Effects of calcium supplementation on lipids, blood pressure, and body composition in healthy older men: a randomized controlled trial

Vitamins and Minerals for Blood Pressure Reduction in the General, Normotensive Population: A Systematic Review and Meta-Analysis of Six Supplements

Hypertension is the leading preventable risk factor for cardiovascular disease and all-cause mortality worldwide. However, studies have shown increased risk of mortality from heart disease and stroke even within the normal blood pressure (BP) range, starting at BPs above 110-115/70-75 mm Hg. Nutraceuticals, such as vitamins and minerals, have been studied extensively for their efficacy in lowering BP and may be of benefit to the general, normotensive population in achieving optimal BP. Our study investigated the effects of six nutraceuticals (Vitamins: C, D, E; Minerals: Calcium, Magnesium, Potassium) on both systolic blood pressure (SBP) and diastolic blood pressure (DBP) in this population. We performed a systematic review and pairwise meta-analysis for all six supplements versus placebo. Calcium and magnesium achieved significant reductions in both SBP and DBP of -1.37/-1.63 mm Hg and -2.79/-1.56 mm Hg, respectively. Vitamin E and potassium only yielded significant reductions in SBP with values of -1.76 mm Hg and -2.10 mm Hg, respectively. Vitamins C and D were not found to significantly lower either SBP or DBP. Future studies should determine optimal dosage and treatment length for these supplements in the general, normotensive population.

Effects of Microfiltered Seawater Intake and Variable Resistance Training on Strength, Bone Health, Body Composition, and Quality of Life in Older Women: A 32-Week Randomized, Double-Blinded, Placebo-Controlled Trial

The aim was to explore the effects of a 32-week resistance training (RT) intervention with elastic bands with or without microfiltered seawater (SW) supplementation on isokinetic strength, bone mineral density (BMD), body composition, and subjective quality of life in postmenopausal women. Ninety-three untrained women (age: 70.00 ± 6.26 years; body mass index: 22.05 ± 3.20 kg/m²; body fat: 37.77 ± 6.38%; 6.66 ± 1.01 s up-and-go test) voluntarily participated in this randomized, double-blinded, controlled trial. Participants were allocated into four groups (RT+SW, RT+PLA, CON+SW, and CON+PLA). The RT intervention (twice weekly) consisted of different exercises for the whole body performed at submaximal intensities with elastic bands. Both control groups were not involved in any exercise program. A two-way mixed analysis of variance of repeated measures revealed significant improvements in almost all the variables in both intervention groups (p < 0.05). However, significant differences with controls were encountered in isokinetic strength, body fat percentage, and bodily pain. Although the group with SW supplementation obtained greater effect sizes, non-significant differences between both RT groups were observed. In conclusion, the determinant factor of the adaptations seems to be RT rather than SW.

Vitamin D supplementation is effective for olanzapine-induced dyslipidemia

Olanzapine is an atypical antipsychotic drug that is clinically applied in patients with schizophrenia. It increases the risk of dyslipidemia, a disturbance of lipid metabolic homeostasis, usually characterized by increased low-density lipoprotein (LDL) cholesterol and triglycerides, and accompanied by decreased high-density lipoprotein (HDL) in the serum. In this study, analyzing the FDA Adverse Event Reporting System, JMDC insurance claims, and electronic medical records from Nihon University School of Medicine revealed that a co-treated drug, vitamin D, can reduce the incidence of olanzapine-induced dyslipidemia. In the following experimental validations of this hypothesis, short-term oral olanzapine administration in mice caused a simultaneous increase and decrease in the levels of LDL and HDL cholesterol, respectively, while the triglyceride level remained unaffected. Cholecalciferol supplementation attenuated these deteriorations in blood lipid profiles. RNA-seq analysis was conducted on three cell types that are closely related to maintaining cholesterol metabolic balance (hepatocytes, adipocytes, and C2C12) to verify the direct effects of olanzapine and the functional metabolites of cholecalciferol (calcifediol and calcitriol). Consequently, the expression of cholesterol-biosynthesis-related genes was reduced in calcifediol- and calcitriol-treated C2C12 cells, which was likely to be mediated by activating the vitamin D receptor that subsequently inhibited the cholesterol biosynthesis process via insulin-induced gene 2 regulation. This clinical big-data-based drug repurposing approach is effective in finding a novel treatment with high clinical predictability and a well-defined molecular mechanism.

Associations of Calcium Intake and Calcium from Various Sources with Blood Lipids in a Population of Older Women and Men with High Calcium Intake

Promoting calcium intake is a cornerstone for osteoporosis management. Some individuals limit dairy product consumption, a major calcium source, due to their high content in saturated fats and their perceived negative impact on lipid profiles. This study explored the associations of calcium from various sources with blood lipids in community-dwelling elderly (n = 717) from the GERICO cohort. Dietary calcium intake was assessed at several timepoints using a validated food frequency questionnaire (FFQ) and calcium supplement use was recorded. Blood lipids were treated as categorical variables to distinguish those with normal and abnormal levels. Increasing total calcium intake was associated with lower risks for high total cholesterol (p = 0.038) and triglycerides (p = 0.007), and low HDL-cholesterol (p = 0.010). Dairy calcium (p = 0.031), especially calcium from milk (p = 0.044) and milk-based desserts (p = 0.039), i.e., low-fat (p = 0.022) and non-fermented (p = 0.005) dairy products, were associated with a lower risk of high total cholesterol. Greater calcium intakes from total dairies (p = 0.020), milk (p = 0.020) and non-fermented dairies (p = 0.027) were associated with a lower risk of hypertriglyceridemia. No association was observed between calcium from non-dairy sources, cheese or high-fat dairies and blood lipids. Increasing calcium through supplements was associated with lower risks for hypertriglyceridemia (p = 0.022) and low HDL-cholesterol (p = 0.001), but not after adjustments. Our results suggest that higher calcium intakes from dietary sources or supplements are not adversely associated with blood lipids in the elderly, whilst total, and particularly low-fat, dairy products are valuable calcium sources potentially related to favorable lipid profiles.

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.

No adverse effects of dairy products on lipid profile: A systematic review and meta-analysis of randomized controlled clinical trials

BACKGROUND AND AIMS

The current study aimed to review the effects of dairy foods on lipid profile in randomized controlled clinical trials (RCTs).

METHODS

We searched PubMed, Scopus, Embase, and Central. RCTs that assess the effects of dairy foods on lipid profile were included.

RESULTS

The overall effects of dairy foods on lipid profile were non-significant. Dairy foods were associated with a non-significant reduction in triacylglycerol level, and a non-significant increase in total cholesterol, low density lipoprotein cholesterol, and high-density lipoprotein cholesterol level.

CONCLUSION

We conclude that dairy foods doesn't have any unfavorable effects on lipids.

The effects of the Dietary Approaches to Stop Hypertension (DASH) diet on metabolic risk factors in patients with chronic disease: A systematic review and meta-analysis of randomized controlled trials

AIMS

The DASH diet was designed for helping control of blood pressure but, fortunately, it can also be prescribed for many other chronic conditions. The current study intended to assess the potential effects of DASH diet on metabolic risk factors in patients with chronic disease.

DATA SYNTHESIS

We carried out a systematic literature search for RCTs from inception until July 2020. A total of 54 clinical trials were included in the final analysis. Compared to control groups, a significant lower effect of the DASH diet was noted for body weight (-1.59 kg; p < 0.001), BMI (-0.64 kg/m²; p < 0.001), and WC (-1.93 cm; p < 0.001) as well as for SBP (-3.94 mmHg; p < 0.001) and DBP (-2.44 mmHg; P < 0.001). The DASH diet significantly decreased TC (-5.12 mg/dl; p = 0.008) and LDL-C levels (-3.53 mg/dl; p = 0.041), but not HDL-C (0.30 mg/dl; p = 0.510), TG (-4.22 mg/dl; p = 0.067), and VLDL-C (-2.16 mg/dl; p = 0.062). No significant effect of the DASH diet was noted for blood glucose (-0.38 mg/dl; p = 0.216), insulin (-0.03 μIU/mL; p = 0.817), HOMA-IR (-0.15; p = 0.132), and CRP (-0.33 mg/l; p = 0.173).

CONCLUSIONS

The DASH diet is a feasible approach to weight loss and to control blood pressure and hypercholesterolemia.

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.

Role of calcium on lipid digestion and serum lipids: a review

Calcium is an essential nutrient for humans that can be taken as supplement or in a food matrix (e.g. dairy products). It is suggested that dietary calcium may have a beneficial effect on cardiovascular risk but the mechanism is not clear. In this review, the main mechanisms of the possible cholesterol-lowering effect of calcium, i.e. interaction with fatty acids and bile acids, are described and clinical evidences are presented. The observations from interventional studies of the possible cholesterol-lowering effect in terms of the main related mechanisms are variable and do not seem to fulfill all the related aspects. It seems that the interplay of calcium in blood lipid metabolism might be due to its complex and multiple roles in the lipid digestion in the small intestine. The interactions between calcium and, fatty acids and bile may lead to impaired mixed micelle formation and solubilization, which is crucial in the lipid absorption and metabolism. In addition, the calcium source and its surrounding matrix will have an influence over the physiological outcome. This research is important for the delivery and formulation of calcium, particularly with the move toward plant-based diets.

Role of dietary calcium and its possible mechanism against metabolic disorders: A concise review

The global prevalence of metabolic disorders including hypertension, dyslipidemia, insulin resistance, nonalcoholic fatty liver, and cardiovascular diseases seemed to affect people of all ages cutting across the national, economic, and demographic barrier. Therefore, the prevention of metabolic disorders is considered of paramount importance. The dietary role of nutrients including vitamins and minerals is one of the recommended preventive measures against metabolic disorders in modern society. Recently, dietary calcium, a common nutrient not only showed a beneficial effect against obesity through weight management, but also gained great attention against the risk of metabolic disorders. Though dietary calcium shows several beneficial effects against metabolic disorders but some inconsistent results were also reported. So, the present review aims to extract recent knowledge as well as their possible underlying mechanisms regarding the role of dietary calcium against metabolic disorders. The present review also discusses the negative impact as well as prospect of calcium intake on health issues. In summary, high calcium diet prevents the harmful consequences of metabolic disorders by regulating hormonal actions, alteration in intracellular calcium level, renin-angiotensin system, intestinal fat absorption, fecal fat excretion, lipid metabolism, carbohydrate metabolism, inflammation, and oxidative stress which together improve the metabolic health of an individual. PRACTICAL APPLICATIONS: Metabolic disorder is a global health issue across all sections of society and is growing rapidly in spite of several attempts by the scientific community to prevent it. Recently dietary calcium gained great attention in the last few years for its role in the management and treatment of metabolic disorders. The current review highlights the beneficial role of dietary calcium against several metabolic complications by exploring their underlying mechanisms at cellular level. This study will provide valuable information regarding the recommendation of dietary calcium in health policy as well as its inclusion in the dietary chart through calcium-rich foods and/or taking calcium supplements which can be a useful approach in preventing the risk of metabolic disorder depending on the health status of an individual.

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.

Meta-analysis of randomized controlled trials on calcium supplements and dairy products for changes in body weight and obesity indices

This meta-analysis was performed to investigate whether calcium supplements and dairy products change obesity indices including fat mass. Original articles published in English between July 2009 and August 2019 were identified. Ten and 14 randomised controlled trials (RCTs) with ≥ 12 weeks interventions of calcium supplements and dairy products among overweight or obese adults aged ≥18 were critically reviewed. Mean difference (MD) or standardised mean difference (SMD) with 95% confidence interval (CI) were obtained using a random effect meta-analysis. Dairy products significantly changed fat mass (SMD, 95% CI; -0.40 [-0.77, -0.02]) and BMI (MD, 95% CI: -0.46 kg/m2 [-0.67, -0.26]), and calcium supplements also showed changes in fat mass (SMD, 95% CI; -0.15[-0.28, -0.02]). However, in the analysis of RCTs with low risk of bias scores, the significant changes remained only in the dairy-products intervention. Our findings suggest that dairy products without distinction of fat percentage may help reduce fat mass and BMI, but calcium supplements may not.

The effect of calcium supplement intake on lipid profile: a systematic review and meta-analysis of randomized controlled clinical trials

Despite the potential role of dietary calcium in fat excretion, the favorable effects of calcium supplements on lipid profile remains inconclusive. The current study aimed to review the effect of calcium supplement intake on lipid profile in randomized controlled clinical trials (RCTs). This systematic review and meta-analysis was conducted in PubMed, Scopus, Embase, and Central. RCTs which assessed the effects of calcium supplementation on lipid profile were included. All outcomes were recorded as continuous variables, and the effect size was measured. We classified studies according to dose of supplement, study duration, and dyslipidemia. Calcium supplement intake was associated with a significant reduction in low density lipoprotein cholesterol (LDL-C) level (WMD:-0.08; 95%CI:-0.16,-0.01)(mmol/l), especially with intakes of at least 1000 mg/day (WMD:-0.13; 95%CI:-0.23,-0.03)(mmol/l), with intakes of at least 12 weeks (WMD:-0.08; 95%CI: -0.16,-0.00)(mmol/l), and in individuals without dyslipidemia (WMD:-0.15; 95%CI:-0.26,-0.04)(mmol/l). Also, in another subgroup analysis, consumption of less than 1000 mg/day calcium supplement caused a significant increase in Total Cholesterol (TC) level (WMD: 0.24; 95%CI: 0.05,0.42) (mmol/l). In other blood lipids or study subgroups we observed no significant effect. We concluded that calcium supplements had a favorable effect on LDL-C level, especially in individuals without dyslipidemia, higher calcium intakes, and longer period of consumption.

Parathyroid Hormone and 25-Hydroxyvitamin D Do Not Mediate the Association between Dietary Calcium, Protein and Vitamin D Intake and Adiposity and Lipid Profile in Patients with Type 2 Diabetes: a Structural Equation Modeling Approach

This study aimed to utilize structural equation modeling (SEM) techniques to determine the effects of dietary calcium, protein and vitamin D on adiposity and lipidemia and to assess mediatory effects of parathyroid hormone (PTH) and 25-hydroxyvitamin D (25(OH)D) in patients with type 2 diabetes. In this cross-sectional study, a total of 150 diabetic patients (93 females and 57 males) were randomly selected. Anthropometric measures, biochemical analyses, and fat mass percent were recorded. Nutritional data were collected. SEM was performed. Based on the primary hypothesis, adiposity and lipidemia were fitted in a model. The direct effects of dietary calcium (λ = -0.165, p value = 0.002) and PTH (λ = -0.143, p value = 0.011) were significantly associated with lipidemia. There were no significant effects for dietary protein on PTH (λ = -0.270, p value = 0.057), 25(OH)D (λ = -0.071, p value = 0.613), lipidemia (λ = -0.044; p value = 0.638) or adiposity (λ = -0.009, p value = 0.949) as well as for dietary vitamin D on PTH (λ = -0.119, p value = 0.194), 25(OH)D (λ = 0.023, p value = 0.806), lipidemia (λ = 0.034, p value = 0.587) or adiposity (λ = -0.221, p value = 0.118). The correlation between calcium intake and lipidemia, and adiposity are not mediated by 25(OH)D and PTH. There were the direct effects of dietary calcium on adiposity in patients with type 2 diabetes. The model can be tested in future longitudinal and intervention studies to identify the predictors of obesity.

Calcium Intake and Health

There are striking inequities in calcium intake between rich and poor populations. Appropriate calcium intake has shown many health benefits, such as reduction of hypertensive disorders of pregnancy, lower blood pressure particularly among young people, prevention of osteoporosis and colorectal adenomas, lower cholesterol values, and lower blood pressure in the progeny of mothers taking sufficient calcium during pregnancy. Studies have refuted some calcium supplementation side effects like damage to the iron status, formation of renal stones and myocardial infarction in older people. Attention should be given to bone resorption in post-partum women after calcium supplementation withdrawal. Mechanisms linking low calcium intake and blood pressure are mediated by parathyroid hormone raise that increases intracellular calcium in vascular smooth muscle cells leading to vasoconstriction. At the population level, an increase of around 400–500 mg/day could reduce the differences in calcium intake between high- and middle-low-income countries. The fortification of food and water seems a possible strategy to reach this goal.

Supplemental calcium intake in the aging individual: implications on skeletal and cardiovascular health

Adequate calcium intake during childhood is necessary to achieve optimal peak bone mass and this has the potential by increasing bone reserves, to modulate the rate of age-associated bone loss. However, data regarding the efficacy of calcium obtained either through the diet or in the form of medicinal supplementation, for prevention of bone loss and osteoporotic fractures in the elderly is conflicting. Calcium alone is unlikely to be of benefit for this purpose though the co-administration of calcium and vitamin D may have modest fracture risk benefits. Supplemental calcium with or without vitamin D has recently come into the spotlight after the publication of the findings from a controversial randomized controlled trial that associated calcium supplementation with an increased risk of myocardial infarction. Since then, multiple studies have explored this potential link. The data remains conflicting and the potential mechanistic link if any exists, remains elusive. This review examines the relationship between supplemental calcium intake and skeletal and cardiovascular health in the aging individual through an appraisal of studies done on the subject in the last three decades. It also briefly details some of the studies evaluating fractional absorption of calcium in the elderly and the rationale behind the current recommended dietary allowances of calcium.

Dietary calcium affects body composition and lipid metabolism in rats

Calcium (Ca) intakes may affect cardiovascular disease risk by altering body composition (body weight and fat) and serum lipid profile, but results have been inconsistent and the underlying mechanisms are not well understood. The effects of dietary Ca on body composition and lipid metabolism were examined in rats. Male Sprague-Dawley rats were fed high-fat, high-energy diets containing (g/kg) low (0.75Ca, 0.86 ± 0.05; 2Ca, 2.26 ± 0.02), normal (5Ca, 5.55 ± 0.08) or high (10Ca, 11.03 ± 0.17; 20Ca, 21.79 ± 0.15) Ca for 10 weeks. Rats fed the lowest Ca diet (0.75Ca) had lower (p < 0.05) body weight and fat mass compared to other groups. Rats fed the high Ca diets had lower serum total and LDL cholesterol compared to rats fed normal or low Ca. Liver total cholesterol was lower in rats fed high compared to low Ca. In general, liver mRNA expression of genes involved in cholesterol uptake from the circulation (Ldlr), cholesterol synthesis (Hmgcr and Hmgcs1), fatty acid oxidation (Cpt2) and cholesterol esterification (Acat2) were higher in rats fed higher Ca. Apparent digestibility of total trans, saturated, monounsaturated and polyunsaturated fatty acids was lower in rats fed the high compared to the low Ca diets, with the largest effects seen on trans and saturated fatty acids. Fecal excretion of cholesterol and total bile acids was highest in rats fed the highest Ca diet (20Ca). The results suggest little effect of dietary Ca on body composition unless Ca intakes are very low. Decreased bile acid reabsorption and reduced absorption of neutral sterols and saturated and trans fatty acids may contribute to the better serum lipid profile in rats fed higher Ca.

Dietary calcium status during maternal pregnancy and lactation affects lipid metabolism in mouse offspring

Calcium plays important roles in lipid metabolism and adipogenesis, but whether its status in early life affects later lipid profiles needs to be clarified. Three to four-week old C57BL/6J female mice were fed with three different reproductive diets containing normal, low (insufficient) and high (excessive) calcium concentrations respectively throughout pregnancy and lactation. At postnatal 21 days, the weaning male and female pups from each group were sacrificed for experiments and the remaining were fed with the normal chow diet for 16 weeks. Meanwhile, some of the weaning female pups from maternal low calcium diet group were fed with the normal calcium, low calcium and high calcium mature diets respectively for 8 weeks. Maternal insufficient or excessive calcium status during pregnancy and lactation programmed an abnormal expression of hepatic and adipose genes (PPAR-γ, C/EBP-α, FABP4, Fasn, UCP2, PPAR-α, HMG-Red1, Acc1, and SREBP-1c) in the offspring and this may lead to dyslipidemia and accumulation of hepatic triglyceride (TG) and total cholesterol (TC) in later life. The effects of maternal calcium status on lipid metabolism were found only in the female adult offspring, but were similar between offspring males and females at postnatal 21 days. Additionally, the dyslipidemia and hepatic lipid accumulation caused by insufficient calcium status in early life may be reversed to some extent by dietary calcium supplementation in later life.

Effects of Taurine and Vitamin D on Antioxidant Enzyme Activity and Lipids Profiles in Rats Fed Diet Deficient Calcium

Calcium deficiency is a worldwide problem affecting both developed and developing countries. The deficiency in calcium leads to a marked decrease of superoxide dismutase. It is known that vitamin D protects cells against oxidative damages while taurine plays an anti-inflammatory and antioxidant role. In this study, we examined whether vitamin D and taurine supplementation had a protective effect on oxidative stress in rats fed calcium deficient diet. Female SD rats (mean weight 60 ∼ 70 g) were divided into four groups; control, taurine, vitamin D, taurine + vitamin D for 6 weeks (taurine: 2 g/100 g diet, vitamin D: 0.5 mg/100 g diet). We then analyzed the level of triglyceride (TG), total cholesterol (TC), LDL-cholesterol (LDL-C), HDL-cholesterol (HDL-C) in serum and level of TC, TG in liver. We investigated antioxidative enzyme activities such as catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px). We observed that weight gain was not significantly different in the experimental groups. Food efficiency ratio (FER) was significantly higher in the normal control group than the taurine and vitamin D groups (p < 0.05). The level of liver TC was significantly lower in taurine, vitamin D, taurine + vitamin D groups than control group (p < 0.05). The concentration of malondialdehyde (MDA) was significantly lower in the taurine group than the control group. The activity of SOD was higher in taurine group than other experimental groups (p < 0.05), but GSH-Px and CAT were not significantly different. In conclusion, taurine has a positive effect on SOD activity but not on vitamin D. Also taurine and vitamin D have a protective effect as observed in liver TC in rats fed with a diet which lacks calcium.

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.

Impact of Dietary Calcium Supplement on Circulating Lipoprotein Concentrations and Atherogenic Indices in Overweight and Obese Individuals: A Systematic Review

Dyslipidemia is the main risk factor for developing cardiovascular disease. There are discrepancies in the effects of calcium supplementation on modulation of lipid status. Therefore, we aimed to summarize the effects of dietary calcium supplement on circulating lipoprotein concentrations and atherogenic indices in overweight and obese individuals. We conducted a systematic literature search from 2000 until July 2016. PubMed, Scopus, Cochran Library, and ISI Web of Science databases were searched for clinical trials written in English. Placebo controlled clinical trials on calcium or calcium with vitamin D supplement in overweight and obese indiciduals were considered. Finally, 11 clinical trials met the criteria and were included. Most studies (n = 9) evaluated Ca/D co-supplementation. Positive effects of calcium supplementation alone or with vitamin D were as follows: serum levels of total cholesterol (TC; n = 1), triglyceride (TG) concentrations (n = 1), serum levels of low-density lipoprotein cholesterol (LDL-C; n = 5) and high-density lipoprotein cholesterol (HDL-C; n = 3). Seven clinical trials reported atherogenic indices and three of them demonstrated beneficial effects of calcium supplementation on at least one atherogenic index. Calcium supplementation may not be helpful to reduce serum levels of TC and TG in overweight and obese individuals. However, it may modulate LDL-C and HDL-C concentration. More studies are warranted to clarify the effects of calcium supplementation on each atherogenic index.

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.

Cheese and Cardiovascular Disease Risk: A Review of the Evidence and Discussion of Possible Mechanisms

Currently, the effect of dairy products on cardiovascular risk is a topic much debated and with conflicting results. The purpose of this review is to give an overview of the existing literature regarding the effect of cheese intake and risk of cardiovascular disease (CVD). Studies included reporting the intake of cheese and risk of CVD or risk markers of CVD represent four human intervention studies, nine prospective studies, one prospective case-cohort study, one prospective nested case-control study, five case-control studies, five cross-sectional studies and three correlation studies. The possible mechanisms that may be of importance include calcium, protein, fermentation and the fatty acid composition of cheese. Results from four prospective studies reported no association between cheese intake and CVD risk, whereas one reported an increased risk, two reported a decreased risk and one reported no association in men but a decreased risk in women. In addition, results from four intervention studies indicated no harmful effect on cholesterol concentrations when comparing fat intake from cheese with fat from butter. The underlying mechanisms for these findings still need to be elucidated.

Effect of vitamin D3 supplementation on blood pressure in adults: An updated meta-analysis

BACKGROUND AND AIMS

Previous randomized clinical trials (RCTs) of the effects of vitamin D3 supplementation (VD3S) on blood pressure have generated inconsistent results. We evaluated the effect of VD3S on systolic blood pressure (SBP) and diastolic blood pressure (DBP) in a meta-analysis.

DATA SYNTHESIS

Literature searches of PubMed, Scopus, Ovid, and Google scholar for publications in English were conducted up to April 2015. RCTs that assessed the effect of VD3S on SBP and DBP were selected.

CONCLUSIONS

A total of 30 RCTs with 41 arms including 4744 participants were included. The mean duration of the studies was 5.6 ± 4.0 months, and doses of VD3S varied between 200 and 12,000 IU/day. VD3S had no effect on SBP (-0.68 mmHg, 95%CI: -2.19 to 0.84), and DBP (-0.57 mmHg, 95%CI: -1.36 to 0.22). Subgroup analysis revealed that daily vitamin D3 therapy at a dose of >800 IU/day for <6 months in subjects ≥50 years old reduced both SBP and DBP (p < 0.001). In addition, VD3S showed hypotensive effects in healthy subjects and hypertensive patients, but a hypertensive effect in overweight and obese subjects. However, after excluding overweight and obese subjects, VD3S significantly reduced SBP and DBP. VD3S in combination with calcium supplementation significantly elevated SBP (3.64 mmHg, 95%CI: 3.15-4.13) and DBP (1.71 mmHg, 95%CI: 1.25-2.18). No evidence of publication bias was found. The effects of VD3S on blood pressure depend on dose of supplementation, treatment regimens, trial duration, and population subgroup. Supplementation may be beneficial at daily doses >800 IU/day for <6 months in subjects ≥50 years old.

Calcium intake: good for the bones but bad for the heart? An analysis of clinical studies

The proper dietary calcium intake and calcium supplementation, when indicated, are important factors in the acquisition of peak bone mass during youth and in the prevention of fractures in old age. In addition to its deposition in bone, calcium confers an increase in its resistance and exhibits important activities in different enzymatic pathways in the body (e.g., neural, hormonal, muscle-related and blood clotting pathways). Thus, calcium supplementation can directly or indirectly affect important functions in the body, such as the control of blood pressure, plasma glucose, body weight, lipid profile and endothelial function. Since one publication reported increased cardiovascular risk due to calcium supplementation, many researchers have studied whether this risk actually exists; the results are conflicting, and the involved mechanisms are uncertain. However, studies that have evaluated the influence of the consumption of foods rich in calcium have reported no increase in the cardiovascular risk, which suggests that nutritional intake should be prioritized as a method for supplementation and that the use of calcium supplements should be reserved for patients who truly need supplementation and are unable to achieve the recommended daily nutritional intake of calcium.

Feasibility of a clinical trial to assess the effect of dietary calcium v. supplemental calcium on vascular and bone markers in healthy postmenopausal women

Whether supplemental Ca has similar effects to dietary Ca on vascular and bone markers is unknown. The present trial investigated the feasibility of applying dietary and supplemental interventions in a randomised-controlled trial (RCT) aiming to estimate the effect of supplemental Ca as compared with dietary Ca on vascular and bone markers in postmenopausal women. In total, thirteen participants were randomised to a Ca supplement group (CaSuppl) (750 mg Ca from CaCO3+450 mg Ca from food+20 µg vitamin D supplement) or a Ca diet group (CaDiet) (1200 mg Ca from food+10 µg vitamin D supplement). Participants were instructed on Ca consumption targets at baseline. Monthly telephone follow-ups were conducted to assess adherence to interventions (±20 % of target total Ca) using the multiple-pass 24-h recall method and reported pill count. Measurements of arterial stiffness, peripheral blood pressure and body composition were performed at baseline and after 6 and 12 months in all participants who completed the trial (n 9). Blood and serum biomarkers were measured at baseline and at 12 months. Both groups were compliant to trial interventions (±20 % of target total Ca intake; pill count ≥80 %). CaSuppl participants maintained a significantly lower average dietary Ca intake compared with CaDiet participants throughout the trial (453 (sd 187) mg/d v. 1241 (sd 319) mg/d; P<0·001). There were no significant differences in selected vascular outcomes between intervention groups over time. Our pilot trial demonstrated the feasibility of conducting a large-scale RCT to estimate the differential effects of supplemental and dietary Ca on vascular and bone health markers in healthy postmenopausal women.

Relationship between dietary calcium intake and adiposity in female adolescents

BACKGROUND AND OBJECTIVE

The prevalence and magnitude of obesity in children and adolescents increase rapidly. Besides genetic and environmental factors, calcium intake has recently been identified as a dietary factor that is inversely related with body mass index and development of overweight and obesity. The purpose of this study was to assess the correlation between dietary calcium intake and body mass index and fat distribution in female adolescents.

MATERIALS AND METHODS

This was a cross-sectional study where anthropometric variables (weight, height, body mass index, waist and hip circumference) were collected in 244 female adolescents to establish total body adiposity and fat distribution. A 24-hour recall and a food frequency questionnaire were used to assess total calorie, calcium, and dairy products intake.

RESULTS

Calcium intake was inversely related to body mass index (P<.05), waist circumference(P<.05), hip circumference (P>.05), and waist to hip ratio (P<.05).Overweight (8.3%) and obese (0.7%) adolescents had a lower mean calcium intake than adolescents of normal weight (P=.06).

CONCLUSIONS

Dietary calcium intake and, to a lesser extent, consumption of dairy products are inversely related to total and abdominal adiposity, and also to the prevalence of overweight in this group of adolescents.

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.

Effect of increasing dietary calcium through supplements and dairy food on body weight and body composition: a meta-analysis of randomised controlled trials

This meta-analysis of randomised controlled trials assessed the effect of Ca on body weight and body composition through supplementation or increasing dairy food intake. Forty-one studies met the inclusion criteria (including fifty-one trial arms; thirty-one with dairy foods (n 2091), twenty with Ca supplements (n 2711). Ca intake was approximately 900 mg/d higher in the supplement groups compared with control. In the dairy group, Ca intake was approximately 1300 mg/d. Ca supplementation did not significantly affect body weight (mean change ( - 0·17, 95% CI - 0·70, 0·37) kg) or body fat (mean change ( - 0·19, 95% CI - 0·51, 0·13) kg) compared to control. Similarly, increased dairy food intake did not affect body weight ( - 0·06, 95% CI - 0·54, 0·43) kg or body fat change ( - 0·36, 95% CI - 0·80, 0·09) kg compared to control. Sub-analyses revealed that dairy supplementation resulted in no change in body weight (nineteen studies, n 1010) ( - 0·32, 95% CI - 0·93, 0·30 kg, P= 0·31), but a greater reduction in body fat (thirteen studies, n 564) ( - 0·96, 95% CI - 1·46, - 0·46 kg, P < 0·001) in the presence of energy restriction over a mean of 4 months compared to control. Increasing dietary Ca intake by 900 mg/d as supplements or increasing dairy intake to approximately 3 servings daily (approximately 1300 mg of Ca/d) is not an effective weight reduction strategy in adults. There is, however, an indication that approximately 3 servings of dairy may facilitate fat loss on weight reduction diets in the short term.

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.

Effects of combined vitamin D--calcium supplements on the cardiovascular system: should we be cautious?

Despite the growing body of evidence on the potential effects of calcium and vitamin D as monotherapies on different cardiovascular (CV) parameters, the combined supplementation with calcium and vitamin D (CaD), which is most frequently encountered in clinical practice, has not received the attention it deserves. A literature search was conducted via EMBASE and Medline and identified 14 randomised controlled trials (RCTs) and 2 meta-analyses reporting on effects of combined supplementation with CaD on CV events, CV death, blood pressure, lipids, glucose metabolism and weight. Overall, the existing evidence does not support beneficial properties of supplementation with CaD on the CV system, nor does it suggest that a re-appraisal of the use of CaD is necessary due to adverse effects, although increased risk of CV events has been reported by some authors. The guidelines for the use of CaD supplementation need not change until well-conducted RCTs that have CV effects as primary outcomes and adjust for major confounders indicate otherwise.

Safety of drugs used in the treatment of osteoporosis

A number of drug classes are licensed for the treatment of osteoporosis including bisphosphonates, recombinant human parathyroid hormone (PTH), strontium, hormone replacement therapy (HRT), selective oestrogen receptor modulators (SERMS) and denosumab. This review discusses the safety of osteoporosis treatments and their efficacies. Recent concerns about the safety of calcium and high-dose vitamin D are discussed. Bisphosphonates have substantial postmarketing experience and a clearer picture of safety issues is emerging. Along with the well recognized effects on the gastrointestinal tract and kidney function, recently described adverse effects such as osteonecrosis of the jaw, oesophageal cancer, atrial fibrillation, subtrochanteric femur fractures and ocular complications of bisphosphonate therapy are discussed. Therapy with PTH is limited to two years' duration because of the development of osteogenic sarcomas in animal studies, which appeared related to dose, duration and timing of therapy. Strontium should be used with caution in patients with renal impairment and its use has been associated with venous thromboembolism. The role of HRT and SERMs in the treatment of postmenopausal osteoporosis is restricted as a result of an increased risk of stroke, venous thromboembolism and breast cancer. Postmarketing experience with denusomab is limited but a number of potential safety concerns including osteonecrosis of the jaw are emerging. All of these drugs have been proven to reduce fractures. The decision to use a drug to reduce fracture risk should be based on risk-benefit analysis of the drug and its suitability for individual patients.

Effect of dairy calcium from cheese and milk on fecal fat excretion, blood lipids, and appetite in young men

BACKGROUND

Calcium from different dairy sources might affect blood lipids and fecal fat excretion differently because of differences in the food matrix and nutritional composition.

OBJECTIVE

We investigated whether milk- and cheese-based diets with similar calcium contents affect a saturated fatty acid-induced increase in blood lipids differently.

DESIGN

Fifteen healthy, young men participated in a randomized 3 × 2-wk crossover study in which the following 3 isocaloric diets that were similar in fat contents and compositions were compared: control diet [nondairy diet (~500 mg Ca/d)], milk diet [semiskimmed milk-based diet (1700 mg Ca/d)], and cheese diet [semihard cow-cheese-based diet (1700 mg Ca/d)]. Blood was drawn before and after each period, and feces were collected for 5 d during each period.

RESULTS

Saturated fatty acid-induced increases in total and low-density lipoprotein (LDL) cholesterol were lower with the milk diet (mean ± SD: 0.57 ± 0.13 and 0.53 ± 0.11 mmol/L, respectively) (P < 0.01) and cheese diet (0.41 ± 0.15 and 0.47 ± 0.12 mmol/L, respectively) (P < 0.05) than with the control diet (0.89 ± 0.12 and 0.84 ± 0.11 mmol/L, respectively). Fecal fat excretion increased more with the consumption of both the milk (5.2 ± 0.4 g/d) and cheese (5.7 ± 0.4 g/d) diets than with the control diet (3.9 ± 0.3 g/d) (P < 0.001). Changes in blood pressure, high-density lipoprotein cholesterol, triglycerides, and lipid ratios did not differ.

CONCLUSIONS

Compared with the control diet, milk- and cheese-based diets attenuated saturated fatty acid-induced increases in total and LDL cholesterol and resulted in increased fecal fat excretion; however, effects of milk and cheese did not differ. Because the diets contained similar amounts of saturated fat, similar increases in total and LDL cholesterol could be expected; however, both milk and cheese attenuated these responses, which seem to be explained by their calcium contents. This trial was registered at clinicaltrials.gov as NCT01317251.

Should we prescribe calcium supplements for osteoporosis prevention?

Advocacy for the use of calcium supplements arose at a time when there were no other effective interventions for the prevention of osteoporosis. Their promotion was based on the belief that increasing calcium intake would increase bone formation. Our current understandings of the biology of bone suggest that this does not occur, though calcium does act as a weak antiresorptive. Thus, it slows postmenopausal bone loss but, despite this, recent meta-analyses suggest no significant prevention of fractures. In sum, there is little substantive evidence of benefit to bone health from the use of calcium supplements. Against this needs to be balanced the likelihood that calcium supplement use increases cardiovascular events, kidney stones, gastrointestinal symptoms, and admissions to hospital with acute gastrointestinal problems. Thus, the balance of risk and benefit seems to be consistently negative. As a result, current recommendations are to obtain calcium from the diet in preference to supplements. Dietary calcium intake has not been associated with the adverse effects associated with supplements, probably because calcium is provided in smaller boluses, which are absorbed more slowly since they come together with quantities of protein and fat, resulting in a slower gastric transit time. These findings suggest that calcium supplements have little role to play in the modern therapeutics of osteoporosis, which is based around the targeting of safe and effective anti-resorptive drugs to individuals demonstrated to be at increased risk of future fractures.

Dietary Intake Ratios of Calcium-to-Phosphorus and Sodium-to-Potassium Are Associated with Serum Lipid Levels in Healthy Korean Adults

The purpose of this study was to identify food sources for major minerals such as calcium (Ca), phosphorus (P), sodium (Na) and potassium (K), and to evaluate the relationship between dietary intake of these minerals and serum lipids in healthy Korean adults. A total of 132 healthy men and women completed a physical examination and dietary record and provided blood samples for lipid profile analysis. Results showed the following daily average mineral intakes: 373.4 mg of calcium, 806.0 mg of phosphorous, 3685.8 mg of sodium, and 1938.3 mg of potassium. The calcium-to-phosphorus and sodium-to-potassium ratio was about 0.5 and 2.0, respectively. The primary sources for each mineral were: vegetables (24.9%) and fishes (19.0%) for calcium, grains (31.4%) for phosphorus, seasonings (41.6%) and vegetables (27.0%) for sodium, and vegetables (30.6%) and grains (18.5%) for potassium. The correlation analysis, which has been adjusted for age, gender, total food consumption, and energy intake, showed significantly positive correlations between Ca/P and serum HDL cholesterol levels, between Na intake and the level of serum total cholesterol, and between Na/K and the level of serum cholesterol and LDL cholesterol. Our data indicates that the level of mineral consumption partially contributes to serum lipid profiles and that a diet consisting of a low Ca/P ratio and a high Na/K ratio may have negative impacts on lipid metabolism.

New reference values for calcium

The nutrition societies of Germany, Austria and Switzerland are the joint editors of the 'reference values for nutrient intake'. They have revised the reference values for the intake of calcium and published them in June 2013. The reference values for the calcium intake for infants are derived from the calcium content of breast milk. For infants from 4 to <12 months of age, the calcium intake from solid foods is included in addition to the calcium intake from breast milk. Thus, the reference values for infants are estimated values; they are 220 mg/day for infants to <4 months and 330 mg/day for infants from 4 to <12 months of age. As a parameter for determining the calcium requirement in children and adolescents, calcium retention is taken into account. The average requirement is calculated by the factorial method. A balanced calcium metabolism is calculated based upon calcium balance studies and used as a parameter for the determination of the calcium requirement in adults. On the basis of the average requirement, recommended calcium intake levels for children, adolescents and adults are derived. Depending on age, the recommended calcium intake ranges between 600 mg/day for children aged 1 to <4 years and 1,200 mg/day for adolescents aged 13 to <19 years; for adults, it is 1,000 mg/day.

Effect of calcium or vitamin D supplementation on vascular outcomes: a meta-analysis of randomized controlled trials

BACKGROUND

Whether calcium or vitamin D supplementation reduces serious vascular outcomes in older people remains unclear. We conducted a meta-analysis based on randomized controlled trials to evaluate the effect of calcium or vitamin D supplementation on the risk of major cardiovascular outcomes.

METHODS

We performed electronic searches in PubMed, Embase, and the Cochrane Library to identify relevant randomized controlled trials. Odds ratios (ORs) were used to measure the effect of calcium or vitamin D supplementation on the risk of major vascular outcomes with a random-effect model.

RESULTS

Of the 1643 identified studies, we included 11 trials reporting data on 50,252 individuals. These studies reported 2685 major cardiovascular events, 1097 events of myocardial infarction, and 1350 events of stroke. Calcium or vitamin D supplementation did not have an effect on major cardiovascular events (OR, 1.03; 95% confidence interval [CI]: 0.94-1.12; P=0.54), myocardial infarction (OR, 1.08; 95% CI: 0.96-1.22; P=0.21), or stroke (OR, 1.01; 95% CI: 0.91-1.13; P=0.80) when compared to the effect with a placebo. Subgroup analysis indicated that calcium supplementation alone might play an important role in increasing the risk of major cardiovascular events, myocardial infarction, and stroke, but this difference could not be identified as statistically significant. Furthermore, males seem to experience more harmful effects with supplements of calcium or vitamin D than the effects experienced by females.

CONCLUSIONS

Calcium supplementation might increase the risk of major cardiovascular events, myocardial infarction, and stroke compared to the risk with a placebo.

Calcium and vitamin D intake and mortality: results from the Canadian Multicentre Osteoporosis Study (CaMos)

CONTEXT

Calcium and vitamin D are recommended for bone health, but there are concerns about adverse risks. Some clinical studies suggest that calcium intake may be cardioprotective, whereas others report increased risk associated with calcium supplements. Both low and high serum levels of 25-hydroxyvitamin D have been associated with increased mortality.

OBJECTIVE

The purpose of this study was to determine the association between total calcium and vitamin D intake and mortality and heterogeneity by source of intake.

DESIGN

The Canadian Multicentre Osteoporosis Study cohort is a population-based longitudinal cohort with a 10-year follow-up (1995-2007).

SETTING

This study included randomly selected community-dwelling men and women.

PARTICIPANTS

A total of 9033 participants with nonmissing calcium and vitamin D intake data and follow-up were studied.

EXPOSURE

Total calcium intake (dairy, nondairy food, and supplements) and total vitamin D intake (milk, yogurt, and supplements) were recorded.

OUTCOME

The outcome variable was all-cause mortality.

RESULTS

There were 1160 deaths during the 10-year period. For women only, we found a possible benefit of higher total calcium intake, with a hazard ratio of 0.95 (95% confidence interval, 0.89-1.01) per 500-mg increase in daily calcium intake and no evidence of heterogeneity by source; use of calcium supplements was also associated with reduced mortality, with hazard ratio of 0.78 (95% confidence interval, 0.66-0.92) for users vs nonusers with statistically significant reductions remaining among those with doses up to 1000 mg/d. These associations were not modified by levels of concurrent vitamin D intake. No definitive associations were found among men.

CONCLUSIONS

Calcium supplements, up to 1000 mg/d, and increased dietary intake of calcium may be associated with reduced risk of mortality in women. We found no evidence of mortality benefit or harm associated with vitamin D intake.

Calcium intake in health maintenance - a systematic review

Background

Calcium (Ca) is an essential nutrient for the human body. Despite lively research, there is uncertainty about Ca requirements in terms of desirable health outcomes including an upper intake level above which the potential for harm increases.

Objectives

The aim was to conduct a review to update requirements and desirable or harmful health effects of Ca on the current scientific evidence.

Methods

We searched Medline and Swemed from January 2000 to December 2011 and included all systematic reviews that reported Ca supplementation or usual Ca intake on health outcomes. Meta-analyses, randomized clinical trials and cohort studies were included in the second search between May 2009 and March 2011 and an additional search covering studies till the end of 2011. This review concentrated on studies reporting independent effects of Ca, although a few recent trials report sole effects of Ca on health outcomes, most trials use Ca in combination with vitamin D vs. placebo.

Results

In total, we reviewed 38 studies addressing the effects of Ca on bone, pregnancy-related outcomes, cancers, cardiovascular outcomes, obesity, and mortality. There was a lot of heterogeneity in the study protocols, which made it difficult to draw any strong conclusions. According to the literature, high Ca intake seems to have a small positive effect on bone mineral content (BMC) or bone mineral density (BMD) in children and postmenopausal women. We did not find any consistent evidence on the effects of Ca on bone health in premenopausal women or men. Also, the evidence that Ca supplementation reduces fracture incidence is scarce and inconsistent. Maternal diet may influence the peak bone mass of offspring but more studies are required. There was no overall effect of Ca intake on cancers. Ca was associated with a decreased risk of breast cancer and a slightly increased risk of prostate cancer in two of the three studies. No associations were found with other cancers. We found no consistent association between cardiovascular outcomes and Ca intake except for blood pressure. A small decrease of 2–4 mmHg in systolic blood pressure was found in pregnant and in hypertensive subjects with Ca supplementation. Reviewed studies did not show consistent evidence relating Ca intake to either mortality or obesity.

Conclusion

Based on this evidence, there is no need to change the Nordic recommendations for Ca intake. However, due to heterogeneity in the studies it is difficult to interpret the results and provide single summary statement.

Relationship between milk and calcium intake and lipid metabolism in female patients with type 2 diabetes

PURPOSE

This study was conducted to determine the association between intake of milk and dairy products as well as calcium and biomarkers related to lipid metabolism in Korean female patients with type 2 diabetes.

MATERIALS AND METHODS

A cohort of 509 female subjects (mean age: 59.0 years; range: 35-80 years) was recruited from Huh's Diabetes Clinic in Seoul between 2005 and 2010. Dietary intake was assessed using a validated food-frequency questionnaire. Subjects were divided into three groups on the basis of their daily intake of milk and dairy products [<50 g/day (0<50 g/day), 50-200 g/day, and >200 g/day (>200-1201 g/day)] and then further divided into two groups according to their daily calcium intake: below and above the estimated average requirement (EAR).

RESULTS

After adjustment for age, body mass index, energy intake, exercise, use of nutritional supplements and cholesterol medication, the level of serum high-density lipoprotein (HDL)-cholesterol was significantly higher in subjects with milk and dairy products consumption of >200 g/day than in subjects in the other two groups. Those subjects with a milk and dairy products consumption of >200 g/day had significantly higher levels of apolipoprotein A-1 and a significantly lower atherogenic index than the other two groups. Patients with a calcium intake above the EAR exhibited a significantly greater serum HDL-cholesterol level than those with a calcium intake below the EAR.

CONCLUSION

Milk and dairy products, good sources of calcium, play a positive role in lipid profiles in female patients with type 2 diabetes.

[Calcium supplementation and the possible increase in cardiovascular risk]

The primary goal of osteoporosis treatment is to prevent the occurrence of fragility fractures, and thereby reduce morbidity and mortality. Among the various approaches to the treatment of this disease include ensuring proper calcium intake and to obtain adequate levels of vitamin D. Virtually all clinical trials with drugs used to treat osteoporosis systematically include calcium and vitamin D supplements. In light of the recent publication of clinical trials and meta-analyses, a possible increase in cardiovascular risk, particularly in the form of a myocrdial infarction, is hypothesised in patients taking calcium supplements. However, data published to date are inconclusive. Until the development of new scientific evidence, it seems reasonable to recommend, whenever practicable and individualized for each patient, increasing calcium intake with food and reserve supplements for patients with very low calcium intake in the diet. It would also be advisable for the administration of total daily dose to be fractionated throughout the day and with meals, and to obtain appropriate levels of vitamin D (25-hydroxycholecalciferol or calcidiol), along with the basic treatment for osteoporosis that is decided to be prescribed to patients.

Calcium plus vitamin D3 supplementation facilitated fat loss in overweight and obese college students with very-low calcium consumption: a randomized controlled trial

BACKGROUND

Recent evidence suggests that higher calcium and/or vitamin D intake may be associated with lower body weight and better metabolic health. Due to contradictory findings from intervention trials, we investigated the effect of calcium plus vitamin D3 (calcium+D) supplementation on anthropometric and metabolic profiles during energy restriction in healthy, overweight and obese adults with very-low calcium consumption.

METHODS

Fifty-three subjects were randomly assigned in an open-label, randomized controlled trial to receive either an energy-restricted diet (-500 kcal/d) supplemented with 600 mg elemental calcium and 125 IU vitamin D3 or energy restriction alone for 12 weeks. Repeated measurements of variance were performed to evaluate the differences between groups for changes in body weight, BMI, body composition, waist circumference, and blood pressures, as well as in plasma TG, TC, HDL, LDL, glucose and insulin concentrations.

RESULTS

Eighty-one percent of participants completed the trial (85% from the calcium + D group; 78% from the control group). A significantly greater decrease in fat mass loss was observed in the calcium + D group (-2.8±1.3 vs.-1.8±1.3 kg; P=0.02) than in the control group, although there was no significant difference in body weight change (P>0.05) between groups. The calcium + D group also exhibited greater decrease in visceral fat mass and visceral fat area (P<0.05 for both). No significant difference was detected for changes in metabolic variables (P>0.05).

CONCLUSION

Calcium plus vitamin D3 supplementation for 12 weeks augmented body fat and visceral fat loss in very-low calcium consumers during energy restriction.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT01447433, http://clinicaltrials.gov/).

Effects of serum calcium and magnesium on heart rate variability in adult women

The present study was designed to evaluate the association of serum calcium (Ca) and magnesium (Mg) levels with heart rate variability (HRV). One hundred and sixteen adult women were recruited in this cross-sectional study. Serum Ca and Mg levels were measured, and HRV in each time and frequency domain was recorded for 5 min. Mean heart rate and standard deviation of the normal to normal interval (SDNN) and root mean square of differences of successive RR interval (RMSSD) in time domain and total power (TP), low-frequency power (LF), high-frequency power (HF), and LF/HF ratio in frequency domain were compared according to the tertiles of serum Ca and Mg levels and Ca/Mg ratio. The associations between serum Ca and Mg levels and Ca/Mg ratio with HRV were evaluated using regression analyses. Mean heart rate tended to increase from the lowest to the highest tertile of Ca levels (p = 0.081), whereas it decreased significantly with higher Mg levels (p = 0.026). Increasing SDNN value was observed from the lowest to the highest tertile of Mg levels (p = 0.009). SDNN value decreased significantly from the lowest to the highest tertile of Ca/Mg ratio (p = 0.030). Participants in the lowest tertile of Ca/Mg ratio had significantly higher TP and LF values compared to those in the middle and highest tertiles (p < 0.05). Decreasing SDNN, TP, and LF values were significantly associated with higher Ca/Mg ratios (p < 0.05). Associations of serum Mg level and Ca/Mg ratio with HRV could be one of the mechanisms involved in cardiovascular diseases.