Global inequities in dietary calcium intake during pregnancy: a systematic review and meta-analysis

Effects of maternal calcium supplementation on offspring blood pressure and growth in childhood and adolescence in a population with a low-calcium intake: follow-up study of a randomized controlled trial

BACKGROUND

The World Health Organization recommends calcium supplementation (1500-2000 mg/d) during pregnancy for women with a low-calcium intake.

OBJECTIVES

The purpose of this study was to investigate whether pregnancy calcium supplementation affects offspring blood pressure and growth in The Gambia where calcium intakes are low (300-400 mg/d).

METHODS

Follow-up of offspring born during a randomized controlled trial of pregnancy calcium supplementation (ISRCTN96502494, 1996-2000) in which mothers were randomly assigned to 1500 mg Ca/d (Ca) or placebo (P) from 20 wk pregnancy to delivery. Offspring were enrolled at age 3 y in studies where blood pressure and anthropometry were measured under standardized conditions at approximately 2-yearly intervals. Mean blood pressure and growth curves were fitted for females and males separately, using the longitudinal SuperImposition by Translation and Rotation (SITAR) mixed effects model. This generates 3 individual-specific random effects: size, timing, and intensity, reflecting differences in size, age at peak velocity, and peak velocity through puberty relative to the mean curve, respectively.

RESULTS

Five hundred twenty-three singleton infants were born during the trial (maternal group assignment: Ca/P = 259/264). Four hundred ninety-one were enrolled as children (females: F-Ca/F-P = 122/129 and males: M-Ca/M-P = 119/121) and measured regularly from 3.0 y to mean age 18.4 y; 90% were measured on ≥8 occasions. SITAR revealed differences in the systolic blood pressure and height curves between pregnancy supplement groups in females, but not in males. F-Ca had lower systolic blood pressure than F-P at all ages (size = -2.1 ± SE 0.8 mmHg; P = 0.005) and lower peak height velocity (intensity = -2.9 ± SE 1.1%, P = 0.009). No significant pregnancy supplement effects were seen for other measures.

CONCLUSIONS

This study showed, in female offspring, that pregnancy calcium supplementation may lower systolic blood pressure and slow linear growth in childhood and adolescence, adding to evidence of offspring sexual dimorphism in responses to maternal supplementation. Further research is warranted on the long-term and intergenerational effects of antenatal supplementations. This trial was registered at ISRCTN Registry as ISRCTN96502494.

Calcium supplementation for people with overweight or obesity

BACKGROUND

Obesity is a major health problem worldwide as it can lead to high blood pressure, heart disease, stroke, diabetes, and insulin resistance. The prevalence of overweight and obesity is increasing worldwide across different age groups. There is evidence of an inverse relationship between calcium intake and body weight. The clinical relevance of a small reduction in body weight has been questioned. However, at a population level, a small effect could mitigate the observed global trends.

OBJECTIVES

To assess the effects of calcium supplementation on weight loss in individuals living with overweight or obesity.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, LILACS (Latin American and Caribbean Health Science Information database), and two clinical trials registries. The date of the last search of all databases (except Embase) was 10 May 2023. No language restrictions were applied.

SELECTION CRITERIA

We included randomised controlled trials evaluating the effect of calcium in participants with overweight or obesity of any age or gender. We excluded studies in participants with absorption problems. We included studies of any dose with a minimum duration of two months. We included the following comparisons: calcium supplementation versus placebo, calcium-fortified food or beverage versus placebo, or calcium-fortified food or beverage versus non-calcium-fortified food or beverage. We excluded studies that evaluated the effect of calcium and vitamin D or mixed minerals compared to placebo.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. Our primary outcomes were body weight, health-related quality of life, and adverse events. Our secondary outcomes were anthropometric measures other than body weight, all-cause mortality, and morbidity.

MAIN RESULTS

We found 18 studies that evaluated the effect of calcium compared to placebo or control, with a total of 1873 randomised participants (950 participants in the calcium supplementation groups and 923 in the control groups). All included studies gave oral calcium supplementation as the intervention. We did not find any studies evaluating calcium-fortified foods. We excluded 38 studies, identified four ongoing studies, and listed one study as 'awaiting classification'. Sixteen studies compared calcium supplementation to placebo; two studies compared different doses of calcium supplementation. Doses ranged from very low (0.162 g of calcium/day) to high (1.5 g of calcium/day). Most studies were performed in the USA and Iran, lasted less than six months, and included only women. Low-certainty evidence suggests that calcium supplementation compared to placebo or control may result in little to no difference in body weight (mean difference (MD) -0.15 kg, 95% confidence interval (CI) -0.55 to 0.24; P = 0.45, I2 = 46%; 17 studies, 1317 participants; low-certainty evidence). We downgraded the certainty of the evidence by two levels for risk of bias and heterogeneity. None of the included studies reported health-related quality of life, all-cause mortality, or morbidity/complications as outcomes. Only five studies assessed or reported adverse events. Low-certainty evidence suggests a low frequency of adverse events, with no clear difference between intervention and control groups. Moderate-certainty evidence shows that calcium supplementation compared to placebo or control probably results in a small reduction in body mass index (BMI) (MD -0.18 kg/m2,95% CI -0.22 to -0.13; P < 0.001, I2 = 0%; 9 studies, 731 participants) and waist circumference (MD -0.51 cm, 95% CI -0.72 to -0.29; P < 0.001, I2 = 0%; 6 studies, 273 participants). Low-certainty evidence suggests that calcium supplementation compared to placebo or control may result in a small reduction in body fat mass (MD -0.34 kg, 95% CI -0.73 to 0.05; P < 0.001, I2 = 97%; 12 studies, 812 participants).

AUTHORS' CONCLUSIONS

Calcium supplementation for eight weeks to 24 months may result in little to no difference in body weight in people with overweight or obesity. The current evidence is of low certainty, due to concerns regarding risk of bias and statistical heterogeneity. We found that the degree of heterogeneity might be partly explained by calcium dosage, the presence or absence of a co-intervention, and whether an intention-to-treat analysis was pursued. While our analyses suggest that calcium supplementation may result in a small reduction in BMI, waist circumference, and fat mass, this evidence is of low to moderate certainty. Future studies could investigate the effect of calcium supplementation on lean body mass to explore if there is a change in body composition.

Equity in prenatal healthcare services globally: an umbrella review

BACKGROUND

Timely, appropriate, and equitable access to quality healthcare during pregnancy is proven to contribute to better health outcomes of birthing individuals and infants following birth. Equity is conceptualized as the absence of differences in healthcare access and quality among population groups. Healthcare policies are guides for front-line practices, and despite merits of contemporary policies striving to foster equitable healthcare, inequities persist. The purpose of this umbrella review is to identify prenatal healthcare practices, summarize how equities/inequities are reported in relation to patient experiences or health outcomes when accessing or using services, and collate equity reporting characteristics.

METHODS

For this umbrella review, six electronic databases were searched (Medline, EMBASE, APA PsychInfo, CINAHL, International Bibliography of the Social Sciences, and Cochrane Library). Included studies were extracted for publication and study characteristics, equity reporting, primary outcomes (prenatal care influenced by equity/inequity) and secondary outcomes (infant health influenced by equity/inequity during pregnancy). Data was analyzed deductively using the PROGRESS-Plus equity framework and by summative content analysis for equity reporting characteristics. The included articles were assessed for quality using the Risk of Bias Assessment Tool for Systematic Reviews.

RESULTS

The search identified 8065 articles and 236 underwent full-text screening. Of the 236, 68 systematic reviews were included with first authors representing 20 different countries. The population focus of included studies ranged across prenatal only (n = 14), perinatal (n = 25), maternal (n = 2), maternal and child (n = 19), and a general population (n = 8). Barriers to equity in prenatal care included travel and financial burden, culturally insensitive practices that deterred care engagement and continuity, and discriminatory behaviour that reduced care access and satisfaction. Facilitators to achieve equity included innovations such as community health workers, home visitation programs, conditional cash transfer programs, virtual care, and cross-cultural training, to enhance patient experiences and increase their access to, and use of health services. There was overlap across PROGRESS-Plus factors.

CONCLUSIONS

This umbrella review collated inequities present in prenatal healthcare services, globally. Further, this synthesis contributes to future solution and action-oriented research and practice by assembling evidence-informed opportunities, innovations, and approaches that may foster equitable prenatal health services to all members of diverse communities.

Adequacy and Distribution Equity of Nutrition Supplies across China

Procuring food enriched with diverse nutrients is pivotal for maintaining a robust immune system. However, the food system is now unprecedentedly globalized and faces challenges arising from climate change, pandemics, and political unrest. This study aims to illuminate the gap in exploring the adequacy and distribution equity of nutrition supplies in response to potential trade fluctuations and restrictions on agrifood within China's local agriculture endowments. Also, it seeks to identify the role of trade in contributing to these indices. Accordingly, we analyzed the distribution of nutrients in agrifood categories from production to consumption and assessed the adequacy and distribution equity of corresponding available nutrition supply from the local food provision system in terms of meeting residents' nutritional requirements, across China, and compared with those in the practical market. The local self-supply system showed that 12 out of 31 provinces have difficulty achieving an iron supply with 11% to 108% deficiencies. Except for iron, 52% (folate)-90% (vitamin B12) of agricultural output was available for diet provisioning nationwide. While food trade emerges as a crucial factor in enhancing secure and equitable nutrition supply, risks associated with micronutrient deficiencies necessitate careful consideration in current global circumstances. Our analysis explored a regional pool of nutrient information in supplements to the conventional food profile in China and could implicate better knowledge toward healthier food supplies and tailored improvements for achieving a resilient nutrition supply.

Two Randomized Trials of Low-Dose Calcium Supplementation in Pregnancy

BACKGROUND

The World Health Organization recommends 1500 to 2000 mg of calcium daily as supplementation, divided into three doses, for pregnant persons in populations with low dietary calcium intake in order to reduce the risk of preeclampsia. The complexity of the dosing scheme, however, has led to implementation barriers.

METHODS

We conducted two independent randomized trials of calcium supplementation, in India and Tanzania, to assess the noninferiority of a 500-mg daily dose to a 1500-mg daily dose of calcium supplementation. In each trial, the two primary outcomes were preeclampsia and preterm birth, and the noninferiority margins for the relative risks were 1.54 and 1.16, respectively.

RESULTS

A total of 11,000 nulliparous pregnant women were included in each trial. The cumulative incidence of preeclampsia was 3.0% in the 500-mg group and 3.6% in the 1500-mg group in the India trial (relative risk, 0.84; 95% confidence interval [CI], 0.68 to 1.03) and 3.0% and 2.7%, respectively, in the Tanzania trial (relative risk, 1.10; 95% CI, 0.88 to 1.36) - findings consistent with the noninferiority of the lower dose in both trials. The percentage of live births that were preterm was 11.4% in the 500-mg group and 12.8% in the 1500-mg group in the India trial (relative risk, 0.89; 95% CI, 0.80 to 0.98), which was within the noninferiority margin of 1.16; in the Tanzania trial, the respective percentages were 10.4% and 9.7% (relative risk, 1.07; 95% CI, 0.95 to 1.21), which exceeded the noninferiority margin.

CONCLUSIONS

In these two trials, low-dose calcium supplementation was noninferior to high-dose calcium supplementation with respect to the risk of preeclampsia. It was noninferior with respect to the risk of preterm live birth in the trial in India but not in the trial in Tanzania. (Funded by the Bill and Melinda Gates Foundation and others; ClinicalTrials.gov number, NCT03350516; Clinical Trials Registry-India number, CTRI/2018/02/012119; and Tanzania Medicines and Medical Devices Authority Trials Registry number, TFDA0018/CTR/0010/5).

Vulnerabilities and reparative strategies during pregnancy, childbirth, and the postpartum period: moving from rhetoric to action

Maternal outcomes throughout pregnancy, childbirth, and the postnatal period are influenced by interlinked and interdependent vulnerabilities. A comprehensive understanding of how various threats and barriers affect maternal and perinatal health is critical to plan, evaluate and improve maternal health programmes. This paper builds on the introductory paper of the Series on the determinants of maternal health by assessing vulnerabilities during pregnancy, childbirth, and the postnatal period. We synthesise and present the concept of vulnerability in pregnancy and childbirth, and map vulnerability attributes and their dynamic influence on maternal outcomes in early and late pregnancy and during childbirth and the postnatal period, with a particular focus on low-income and middle-income countries (LMICs). We summarise existing literature and present the evidence on the effects of various reparative strategies to improve pregnancy and childbirth outcomes. Lastly, we discuss the implications of the identified vulnerability attributes and reparative strategies for the efforts of policymakers, healthcare professionals, and researchers working towards improving outcomes for women and birthing people in LMICs.

Global Health Disparities in Childhood Rickets

Nutritional rickets is a global health problem reflecting both historical and contemporary health disparities arising from racial, ethnic, environmental, and geopolitical circumstances. It primarily affects marginalized populations and can contribute to long-term morbidity. Deficits in bone health in childhood may also contribute to osteomalacia/osteoporosis. Solutions require a global public health approach.

Plant-based alternative proteins-are they nutritionally more advantageous?

BACKGROUND

The transition towards sustainable nutrition as well as the exploration of alternative sources of protein have been at the forefront of thinking in the 21st century. However, further research is required to ascertain if a diet composed of alternative plant-based proteins has similar nutritional advantages to a plant-based diet. This study aims to model the replacement of a diet consisting of animal-based proteins with plant-based alternatives (PBA), in a group of Asians.

METHODS

A 4-day food record was collected from 50 individuals residing in Singapore and nutrient profiles were generated for each individual. Food records were analysed, and meat, dairy, and seafood ingredients were substituted gram-for-gram with their PBA. The original and replaced nutrient profiles were compared against each other and the differences in macro and micronutrients were analysed.

RESULTS

A significant increase in carbohydrates, dietary fibre, as well as in micronutrients such as sodium and calcium was observed. Conversely, there was a significant decreased intake in overall energy, protein and fat (p < 0.005).

CONCLUSIONS

The significant nutritional impact of substituting animal-based proteins for PBA may present benefits for bone health and individuals on a caloric restriction diet. However, higher sodium levels may be undesirable for individuals with cardiovascular conditions and hypertension, and the low bioavailability of iron in plant-based sources may present issues for iron deficient populations. Bearing some of these key findings in mind, researchers and manufacturers need to consider these when developing alternative protein products to meet consumer demands for palatable and nutritious plant-based products.

Calcium supplementation in pregnancy: An analysis of potential determinants in an under-resourced setting

INTRODUCTION

Despite the evidence that calcium supplementation in pregnancy improves maternofoetal outcomes, many women still do not take calcium supplements during pregnancy in Cameroon. This study identifies factors that influence calcium supplementation during pregnancy in a low resource setting.

METHODS

We conducted a cross-sectional hospital-based study (from November 2020 to September 2021) targeting 1074 healthy women in late pregnancy at the maternities of four major health facilities in the Nkongsamba Health District, Cameroon. Data were collected using an interview-administered semi-structured questionnaire and analysed using Epi Info version 7.2.4.0, and the statistical threshold for significance set at p-value = 0.05.

RESULTS

The mean age of the participants was 28.20±6.08 years, with a range of 15-47 years. The proportion of women who reported taking any calcium supplements in pregnancy was 72.62 [69.85-75.22]%. Only 12% of calcium-supplemented women took calcium supplements throughout pregnancy, while a majority (50%) took calcium supplements just for 4-5 months. Women believe that taking calcium supplements is more for foetal growth and development (37.12%) and prevention of cramps (38.86%), than for the prevention of hypertensive diseases in pregnancy (2.84%). About all pregnant women (97.65%) took iron and folic acid supplements during pregnancy, and 99.24% took these supplements at least once every two days. Upon control for multiple confounders, the onset of antenatal care before 4 months of pregnancy (AOR = 2.64 [1.84-3.78], p-value = 0.000), having had more than 3 antenatal care visits (AOR = 6.01 [3.84-9.34], p-value = 0.000) and support/reminder from a partner on the necessity to take supplements in pregnancy (AOR = 2.00 [1.34-2.99], p-value = 0.001) were significantly associated with higher odds of taking any calcium supplements in pregnancy.

CONCLUSION

Calcium supplementation practices in pregnancy remain poor in this population and far from WHO recommendations. Early initiation of antenatal care, a high number of antenatal visits and reminders or support from the partner on supplement intake significantly increase the odds of taking any calcium supplements in pregnancy. In line with WHO recommendations, women of childbearing age should be sensitised to initiate antenatal care earlier and attain as many visits as possible. Male involvement in prenatal care might also boost the likelihood of these women taking calcium supplements.

The association between dietary mineral intake and the risk of preeclampsia in Chinese pregnant women: a matched case-control study

Previous studies on the relationship between dietary minerals and preeclampsia (PE) have given inconsistent results. The aim of this study was to further clarify the relationship between dietary minerals intake and PE in Chinese pregnant women. In this study, 440 pairs of hospital-based preeclamptic and healthy women were matched 1:1. Dietary intake was obtained through a 78-item semi-quantitative food frequency questionnaire. Multivariate conditional logistic regression was used to estimate the odds ratios (ORs) and 95% confidence intervals (CIs). Restricted cubic splines were plotted to evaluate the dose-response relationship between dietary minerals intake and PE. This study found significant inverse associations for dietary intake of calcium, magnesium, phosphorus, iron, copper, manganese and zinc and the risk of PE in both univariate and multivariate models (all P- trend < 0.05). After adjusting for possible confounders, compared with the lowest quartile, the odds ratio of the highest quartile was 0.74 (95% CI 0.56-0.98) for calcium, 0.63 (95% CI 0.42-0.93) for magnesium, 0.45 (95% CI 0.31-0.65) for phosphorus, 0.44 (95% CI 0.30-0.65) for iron, 0.72 (95% CI 0.53-0.97) for copper, 0.66 (95% CI 0.48-0.91) for manganese and 0.38 (95% CI 0.25-0.57) for zinc. In addition, a reverse J-shaped relationship between dietary minerals intake and PE risk was observed (P-overall association < 0.05). In Chinese pregnant women, a higher intake of dietary minerals, including calcium, magnesium, phosphorus, copper, iron, manganese, and zinc was associated with a lower odds of PE.

A comprehensive review on the impact of calcium and vitamin D insufficiency and allied metabolic disorders in females

Calcium is imperative in maintaining a quality life, particularly during later ages. Its deficiency results in a wide range of metabolic disorders such as dental changes, cataracts, alterations in brain function, and osteoporosis. These deficiencies are more pronounced in females due to increased calcium turnover throughout their life cycle, especially during pregnancy and lactation. Vitamin D perform a central role in the metabolism of calcium. Recent scientific interventions have linked calcium with an array of metabolic disorders in females including hypertension, obesity, premenstrual dysphoric disorder, polycystic ovary syndrome (PCOS), multiple sclerosis, and breast cancer. This review encompasses these female metabolic disorders with special reference to calcium and vitamin D deficiency. This review article aims to present and elaborate on available data regarding the worldwide occurrence of insufficient calcium consumption in females and allied health risks, to provide a basis for formulating strategies and population-level scientific studies to adequately boost calcium intake and position where required.

Including calcium-fortified water or flour in modeled diets based on local foods could improve calcium intake for women, adolescent girls, and young children in Bangladesh, Uganda, and Guatemala

Adequate calcium intake is essential for health, especially for infants, children, adolescents, and women, yet is difficult to achieve with local foods in many low- and middle-income countries. Previous analysis found it was not always possible to identify food-based recommendations (FBRs) that reached the calcium population recommended intake (PRI) for these groups in Bangladesh, Guatemala, and Uganda. We have modeled the potential contribution of calcium-fortified drinking water or wheat flour to FBR sets, to fill the remaining intake gaps. Optimized diets containing fortified products, with calcium-rich local foods, achieved the calcium PRI for all target groups. Combining fortified water or flour with FBRs met dietary intake targets for adolescent girls in all geographies and allowed a reduction from 3-4 to the more feasible 1-2 FBRs. Water with a calcium concentration of 100 mg/L with FBRs was sufficient to meet calcium targets in Uganda, but higher concentrations (400-500 mg/L) were mostly required in Guatemala and Bangladesh. Combining calcium-fortified wheat flour at 400 mg/100 g of flour and the FBR for small fish resulted in diets meeting the calcium PRI in Bangladesh. Calcium-fortified water or flour could improve calcium intake for vulnerable populations, especially when combined with FBRs based on locally available foods.

Could local foods achieve recommended calcium intakes for nutritionally vulnerable populations in Uganda, Guatemala, and Bangladesh?

Globally, dietary intake of calcium is often insufficient, and it is unclear if adequacy could be achieved by promoting calcium-rich local foods. This study used linear programming and household consumption data from Uganda, Bangladesh, and Guatemala to assess whether local foods could meet calcium population reference intakes (Ca PRIs). The most promising food-based approaches to promote dietary calcium adequacy were identified for 12- to 23-month-old breastfed children, 4- to 6-year-old children, 10- to 14-year-old girls, and nonpregnant and nonbreastfeeding (NPNB) women of reproductive age living in two regions of each country. Calcium-optimized diets achieved 75-253% of the Ca PRI, depending on the population, and were <100% for 4- to 6-year-olds in one region of each country and 10- to 14-year-old girls in Sylhet, Bangladesh. The best food sources of calcium were green leafy vegetables and milk, across geographic locations, and species of small fish, nixtamalized (lime-treated) maize products, sesame seeds, and bean varieties, where consumed. Food-based recommendations (FBRs) achieving the minimum calcium threshold were identified for 12- to 23-month-olds and NPNB women across geographic locations, and for 4- to 6-year-olds and 10-to 14-year-old girls in Uganda. However, for 4- to 6-year-olds and 10- to 14-year-old girls in Bangladesh and Guatemala, calcium-adequate FBRs could not be identified, indicating a need for alternative calcium sources or increased access to and consumption of local calcium-rich foods.

A Retrospective Cohort Study of the Association Between Calcium Serum Level and Hypertension in Older Adults

INTRODUCTION

 One of the major global risk factors for cardiovascular morbidity and death is hypertension. Earlier research has been conducted on the connection between calcium consumption and blood pressure.

OBJECTIVE

This study aims to investigate the association between calcium serum levels and hypertension in older hypertensive adults.

METHODS

 A retrospective cohort study of 121 of hypertension patients was conducted in Prince Faisal Bin Khalid Cardiac Center. The data of all patients were collected by records, including lab, pathology, and medical review, in order to determine the effects on patients, providers, and institutions. Statistical analyses were performed using SPSS Statistics version 26.0. A p-value of <0.05 was considered statistically significant.

RESULTS

 The study included 121 adult hypertensive patients with a mean of age 60.29 ± 13.92. The majority of included patients were male (81%). More than one-third of patients were obese (39.7%), about one-third (33.9%) were overweight, and 26.4% of patients were in normal weight. The majority of patients had co-morbidities (68.3%); about one-half of them had diabetes mellitus (52.1%). The calcium level mean was 5.07 ± 1.26. The creatine kinase (CK) (initial day) mean ± SD was 813.22 ± 1146.37 became 221.4 ± 330.67 on the last day. The CK-myocardial band (CK-MB) (initial day) was 65.43 ± 118.9 and became 24.38 ± 23.26 on the last day. Additionally, the troponin (initial day) mean was 23.49 ± 104.26 and became 1.65 ± 2.66 on the last day. The most common discharge medications were anti-platelets (95%), beta-blockers (78.5%), statins (70.2%), and proton-pump inhibitors (PPI) (64.5%). The hospital stay days ranged from 1 to 20 days with a mean of 4.83 ± 3.38. The ICU stay days ranged from 1 to 15 days with a mean of 3.57 ± 2.72. Most of the patients (90.9%) improved.

CONCLUSION

There is no significant correlation between calcium levels in hypertensive patients and the demographic characteristics of patients, home or current medications, ECHO findings, or procedures done. However, there is a significant correlation between the calcium level and CK level among patients with hypertension. Further investigations are required to verify the relationship between CK and calcium levels in hypertensive patients.

Comprehensive Review of Hypertensive Disorders Related to Pregnancy

Hypertensive disorder of pregnancy is a common complication during pregnancy that affects approximately 10% of pregnancies and is responsible for nearly 14% of maternal deaths worldwide. It affects the mother and the fetus simultaneously, sometimes putting the health of the mother and the fetus at odds with each other. It may present with only hypertension and proteinuria or with life-threatening complications in the mother such as eclampsia; stroke; acute pulmonary edema; acute renal failure; disseminated intravascular coagulation; placental abruption; hemolysis, elevated liver enzymes, and low platelet syndrome; pregnancy loss; and fetal growth restriction and prematurity resulting from the frequent need of delivering preterm in the fetus. In this review, we aimed to describe hypertensive disorders of pregnancy, mainly preeclampsia and chronic hypertension in pregnancy, by discussing the pathophysiology, the central role of abnormal placentation, the release of antiangiogenic factors in the circulation and immunological factors, the clinical outcome in the mother and the fetus, and the diagnostic criteria and principles of management of both the conditions. We also discuss possible screening methods and prevention of preeclampsia using low-dose aspirin and eclampsia prophylaxis.

Calcium supplementation to prevent pre-eclampsia: protocol for an individual participant data meta-analysis, network meta-analysis and health economic evaluation

INTRODUCTION

Low dietary calcium intake is a risk factor for pre-eclampsia, a major contributor to maternal and perinatal mortality and morbidity worldwide. Calcium supplementation can prevent pre-eclampsia in women with low dietary calcium. However, the optimal dose and timing of calcium supplementation are not known. We plan to undertake an individual participant data (IPD) meta-analysis of randomised trials to determine the effects of various calcium supplementation regimens in preventing pre-eclampsia and its complications and rank these by effectiveness. We also aim to evaluate the cost-effectiveness of calcium supplementation to prevent pre-eclampsia.

METHODS AND ANALYSIS

We will identify randomised trials on calcium supplementation before and during pregnancy by searching major electronic databases including Embase, CINAHL, MEDLINE, CENTRAL, PubMed, Scopus, AMED, LILACS, POPLINE, AIM, IMSEAR, ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform, without language restrictions, from inception to February 2022. Primary researchers of the identified trials will be invited to join the International Calcium in Pregnancy Collaborative Network and share their IPD. We will check each study's IPD for consistency with the original authors before standardising and harmonising the data. We will perform a series of one-stage and two-stage IPD random-effect meta-analyses to obtain the summary intervention effects on pre-eclampsia with 95% CIs and summary treatment-covariate interactions (maternal risk status, dietary intake, timing of intervention, daily dose of calcium prescribed and total intake of calcium). Heterogeneity will be summarised using tau2, I2 and 95% prediction intervals for effect in a new study. Sensitivity analysis to explore robustness of statistical and clinical assumptions will be carried out. Minor study effects (potential publication bias) will be investigated using funnel plots. A decision analytical model for use in low-income and middle-income countries will assess the cost-effectiveness of calcium supplementation to prevent pre-eclampsia.

ETHICS AND DISSEMINATION

No ethical approvals are required. We will store the data in a secure repository in an anonymised format. The results will be published in peer-reviewed journals.

PROSPERO REGISTRATION NUMBER

CRD42021231276.

Nutrient intakes of pregnant and lactating women in Indonesia and Malaysia: Systematic review and meta-analysis

Introduction

Optimizing dietary intake during pregnancy and lactation is crucial to the growth and development of children and their lifelong health. We performed a systematic review and meta-analysis to describe the nutrient intakes of pregnant and lactating women in Indonesia and Malaysia, countries that are experiencing rapid nutrition transition in Southeast Asia.

Methods

We screened 2,258 studies published between January 1980 and March 2021. The nutrient intakes of pregnant and lactating women were quantitatively analyzed to calculate the percentage of adequacy using national recommended daily allowances or nutrient intakes (RDA/RNI) and estimated average requirements (EAR) for micronutrients. Standardized mean differences (SMD) between dietary intake and RDA/RNI were determined for selected nutrients.

Results

Fifty-three studies were included and showed that energy and macronutrient intakes among pregnant and lactating women in both countries were below the RDA/RNI. In addition, most studies reported that women failed to meet the EAR for vitamin D (&lt;70% EAR), vitamin E (&lt;50% EAR), and water-soluble vitamins (&lt;80% EAR) except for vitamin C and A among Malaysians. Moreover, calcium, potassium, and iron intakes of pregnant women were &lt;60% EAR in Indonesia and &lt;80% EAR in Malaysia. Phosphorus intake among pregnant women in both countries and sodium intake among Malaysian pregnant women exceeded 100% EAR. Indonesian lactating women had &lt;60% EAR for calcium and potassium intakes, while Malaysian women had more than 100% EAR. For 21 studies reporting overall protein intakes, the standard mean difference (SMD) was −2.26 (95% CI; −2.98, −1.54) below the RDA/RNI for pregnant women and −0.67 SMD (95% CI −15.7, −11.5) for lactating women. When the four studies from Malaysia were analyzed separately, protein intakes of pregnant women were above the RNI. Moreover, low intakes of vitamin D, vitamin C, calcium, and iron, but sufficient intakes in vitamin A, zinc, and phosphorus were observed in pregnant women in both countries.

Conclusion

Dietary intakes of energy, macronutrients, and micronutrients (vitamin D, vitamin E, water-soluble vitamins, calcium, and iron) of pregnant and lactating women in Indonesia and Malaysia were below the recommendations. Important heterogeneities were observed even between these two countries for specific essential nutrient intakes. Innovative research and targeted programs to address specific deficiencies should be prioritized.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021252204, identifier: CRD42021252204.

Counseling pregnant women on calcium: effects on calcium intake

OBJECTIVES

To evaluate the effect of incorporating calcium advice into early pregnancy counseling on calcium intake during pregnancy in the Netherlands.

METHODS

A multicenter prospective before-after cohort study was conducted introducing risk-based care including calculating individual pre-eclampsia risk. Part of the intervention was to incorporate calcium advice into routine counseling. We calculated individual daily calcium intake and adequacy of calcium intake (≥1,000 mg/day) at 16, 24 and 34 weeks of pregnancy. We performed a multiple logistic regression adjusting for covariates to identify any differences in the risk of inadequate calcium intake between RC and CAC.

RESULTS

In regular care (RC, 2013-2015, n=2,477) 60% had inadequate calcium intake, compared to 49% during calcium advice care (CAC, 2017-2018, n=774) (aOR 0.75, 95% CI 0.64-0.88). Specific calcium supplements were used by 2% and 29% in RC and CAC, respectively (OR 25.1, 95% CI 17.8-36.0). Determinants of an inadequate calcium intake were lower age (aOR per additional year 0.96, 95% CI: 0.94-0.98), nulliparity (aOR 1.22, 95% CI: 1.03-1.45) and non-Caucasian origin (aOR 1.83, 95% CI 1.09-3.09). In CAC, risk of inadequate intake decreased with increasing predicted pre-eclampsia risk, which was a trend reversal compared to RC.

CONCLUSIONS

Incorporating calcium advice into early pregnancy counseling was shown to lead to a decrease in the risk of inadequate calcium intake during pregnancy, but still inadequate intake in half of the women suggesting the need for further study on improving implementation. Awareness of individual increased PE risk had positive effect on calcium intake.

Calculation of the contribution of water to calcium intake in low- and middle-income countries

Dietary calcium intake is low in many countries, particularly in low- and middle-income countries (LMICs). Water is often overlooked as a source of dietary calcium despite it being universally consumed and providing good calcium bioavailability. Our objective was to assess water distribution systems in LMICs and to develop a formula to simulate the contribution of different water sources to calcium availability. We calculated the contribution of drinking water considering different calcium concentration levels to estimate total calcium availability. We consider a country's households' access to drinking water sources and the distribution of the country's population by age and gender. Calcium availability could be increased by an average of 49 mg of calcium per person per day in the 62 countries assessed if calcium in drinking water was considered. In 22 (31%) of the countries studied, 80% of households are supplied by water sources that could increase calcium availability. Improving calcium concentration in water could be considered as a strategy in LMICs to slightly improve calcium availability.

Maternal diet, nutritional status and infant birth weight in Malaysia: a scoping review

BACKGROUND

Women's diet and nutritional status during pregnancy are important in influencing birth outcomes. We conducted a systematic scoping review of the best available evidence regarding dietary intake of Malaysian pregnant women, and the associations of maternal diet, anthropometry, and nutrition-related co-morbidities with the infant's birth weight (IBW). The study objectives were to examine: (1) the adequacy of micronutrient intake among pregnant women; and (2) the association of maternal factors (anthropometry, diet, plasma glucose and blood pressure) during pregnancy with IBW.

METHODS

Eleven search engines such as Proquest, EbscoHost, Scopus, Cochrane Library, Science Direct, Wiley Online Library, PubMed, Google Scholar, MyJournal, BookSC and Inter Library Loan with Medical Library Group were extensively searched to identify the primary articles. Three reviewers independently screened the abstracts and full articles based on the inclusion and exclusion criteria. Extracted data included details about the population characteristics, study methods and key findings related to the review objectives. Seventeen studies published from 1972 to 2021 were included, following the PRISMA-ScR guideline.

RESULTS

Studies showed that maternal micronutrient intakes including calcium, iron, vitamin D, folic acid, and niacin fell short of the national recommendations. Increased maternal fruit intake was also associated with increased birth weight. Factors associated with fetal macrosomia included high pre-pregnancy body mass index (BMI), excess gestational weight gain (GWG) and high blood glucose levels. Low pre-pregnancy BMI, inadequate GWG, intake of confectioneries and condiments, and high blood pressure were associated with low birth weight.

CONCLUSION

This review identified several factors such as the mother's food habits, comorbidities, BMI and gestational weight gain as the determinants of low birth weight. This implies that emphasis should be given on maternal health and nutrition for the birth outcome.

Fortification of staple foods with calcium: a novel costing tool to inform decision making

Low calcium intake and its impact on maternal and child health are a major concern in low- and middle-income countries. Given the low calcium in diet, as well as the low adherence and acceptability of calcium pills in those settings, the discussion about policies to increase calcium intake has moved toward staple food fortification strategies. Nevertheless, there is scarce information on the economic feasibility of implementing these strategies. We aimed to design and propose a novel costing tool to estimate the cost of the flour fortification with calcium by carrying out a literature review about costing studies for staple food fortification programs and costing tools previously developed. A deliberative meeting with stakeholders was held to discuss and face-validate the conceptual framework proposed. We showed the costing tool application for the case of Costa Rica (a country with a population with low calcium intake), including the absolute cost of the staple food fortification production process, the incremental cost of fortification according to the public/private sector, and the incremental cost by target population. This open-source and publicly available costing tool can be useful to inform policymaking in countries considering the implementation of staple food fortification programs.

Calcium deficiency worldwide: prevalence of inadequate intakes and associated health outcomes

Dietary calcium deficiency is considered to be widespread globally, with published estimates suggesting that approximately half of the world's population has inadequate access to dietary calcium. Calcium is essential for bone health, but inadequate intakes have also been linked to other health outcomes, including pregnancy complications, cancers, and cardiovascular disease. Populations in low- and middle-income countries (LMICs) are at greatest risk of low calcium intakes, although many individuals in high-income countries (HICs) also do not meet recommendations. Paradoxically, many LMICs with lower calcium intakes show lower rates of osteoporotic fracture as compared with HICs, though data are sparse. Calcium intake recommendations vary across agencies and may need to be customized based on other dietary factors, health-related behaviors, or the risk of calcium-related health outcomes. The lack of standard methods to assess the calcium status of an individual or population has challenged efforts to estimate the prevalence of calcium deficiency and the global burden of related adverse health consequences. This paper aims to consolidate available evidence related to the global prevalence of inadequate calcium intakes and associated health outcomes, with the goal of providing a foundation for developing policies and population-level interventions to safely improve calcium intake and status where necessary.

Testing for sensory threshold in drinking water with added calcium: a first step towards developing a calcium fortified water

Background: Food fortification is an effective strategy that has been recommended for improving population calcium inadequate intakes. Increasing calcium concentration of water has been proposed as a possible strategy to improve calcium intake. The objective of this study was to determine the sensory threshold of different calcium salts added to drinking water using survival analysis. Methods: We performed the triangle test methodology for samples of water with added calcium using three different calcium salts: calcium chloride, calcium gluconate and calcium lactate. For each salt, a panel of 54 consumers tested seven batches of three water samples. Data were adjusted for chance and sensory threshold was estimated using the survival methodology and a discrimination of 50%. Results: The threshold value estimation for calcium gluconate was 587 ± 131 mg/L of water, corresponding to 25% discrimination, for calcium lactate was 676 ± 186 mg/L, corresponding to 50% discrimination, and for calcium chloride was 291 ± 73 mg/L, corresponding to 50% discrimination. Conclusions: These results show that water with calcium added in different salts and up to a concentration of 500 mg of calcium/L of water is feasible. The calcium salt allowing the highest calcium concentration with the lowest perceived changes in taste was calcium gluconate. Future studies need to explore stability and acceptability over longer periods of time.

Calcium supplementation for the prevention of hypertensive disorders of pregnancy: current evidence and programmatic considerations

Most low‐ and middle‐income countries present suboptimal intakes of calcium during pregnancy and high rates of mortality due to maternal hypertensive disorders. Calcium supplementation during pregnancy is known to reduce the risk of these disorders and associated complications, including preeclampsia, maternal morbidity, and preterm birth, and is, therefore, a recommended intervention for pregnant women in populations with low dietary calcium intake (e.g., where ≥25% of individuals in the population have intakes less than 800 mg calcium/day). However, this intervention is not widely implemented in part due to cost and logistical issues related to the large dose and burdensome dosing schedule (three to four 500‐mg doses/day). WHO recommends 1.5–2 g/day but limited evidence suggests that less than 1 g/day may be sufficient and ongoing trials with low‐dose calcium supplementation (500 mg/day) may point a path toward simplifying supplementation regimens. Calcium carbonate is likely to be the most cost‐effective choice, and it is not necessary to counsel women to take calcium supplements separately from iron‐containing supplements. In populations at highest risk for preeclampsia, a combination of calcium supplementation and food‐based approaches, such as food fortification with calcium, may be required to improve calcium intakes before pregnancy and in early gestation.

Calcium and vitamin D supplementation: when and why

Osteoporosis is a common disease, with fragility fractures representing its dreaded complications. The role of calcium and vitamin D supplementation needs to be addressed in the context of a heavy health burden, with a massive impact on individuals, healthcare systems, and societies as a whole. Calcium and vitamin D are often discussed together as interventions for promoting bone health. Still, it is essential to remember that they are quite distinct entities that play different roles in mineral metabolism. Insufficient calcium intake and vitamin D deficiency are common and widespread. Furthermore, a strong association between vitamin D deficiency and extra-skeletal outcomes has emerged over the last decades. When dietary intake is insufficient, with little room for improvement, several supplementation strategies have proved to be effective and safe. Adequate calcium intake and vitamin D serum levels should be pursued efficiently in the general population, and deficiency should be considered unacceptable in subsets particularly at risk. The aim of this narrative review was to present an overview of calcium and vitamin D intake and their supplementation.

Calcium supplementation during pregnancy and maternal and offspring bone health: a systematic review and meta-analysis

Insufficient calcium intake during pregnancy may lead to maternal bone resorption and lower bone density of offspring. We evaluated the impact of supplementary calcium with or without vitamin D during pregnancy on maternal and offspring bone mineral density (BMD) and teeth firmness of the offspring. Randomized controlled trials (RCTs) were searched systematically in 11 databases. Two researchers independently screened the titles and abstracts of 3555 records and the full texts of 31 records to examine eligibility. The search yielded seven RCTs (11 reports, n = 1566).  No advantage of calcium supplementation was found on maternal BMD after delivery or during breastfeeding, or on offspring BMD, even when dietary calcium intake was low. The results were neither modified by the dose of calcium nor concomitant vitamin D administration. A suspicion of some long‐term harm of the intervention on maternal BMD and growth of female offspring was raised based on the data. One study suggested some benefit of high‐dose calcium supplementation on offspring teeth firmness at 12 years old. A low number of the studies and abundant missing data reduced the quality of the findings. The impact of calcium supplementation on maternal and offspring bone health was deemed unknown because of inconclusive research results.

[Synthesis of evidence and recommendations for the management of calcium supplementation before and during pregnancy for the prevention of preeclampsia and its complicationsSíntese de evidências e recomendações para o manejo da suplementação com cálcio antes e durante a gravidez para a prevenção da pré-eclâmpsia e de suas complicações]

Introducción.

La preeclampsia es una de las principales causas de morbimortalidad maternofetal en el mundo. La suplementación con calcio ha demostrado prevenir este trastorno y, por lo tanto, es importante contar con guías que emitan recomendaciones respecto de su uso.

Objetivos.

Sintetizar las recomendaciones relacionadas con la preeclampsia desarrolladas por la Organización Mundial de la Salud (OMS) con el fin de mejorar la calidad del cuidado y desenlaces en salud de las mujeres en edad reproductiva y embarazadas, y abordar aspectos sobre su implementación.

Métodos.

Las guías elaboradas por la OMS siguen los métodos de elaboración de las guías GRADE (Grading of Recommendations Assessment Development and Evaluation) del Manual para la elaboración de directrices de la OMS. Se llevó a cabo una síntesis de las recomendaciones de dos guías de la OMS. Además, se realizó una búsqueda sistemática en PubMed, Lilacs, Health Systems Evidence, Epistemonikos y literatura gris de estudios desarrollados en la Región de las Américas con el fin de identificar barreras, facilitadores y estrategias de implementación, así como determinar indicadores.

Resultados.

Se formularon dos recomendaciones relacionadas con preeclampsia, eclampsia y sus complicaciones para aplicar antes y durante el embarazo. Se identificaron barreras, facilitadores para la implementación y se crearon indicadores de adherencia y resultado.

Conclusiones.

Las recomendaciones formuladas buscan proveer orientación sobre cómo prevenir la preeclampsia a través del consumo de calcio con consideraciones para su implementación en América Latina y el Caribe.

Testing for sensory threshold in drinking water with added calcium: a first step towards developing a calcium fortified water

Background: Food fortification is an effective strategy that has been recommended for improving population calcium inadequate intakes. Increasing calcium concentration of water has been proposed as a possible strategy to improve calcium intake. The objective of this study was to determine the sensory threshold of different calcium salts added to drinking water using survival analysis. Methods: We performed the triangle test methodology for samples of water with added calcium using three different calcium salts: calcium chloride, calcium gluconate and calcium lactate. For each salt, a panel of 54 consumers tested seven batches of three water samples. Data were adjusted for chance and sensory threshold was estimated using the survival methodology and a discrimination of 50%. Results: The threshold value estimation for calcium gluconate was 587 ± 131 mg/L of water, corresponding to 25% discrimination, for calcium lactate was 676 ± 186 mg/L, corresponding to 50% discrimination, and for calcium chloride was 291 ± 73 mg/L, corresponding to 50% discrimination. Conclusions: These results show that water with calcium added in different salts and up to a concentration of 500 mg of calcium/L of water is feasible. The calcium salt allowing the highest calcium concentration with the lowest perceived changes in taste was calcium gluconate. Future studies need to explore stability and acceptability over longer periods of time.

Parathyroid hormone in Sri Lankan pregnant women: Vitamin D and other determinants

Introduction

Determinants of parathyroid hormone level during pregnancy have been less frequently studied. We aimed to describe the serum parathyroid hormone (PTH) and its determinants in Sri Lankan pregnant women in a community setting.

Materials and methods

In this cross-sectional analysis, 390 pregnant mothers in their third trimester were enrolled from primary care centers of 15 health divisions in the Colombo District in Sri Lanka. Venous blood was analyzed for a total 25-hydroxyvitamin-D [25(OH)D], serum parathyroid hormone (PTH), serum calcium, and alkaline phosphatase. The bone quality was assessed in terms of speed of sound (SOS) using the quantitative ultrasound scan (QUS). Univariate and multivariate regression analysis was used to examine the determinants of PTH concentration in blood.

Results

Median serum 25(OH)D was 17.5ng/mL. Most (61.6%) were vitamin D deficient (<20ng/mL). Median PTH was 23.7pg/mL. Only 0.8% had hyperparathyroidism (PTH >65pg/mL). The correlation between 25(OH)D and PTH was weak but significant (r = -0.197; p<0.001). SOS Z-score was below the cut-off (≤−2) in fifty-six women (14.7%), and SOS did not relate significantly to PTH. In regression analysis, serum 25(OH)D, serum calcium, body mass index, educational level, and weeks of pregnancy were significant independent variables when adjusted. The model explained 16% of the variation in the PTH level.

Conclusions

A high prevalence of vitamin D deficiency was observed among Sri Lankan pregnant women in the present study. Serum 25(OH)D, calcium, weeks of pregnancy, and educational level were determinants of serum PTH.

The Effect of Calcium Supplementation on Body Weight Before and During Pregnancy in Women Enrolled in the WHO Calcium and Preeclampsia Trial

INTRODUCTION

Obesity is a major and challenging public health problem. The aim of this substudy is to evaluate the effect of calcium supplementation on body weight in women recruited in the Calcium and Preeclampsia trial.

METHODS

Women were recruited before pregnancy and randomized to receive a calcium supplement containing 500 mg of elemental calcium or placebo until 20 weeks' gestation; all women received 1.5 g from 20 weeks until delivery.

RESULTS

A total of 630 women conceived during the study, 322 allocated to calcium and 308 to placebo. Among these, 230 allocated to calcium and 227 allocated to placebo had information on body weight at baseline and at 8 weeks' gestation. During the study period, women allocated to calcium had a mean weight increase of 1.1 (SD ±5.5) kg, whereas those allocated to placebo had a mean increase of 1.5 (SD ±6.1) kg, a mean difference of 0.4 kg (95% -0.4 (-1.4 to 0.6); P = .408). Women classified as obese at the start of the trial had a lower body weight gain at 8 weeks' gestation (1.0 kg; 95% CI: -3.2 to 1.2; P = .330) and at 32 weeks' gestation (2.1 kg; 95% CI: 5.6-1.3; P = .225) if they received calcium as compared to placebo. However, none of these differences were statistically significant.

CONCLUSION

The smaller increase in body weight found in women supplemented with 500 mg elemental calcium daily is quantitatively consistent with previous studies. However, in this study, the difference was not statistically significant.

Maternal mortality reduction: a need to focus actions on the prevention of hypertensive disorders of pregnancy

Maternal mortality (MM) reflects one of the most striking global health inequalities. Global figures of MM fell significantly from 1990 to 2017. The reduction was largely due to a 70% fall in haemorrhages, and a limited (18.2%) improvement in hypertensive disorders of pregnancy (HDP). If this trend continues, by 2021 HDP will be the main cause of global MM.MM reductions due to haemorrhage is reassuring, however MM due to HDP show a more complex situation as early detection of HDP requires regular contact of pregnant women with the health system. In order to reduce MM due to HDP, population wide preventive actions such as low dose aspirin and adequate calcium intake are required, especially in areas where women have little contact with the health systems.Calcium supplementation for women with low calcium intake has reduced the risk of pre-eclampsia, with further reductions starting daily supplementation with 500 mg of calcium preconceptionally, however adherence to supplementation is limited.To reduce global inequities in calcium intake and consequently in the HDP, food fortification seem to be an attractive strategy to achieve an increase of calcium intake.

No effect of calcium and vitamin D intake on maternal blood pressure in a healthy pregnant population

OBJECTIVES

Clinical studies have reported an inverse relationship between calcium and vitamin D intake and hypertensive disorders of pregnancy (HDP). The aim of this study was to investigate if there was an association between calcium/vitamin D intake, and vitamin D (25OHD) status, and maternal blood pressure (BP), during pregnancy and at 5-year follow-up.

STUDY DESIGN

This was an observational study of 415 women who participated in the ROLO (Randomised cOntrolled trial of LOw glycaemic index diet for the prevention of recurrence of macrosomia) study. Maternal BP measurements were taken during each trimester and at 5-year follow-up. Calcium and vitamin D intake were determined at each trimester and 25OHD was measured in early and late pregnancy.

RESULTS

Over two-thirds of the cohort were vitamin D sufficient (25OHD > 30 nmol/L) and had adequate calcium intake (>750 mg/day). There was no correlation between calcium intake or vitamin D intake and maternal BP in trimester 1 to 3 or at 5-year follow-up. Vitamin D status at 13 weeks' gestation negatively correlated with mean arterial pressure in trimester 1 (r = -0.152, p = 0.044). There was no correlation however between 25OHD at 28 weeks' gestation and BP at 28 or 34 weeks' gestation or 25OHD and BP at 5-year follow-up.

CONCLUSIONS

In a healthy population of women with adequate calcium and vitamin D intake, no clinically significant correlation existed between calcium and vitamin D and maternal BP.

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).

Exploratory Efficacy of Calcium-Vitamin D Milk Fortification and Periodontal Therapy on Maternal Oral Health and Metabolic and Inflammatory Profile

In this 2 × 2 factorial, outcome-assessor blinded, feasibility randomised trial we explored the effect of a non-pharmaceutical multi-component intervention on periodontal health and metabolic and inflammatory profiles among pregnant women with periodontitis receiving prenatal care in a Brazilian public health centre. 69 pregnant women (gestational age ≤20 weeks, T0) were randomly allocated into four groups: (1) fortified sachet (vitamin D and calcium) and powdered milk plus periodontal therapy during pregnancy (early PT) (n = 17); (2) placebo sachet and powdered milk plus early PT (n = 15); (3) fortified sachet and powdered milk plus late PT (after delivery) (n = 19); (4) placebo sachet and powdered milk plus late PT (n = 18). Third trimester (T1) and 6-8 weeks postpartum (T2) exploratory outcomes included periodontal health (% sites with bleeding on probing (BOP)), glucose, insulin, C-Reactive Protein, serum calcium and vitamin D. The mean BOP was significantly reduced in the early PT groups, while BOP worsened in the late PT groups. No significant effect of fortification on BOP was observed. Changes in glucose levels and variation on birthweight did not differ among groups This feasibility trial provides preliminary evidence for estimating the minimum clinically important differences for selected maternal outcomes. A large-scale trial to evaluate the interventions' clinical benefits and cost-effectiveness is warranted.

Calcium-fortified foods in public health programs: considerations for implementation

Low calcium intake is common worldwide and can result in nutritional rickets in children and osteomalacia in adults. Calcium-fortified foods could improve calcium intake. However, there is limited calcium fortification experience, with technical and practical issues that may hamper its adoption. The objective of this landscape review is to summarize these issues to help policymakers guide the planning and design of calcium fortification as a public health strategy. One challenge is the low bioavailability of calcium salts (∼20-40%); thus, large amounts need to be added to food to have a meaningful impact. Solubility is important when fortifying liquids and acidic foods. Calcium salts could change the flavor, color, and appearance of the food and may account for 70-90% of the total fortification cost. Safety is key to avoid exceeding the recommended intake; so the amount of added calcium should be based on the target calcium intake and the gap between inadequate and adequate levels. Monitoring includes the quality of the fortified food and population calcium intake using dietary assessment methods. Calcium fortification should follow regulations, implemented in an intersectorial way, and be informed by the right to health and equity. This information may help guide and plan this public health strategy.

Effect of Calcium Fortified Foods on Health Outcomes: A Systematic Review and Meta-Analysis

Calcium supplementation and fortification are strategies widely used to prevent adverse outcome in population with low-calcium intake which is highly frequent in low-income settings. We aimed to determine the effectiveness and cost-effectiveness of calcium fortified foods on calcium intake and related health, or economic outcomes. We performed a systematic review and meta-analysis involving participants of any age or gender, drawn from the general population. We searched PubMed, Agricola, EMBASE, CINAHL, Global Health, EconLit, the FAO website and Google until June 2019, without language restrictions. Pair of reviewers independently selected, extracted data and assessed the risk of bias of included studies using Covidence software. Disagreements were resolved by consensus. We performed meta-analyses using RevMan 5.4 and subgroup analyses by study design, age group, and fortification levels. We included 20 studies of which 15 were randomized controlled trials (RCTs), three were non-randomised studies and two were economic evaluations. Most RCTs had high risk of bias on randomization or blinding. Most represented groups were women and children from 1 to 72 months, most common intervention vehicles were milk and bakery products with a fortification levels between 96 and 1200 mg per 100 g of food. Calcium intake increased in the intervention groups between 460 mg (children) and 1200 mg (postmenopausal women). Most marked effects were seen in children. Compared to controls, height increased 0.83 cm (95% CI 0.00; 1.65), plasma parathyroid hormone decreased -1.51 pmol/L, (-2.37; -0.65), urine:calcium creatinine ratio decreased -0.05, (-0.07; -0.03), femoral neck and hip bone mineral density increased 0.02 g/cm2 (0.01; 0.04) and 0.03 g/cm2 (0.00; 0.06), respectively. The largest cost savings (43%) reported from calcium fortification programs came from prevented hip fractures in older women from Germany. Our study highlights that calcium fortification leads to a higher calcium intake, small benefits in children's height and bone health and also important evidence gaps for other outcomes and populations that could be solved with high quality experimental or quasi-experimental studies in relevant groups, especially as some evidence of calcium supplementation show controversial results on the bone health benefit on older adults.

Calcium Consumption During Pregnancy: A Multicenter Study in a Middle-Income Country in Southeast Asia

Objective

To perform a cross-sectional observational study of calcium consumption among pregnant women from multicenter tertiary care hospitals in the middle-income country in Southeast Asia.

Study Design

A cross-sectional observational study.

Setting

The study was conducted in four geographical regions (northern, northeastern, southern, and central) of Thailand. Five participating hospitals consisted of one university hospital in each region and one additional tertiary care hospital in the central region.

Materials and Methods

A cross-sectional study was performed nationwide from 1st November 2017 to 31st January 2019. All singleton aged 19-40 years were included. Exclusion criteria were any conditions that influenced calcium-containing food consumption. Dietary intake self-records immediately after eating for two working days and one holiday were analyzed via INMUCAL-NV3.0 dietary program.

Results

The 1549 records were obtained. The mean age was 29 ± 5.7 years. Most participants were primigravida (48.6%). The average gestational age was 20.6 ± 8.8 weeks. Mean calcium consumption was 602.4 mg/day (95% CI; 589.2615.6 mg/day) mg/dL. Inadequate calcium consumption prevalence based on the Thai dietary reference intake (less than 800 mg/day) and US Institute of Medicine (less than 1000 mg/day) were 82.0% and 93.4%, respectively.

Conclusion

The mean calcium consumption among pregnant women in the middle-income country in Southeast Asia was 602.4 mg/day (95% CI 589.2-615.6 mg/day). Inadequate calcium consumption of Thai pregnant women prevalence was 82.0% and 93.4% according to Thai dietary reference intake in pregnancy and the US Institute of Medicine.

Impact of flour fortification with calcium on calcium intake: a simulation study in seven countries

Calcium intake is low in many countries, especially in low-income countries. Our objective was to perform a simulation exercise on the impact, effectiveness, and safety of a flour fortification strategy using the Intake Modelling, Assessment, and Planning Program. Modeling of calcium fortification scenarios was performed with available dietary intake databases from Argentina, Bangladesh, Italy, the Lao People's Democratic Republic (Lao PDR), Uganda, Zambia, and the United States. This theoretical exercise showed that simulating a fortification with 156 mg of calcium per 100 g of flour would decrease the prevalence of low calcium intake, and less than 2% of the individuals would exceed the recommended calcium upper limit (UL) in Argentina, Italy, Uganda, and Zambia. Bangladesh and the Lao PDR showed little impact, as flour intake is uncommon. By contrast, in the United States, this strategy would lead to some population groups exceeding the UL. This exercise should be replicated and adapted to each country, taking into account the updated prevalence of calcium inadequacy, flour consumption, and technical compatibility between calcium and the flour-type candidate for fortification. A fortification plan should consider the impact on all age groups to avoid the risk of exceeding the upper levels of calcium intake.

Current calcium fortification experiences: a review

Low dietary calcium is very common in many populations, contributing to nutritional rickets/osteomalacia in children/adults and increasing the risk of several health problems. Calcium is a nutrient of concern as the recommended nutrient requirements are difficult to meet in the absence of dairy products. The provision of culturally acceptable calcium-fortified foods may improve calcium intake when it is a feasible and cost-effective strategy in a particular setting. This landscape review was conducted in 2019 and describes current calcium fortification efforts and lessons learned from these experiences. Worldwide, the United Kingdom is the only country where calcium fortification of wheat flour is mandatory. It is estimated that this fortified staple ingredient contributes to 13-14% of calcium intake of the British population. Other items voluntary fortified with calcium include maize flour, rice, and water. Current calcium fortification programs may lack qualified personnel/training, clear guidelines on implementation, regulation, monitoring/evaluation, and functional indicators. Also, the cost of calcium premix is high and the target groups may be hard to reach. There is a lack of rigorous evaluation, particularly in settings with multiple micronutrient programs implemented simultaneously, with low quality of the evidence. Further research is needed to assess the impact of calcium fortification programs.

Hypocalcaemia and calcium intake in pregnancy: A research protocol for critical analysis of risk factors, maternofoetal outcomes and evaluation of diagnostic methods in a third-category health facility, Cameroon

INTRODUCTION

Hypocalcaemia in pregnancy remains a major health issue, particularly in the developing world where daily calcium intakes are suboptimal. This electrolyte imbalance can lead to severe maternofoetal and childhood consequences. Calcium supplementation, amongst others, contributes significantly to meeting calcium demands in pregnancy. With ionised calcaemia as the gold standard for diagnosis, total calcaemia and albumin-corrected calcaemia in other pathological states have been found to overestimate the burden of hypocalcaemia. The main objectives of this study are to describe the blood calcium level (total, albumin corrected, and ionised calcaemia) and associated maternofoetal outcomes while identifying determinants of calcium supplementation and ionised hypocalcaemia. This study will also evaluate the sensitivity and specificity of albumin corrected calcaemia as a diagnostic tool for hypocalcaemia (ionised calcaemia as the gold standard) among pregnant women in the Nkongsamba Regional Hospital, Cameroon.

METHODS

Our study will target a total of 1067 term pregnant women who shall be included consecutively into the study as they arrive the maternity of the Nkongsamba Regional Hospital for their last antenatal care visit. Data shall be collected using a semi-structured interview-administered questionnaire and blood samples collected for total plasma calcium, albumin and serum ionized calcium assays. Additional data will be collected at birth (maternal and foetal variables; foetal outcomes evaluated as secondary outcomes). Total calcaemia and albuminemia shall be measured by atomic absorption spectrophotometry, while ionised calcaemia will be measured by ion-selective electrode potentiometry(using MSLEA15-H electrolyte analyzer) per standard BIOLABO and MSLEA15 protocols, respectively. Data will be analysed using the statistical softwares epi-Info version 7.2.2.16 and STATA version 16.

EXPECTED RESEARCH OUTCOME

This study will present a more precise estimate of the burden of hypocalcaemia in late pregnancy as well as identify and analyse the different factors associated with calcium supplementation and ionised hypocalcaemia among term pregnant women in a developing world setting. Maternofoetal outcomes associated with hypocalcaemia will be determined as well as the sensitivity and specificity of total and albumin-corrected calcaemia in diagnosing hypocalcaemia. Our findings will contribute significantly to designing or strengthening interventions to control this electrolyte imbalance.

Sex-specific maternal calcium requirements for the prevention of nonalcoholic fatty liver disease by altering the intestinal microbiota and lipid metabolism in the high-fat-diet-fed offspring mice

The significance of maternal appropriate calcium intakes for energy metabolism in the offspring has been recognized. Nonalcoholic fatty liver disease (NAFLD) is considered as the hepatic manifestation of metabolic syndrome. So in this study, we proposed that there were long-term effects of maternal calcium status on the progress of NAFLD by altering the intestinal microbiota and lipid metabolism with attention to potential sex differences among the mouse offspring. Thirty-four-week female C57BL/6 J mice were subjected to obtain low, normal and high calcium reproductive diets throughout the gestation and lactation. After weaning, both the male and female mouse offspring were fed with the high-fat diet for 16 weeks, with the normal diet as control. Biochemical indicators in the plasma and hepatic tissue were measured using ELISA or enzymatic methods. The expression of lipid metabolism, inflammatory and fibrosis related genes was determined by RT-PCR. The intestinal microbiota was analyzed by 16S rRNA high-throughput sequencing. Maternal normal and low calcium intake could, respectively, inhibit the progress of high-fat diet induced NAFLD in the male and female mouse offspring, which was characterized by the least lipid droplets, inflammatory infiltration and fibrosis, the lowest concentrations of free fatty acids and triglyceridethe lowest expression of genes involving in de novo lipogenesis and the highest expression of genes related to lipid oxidation and  hydrolysis, inflammatory, and fibrosis. Pyrosequencing of 16S rRNA genes revealed that the male mouse offspring with maternal normal calcium intake and the female mouse offspring with maternal low calcium intake, after the high-fat diet feeding, had distinct intestinal microbiota, which was closer to thosein mice with the normal diet feeding. Analysis of the functional features for the different microbiota was compatible with the expression of genes associated with lipogenesis, lipid oxidation and hydrolysis. Thus, there is a sex-specific manner for maternal calcium requirement to inhibit the progress of offspring NAFLD, that might be less for the female offspring and more for the male offspring.

Effect of vitamin A, calcium and vitamin D fortification and supplementation on nutritional status of women: an overview of systematic reviews

BACKGROUND

Micronutrient deficiency affects the health and development of vulnerable population such as children and pregnant women. Measures such as fortification of food and supplementation have been implemented to prevent or control deficiencies related to micronutrients.

OBJECTIVE

To assess the effect of vitamin A, vitamin D, and calcium fortification and supplementation on nutritional status of women in reproductive age group. To assess the toxicities and adverse events related to intervention.

METHODOLOGY

Systematic reviews including RCTs on women of reproductive age group provided with vitamin A, vitamin D, and calcium supplementation or fortified food were included, to report all malnutrition-related outcomes due to deficiency of the abovementioned micronutrients. The Cochrane Database of Systematic Reviews, EPPI Centre, Campbell Collaboration, PubMed, Web of Science, and Scopus were searched electronically for English language publications, until 31 March 2018. Hand searching of the articles was done from the Journal of Food Science and Technology. Two independent reviewers selected the systematic reviews, extracted data, and assessed for the quality.

RESULTS

A total of 16 systematic reviews were included in narrative synthesis. Supplementation of vitamin A was reported to result in increased maternal serum retinol concentrations and increased breast milk retinol concentration. It reduced the risk of anemia (Hb < 11 g/dL) and reduced maternal clinical infection. Vitamin D supplementation increased 25-hydroxy vitamin D levels. There was insufficient evidence for the effect on bone mineral density and serum calcium levels. Calcium supplementation did not have any significant effect on body weight, weight gain, and body mass index of the participants.

CONCLUSION

This overview of systematic reviews reiterates the nutritional importance of vitamin A, vitamin D, and calcium supplementation for the reproductive age women. However, there was no empirical evidence available for fortification of food with vitamin A, vitamin D, and calcium and nutritional benefits of the same for reproductive age women, therefore thrusting upon the need of conducting future quality research, i.e., clinical trials and systematic reviews for food fortification.

SYSTEMATIC REVIEW REGISTRATION

A priori protocol for this overview of systematic reviews was registered in PROSPERO with registration number CRD42018089403 .

Contribution of calcium in drinking water from a South American country to dietary calcium intake

Objective

To describe the calcium concentration of tap and bottled waters from Argentina and to estimate the contribution of drinking water to calcium recommendations.

Results

Calcium concentrations provided by water authorities ranged from 6 to 105 mg/L. The mean calcium level of samples analysed at the Laboratorio de Ingeniería Sanitaria, National University of La Plata was 15.8 (SD ± 13.2) mg/L and at the Bone Biology Laboratory of the National University of Rosario was 13.1 (± 10.0) mg/L. Calcium values of samples from supply systems and private wells was similar. Most bottled waters had calcium levels well below 50 mg/L. The intake of one litre of drinking water from Argentina could represent in average between 1.2 and 8.0% of the calcium daily values for an adult.

Integrating Calcium Into Antenatal Iron-Folic Acid Supplementation in Ethiopia: Women's Experiences, Perceptions of Acceptability, and Strategies to Support Calcium Supplement Adherence

Recommendations for antenatal calcium supplementation to prevent preeclampsia could substantially reduce maternal mortality, but adherence to multiple daily doses may constrain effectiveness. World Health Organization guidelines recommend 3 daily calcium supplements (1.5-2 g/d), taken separately from 1 iron-folic acid (IFA) supplement; however, limited data suggest lower calcium doses may also be effective. We conducted mixed-methods household trials to identify strategies for supporting adherence and integrating calcium into antenatal IFA supplementation programming in Ethiopia. Participants were randomly assigned to 3 regimens varying in dose and timing and were later given a choice of regimens. Semistructured interviews conducted over 6 weeks explored acceptability, barriers, and facilitators and offered opportunities to choose calcium pill type. Interviews were transcribed, translated, and analyzed thematically. Calcium adherence was measured using medication event monitoring. All participants (N=48) agreed to try supplementation. Adherence barriers included forgetting to take pills when busy or travelling and perceived side effects. Midday doses were the most challenging because of farming, market, and social events; women avoided taking supplements in public due to fear of being perceived as HIV positive. Social support from families, visual reminders, and anticipated benefits motivated adherence. More participants (75%) selected chewable versus conventional supplements due to organoleptic properties, but this preference declined over time. Adherence rates did not substantially differ across regimens with 2 (81.1%), 3 (83.4%), or 4 (77.1%) pill-taking events. Women indicated that the 2-event regimen was more acceptable than 3- and 4-event regimens, but this acceptability was not associated with higher adherence. Consequently, mean daily calcium consumption (811.3 mg) was lower than for 3-event (1,251.1 mg) and 4-event (1,156.4 mg) regimens. Integrating calcium into antenatal IFA supplementation is acceptable to Ethiopian women, with a 3-event regimen yielding the highest consumption rates. Despite women experiencing challenges with midday dosing and stigma, using simple home-based strategies and being counseled on the purpose of supplementation were more effective than reducing dosage for mitigating barriers and improving adherence.

Impact of water fortification with calcium on calcium intake in different countries: a simulation study

Objective:

To simulate the impact – effectiveness and safety – of water fortification with different concentrations of Ca using the Intake Modelling, Assessment and Planning Program.

Design:

This is a secondary analysis of national or sub-national dietary intake databases.

Setting and Participants:

Uganda, Lao People’s Democratic Republic (PDR), Bangladesh, Zambia, Argentina, USA and Italy.

Results:

We found that for dietary databases assessed from low- and middle-income countries (LMIC), the strategy of fortifying water with 500 mg of Ca/l would decrease the prevalence of low Ca intake in all age groups. We also found that this strategy would be safe as no group would present a percentage of individuals exceeding the upper limit in >2 %, except women aged 19–31 years in Lao PDR, where 6·6 % of women in this group would exceed the upper limit of Ca intake. The same strategy would lead to some groups exceeding the upper limit in USA and Italy.

Conclusions:

We found that for most LMIC countries, water fortified with Ca could decrease the prevalence of Ca intake inadequacy without exceeding the upper levels of Ca intake.

Influence of breakfast and meal frequency in calcium intake among pregnant adolescents

Calcium is an essential micronutrient that plays a role in growing and pregnancy, and its necessity is increased during pregnancy in adolescence. Thus, the aim of the study is to describe the daily calcium intake and its associations with dietetic habits, sociodemographic data and perinatal outcomes among pregnant adolescents. A prospective cohort study was conducted among primiparous adolescents who started prenatal care before 20 weeks of gestation. Sociodemographic data, weight and height, 24‐h dietary recall (24hRec) and perinatal outcomes were collected over four meetings (three during pregnancy and one in puerperium). All 24hRecs were analysed by the Nutrition Data System for Research (NDSR)® programme, and descriptive analysis and univariate and multivariate logistic regression were done. A total of 150 pregnant adolescents were included, with a mean of daily calcium intake of 659.9 mg (50% of recommended intake). Adolescents who ate more than three meals per day (89.3%), and ate breakfast every day (69.3%), were shown to have higher daily calcium intake, odds ratio (OR CI 95%) of 3.4 (1.0, 11.0) and 16.8 (1.0, 302.1), respectively. No correlation was observed between calcium daily intake and sociodemographic data or perinatal outcomes. Dairy products were the foods that mostly contributed to achieving recommended daily calcium intake. In our cohort, pregnant adolescents had a low daily calcium intake. They should be advised to eat more than three meals per day, eat breakfast in particular, increase the consumption of calcium rich‐foods, such as dairy products and green leafy vegetables, and consider calcium supplementation.

Regulatory and Policy-Related Aspects of Calcium Fortification of Foods. Implications for Implementing National Strategies of Calcium Fortification

Daily calcium intake is well below current recommendations in most low- and middle-income countries (LMICs). Calcium intake is usually related to bone health, however an adequate calcium intake has also been shown to reduce hypertensive disorders of pregnancy, lower blood pressure and cholesterol values, and to prevent recurrent colorectal adenomas. Fortification of foods has been identified as a cost-effective strategy to overcome micronutrient gaps in public health. This review summarizes regulatory aspects of fortification of commonly consumed foods with micronutrients, with an emphasis on calcium. We selected a convenient sample of 15 countries from different WHO regions and described the regulatory framework related to calcium fortification of staple foods. We assessed the relevant policies in electronic databases including the WHO Global database on the Implementation of Nutrition Action (GINA) for fortification policies and the Global Fortification Data Exchange Database, a fortification database developed and maintained by Food Fortification Initiative (FFI), Global Alliance for Improved Nutrition (GAIN), Iodine Global Network (IGN), and Micronutrient Forum. Food fortification with micronutrients is widely used in many of the selected countries. Most countries had national legislation for the addition of micronutrients to staple foods, especially wheat flour. These national legislations, that includes regulations and standards, can provide the framework to consider the implementation of adding calcium to the fortification strategies, including the selection of the adequate food vehicle to reach the targeted population at risk safely. The strategy to include calcium in the fortification mix in fortified staple foods seems promising in these countries. However, potential undesired changes on the organoleptic characteristics of fortified foods and products thereof, and operational feasibility at the manufacturing site should be evaluated by the stakeholders during the planning stage. Codex Alimentarius standards should be considered by regulators in order to assure adherence to international standards. While the selected countries already have established national regulations and/or standards for fortification of key staple food vehicles, and there are experiences in the implementation of fortification of some staple foods, national food intake surveys can help plan, design, and modify existing fortification programs as well as monitor food and nutrient consumption to assess risk and benefits.

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.