disease and mortality, thus highlighting the importance of cardiovascular profiling of osteoporosis interventions. Although calcium and vitamin D are essential for a healthy bone metabolism, excessive supplementation may be associated with increased risk. Conversely, early pre-clinical data have suggested a possible cardiovascular benefit from bisphosphonate therapy. This review evaluates the evidence behind the cardiovascular benefits and risks that may be associated with osteoporosis therapy.

Calcium supplementation for prevention of primary hypertension

BACKGROUND

Hypertension is a major public health problem that increases the risk of cardiovascular and kidney diseases. Several studies have shown an inverse association between calcium intake and blood pressure, as small reductions in blood pressure have been shown to produce rapid reductions in vascular disease risk even in individuals with normal blood pressure ranges. This is the first update of the review to evaluate the effect of calcium supplementation in normotensive individuals as a preventive health measure.

OBJECTIVES

To assess the efficacy and safety of calcium supplementation versus placebo or control for reducing blood pressure in normotensive people and for the prevention of primary hypertension.

SEARCH METHODS

The Cochrane Hypertension Information Specialist searched the following databases for randomised controlled trials up to September 2020: the Cochrane Hypertension Specialised Register, CENTRAL (2020, Issue 9), Ovid MEDLINE, Ovid Embase, the WHO International Clinical Trials Registry Platform, and the US National Institutes of Health Ongoing Trials Register, ClinicalTrials.gov. We also contacted authors of relevant papers regarding further published and unpublished work. The searches had no language restrictions.

SELECTION CRITERIA

We selected trials that randomised normotensive people to dietary calcium interventions such as supplementation or food fortification versus placebo or control. We excluded quasi-random designs. The primary outcomes were hypertension (defined as blood pressure ≥ 140/90 mmHg) and blood pressure measures.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, abstracted the data and assessed the risks of bias. We used the GRADE approach to assess the certainty of evidence.

MAIN RESULTS

The 2020 updated search identified four new trials. We included a total of 20 trials with 3512 participants, however we only included 18 for the meta-analysis with 3140 participants. None of the studies reported hypertension as a dichotomous outcome. The effect on systolic and diastolic blood pressure was: mean difference (MD) -1.37 mmHg, 95% confidence interval (CI) -2.08, -0.66; 3140 participants; 18 studies; I2 = 0%, high-certainty evidence; and MD -1.45, 95% CI -2.23, -0.67; 3039 participants; 17 studies; I2 = 45%, high-certainty evidence, respectively. The effect on systolic and diastolic blood pressure for those younger than 35 years was: MD -1.86, 95% CI -3.45, -0.27; 452 participants; eight studies; I2 = 19%, moderate-certainty evidence; MD -2.50, 95% CI -4.22, -0.79; 351 participants; seven studies ; I2 = 54%, moderate-certainty evidence, respectively. The effect on systolic and diastolic blood pressure for those 35 years or older was: MD -0.97, 95% CI -1.83, -0.10; 2688 participants; 10 studies; I2 = 0%, high-certainty evidence; MD -0.59, 95% CI -1.13, -0.06; 2688 participants; 10 studies; I2 = 0%, high-certainty evidence, respectively. The effect on systolic and diastolic blood pressure for women was: MD -1.25, 95% CI -2.53, 0.03; 1915 participants; eight studies; I2 = 0%, high-certainty evidence; MD -1.04, 95% CI -1.86, -0.22; 1915 participants; eight studies; I2 = 4%, high-certainty evidence, respectively. The effect on systolic and diastolic blood pressure for men was MD -2.14, 95% CI -3.71, -0.59; 507 participants; five studies; I2 = 8%, moderate-certainty evidence; MD -1.99, 95% CI -3.25, -0.74; 507 participants; five studies; I2 = 41%, moderate-certainty evidence, respectively. The effect was consistent in both genders regardless of baseline calcium intake. The effect on systolic blood pressure was: MD -0.02, 95% CI -2.23, 2.20; 302 participants; 3 studies; I2 = 0%, moderate-certainty evidence with doses less than 1000 mg; MD -1.05, 95% CI -1.91, -0.19; 2488 participants; 9 studies; I2 = 0%, high-certainty evidence with doses 1000 to 1500 mg; and MD -2.79, 95% CI -4.71, 0.86; 350 participants; 7 studies; I2 = 0%, moderate-certainty evidence with doses more than 1500 mg. The effect on diastolic blood pressure was: MD -0.41, 95% CI -2.07, 1.25; 201 participants; 2 studies; I2 = 0, moderate-certainty evidence; MD -2.03, 95% CI -3.44, -0.62 ; 1017 participants; 8 studies; and MD -1.35, 95% CI -2.75, -0.05; 1821 participants; 8 studies; I2 = 51%, high-certainty evidence, respectively. None of the studies reported adverse events.

AUTHORS' CONCLUSIONS

An increase in calcium intake slightly reduces both systolic and diastolic blood pressure in normotensive people, particularly in young people, suggesting a role in the prevention of hypertension. The effect across multiple prespecified subgroups and a possible dose response effect reinforce this conclusion. Even small reductions in blood pressure could have important health implications for reducing vascular disease. A 2 mmHg lower systolic blood pressure is predicted to produce about 10% lower stroke mortality and about 7% lower mortality from ischaemic heart disease. There is a great need for adequately-powered clinical trials randomising young people. Subgroup analysis should involve basal calcium intake, age, sex, basal blood pressure, and body mass index. We also require assessment of side effects, optimal doses and the best strategy to improve calcium intake.

Calcium supplementation for prevention of primary hypertension

BACKGROUND

Hypertension is a major public health problem that increases the risk of cardiovascular and kidney diseases. Several studies have shown an inverse association between calcium intake and blood pressure, as small reductions in blood pressure have been shown to produce rapid reductions in vascular disease risk even in individuals with normal blood pressure ranges. This is the first update of the review to evaluate the effect of calcium supplementation in normotensive individuals as a preventive health measure.

OBJECTIVES

To assess the efficacy and safety of calcium supplementation versus placebo or control for reducing blood pressure in normotensive people and for the prevention of primary hypertension.

SEARCH METHODS

The Cochrane Hypertension Information Specialist searched the following databases for randomised controlled trials up to September 2020: the Cochrane Hypertension Specialised Register, CENTRAL (2020, Issue 9), Ovid MEDLINE, Ovid Embase, the WHO International Clinical Trials Registry Platform, and the US National Institutes of Health Ongoing Trials Register, ClinicalTrials.gov. We also contacted authors of relevant papers regarding further published and unpublished work. The searches had no language restrictions.

SELECTION CRITERIA

We selected trials that randomised normotensive people to dietary calcium interventions such as supplementation or food fortification versus placebo or control. We excluded quasi-random designs. The primary outcomes were hypertension (defined as blood pressure ≥ 140/90 mmHg) and blood pressure measures.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, abstracted the data and assessed the risks of bias. We used the GRADE approach to assess the certainty of evidence.

MAIN RESULTS

The 2020 updated search identified four new trials. We included a total of 20 trials with 3512 participants, however we only included 18 for the meta-analysis with 3140 participants. None of the studies reported hypertension as a dichotomous outcome. The effect on systolic and diastolic blood pressure was: mean difference (MD) -1.37 mmHg, 95% confidence interval (CI) -2.08, -0.66; 3140 participants; 18 studies; I² = 0%, high-certainty evidence; and MD -1.45, 95% CI -2.23, -0.67; 3039 participants; 17 studies; I² = 45%, high-certainty evidence, respectively. The effect on systolic and diastolic blood pressure for those younger than 35 years was: MD -1.86, 95% CI -3.45, -0.27; 452 participants; eight studies; I² = 19%, moderate-certainty evidence; MD -2.50, 95% CI -4.22, -0.79; 351 participants; seven studies ; I² = 54%, moderate-certainty evidence, respectively. The effect on systolic and diastolic blood pressure for those 35 years or older was: MD -0.97, 95% CI -1.83, -0.10; 2688 participants; 10 studies; I² = 0%, high-certainty evidence; MD -0.59, 95% CI -1.13, -0.06; 2688 participants; 10 studies; I² = 0%, high-certainty evidence, respectively. The effect on systolic and diastolic blood pressure for women was: MD -1.25, 95% CI -2.53, 0.03; 1915 participants; eight studies; I² = 0%, high-certainty evidence; MD -1.04, 95% CI -1.86, -0.22; 1915 participants; eight studies; I² = 4%, high-certainty evidence, respectively. The effect on systolic and diastolic blood pressure for men was MD -2.14, 95% CI -3.71, -0.59; 507 participants; five studies; I² = 8%, moderate-certainty evidence; MD -1.99, 95% CI -3.25, -0.74; 507 participants; five studies; I² = 41%, moderate-certainty evidence, respectively. The effect was consistent in both genders regardless of baseline calcium intake. The effect on systolic blood pressure was: MD -0.02, 95% CI -2.23, 2.20; 302 participants; 3 studies; I² = 0%, moderate-certainty evidence with doses less than 1000 mg; MD -1.05, 95% CI -1.91, -0.19; 2488 participants; 9 studies; I² = 0%, high-certainty evidence with doses 1000 to 1500 mg; and MD -2.79, 95% CI -4.71, 0.86; 350 participants; 7 studies = 8; I² = 0%, moderate-certainty evidence with doses more than 1500 mg. The effect on diastolic blood pressure was: MD -0.41, 95% CI -2.07, 1.25; 201 participants; 2 studies; I² = 0, moderate-certainty evidence; MD -2.03, 95% CI -3.44, -0.62 ; 1017 participants; 8 studies; and MD -1.35, 95% CI -2.75, -0.05; 1821 participants; 8 studies; I² = 51%, high-certainty evidence, respectively. None of the studies reported adverse events.

AUTHORS' CONCLUSIONS

An increase in calcium intake slightly reduces both systolic and diastolic blood pressure in normotensive people, particularly in young people, suggesting a role in the prevention of hypertension. The effect across multiple prespecified subgroups and a possible dose response effect reinforce this conclusion. Even small reductions in blood pressure could have important health implications for reducing vascular disease. A 2 mmHg lower systolic blood pressure is predicted to produce about 10% lower stroke mortality and about 7% lower mortality from ischaemic heart disease. There is a great need for adequately-powered clinical trials randomising young people. Subgroup analysis should involve basal calcium intake, age, sex, basal blood pressure, and body mass index. We also require assessment of side effects, optimal doses and the best strategy to improve calcium intake.

Cardiovascular safety of calcium, magnesium and strontium: what does the evidence say?

Calcium, magnesium and strontium have all been implicated in both musculoskeletal and cardiovascular health and disease. However, despite these three elements being closely chemically related, there is marked heterogeneity of their characteristics in relation to cardiovascular outcomes. In this narrative review, we describe the relevant evidential landscape, focusing on clinical trials where possible and incorporating findings from observational and causal analyses, to discern the relative roles of these elements in musculoskeletal and cardiovascular health. We conclude that calcium supplementation (for bone health) is most appropriately used in combination with vitamin D supplementation and targeted to those who are deficient in these nutrients, or in combination with antiosteoporosis medications. Whilst calcium supplementation is associated with gastrointestinal side effects and a small increased risk of renal stones, purported links with cardiovascular outcomes remain unconvincing. In normal physiology, no mechanism for an association has been elucidated and other considerations such as dose response and temporal relationships do not support a causal relationship. There is little evidence to support routine magnesium supplementation for musculoskeletal outcomes; greater dietary intake and serum concentrations appear protective against cardiovascular events. Strontium ranelate, which is now available again as a generic medication, has clear anti-fracture efficacy but is associated with an increased risk of thromboembolic disease. Whilst a signal for increased risk of myocardial infarction has been detected in some studies, this is not supported by wider analyses. Strontium ranelate, under its current licence, thus provides a useful therapeutic option for severe osteoporosis in those who do not have cardiovascular risk factors.

The effect of calcium supplementation on blood pressure in non-pregnant women with previous pre-eclampsia: A randomized placebo-controlled study

BACKGROUND

Low dietary calcium is associated with the hypertensive disorders of pregnancy, and evidence suggests that the risks associated with pre-eclampsia are reduced by calcium supplementation. In the general (non-pregnant) population, low dietary calcium intake is associated with hypertension with inconsistent evidence that calcium supplementation may reduce blood pressure. Women with pre-eclampsia are also at risk of hypertension later in life. An exploratory sub-study among early participants enrolled in the WHO long-term calcium supplementation in women at high risk of pre-eclampsia (CAP) study reported a trend to more blood pressure reduction with calcium in non-pregnant women with previous severe as opposed to non-severe pre-eclampsia. The current study reports the effects of low-dose calcium supplementation in non-pregnant women in the complete trial cohort.

METHODS

The CAP Study was a multi-country randomized, double-blind placebo-controlled clinical trial to test the hypothesis that calcium deficiency may play a role in the genesis of pre-eclampsia in early pregnancy. From 2011 to 2016, non-pregnant women who had pre-eclampsia or eclampsia in their most recent pregnancy were randomized to receive either 500 mg/day elemental calcium or placebo. In this sub-study we compared the change in blood pressure from baseline to the 12-week visit between participants receiving calcium versus placebo for those not pregnant at the 12-week visit.

RESULTS

Of 1355 women randomized, 810 attended a 12-week visit without being pregnant, of whom 791 had blood pressure measurements available for both baseline and 12-week visits. There was a greater reduction in blood pressure in the calcium group compared with the placebo group for systolic pressure (difference 3.1 mmHg, 95% CI 0.8 to 5.4) and mean arterial pressure (MAP) (difference 2.0 mmHg, 95% CI 0.1 to 3.8). The difference in diastolic blood pressure reduction (1.4 mmHg, 95% CI -0.5 to 3.3) was not statistically significant (p = 0.140). For women with previous pre-eclampsia with severe features (n = 447), there was significantly greater reduction in blood pressure in the calcium than the placebo group (difference for systolic 4.0, 95% CI 0.7 to 7.3; diastolic 3.0, 95% CI 0.5 to 5.5 and mean arterial pressure 3.3, 95% CI 0.8 to 5.9 mmHg). For women with previous pre-eclampsia without severe features (n = 344), there were no significant differences between calcium and placebo groups. ANOVA analysis found no statistically significant interaction between previous pre-eclampsia severity and treatment, for systolic (p = 0.372), diastolic (p = 0.063) or mean blood pressure (p = 0.103).

CONCLUSIONS

Low-dose calcium supplementation significantly reduced systolic and mean arterial pressure in non-pregnant women with previous pre-eclampsia. We did not confirm a greater calcium effect in women with previous pre-eclampsia with severe versus non-severe features. The effect of low-dose calcium is of importance since even modest blood pressure reductions at a population level may have important benefits in terms of reduced major complications of hypertension. This study adds to the mounting evidence of health benefits which could be achieved for populations with low dietary calcium through strategies to increase calcium intake, particularly among women at high risk due to previous pre-eclampsia.

CLINICAL TRIAL REGISTRATION

The trial was registered with the Pan-African Clinical Trials Registry, registration number PACTR201105000267371 (https://pactr.samrc.ac.za/TrialDisplay.aspx?TrialID=267).

Impact of Micronutrients on Hypertension: Evidence from Clinical Trials with a Special Focus on Meta-Analysis

Hypertension (HT) is one of the pivotal risk factors for various detrimental diseases like cardiovascular diseases (CVDs), cerebrovascular disease, and renal dysfunction. Currently, many researchers are paying immense attention to various diet formula (dietary approach) with a special focus on micro and macronutrients along with modified lifestyle and standard anti-hypertensive drugs. Micronutrients (minerals/vitamins) play a central role in the regulation of blood pressure (BP) as they aid the function of macronutrients and also improve the anti-hypertensive functions of some anti-hypertensive agents. Even though several studies have demonstrated the beneficial effects of micronutrients on controlling BP, still some ambiguity exists among the nutritionists/doctors, which combination or individual mineral (dietary approach) contributes to better BP regulation. Therefore, this critical review article was attempted to delineate the underlying role of micronutrients (minerals and vitamins) for the management and prevention or delaying of HT and their related complications with strong affirmation from clinical trials as well as its mechanism of controlling BP. Moreover, the major source and recommended daily allowance (RDA) of various micronutrients are included in this review for guiding common readers (especially HT subjects) and dieticians to choose/recommend a better micronutrient and their combinations (other nutrients and standard anti-hypertensive drugs) for lowering the risk of HT and its related co-morbid conditions like CVDs.

The effect of probiotics supplementation on blood pressure: a systemic review and meta-analysis

Background

Fermented milk has over the last decade been intensively studied because of the putative antihypertensive effect. The aim of our study is to investigate the role of probiotics support therapy in blood pressure and, as a kind of convenient and economic drugs for prevention and auxiliary treatment of hypertension.

Materials and methods

We performed a systemic review and meta-analysis to examine the effect of probiotics consumption on blood pressure. Databases including MEDLINE, EMBASE, Clinical trials, CNKI and the Cochrane library were searched. Also, the grey literature and references were searched.

Results

Twenty-three randomized controlled trials (RCTs) involving 2037 participants met the inclusion criteria and were included. Probiotic consumption significantly changed systolic blood pressure (SBP) by − 3.05 mmHg (95%CI: − 4.67, − 1.44; P < 0.001) and diastolic blood pressure (DBP) by − 1.51 mmHg (95%CI: − 2.38, − 0.65; P = 0.001). Subgroup analysis indicated that the benefit effect of probiotics supplementation in SBP was only observed in hypertension [weight mean difference (WMD) = − 3.31 mmHg, 95%CI: − 5.71, − 0.92; P = 0.007] or type 2 diabetes (WMD = -4.85 mmHg, 95%CI: − 9.28, − 0.42; P = 0.032) patients, and the decreased DBP level by probiotics supplementation was only observed in hypertension patients (WMD = -2.02 mmHg, 95%CI: − 3.68, − 0.36; P = 0.017).This effect could only last for a short-term time of 8 or 10 weeks, but not for a long-term time.

Conclusion

This meta-analysis found a moderate and statistically significant reduction for either SBP or DBP with probiotics supplement compared with controls. Thus, probiotics is a potential for the dietary treatment of hypertension.

Calcium supplementation commencing before or early in pregnancy, for preventing hypertensive disorders of pregnancy

BACKGROUND

The hypertensive disorders of pregnancy include pre-eclampsia, gestational hypertension, chronic hypertension, and undefined hypertension. Pre-eclampsia is considerably more prevalent in low-income than in high-income countries. One possible explanation for this discrepancy is dietary differences, particularly calcium deficiency. Calcium supplementation in the second half of pregnancy reduces the serious consequences of pre-eclampsia, but has limited effect on the overall risk of pre-eclampsia. It is important to establish whether calcium supplementation before, and in early pregnancy (before 20 weeks' gestation) has added benefit. Such evidence could count towards justification of population-level interventions to improve dietary calcium intake, including fortification of staple foods with calcium, especially in contexts where dietary calcium intake is known to be inadequate. This is an update of a review first published in 2017.

OBJECTIVES

To determine the effect of calcium supplementation, given before or early in pregnancy and for at least the first half of pregnancy, on pre-eclampsia and other hypertensive disorders, maternal morbidity and mortality, and fetal and neonatal outcomes.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Trials Register (31 July 2018), PubMed (13 July 2018), ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP; 31 July 2018), and reference lists of retrieved studies.

SELECTION CRITERIA

Eligible studies were randomised controlled trials (RCT) of calcium supplementation, including women not yet pregnant, or women in early pregnancy. Cluster-RCTs, quasi-RCTs, and trials published as abstracts were eligible, but we did not identify any.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and risk of bias, extracted data, and checked them for accuracy. They assessed the quality of the evidence for key outcomes using the GRADE approach.

MAIN RESULTS

Calcium versus placeboWe included one study (1355 women), which took place across multiple hospital sites in Argentina, South Africa, and Zimbabwe. Most analyses were conducted only on 633 women from this group who were known to have conceived, or on 579 who reached 20 weeks' gestation; the trial was at moderate risk of bias due to high attrition rates pre-conception. Non-pregnant women with previous pre-eclampsia received either calcium 500 mg daily or placebo, from enrolment until 20 weeks' gestation. All participants received calcium 1.5 g daily from 20 weeks until birth.Primary outcomes: calcium supplementation commencing before conception may make little or no difference to the risk of pre-eclampsia (69/296 versus 82/283, risk ratio (RR) 0.80, 95% confidence interval (CI) 0.61 to 1.06; low-quality evidence). For pre-eclampsia or pregnancy loss or stillbirth (or both) at any gestational age, calcium may slightly reduce the risk of this composite outcome, however the 95% CI met the line of no effect (RR 0.82, 95% CI 0.66 to 1.00; low-quality evidence). Supplementation may make little or no difference to the severe maternal morbidity and mortality index (RR 0.93, 95% CI 0.68 to 1.26; low-quality evidence), pregnancy loss or stillbirth at any gestational age (RR 0.83, 95% CI 0.61 to 1,14; low-quality evidence), or caesarean section (RR 1.11, 95% CI 0.96 to 1,28; low-quality evidence).Calcium supplementation may make little or no difference to the following secondary outcomes: birthweight < 2500 g (RR 1.00, 95% CI 0.76 to 1.30; low-quality evidence), preterm birth < 37 weeks (RR 0.90, 95% CI 0.74 to 1.10), early preterm birth < 32 weeks (RR 0.79, 95% CI 0.56 to 1.12), and pregnancy loss, stillbirth or neonatal death before discharge (RR 0.82, 95% CI 0.61 to 1.10; low-quality evidence), no conception, gestational hypertension, gestational proteinuria, severe gestational hypertension, severe pre-eclampsia, severe pre-eclamptic complications index. There was no clear evidence on whether or not calcium might make a difference to perinatal death, or neonatal intensive care unit admission for > 24h, or both (RR 1.11, 95% CI 0.77 to 1.60; low-quality evidence).It is unclear what impact calcium supplementation has on Apgar score < 7 at five minutes (RR 0.43, 95% CI 0.15 to 1.21; very low-quality evidence), stillbirth, early onset pre-eclampsia, eclampsia, placental abruption, intensive care unit admission > 24 hours, maternal death, hospital stay > 7 days from birth, and pregnancy loss before 20 weeks' gestation.

AUTHORS' CONCLUSIONS

The single included study suggested that calcium supplementation before and early in pregnancy may reduce the risk of women experiencing the composite outcome pre-eclampsia or pregnancy loss at any gestational age, but the results are inconclusive for all other outcomes for women and babies. Therefore, current evidence neither supports nor refutes the routine use of calcium supplementation before conception and in early pregnancy.To determine the overall benefit of calcium supplementation commenced before or in early pregnancy, the effects found in the study of calcium supplementation limited to the first half of pregnancy need to be added to the known benefits of calcium supplementation in the second half of pregnancy.Further research is needed to confirm whether initiating calcium supplementation pre- or in early pregnancy is associated with a reduction in adverse pregnancy outcomes for mother and baby. Research could also address the acceptability of the intervention to women, which was not covered by this review update.

Is vitamin D-fortified yogurt a value-added strategy for improving human health? A systematic review and meta-analysis of randomized trials

Yogurt is a good source of probiotics, calcium, and proteins, but its content of vitamin D is low. Therefore, yogurt could be a good choice for vitamin D fortification to improve the positive health outcomes associated with its consumption. The primary aim of this systematic review and meta-analysis was to investigate the effect of vitamin D-fortified yogurt compared with plain yogurt on levels of serum 25-hydroxy vitamin D (25OHD). The secondary aim was to evaluate the effect of fortified yogurt on parathyroid hormone, anthropometric parameters, blood pressure, glucose metabolism, and lipid profile. We searched PubMed, Scopus, and Google Scholar for eligible studies; that is, randomized controlled trials (RCT) that compared vitamin D-fortified yogurt with control treatment without any additional supplement. Random-effects models were used to estimate pooled effect sizes and 95% confidence intervals. Findings from 9 RCT (n = 665 participants) that lasted from 8 to 16 wk are summarized in this review. The meta-analyzed mean differences for random effects showed that vitamin D-fortified yogurt (from 400 to 2,000 IU) increased serum 25OHD by 31.00 nmol/L. In addition, vitamin D-fortified yogurt decreased parathyroid hormone by 15.47 ng/L, body weight by 0.92 kg, waist circumference by 2.01 cm, HOMA-IR by 2.18 mass units, fasting serum glucose by 22.54 mg/dL, total cholesterol by 13.38 mg/dL, and triglycerides by 30.12 mg/dL compared with the controlled treatments. No publication bias was identified. Considerable between-study heterogeneity was observed for most outcomes. Vitamin D-fortified yogurt may be beneficial in improving serum 25OHD, lipid profile, glucose metabolism, and anthropometric parameters and decreasing parathyroid hormone level in pregnant women and adult and elderly subjects with or without diabetes, prediabetes, or metabolic syndrome.

The management of hypertension in women planning for pregnancy

INTRODUCTION OR BACKGROUND

Poorly-controlled hypertension in the first trimester significantly increases maternal and fetal morbidity and mortality. The majority of guidelines and clinical trials focus on the management and treatments for hypertension during pregnancy and breast-feeding, while limited evidence could be applied to the management for hypertension before pregnancy. In this review, we summarized the existing guidelines and treatments of pre-pregnancy treatment of hypertension.

SOURCES OF DATA

PubMed.

AREAS OF AGREEMENT

Methyldopa and labetalol are considered the first choice, but angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) need to be withdrawn if a hypertensive woman wishes to become pregnant. In women with chronic hypertension, it is very important to make an assessment before conception to exclude secondary causes of hypertension, evaluate their hypertensive control to ensure that it is optimal, discuss the increased risks of pre-eclampsia, and provide education regarding any drug alterations before they become pregnant.

AREAS OF CONTROVERSY

There is increasing debate regarding discouraging the use of diuretics. There is also controversy regarding the use of supplementations such as calcium, antioxidants and low-dose aspirin.

GROWING POINTS

A less restricted blood-pressure goal could be set for hypertensive women planning for pregnancy. A healthy body weight before pregnancy could lower the risk of pregnancy-related hypertensive disorders. Recent guidelines also encourage women with chronic hypertension to keep their dietary sodium intake low, either by reducing or substituting sodium salt before pregnancy.

TIMELY AREAS FOR DEVELOPING RESEARCH

Large, worldwide, randomized trials should be conducted to see the outcomes for hypertensive women who take antioxidants/physical activity before pregnancy.

Dietary calcium intake and hypertension risk: a dose-response meta-analysis of prospective cohort studies

The association of calcium intake with risk of developing hypertension in the general population has not been established yet. We systematically searched PubMed and Scopus databases up to February 2018 to find prospective observational studies investigating the association of calcium intake with risk of developing hypertension. The reported risk estimates were pooled using a random-effects model. Eight prospective cohort studies (248,398 participants and 30,838 cases) were included. Seven studies measured dietary calcium intake, but one study measured total calcium intake (calcium from food and supplements). A significant inverse association was found for the highest versus lowest category of calcium intake (relative risk: 0.89, 95%CI: 0.86, 0.93; I² = 0%, n = 8), and for each 500 mg/d increment (relative risk: 0.93, 95%CI: 0.90, 0.97; I² = 64%, n = 7). Summary results were the same with the main analyses when the analyses were restricted only to dietary calcium intake. A nonlinear dose-response meta-analysis exhibited a linear inverse association, with a somewhat steeper trend within the low and moderate intakes. In conclusion, higher dietary calcium intake, independent of adiposity and intake of other blood pressure-related minerals, is slightly associated with a lower risk of developing hypertension.

Calcium and Vitamin D Supplementation Are Not Associated With Risk of Incident Ischemic Cardiac Events or Death: Findings From the UK Biobank Cohort

We investigated associations between calcium/vitamin D supplementation and incident cardiovascular events/deaths in a UK population-based cohort. UK Biobank is a large prospective cohort comprising 502,637 men and women aged 40 to 69 years at recruitment. Supplementation with calcium/vitamin D was self-reported, and information on incident hospital admission (ICD-10) for ischemic heart disease (IHD), myocardial infarction (MI), and subsequent death was obtained from linkage to national registers. Cox proportional hazards models were used to investigate longitudinal relationships between calcium/vitamin D supplementation and hospital admission for men/women, controlling for covariates. A total of 475,255 participants (median age 58 years, 55.8% women) had complete data on calcium/vitamin D supplementation. Of that number, 33,437 participants reported taking calcium supplements; 19,089 vitamin D; and 10,007 both. In crude and adjusted analyses, there were no associations between use of calcium supplements and risk of incident hospital admission with either IHD, or subsequent death. Thus, for example, in unadjusted models, the hazard ratio (HR) for admission with myocardial infarction was 0.97 (95% confidence interval [CI] 0.79-1.20, p = 0.79) among women taking calcium supplementation. Corresponding HR for men is 1.16 (95% CI 0.92-1.46, p = 0.22). After full adjustment, HR (95% CI) were 0.82 (0.62-1.07), p = 0.14 among women and 1.12 (0.85-1.48), p = 0.41 among men. Adjusted HR (95% CI) for admission with IHD were 1.05 (0.92-1.19), p = 0.50 among women and 0.97 (0.82-1.15), p = 0.77 among men. Results were similar for vitamin D and combination supplementation. There were no associations with death, and in women, further adjustment for hormone-replacement therapy use did not alter the associations. In this very large prospective cohort, there was no evidence that use of calcium/vitamin D supplementation was associated with increased risk of hospital admission or death after ischemic cardiovascular events. © 2018 The Authors. Journal of Bone and Mineral Research Published by Wiley Periodicals, Inc.

The relationship between dietary intake and other cardiovascular risk factors with blood pressure in individuals without a history of a cardiovascular event: Evidence based study with 5670 subjects

BACKGROUND AND AIM

Raised blood pressure is a leading cause of morbidity and mortality worldwide; improved nutritional approaches to population-wide prevention are required.We aimed to investigate the relationship between dietary intake and other cardiovascular risk factors with blood pressure in individuals without a history of a cardiovascular event in an Iranian cohort.

MATERIAL AND METHOD

A cross-sectional study of 5670 healthy subjects [approximately 40% (n=2179) males and 60% (n=3491) females] was undertaken in a sample from northeastern Iran. Subjects were recruited from an urban population, using a stratified-cluster method and derived from the Mashhad Stroke Heart Atherosclerosis Disorder (MASHAD) study, Mashhad, Iran. The age of the subjects was between 35 and 64 years. None of the subjects had a past history of major disease.

RESULTS

The mean ages for the male and female subgroups were 50.1± 8.1years and 48.2 ±7.8 y respectively. Not unexpectedly, subjects without hypertension (HTN) were younger than those with established HTN. Individuals with HTN were significantly more adipose than those without (p<0.01). We found no significant differences in crude or total energy adjusted intake of nutrients between the three groups (p>0.05), except for crude and energy adjusted phosphorus intake (p<0.05) and crude intake of the cholesterol (p<0.05). There was a significant correlation between the dietary intake of total fatty acids, phosphorus and vitamin E with both systolic blood pressure (SBP) and diastolic blood pressure (DBP). PUFA (odds ratio [OR] [95% confidence interval (CI)], 1.56 [1.05-1.06]; P<0.01), sodium (OR [95% CI], 1.00 [(1.00-1.01)]; P<0.01) and phosphorus (OR [95% CI], 1.00 [(1.00-1.01)]; P<0.01)were significant independent predictors of HTN after adjustment for energy intake.

CONCLUSION

In our representative population from North-Eastern Iran, it appears that in adults without a history of cardiovascular disease, crude or energy adjusted intake of phosphorus and total fatty acid intake were significant determinants of BP, however we found no association between sodium and potassium intake with BP.

Calcium supplementation commencing before or early in pregnancy, or food fortification with calcium, for preventing hypertensive disorders of pregnancy

BACKGROUND

Pre-eclampsia is considerably more prevalent in low- than high-income countries. One possible explanation for this discrepancy is dietary differences, particularly calcium deficiency. Calcium supplementation in the second half of pregnancy reduces the serious consequences of pre-eclampsia and is recommended by the World Health Organization (WHO) for women with low dietary calcium intake, but has limited effect on the overall risk of pre-eclampsia. It is important to establish whether calcium supplementation before and in early pregnancy has added benefit. Such evidence would be justification for population-level fortification of staple foods with calcium.

OBJECTIVES

To determine the effect of calcium supplementation or food fortification with calcium, commenced before or early in pregnancy and continued at least until mid-pregnancy, on pre-eclampsia and other hypertensive disorders, maternal morbidity and mortality, as well as fetal and neonatal outcomes.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Trials Register (10 August 2017), PubMed (29 June 2017), ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (10 August 2017) and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials of calcium supplementation or food fortification which include women of child bearing age not yet pregnant, or in early pregnancy. Cluster-RCTs, quasi-RCTs and trials published in abstract form only would have been eligible for inclusion in this review but none were identified. Cross-over designs are not appropriate for this intervention.The scope of this review is to consider interventions including calcium supplementation with or without additional supplements or treatments, compared with placebo or no intervention.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy.

MAIN RESULTS

This review is based on one RCT (involving 60 women) which looked at calcium plus additional supplements versus control. The women (who had low antioxidant status) were in the early stages of pregnancy. We did not identify any studies where supplementation commenced pre-pregnancy. Another RCT comparing calcium versus placebo is ongoing but not yet complete. We did not identify any studies looking at any of our other planned comparisons. Calcium plus antioxidants and other supplements versus placeboWe included one small study (involving 60 women with low antioxidant levels) which was conducted in an academic hospital in Indondesia. The study was at low risk of bias for all domains with the exception of selective reporting, for which it was unclear. Women in the intervention group received calcium (800 mg) plus N-acetylcysteine (200 mg), Cu (2 mg), Zn (15 mg), Mn (0.5 mg) and selenium (100 mcg) and vitamins A (1000 IU), B6 (2.2 mg), B12 (2.2 mcg), C (200 mg), and E (400 IU) versus the placebo control group of women who received similar looking tablets containing iron and folic acid. Both groups received iron (30 mg) and folic acid (400 mcg). Tablets were taken twice daily from eight to 12 weeks of gestation and then throughout pregnancy.The included study found that calcium supplementation plus antioxidants and other supplements may slightly reduce pre-eclampsia (gestational hypertension and proteinuria) (risk ratio (RR) 0.24, 95% confidence interval (CI) 0.06 to 1.01; low-quality evidence), but this is uncertain due to wide confidence intervals just crossing the line of no effect, and small sample size. It appears that earlypregnancy loss before 20 weeks' gestation (RR 0.06, 95% CI 0.00 to 1.04; moderate-quality evidence) may be slightly reduced by calcium plus antioxidants and other supplements, but this outcome also has wide confidence intervals, which just cross the line of no effect. Very few events were reported under the composite outcome, severe maternal morbidity and mortality index and no clear difference was seen between groups (RR 0.36, 95% CI 0.04 to 3.23; low-quality evidence). However, the included study observed a reduction in the composite outcome pre-eclampsia and/or pregnancy loss at any gestational age (RR 0.13, 95% CI 0.03 to 0.50; moderate-quality evidence), and pregnancy loss/stillbirth at any gestational age (RR 0.06, 95% CI 0.00 to 0.92; moderate-quality evidence) in the calcium plus antioxidant/supplement group.Other outcomes reported (placental abruption, severe pre-eclampsia and preterm birth (less than 37 weeks' gestation)) were too infrequent for meaningful analysis. No data were reported for the outcomes caesarean section, birthweight < 2500 g, Apgar score less than seven at five minutes, death or admission to neonatal intensive care unit (ICU), or pregnancy loss, stillbirth or neonatal death before discharge from hospital.

AUTHORS' CONCLUSIONS

The results of this review are based on one small study in which the calcium intervention group also received antioxidants and other supplements. Therefore, we are uncertain whether any of the effects observed in the study were due to calcium supplementation or not. The evidence in this review was graded low to moderate due to imprecision. There is insufficient evidence on the effectiveness or otherwise of pre- or early-pregnancy calcium supplementation, or food fortification for preventing hypertensive disorders of pregnancy.Further research is needed to determine whether pre- or early-pregnancy supplementation, or food fortification with calcium is associated with a reduction in adverse pregnancy outcomes such as pre-eclampsia and pregnancy loss. Such studies should be adequately powered, limited to calcium supplementation, placebo-controlled, and include relevant outcomes such as those chosen for this review.There is one ongoing study of calcium supplementation alone versus placebo and this may provide additional evidence in future updates.

Calcium intake and the associations with faecal fat and energy excretion, and lipid profile in a free-living population

The aim of the present study was to investigate the associations between the habitual Ca intake and faecal fat and energy excretion as well as blood lipid profile in free-living normal-weight and overweight individuals. The participants were enrolled for an 8-d period where data from a 7-d diet registration (days 1–7), a 5-d faeces collection (days 3–7), a 2-d urine collection (days 5–7), and anthropometric measurements and a fasting blood sample (day 8) were collected. Analyses showed that dietary Ca intake (g/10 MJ per d) was positively associated with excretion of faecal fat (P = 0·004) and energy (P = 0·031) when adjusted for BMI, age, sex and intake of Ca-containing supplements. However, after adjustment for intake of fibre, the effect of Ca intake disappeared. Nevertheless, total cholesterol (CHOL) and LDL-CHOL concentrations were associated negatively with Ca intake (β −0·62 (95 % CI −0·96, −0·28) mmol/l, P < 0·001, and β −0·49 (95 % CI −0·78, −0·20) mmol/l, P = 0·001, respectively, per 1000 mg/10 MJ per d increase in Ca intake). In conclusion, incorporation of Ca-rich food products in a habitual diet was associated with reduced total CHOL and LDL-CHOL concentrations, which may lower the risk of CVD in the long term.

Effects of calcium plus vitamin D supplementation on blood pressure: a systematic review and meta-analysis of randomized controlled trials

The effect of calcium or vitamin D supplement on blood pressure (BP) has been explored in previous meta-analyses, but the results are conflicting. The combined efficacy of calcium and vitamin D on BP has not been systematically assessed. Thus, we conducted a meta-analysis of randomized controlled trials (RCTs) to explore the effect of calcium plus vitamin D (CaD) supplementation on changes of systolic blood pressure (SBP) and diastolic blood pressure among male and female participants (with and without diagnosed hypertension) aged 18 years or older. The PubMed, the Embase and the Cochrane Central Register of controlled trials were searched. A random effects model was used to calculate the pooled weighted mean differences (WMDs) with 95% confidence intervals (CIs) for the continuous outcome data. Cochrane Collaboration tool was used to assess the study quality of each trial. We further performed subgroup analysis and meta-regression by ethnicity, gender, age, health status, supplement dose, co-interventions, supplement duration and quality assessment. Eight RCTs involving 36 806 participants were assessed. The follow-up time ranged from 15 weeks to a maximum of 7 years. No meaningful effect on daytime office BP was detected in the present study, with evidence of significant heterogeneity. Subgroup analysis by gender indicated some evidence of elevated SBP in male participants, and the WMD (95% CI) was 1.49 mm Hg (1.03, 1.95). Further high-quality research is still warranted to confirm the magnitude of the effect of CaD supplementation on the changes of BP among participants with different ethnicity, gender, health status and CaD supplements.

Antihypertensive peptides of animal origin: A review

Many bioactive peptides trigger certain useful antihypertensive activities in the living body system and there is a mounting worldwide interest in the therapeutic potential of these bioactive peptides for exploitation in vivo against the hypertension. Studies suggest the antihypertensive properties for many bioactive peptides of animal origin with underlying mechanisms ranging from inhibition of angiotensin-converting enzyme to additional mechanisms to lower blood pressure such as opioid-like activities and mineral-binding and antithrombotic properties. Antihypertensive peptides are the most extensively studied of all the bioactivities induced by food protein hydrolysates, highlighting their importance in human health and disease prevention and treatment. There exist enormous opportunities for the production of novel peptide-based products in biopharmaceutical manufacturing industries for the treatment, prevention, and mitigation of hypertension. Numerous products have already struck on the global market and many more are in process. This article focuses on antihypertensive peptides identified in the meat, fish, blood, milk, dairy products, and egg and their probable application as novel ingredients in the development of functional food products as dietary treatment of hypertension.

The role of calcium supplementation in healthy musculoskeletal ageing : An expert consensus meeting of the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) and the International Foundation for Osteoporosis (IOF)

The place of calcium supplementation, with or without concomitant vitamin D supplementation, has been much debated in terms of both efficacy and safety. There have been numerous trials and meta-analyses of supplementation for fracture reduction, and associations with risk of myocardial infarction have been suggested in recent years. In this report, the product of an expert consensus meeting of the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) and the International Foundation for Osteoporosis (IOF), we review the evidence for the value of calcium supplementation, with or without vitamin D supplementation, for healthy musculoskeletal ageing. We conclude that (1) calcium and vitamin D supplementation leads to a modest reduction in fracture risk, although population-level intervention has not been shown to be an effective public health strategy; (2) supplementation with calcium alone for fracture reduction is not supported by the literature; (3) side effects of calcium supplementation include renal stones and gastrointestinal symptoms; (4) vitamin D supplementation, rather than calcium supplementation, may reduce falls risk; and (5) assertions of increased cardiovascular risk consequent to calcium supplementation are not convincingly supported by current evidence. In conclusion, we recommend, on the basis of the current evidence, that calcium supplementation, with concomitant vitamin D supplementation, is supported for patients at high risk of calcium and vitamin D insufficiency, and in those who are receiving treatment for osteoporosis.

Acute effects of calcium supplements on blood pressure: randomised, crossover trial in postmenopausal women

Calcium supplements appear to increase cardiovascular risk, but the mechanism is unknown. We investigated the acute effects of calcium supplements on blood pressure in postmenopausal women. The reduction in systolic blood pressure was smaller after calcium compared with the placebo in the hours following dosing.

INTRODUCTION

Calcium supplements appear to be associated with increased cardiovascular risk; however, the mechanism of this is uncertain. We previously reported that blood pressure declined over a day in older women, and that this reduction was smaller following a calcium supplement. To confirm this finding, we investigated the acute effects of calcium supplements on blood pressure.

METHODS

This was a randomised controlled crossover trial in 40 healthy postmenopausal women (mean age 71 years and BMI 27.2 kg/m²). Women attended on two occasions, with visits separated by ≥7 days. At each visit, they received either 1 g of calcium as citrate, or placebo. Blood pressure and serum calcium concentrations were measured immediately before, and 2, 4 and 6 h after each intervention.

RESULTS

Ionised and total calcium concentrations increased after calcium (p < 0.0001 versus placebo). Systolic blood pressure decreased after both calcium and placebo, but significantly less so after calcium (p = 0.02). The reduction in systolic blood pressure from baseline was smaller after calcium compared with placebo by 6 mmHg at 4 h (p = 0.036) and by 9 mmHg at 6 h (p = 0.002). The reduction in diastolic blood pressure was similar after calcium and placebo.

CONCLUSIONS

These findings are consistent with those of our previous trial and indicate that the use of calcium supplements in postmenopausal women attenuates the post-breakfast reduction in systolic blood pressure by around 6-9 mmHg. Whether these changes in blood pressure influence cardiovascular risk requires further study.

Circulating active serum calcium reduces the risk of hypertension

Purpose Calcium, which is one the most abundant mineral elements in the body, has been suggested to be involved in blood pressure regulation. We aimed to assess the association of active serum calcium (which is the ionised and physiologically active form of serum calcium) with the future risk of hypertension. Methods The active serum calcium concentration was assessed at baseline in the Finnish Kuopio Ischemic Heart Disease population-based prospective cohort study of 1562 normotensive men aged 42-61 years at baseline. Cox proportional hazard models were used to assess the hazard ratios (95% confidence intervals (CIs)) for incident hypertension. Results During a median follow-up of 24.9 years, 247 men developed new-onset hypertension. Active serum calcium was inversely associated with incident hypertension in an approximately linear fashion. In age-adjusted analysis, the hazard ratio for hypertension per 1 standard deviation increase in active serum calcium was 0.86 (95% CI 0.76-0.98), which remained consistent after adjustment for several established risk factors and potential confounders 0.82 (0.71-0.94). In a comparison of extreme quintiles of active serum calcium levels, the corresponding adjusted hazard ratios were 0.59 (95% CI 0.39-0.90) and 0.54 (95% CI 0.35-0.82), respectively. Conclusion Active serum calcium is protective of future hypertension in a middle-aged male Caucasian population. Further research is needed to confirm these findings and help unravel the mechanistic pathways of calcium in the pathogenesis of hypertension.

Gamma-glutamyltransferase and risk of prostate cancer: Findings from the KIHD prospective cohort study

Increased circulating serum gamma-glutamyltransferase (GGT) has been linked with an increased risk of chronic disease outcomes, including overall and several site-specific cancers. However, the relationship of GGT with prostate cancer risk is uncertain. We aimed to assess the prospective association of GGT with risk of prostate cancer. Serum GGT activity was assessed at baseline in the Finnish Kuopio Ischemic Heart Disease prospective cohort of 2,390 men aged 42-61 years without a history of cancer at baseline. We corrected for within-person variability in GGT values using data from repeat measurements taken several years apart. During a median follow-up of 24.6 years, 230 cases of prostate cancer occurred. The age-adjusted regression dilution ratio for log_e GGT was 0.69 [95% confidence interval (CI): 0.63-0.74]. Serum GGT was nonlinearly associated with risk of prostate cancer. In age-adjusted Cox regression analysis, the hazard ratio (95% CIs) for prostate cancer in a comparison of the top quartile versus bottom quartiles 1-3 of GGT values was 1.43 (1.07 to 1.93; p = 0.017), which persisted on adjustment for several established cancer risk factors 1.46 (1.06 to 2.02; p = 0.020). The association remained unchanged on further adjustment for total energy intake, socioeconomic status, physical activity and C-reactive protein. The association did not importantly vary across several clinical subgroups. GGT is positively and independently associated with future risk of prostate cancer in a middle-aged Finnish male population over long-term follow-up. Further research is needed to understand the mechanistic pathways involved and if GGT may have potential relevance in prostate cancer prevention.

Review of epidemiological studies on drinking water hardness and cardiovascular diseases

BACKGROUND

Major risk factors do not entirely explain the worldwide variability of morbidity and mortality due to cardiovascular disease. Environmental exposures, including drinking water minerals may affect cardiovascular disease risks.

METHOD

We conducted a qualitative review of the epidemiological studies of cardiovascular disease and drinking water hardness and calcium and magnesium levels.

RESULTS

Many but not all ecological studies found an inverse (i.e., protective) association between cardiovascular disease mortality and water hardness, calcium, or magnesium levels; but results are not consistent. Some case-control studies and one cohort study found either a reduced cardiovascular disease mortality risk with increased drinking water magnesium levels or an increased risk with low magnesium levels. However, the analytical studies provide little evidence that cardiovascular risks are associated with drinking water hardness or calcium levels.

CONCLUSION

Information from epidemiological and other studies supports the hypothesis that a low intake of magnesium may increase the risk of dying from, and possibly developing, cardiovascular disease or stroke. Thus, not removing magnesium from drinking water, or in certain situations increasing the magnesium intake from water, may be beneficial, especially for populations with an insufficient dietary intake of the mineral.

The Effects of an Olive Fruit Polyphenol-Enriched Yogurt on Body Composition, Blood Redox Status, Physiological and Metabolic Parameters and Yogurt Microflora

In the present study we investigated the effects of an olive polyphenol-enriched yogurt on yogurt microflora, as well as hematological, physiological and metabolic parameters, blood redox status and body composition. In a randomized double-blind, crossover design, 16 (6 men, 10 women) nonsmoking volunteers with non-declared pathology consumed either 400 g of olive fruit polyphenol-enriched yogurt with 50 mg of encapsulated olive polyphenols (experimental condition—EC) or 400 g of plain yogurt (control condition—CC) every day for two weeks. Physiological measurements and blood collection were performed before and after two weeks of each condition. The results showed that body weight, body mass index, hip circumference and systolic blood pressure decreased significantly (p < 0.05) following the two-week consumption of yogurt regardless of condition. A tendency towards significance for decreased levels of low density lipoprotein (LDL) cholesterol (p = 0.06) and thiobarbituric acid reactive substances (p < 0.05) following two weeks of polyphenol-enriched yogurt consumption was observed. The population of lactic acid bacteria (LAB) and production of lactate in yogurt were significantly enhanced after addition of olive polyphenols, contrary to the population of yeasts and molds. The results indicate that consumption of the polyphenol-enriched yogurt may help individuals with non-declared pathology reduce body weight, blood pressure, LDL cholesterol levels and lipid peroxidation, and promote growth of beneficial LAB.

Serum Calcium Increase Correlates With Worsening of Lipid Profile: An Observational Study on a Large Cohort From South Italy

Despite the well-documented role of calcium in cell metabolism, its role in the development of cardiovascular disease is still under heavy debate. Several studies suggest that calcium supplementation might be associated with an increased risk of coronary heart disease, whereas others underline a significant effect on lowering high blood pressure and hyperlipidemia. The purpose of this study was to investigate, in a large nonselected cohort from South Italy, if serum calcium levels correlate with lipid values and can therefore be linked to higher individual cardiovascular risk.Eight-thousand-six-hundred-ten outpatients addressed to the Laboratory of Clinical Biochemistry, University of Magna Græcia, Catanzaro, Italy from January 2012 to December 2013 for routine blood tests, were enrolled in the study. Total HDL-, LDL- and non-HDL colesterol, triglycerides, and calcium were determined with standard methods.We observed a significant association between total cholesterol, LDL-cholesterol, HDL-cholesterol, non-HDL cholesterol, triglycerides, and serum calcium in men and postmenopause women. Interestingly, in premenopause women, we only found a direct correlation between serum calcium, total cholesterol, and HDL-cholesterol. Calcium significantly increased while increasing total cholesterol and triglycerides in men and postmenopause women.Our results confirm that progressive increase of serum calcium level correlates with worsening of lipid profile in our study population. Therefore, we suggest that a greater caution should be used in calcium supplement prescription particularly in men and women undergoing menopause, in which an increase of serum lipids is already known to be associated with a higher cardiovascular risk.

Dairy consumption and CVD: a systematic review and meta-analysis

Inverse associations between dairy consumption and CVD have been reported in several epidemiological studies. Our objective was to conduct a meta-analysis of prospective cohort studies of dairy intake and CVD. A comprehensive literature search was conducted to identify studies that reported risk estimates for total dairy intake, individual dairy products, low/full-fat dairy intake, Ca from dairy sources and CVD, CHD and stroke. Random-effects meta-analyses were used to generate summary relative risk estimates (SRRE) for high v. low intake and stratified intake dose-response analyses. Additional dose-response analyses were performed. Heterogeneity was examined in sub-group and sensitivity analyses. In total, thirty-one unique cohort studies were identified and included in the meta-analysis. Several statistically significant SRRE below 1.0 were observed, namely for total dairy intake and stroke (SRRE=0·91; 95% CI 0·83, 0·99), cheese intake and CHD (SRRE=0·82; 95% CI 0·72, 0·93) and stroke (SRRE=0·87; 95% CI 0·77, 0·99), and Ca from dairy sources and stroke (SRRE=0·69; 95% CI 0·60, 0·81). However, there was little evidence for inverse dose-response relationships between the dairy variables and CHD and stroke after adjusting for within-study covariance. The results of this meta-analysis of prospective cohort studies have shown that dairy consumption may be associated with reduced risks of CVD, although additional data are needed to more comprehensively examine potential dose-response patterns.

An Update on Nutrients and Blood Pressure

Adverse blood pressure (BP) is a major independent risk factor for epidemic cardiovascular diseases affecting almost one-quarter of the adult population worldwide. Dietary intake is a major determinant in the development and progression of high BP. Lifestyle modifications, including recommended dietary guidelines, are advocated by the American Society of Hypertension, the International Society of Hypertension, the Japanese Society of Hypertension, and many other organisations for treating all hypertensive people, prior to initiating drug therapy and as an adjunct to medication in persons already on drug therapy. Lifestyle modification can also reduce high BP and prevent development of hypertension. This review synthesizes results from the International Study of Macro/Micronutrients and Blood Pressure (INTERMAP), a cross-sectional epidemiological study of 4,680 men and women aged 40-59 years from Japan, the People's Republic of China, the United Kingdom, and the United States, published over the past few years on cross cultural BP differences. INTERMAP has previously reported that intakes of vegetable protein, glutamic acid, total and insoluble fibre, total polyunsaturated fatty acid and linoleic acid, total n-3 fatty acid and linolenic acid, phosphorus, calcium, magnesium, and non-heme iron were inversely related to BP. Direct associations of sugars (fructose, glucose, and sucrose) and sugar-sweetened beverages (especially combined with high sodium intake), cholesterol, glycine, alanine, and oleic acid from animal sources with BP were also reported by the INTERMAP Study.

Effects of supplementation with a calcium-rich marine-derived multi-mineral supplement and short-chain fructo-oligosaccharides on serum lipids in postmenopausal women

Recent literature suggests that Ca supplements have adverse effects on cardiovascular health. The effects of a Ca-rich supplement administered alone or in combination with short-chain fructo-oligosaccharides (scFOS) on serum lipids in postmenopausal women were examined using secondary data from a 24-month double-blind randomised controlled study. A total of 300 postmenopausal women were randomly assigned to daily supplements of 800 mg of Ca (2·4 g Aquamin) (Ca), 800 mg of Ca with 3 g of scFOS (CaFOS) or control (maltodextrin) (MD). A full lipid profile, body composition, blood pressure and a range of cytokines were measured at baseline and after 24 months. Intention-to-treat ANCOVA assessed treatment effects between the groups. A significant time-by-treatment effect was observed for LDL and total cholesterol for the Ca and CaFOS groups, with both groups having lower LDL and total cholesterol concentrations compared with MD after 24 months. The control group had mean (5·2 mmol/l) total cholesterol concentrations above the normal range (≤5 mmol/l) at 24 months, whereas values remained within the normal range in the treatment groups. There was no significant treatment effect on HDL-cholesterol, TAG, body composition, blood pressure or cytokine concentrations at 24 months, with the exception of IL-4, where there was a significant increase in the CaFOS group compared with the placebo. This study demonstrates a lipid-lowering effect of both the Ca-rich supplement alone and the supplement with scFOS. At the 4-year follow-up, there was no significant difference between the groups for reported diagnosed cardiovascular conditions.

Dietary and pharmacological compounds altering intestinal calcium absorption in humans and animals

The intestine is the only gate for the entry of Ca to the body in humans and mammals. The entrance of Ca occurs via paracellular and intracellular pathways. All steps of the latter pathway are regulated by calcitriol and by other hormones. Dietary and pharmacological compounds also modulate the intestinal Ca absorption process. Among them, dietary Ca and P are known to alter the lipid and protein composition of the brush-border and basolateral membranes and, consequently, Ca transport. Ca intakes are below the requirements recommended by health professionals in most countries, triggering important health problems. Chronic low Ca intake has been related to illness conditions such as osteoporosis, hypertension, renal lithiasis and incidences of human cancer. Carbohydrates, mainly lactose, and prebiotics have been described as positive modulators of intestinal Ca absorption. Apparently, high meat proteins increase intestinal Ca absorption while the effect of dietary lipids remains unclear. Pharmacological compounds such as menadione, dl-butionine-S,R-sulfoximine and ursodeoxycholic acid also modify intestinal Ca absorption as a consequence of altering the redox state of the epithelial cells. The paracellular pathway of intestinal Ca absorption is poorly known and is under present study in some laboratories. Another field that needs to be explored more intensively is the influence of the gene × diet interaction on intestinal Ca absorption. Health professionals should be aware of this knowledge in order to develop nutritional or medical strategies to stimulate the efficiency of intestinal Ca absorption and to prevent diseases.

Digestion and Postprandial Metabolism in the Elderly

The elderly are an increasing segment of the population. Despite the rapid gains in medical knowledge and treatments, older adults are more likely to experience chronic illnesses that decrease quality of life and accelerate mortality. Nutrition is a key modifiable lifestyle factor which greatly impacts chronic disease risk. Yet despite the importance of nutrition, relatively little is known of the impact of advancing age on the gastrointestinal function, the digestive responses, and the post-meal metabolic adaptations that occur in response to ingested food. Knowledge of the age-related differences in digestion and metabolism in the elderly is essential to the development of appropriate nutritional recommendations for the maintenance of optimal health and prevention of disease.

Calcium supplements: benefits and risks

Calcium is an essential element in the diet, but there is continuing controversy regarding its optimal intake, and its role in the pathogenesis of osteoporosis. Most studies show little evidence of a relationship between calcium intake and bone density, or the rate of bone loss. Re-analysis of data from the placebo group from the Auckland Calcium Study demonstrates no relationship between dietary calcium intake and rate of bone loss over 5 years in healthy older women with intakes varying from <400 to >1500 mg day(-1) . Thus, supplements are not needed within this range of intakes to compensate for a demonstrable dietary deficiency, but might be acting as weak anti-resorptive agents via effects on parathyroid hormone and calcitonin. Consistent with this, supplements do acutely reduce bone resorption and produce small short-term effects on bone density, without evidence of a cumulative density benefit. As a result, anti-fracture efficacy remains unproven, with no evidence to support hip fracture prevention (other than in a cohort with severe vitamin D deficiency) and total fracture numbers are reduced by 0-10%, depending on which meta-analysis is considered. Five recent large studies have failed to demonstrate fracture prevention in their primary analyses. This must be balanced against an increase in gastrointestinal side effects (including a doubling of hospital admissions for these problems), a 17% increase in renal calculi and a 20-40% increase in risk of myocardial infarction. Each of these adverse events alone neutralizes any possible benefit in fracture prevention. Thus, calcium supplements appear to have a negative risk-benefit effect, and so should not be used routinely in the prevention or treatment of osteoporosis.

Acute effects of calcium supplements on blood pressure and blood coagulation: secondary analysis of a randomised controlled trial in post-menopausal women

Recent evidence suggests that Ca supplements increase the risk of cardiovascular events, but the mechanism(s) by which this occurs is uncertain. In a study primarily assessing the effects of various Ca supplements on blood Ca levels, we also investigated the effects of Ca supplements on blood pressure and their acute effects on blood coagulation. We randomised 100 post-menopausal women to 1 g/d of Ca or a placebo containing no Ca. Blood pressure was measured at baseline and every 2 h up to 8 h after their first dose and after 3 months of supplementation. Blood coagulation was measured by thromboelastography (TEG) in a subgroup of participants (n 40) up to 8 h only. Blood pressure declined over 8 h in both the groups, consistent with its normal diurnal rhythm. The reduction in systolic blood pressure was smaller in the Ca group compared with the control group by >5 mmHg between 2 and 6 h (P≤0·02), and the reduction in diastolic blood pressure was smaller at 2 h (between-groups difference 4·5 mmHg, P=0·004). Blood coagulability, assessed by TEG, increased from baseline over 8 h in the calcium citrate and control groups. At 4 h, the increase in the coagulation index was greater in the calcium citrate group compared with the control group (P=0·03), which appeared to be due to a greater reduction in the time to clot initiation. These data suggest that Ca supplements may acutely influence blood pressure and blood coagulation. Further investigation of this possibility is required.

Dietary intake of calcium and magnesium and the metabolic syndrome in the National Health and Nutrition Examination (NHANES) 2001-2010 data

Higher dietary intakes of Mg and Ca, individually, have been associated with a decreased risk for the metabolic syndrome (MetSyn). Experimental studies suggest that a higher intra-cellular ratio of Ca:Mg, which may be induced by a diet high in Ca and low in Mg, may lead to hypertension and insulin resistance. However, no previous epidemiological studies have examined the effects of the combined intake of Mg and Ca on MetSyn. Thus, we evaluated the association between dietary intakes of Ca and Mg (using 24-h recalls), independently and in combination, and MetSyn in the National Health and Nutrition Examination Study 2001-2010 data, which included 9148 adults (4549 men and 4599 women), with complete information on relevant nutrient, demographic, anthropometric and biomarker variables. We found an inverse association between the highest (>355 mg/d) v. the lowest (<197 mg/d) quartile of Mg and MetSyn (OR 0.70; 95% CI 0.57, 0.86). Women who met the RDA for both Mg (310-320 mg/d) and Ca (1000-1200 mg/d) had the greatest reduced odds of MetSyn (OR 0.59; 95% CI 0.45, 0.76). In men, meeting the RDA for Mg (400-420 mg/d) and Ca (1000-1200 mg/d), individually or in combination, was not associated with MetSyn; however, men with intakes in the highest quartile for Mg (≥ 386 mg/d) and Ca (≥ 1224 mg/d) had a lower odds of MetSyn (OR 0.74; 95% CI 0.59, 0.93). Our results suggest that women who meet the RDA for Mg and Ca have a reduced odds of MetSyn but men may require Ca levels higher than the RDA to be protected against MetSyn.

Calcium Supplements and Cardiovascular Disease: A Review

Dietary or supplemental calcium intake has long been encouraged for optimal bone health. However, more recently, the safety of calcium supplementation has been questioned because of a possible association between supplemental calcium and cardiovascular risk. Whereas calcium may have a beneficial or neutral effect on cardiovascular risk factors such as blood pressure, cholesterol, weight, and diabetes, available evidence does not provide a definitive answer for an association with cardiovascular disease (CVD). To date, no calcium trials have studied cardiovascular disease as a primary end point, and larger trials with longer follow-up are needed. In this review, we present results from observational studies and randomized controlled trials (RCTs) that have evaluated calcium intake (dietary or supplemental) in relation to cardiovascular risk factors and cardiovascular disease as a secondary outcome. Results from RCTs are mixed regarding CVD risk in those using supplemental calcium with or without vitamin D, and more large-scale randomized trials designed specifically with CVD as the primary end point are needed. Evidence suggests that it is reasonable to encourage adequate dietary calcium intake, especially for postmenopausal women who are at greatest risk for osteoporotic fracture.

Calcium supplementation for prevention of primary hypertension

BACKGROUND

Hypertension is a major public health problem that increases the risk of cardiovascular and kidney diseases. Several studies have shown an inverse association between calcium intake and blood pressure. As small reductions in blood pressure have been shown to produce rapid reductions in vascular disease risk even in individuals with normal blood pressure ranges, this review intends to evaluate the effect of calcium supplementation in normotensive individuals as a preventive health measure.

OBJECTIVES

To assess the efficacy and safety of calcium supplementation versus placebo or control for reducing blood pressure in normotensive people.

SEARCH METHODS

We searched the Cochrane Hypertension Group Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, MEDLINE In-Process, EMBASE and ClinicalTrials.gov for randomised controlled trials up to October 2014. The WHO International Clinical Trials Registry Platform (ICTRP) is searched for inclusion in the Group's Specialised Register. We also reviewed reference lists from retrieved studies and contacted authors of relevant papers. We applied no language restrictions.

SELECTION CRITERIA

We selected trials that randomised normotensive people to dietary calcium interventions such as supplementation or food fortification versus placebo or control. We excluded quasi-random designs. The primary outcomes were hypertension (defined as blood pressure ≥ 140/90 mmHg) and blood pressure measures.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, abstracted the data and assessed the risks of bias.

MAIN RESULTS

We included 16 trials with 3048 participants. None of the studies reported hypertension as a dichotomous outcome. The effect on systolic and diastolic blood pressure was mean difference (MD) -1.43 mmHg (95% confidence interval (CI) -2.15 to -0.72) and -0.98 mmHg (95%CI -1.46 to -0.50) respectively. The effect on systolic and diastolic blood pressure for those younger than 35 years (7 trials with 399 participants) was -2.11 mmHg (95%CI -3.58 to -0.64) / -2.61 mmHg (95% CI -3.74, -1.49). The effect on systolic and diastolic blood pressure for those 35 years or more (9 trials with 2649 participants) was -0.96 mmHg (95%CI -1.83 to -0.09) / -0.59 mmHg (95%CI -1.13 to -0.06). The effect on systolic and diastolic blood pressure for women (6 trials with 1823 participants) was -1.45 mmHg (95% CI -2.78 to -0.12) / -0.92 mmHg (95% CI -1.71 to -0.14). The effect on systolic and diastolic blood pressure for men (5 trials with 617 participants) was -2.07 (95%CI -3.56 to -0.59] / -1.91 (95%CI -2.80 to -1.02).The quality of evidence for each of these outcomes was high. The effect is consistent in both genders regardless of baseline calcium intake.The effect on systolic blood pressure was 0.08 mmHg (95% CI -2.16 to 2.32) with doses less than 1000 mg, -1.14 mmHg (95% CI -2.01 to -0.27) with 1000 - 1500 mg, and -2.79 mmHg (95% CI -4.71 to -0.86) with more than 1500 mg. The effect on diastolic blood pressure was -0.54 mmHg (95% CI -2.23 to 1.15), -0.71 mmHg (95% CI -1.37 to -0.06) and -1.43 mmHg (95% CI -2.22 to -0.64) respectively. The quality of evidence for each of these outcomes was high.None of the studies reported adverse events.

AUTHORS' CONCLUSIONS

An increase in calcium intake slightly reduces both systolic and diastolic blood pressure in normotensive people, particularly in young people, suggesting a role in the prevention of hypertension. These results should be interpreted with caution, since the proposed biological mechanism explaining the relationship between calcium and blood pressure has not been fully confirmed. The effect across multiple prespecified subgroups and a possible dose response effect reinforce this conclusion. Even small reductions in blood pressure could have important health implications for reducing vascular disease.There is a great need for adequately-powered clinical trials randomising young people. Subgroup analysis should involve basal calcium intake, age, sex, basal blood pressure, and body mass index. We also require assessment of side effects, optimal doses and the best strategy to improve calcium intake.

Metabolomics to Explore Impact of Dairy Intake

Dairy products are an important component in the Western diet and represent a valuable source of nutrients for humans. However, a reliable dairy intake assessment in nutrition research is crucial to correctly elucidate the link between dairy intake and human health. Metabolomics is considered a potential tool for assessment of dietary intake instead of traditional methods, such as food frequency questionnaires, food records, and 24-h recalls. Metabolomics has been successfully applied to discriminate between consumption of different dairy products under different experimental conditions. Moreover, potential metabolites related to dairy intake were identified, although these metabolites need to be further validated in other intervention studies before they can be used as valid biomarkers of dairy consumption. Therefore, this review provides an overview of metabolomics for assessment of dairy intake in order to better clarify the role of dairy products in human nutrition and health.

Parathyroid hormone, calcium, and sodium bridging between osteoporosis and hypertension in postmenopausal Korean women

The coexistence of osteoporosis and hypertension, which are considered distinct diseases, has been widely reported. In addition, daily intake of calcium and sodium, as well as parathyroid hormone levels (PTH), is known to be associated with osteoporosis and hypertension. This study aimed to determine the association of low calcium intake, high sodium intake, and PTH levels with osteoporosis and hypertension in postmenopausal Korean women. Data for postmenopausal Korean women aged 50 years or older were obtained from the Korea National Health and Nutrition Examination Survey 2008-2011. Osteoporosis was diagnosed using dual energy X-ray absorptiometry, while hypertension was diagnosed using blood pressure data. The odds ratios for osteoporosis and hypertension were calculated using logistic regression analysis for quartiles of the daily calcium intake, daily sodium intake, and PTH levels. Women with hypertension had a high coexistence of osteoporosis (43.6 vs. 36.5 %; P = 0.022), and vice versa (21.1 vs. 16.6 %; P = 0.022). PTH was significantly associated with osteoporosis and hypertension, and a high intake of calcium was strongly correlated with a low incidence of osteoporosis. This is the first study to report the characteristics of postmenopausal Korean women who have high dietary sodium intake and low dietary calcium intake, in association with the incidence of osteoporosis and hypertension. Osteoporosis and hypertension were strongly associated with each other, and PTH appears to be a key mediator of both diseases, suggesting a possible pathogenic link.

The effect of calcium supplementation on blood pressure in non-pregnant women with previous pre-eclampsia: An exploratory, randomized placebo controlled study

BACKGROUND

Epidemiological findings suggest that the link between poverty and pre-eclampsia might be dietary calcium deficiency. Calcium supplementation has been associated with a modest reduction in pre-eclampsia, and also in blood pressure (BP).

METHODS

This exploratory sub-study of the WHO Calcium and Pre-eclampsia (CAP) trial aims to determine the effect of 500mg/day elemental calcium on the blood pressure of non-pregnant women with previous pre-eclampsia. Non-pregnant women with at least one subsequent follow-up trial visit at approximately 12 or 24weeks after randomization were included.

RESULTS

Of 836 women randomized by 9 September 2014, 1st visit data were available in 367 women of whom 217 had previously had severe pre-eclampsia, 2nd visit data were available in 201 women. There was an overall trend to reduced BP in the calcium supplementation group (1-2.5mmHg) although differences were small and not statistically significant. In the subgroup with previous severe pre-eclampsia, the mean diastolic BP change in the calcium group (-2.6mmHg) was statistically larger than in the placebo group (+0.8mmHg), (mean difference -3.4, 95% CI -0.4 to -6.4; p=0.025). The effect of calcium on diastolic BP at 12weeks was greater than in those with non-severe pre-eclampsia (p=0.020, ANOVA analysis).

CONCLUSIONS

There is an overall trend to reduced BP but only statistically significant in the diastolic BP of women with previous severe pre-eclampsia. This is consistent with our hypothesis that this group is more sensitive to calcium supplementation, however results need to be interpreted with caution.

Calcium Intake, Major Dietary Sources and Bone Health Indicators in Iranian Primary School Children

Background:

Adequate calcium intake may have a crucial role with regards to prevention of many chronic diseases, including hypertension, hypercholesterolemia, different types of cancer, obesity and osteoporosis. In children, sufficient calcium intake is especially important to support the accelerated growth spurt during the preteen and teenage years and to increase bone mineral mass to lay the foundation for older age.

Objectives:

This study aimed to assess daily calcium intake in school-age children to ensure whether they fulfill the FGP dairy serving recommendations, the recommended levels of daily calcium intake and to assess the relationship between dietary calcium intake and major bone health indicators.

Patients and Methods:

A total of 501 Iranian school-age children were randomly selected. Calcium intake was assessed using a semi-quantitative food frequency questionnaire. Bone health indicators were also assessed.

Results:

Dairy products contributed to 69.3% of the total calcium intake of the children. Daily adequate intake of calcium was achieved by 17.8% of children. Only 29.8% met the Food guide pyramid recommendations for dairy intake. Dietary calcium intake was not significantly correlated with serum calcium and other selected biochemical indicators of bone health.

Conclusions:

The need for planning appropriate nutrition strategies for overcoming inadequate calcium intake in school age children in the city of Tehran is inevitable.