[Are there differences between men and women with respect to the factors associated with calcium intake?] / Existem diferenças entre homens e mulheres quanto aos fatores associados à ingestão de cálcio?

The scope of this article is to verify if there are differences in factors associated with calcium intake between men and women. It is based on a study conducted with data from a health survey in a sample of 1641 individuals aged 20 years or more living in the urban area of the city of Campinas, in the State of São Paulo. Calcium intake was obtained from a 24-hour recall (24hr recall method) and analyzed according to sociodemographic variables, health behavior, frequency of meals and body mass index (BMI). The existence of associations was verified by multiple linear regression tests, and it was detected that the profile of associated factors differed between genders. Physical exercise in the leisure context was only associated with calcium intake in males, while skin color, smoking, income, overweight/obesity, and frequency of having breakfast only revealed an association in females. Schooling and having snacks were associated with calcium intake in both sexes. The analysis of the associated factors indicates segments of the female and male population in which the importance of calcium intake needs to be more closely examined. Furthermore, it highlights the importance of conducting health analyses stratified by sex due to the different behavioral patterns that prevail between the sexes.

O objetivo do artigo é verificar se existem diferenças entre os sexos quanto aos fatores que se associam à ingestão de cálcio. Estudo realizado com dados de inquérito de saúde, em amostra de 1.640 indivíduos de 20 anos ou mais residentes no município de Campinas-SP. A ingestão de cálcio foi obtida por meio de um recordatório de 24 horas (R24h) e analisada segundo variáveis sociodemográficas, de comportamentos de saúde, frequência de refeições e índice de massa corporal (IMC); a presença de associações foi verificada por meio de testes de regressão linear múltipla. O perfil de fatores associados à ingestão de cálcio diferiu entre os sexos. A prática de atividade física no contexto de lazer só se associou ao consumo de cálcio no sexo masculino, enquanto cor da pele, tabagismo, renda, excesso de peso e frequência do café da manhã mostraram associação apenas no sexo feminino. Escolaridade e realização de lanches intermediários mostraram-se associadas à ingestão de cálcio em ambos os sexos. A análise aponta segmentos da população feminina e masculina em que a importância da ingestão de cálcio precisa ser mais enfatizada; além disso, alerta para a importância do desenvolvimento de análises de saúde estratificadas por sexo em decorrência de diferentes padrões comportamentais que prevalecem entre os sexos.

Global prevalence of diet low in calcium and the disease burden: results from the Global Burden of Disease Study 2019.

BACKGROUND: Due to the essential role of calcium in vital biological functions, diet low in calcium (DLC) is associated with various diseases. However, there is a lack of study about the current prevalence and health burden due to DLC using reliable data sources. METHODS: We used data from the Global Burden of Disease study 2019 (GBD 2019) to estimate the prevalence and health burden of DLC in 204 countries from 1990 to 2019, by age, sex, and sociodemographic index (SDI). The estimates were produced in DisMod-MR 2.1, a Bayesian meta-regression tool. Summary exposure value (SEV) was used to show the prevalence of DLC, while diseases adjusted life year (DALY) was used to represent the disease burden. The disease burden was estimated for DLC-induced colorectal cancer. Spearman Rank Order correlation was used for correlation analysis, and estimated annual percentage (EAPC) was used to reflect the temporal trends. RESULTS: From 1990 to 2019, the global prevalence of DLC decreased (EAPC of SEV, -0.47; 95% CI, -0.5 to -0.43), but have increased in Oceania region and in many countries, such as United Arab Emirates, New Zealand, Japan, and France. The global DALYs associated with low in calcium were estimated to be 3.14 million (95% uncertainty interval (UI), 2.25-4.26 million) in 2019, with an age standardized rate of 38.2 (95% UI, 27.2-51.8) per 100,000. Unlike the prevalence, the global age standardized DALY rates has remained unchanged (EAPC, -0.03; 95% CI, -0.12 to 0.07), but has increased in over 80 of the 204 countries, located mainly in Asia, Africa, and South America. In all years and regions, the age standardized SEV and DALY rates were higher in male people than that in female people. The prevalence (rho = -0.823; P < 0.001) and disease burden (rho = -0.433; P < 0.001) associated with diet in low calcium were strongly correlated to SDI. The prevalence decreased with age, but the DALY rates increased with age and peaked at about 90 years. The prevalence of DLC has decreased worldwide and in most countries, but the disease burden of DLC induced colorectal cancer has increased in over 40% of countries worldwide. CONCLUSION: Countries with low sociodemographic level and male people are more likely to experience the risk of DLC and related disease burden. Related measures in improve dietary calcium intake are in need to address diet in low calcium related health problems.

Calcium- and Sodium-Rich Food Intake among Koreans with and without Metabolic Syndrome: Cross-Sectional Analysis of the Korean Genome and Epidemiology Study.

BACKGROUND: The prevalence of metabolic syndrome (MetS) is increasing. While calcium and sodium are known nutritional factors used for managing MetS, few studies have focused on food-based analyses. This cross-sectional study examined the distribution of calcium- and sodium-rich food intake among Koreans with MetS. METHODS: This cross-sectional analysis evaluated 130,423 participants from the Health Examinees-Gem cohort study. Foods contributing up to 90% of the calcium and sodium intake were selected from the semi-quantitative food frequency questionnaire, and consumption levels were calculated. MetS was defined as satisfying three or more criteria from the National Cholesterol Education Program Adult Treatment Panel III. The results are presented as odds ratios (OR) with an interquartile range (ORIQR) and 95% confidence interval. RESULTS: Participants with MetS showed a low calcium intake (ORIQR = 0.95 and 0.92 for men and women, respectively), low consumption of dairy products (ORIQR = 0.92 and 0.89), beverages except for coffee or green tea (ORIQR = 0.97 and 0.96), and bread (ORIQR = 0.96 and 0.94). Men with MetS consumed high total sodium (ORIQR = 1.04), and large amounts of Kimchi (ORIQR = 1.03), fermented paste (ORIQR = 1.04), and noodles (ORIQR = 1.07). Women with MetS consumed more Kimchi than those without MetS (ORIQR = 1.04). The odds ratio for the low calcium and high sodium group compared to the high calcium and low sodium group was 1.26. CONCLUSION: The MetS group consumed less calcium-rich foods and more sodium-rich foods than those without MetS. Patients with MetS might benefit from precise recommendations of high calcium-rich and low sodium-rich foods.

Caffeine and Ovariectomy Debilitate Bone Health in Rats on Calcium-deficient Diet.

This study investigated the effects of ovariectomy and caffeine intake on bone health in rats on calcium-deficient diet. Forty adults female Wistar rats were divided into 4 groups in a 2x2 factorial design: Ovary (OVX/SHAM) and Caffeine (placebo/caffeine). The animals were housed in individual cages for 8 weeks, receiving 18-20g of AIN-93M diet per day, containing 50% of the daily recommended intake of calcium. The rats underwent ovariectomy (OVX) or laparotomy (SHAM) surgery. Caffeine groups received 6mg of caffeine/kg/day. After euthanasia, the tibia and femur were dissected to determine the calcium content and bone fracture strength, respectively. Blood sample was collected to determine serum Ostase. 24-hour urine was analyzed for excreted calcium and NTx. Reduced bone fracture strength and calcium content were observed in OVX and Caffeine groups. When observed separately, OVX group showed increased urinary NTx and lower bone weight, blood ostase, and urinary calcium. Caffeine groups showed elevated urinary calcium. There was a positive correlation between bone fracture strength and calcium content. NTx correlated negatively with bone calcium, fracture strength and thickness. In conclusion, both OVX and caffeine intake debilitate bone health in rats on calcium-deficient diet.

The Effects of Different Dietary Patterns on Bone Health.

Bone metabolism is a process in which osteoclasts continuously clear old bone and osteoblasts form osteoid and mineralization within basic multicellular units, which are in a dynamic balance. The process of bone metabolism is affected by many factors, including diet. Reasonable dietary patterns play a vital role in the prevention and treatment of bone-related diseases. In recent years, dietary patterns have changed dramatically. With the continuous improvement in the quality of life, high amounts of sugar, fat and protein have become a part of people's daily diets. However, people have gradually realized the importance of a healthy diet, intermittent fasting, calorie restriction, a vegetarian diet, and moderate exercise. Although these dietary patterns have traditionally been considered healthy, their true impact on bone health are still unclear. Studies have found that caloric restriction and a vegetarian diet can reduce bone mass, the negative impact of a high-sugar and high-fat dietary (HSFD) pattern on bone health is far greater than the positive impact of the mechanical load, and the relationship between a high-protein diet (HPD) and bone health remains controversial. Calcium, vitamin D, and dairy products play an important role in preventing bone loss. In this article, we further explore the relationship between different dietary patterns and bone health, and provide a reference for how to choose the appropriate dietary pattern in the future and for how to prevent bone loss caused by long-term poor dietary patterns in children, adolescents, and the elderly. In addition, this review provides dietary references for the clinical treatment of bone-related diseases and suggests that health policy makers should consider dietary measures to prevent and treat bone loss.

Prevalence of osteoporosis and associated factors among people aged 50 years and older in the Madhesh province of Nepal: a community-based cross-sectional study.

BACKGROUND: The high prevalence of osteoporosis has increased the economic burden on the health system globally. The burden of osteoporosis and its associated factors have not been adequately assessed in community settings in the Nepalese context thus far. Therefore, this study aimed to assess the prevalence of osteoporosis and its associated factors, lifestyle behaviors, and dietary calcium intake. METHODS: A community-based cross-sectional study was conducted among 395 people aged 50 years and older in the Madhesh Province of Nepal between July 2022 and August 2023. The Osteoporosis Self-assessment Tools for Asians (OSTA) index was used to measure osteoporosis. A structured questionnaire was used to collect sociodemographic information, anthropometric data, lifestyle behavior, daily dietary calcium intake, and frequency of calcium-rich food consumption. A food frequency questionnaire and 24-hour recall methods were used to assess dietary intake. The chi-square test, binary logistic regression and Mann‒Whitney U test were applied to measure the association between predictors and the outcome of interest. RESULTS: The prevalence of no risk, moderate risk and high risk of osteoporosis were 38.7%, 39%, and 22.3% respectively. The risk of osteoporosis was higher in females (aOR = 5.18, CI: 2.10-12.75, p < 0.001) and increased risk with advancing age (aOR = 32.49, CI: 14.02-75.28, p < 0.001). Similarly, underweight was associated with increased odds of having osteoporosis (aOR = 13.42, CI = 4.58-39.30, p < 0.001). The incidence of osteoporosis was strongly associated with daily calcium intake of 225 mg (100, 386). CONCLUSION: This study revealed a high prevalence of osteoporosis among people aged 50 years and older due to the combined effect of being underweight and having inadequate calcium intake. Nutritional counselling services encourage people to consume sufficient calcium-rich food and adopt an appropriate lifestyle behaviours to maintain healthy body weight so that osteoporosis and osteoporotic fractures could be prevented. Further research can explore the impact of socioeconomic status and medical comorbidities on a large scale.

The contribution of milk substitutes to the nutritional status of children with cow's milk allergy.

BACKGROUND: The impact of alternative milk substitutes on the nutritional status of children with cow's milk allergy (CMA), the prevailing cause of food allergies, is unresolved. METHODS: A cross-sectional study was performed in children older than 2 years with IgE-mediated CMA. Patients' clinical characteristics, anthropometric measurements, dietary intake (by 3-day food diary), and biochemical markers of nutritional status were assessed. RESULTS: One hundred two children with CMA (68.6% boys; median age, 3.7 years; 51% multiple food allergies) were evaluated. 44.1% of the children consumed plant-based beverages (PBB), 19.6% therapeutic formula and 36.3% did not consume any milk substitutes. In all age groups, dietary calcium, riboflavin, and vitamin D intake of those who did not use milk substitutes were lower than those who consumed formula or PBB (p < .01). Also in the 2-3 years old age group, dietary zinc (p = .011) and iron intake (p = .004) of the formula-fed group was higher. Formula-fed patients had higher levels of 25-OH vitamin D (µg/L) and serum vitamin B12 (ng/L) than PBB-fed patients (respectively; p < .001, p = .005) and those who did not consume any milk substitute (p < .001). Patients of all ages who did not utilize a milk substitute failed to obtain an adequate amount of dietary calcium. CONCLUSION: The use of milk substitutes positively affects dietary calcium, riboflavin, and vitamin D intake in CMA, but their contribution is variable. Those who do not use milk substitutes are at greater risk inadequate of dietary calcium intake. Personalized nutritional advice, given the clinical diversity and the impact of individual differences, is required.

Dietary calcium intake at breakfast is associated with a lower risk of cognitive impairment than at dinner in Chinese adults: the CHNS cohort study.

BACKGROUND AND OBJECTIVES: If the proportion of calcium intake over a whole day is related to the risk of cognitive impairment in adults is still largely unknown. This research aimed to examine the relation of dietary calcium intake at dinner versus breakfast with the risk of cognitive impairment by using data from the China Health and Nutrition Survey (CHNS). METHODS AND STUDY DESIGN: A total of 2,099 participants (including 668 cognitive impairment) in the CHNS (1997-2006) were included. The participants were categorized into 5 groups in accordance with the ratio of dietary calcium intake at dinner and breakfast (Δ = dinner/breakfast). After adjustment was conducted for a series of confounding factors, Cox hazard regression modelling was performed to discuss the relation of Δ with cognitive impairment. Dietary substitution models were used to explore the changes in cognitive impairment risk when a 5% dietary calcium intake at dinner was replaced with dietary calcium intake at breakfast. RESULTS: Participants in the highest distribution of Δ showed a greater susceptibility to cognitive impairment than those in the lowest quintile, with an adjusted hazard ratio of cognitive impairment of 1.38 (95% CI: 1.08-1.76). When maintaining total calcium intake, substituting 5% of dietary calcium intake at dinner with calcium intake at breakfast was related to an 8% decrease in the risk of cognitive impairment. CONCLUSIONS: Higher dietary calcium intake at dinner was associated with an increased risk of cognitive impairment, emphasizing the importance of appropriately distributing dietary calcium intake between breakfast and dinner.

Increased calcium intake from skimmed milk in energy-restricted diets reduces glycation markers in adults with type 2 diabetes and overweight: A secondary analysis of a randomized clinical trial.

The effect of calcium (Ca) on glycation markers is unknown. We hypothesized that increased Ca intake from skimmed milk associated with an energy-restricted diet intake will reduce glycation markers. This reduction will be associated with a greater improvement in markers of metabolic control in adults with type 2 diabetes, overweight, and low habitual Ca intake (<600 mg/d). In this secondary data analysis based on a crossover clinical trial, 14 adults were allocated into 2 groups: high calcium (shake containing 700 mg Ca/day) or low calcium (shake with 6.4 mg Ca/day), for 12 consecutive weeks per session. Energy-restricted diets were also prescribed (-500 kcal/d, 800 mg of dietary Ca/d) to all participants. Advanced glycation end products (AGEs), soluble receptor for AGEs (sRAGE), glycemic control, and lipid profile were assessed at baseline and after 12 weeks. High-calcium serum AGE concentrations and AGE/sRAGE ratio were lower at the end of the study. ΔAGE and ΔAGE/sRAGE ratio were both positively associated with Δtriglycerides, Δtotal cholesterol, Δtriglyceride-glucose index and variations, and Δvisceral adiposity index. ΔAGE/sRAGE was positively associated with Δfructosamine and Δhigh-density lipoprotein-cholesterol, and negatively associated with male sex. Consumption of approximately 1200 mg/day of calcium (3 servings of skim milk) reduced serum AGEs concentrations and the AGE/sRAGE ratio in individuals with diabetes. In general, positive changes in glycation markers are associated with lipid profile, insulin resistance, and adiposity markers worsening. ΔAGEs/ΔsRAGE ratio seems to be a better marker of metabolic status than ΔAGEs and ΔsRAGE alone. Registered in ClinicalTrials.gov (NCT02377076).

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.

A simulation study to improve calcium intake through wheat flour fortification.

OBJECTIVE: To simulate the impact on calcium intake - effectiveness and safety - of fortifying wheat flour with 200, 400 and 500 mg of calcium per 100 g of flour. DESIGN: Secondary analysis of cross-sectional data collected through repeated 24 h dietary recalls using the Iowa State University Intake Modelling, Assessment and Planning Program. SETTING: Urban cities in the National Health and Nutrition Survey of Argentina (ENNyS 2018-2019). PARTICIPANTS: 21 358 participants, including children, adolescents and adults. RESULTS: Most individuals in all age groups reported consuming wheat flour. The prevalence of low calcium intake was above 80 % in individuals older than 9 years. Simulating the fortification of 500 mg of calcium per 100 g of wheat flour showed that the prevalence of low calcium intake could be reduced by more than 40 percentage points in girls and women aged 19 to less than 51 years and boys and men aged 4 to less than 71 years, while it remained above 65 % in older ages. The percentages above the upper intake level remained below 1·5 % in all age groups. CONCLUSIONS: Calcium flour fortification could be further explored to improve calcium intake. Subnational simulations could be performed to identify groups that might not be reached by this strategy that could be explored in Argentina. This analysis could be used to advocate for a strategy to fortify wheat flour.

Nutrition, Vitamin D, and Calcium in Elderly Patients before and after a Hip Fracture and Their Impact on the Musculoskeletal System: A Narrative Review.

Hip fractures are a major health issue considerably impacting patients' quality of life and well-being. This is particularly evident in elderly subjects, in which the decline in bone and muscle mass coexists and predisposes individuals to fall and fracture. Among interventions to be implemented in hip fractured patients, the assessment and management of nutritional status is pivotal, particularly in subjects older than 65. Nutrition plays a central role in both primary and secondary preventions of fracture. An adequate protein intake improves muscle mass and strength and the intestinal absorption of calcium. Other nutrients with recognized beneficial effects on bone health are calcium, vitamins D, K, and C, potassium, magnesium, folate, and carotenoids. With reference to calcium, results from longitudinal studies showed that the consumption of dairy foods has a protective role against fractures. Moreover, the most recent systematic reviews and meta-analyses and one umbrella review demonstrated that the combination of calcium and vitamin D supplementation significantly reduces hip fracture risk, with presumed higher efficacy in older and institutionalized subjects. Owing to these reasons, the adequate intake of calcium, vitamin D, protein, and other macro and micronutrients has been successfully implemented in the Fracture Liaison Services (FLSs) that represent the most reliable model of management for hip fracture patients. In this narrative review, papers (randomized controlled trials, prospective and intervention studies, and systematic reviews) retrieved by records from three different databases (PubMed, Embase, and Medline) have been analyzed, and the available information on the screening, assessment, and management of nutritional and vitamin D status and calcium intake in patients with hip fractures is presented along with specific prevention and treatment measures.

National trends in nine key minerals intake (quantity and source) among U.S. adults, 1999 to march 2020.

BACKGROUND: Changes in economy and dietary guidelines brought a great shock to diet quality and meal behaviors, but if these transformations have extended to minerals intake and their sources was still poorly understood. It is essential to evaluate time trends in minerals intake and their sources to inform policy makers. OBJECTIVE: To investigate trends in minerals intake and their sources among U.S. adults. METHODS: This analysis used dietary data collected by 24-h recalls from U.S. adults (≥ 20 years) in NHANES (1999-March 2020). Minerals intake, age-adjusted percentage of participants meeting recommendations, and minerals sources were calculated among all participants and by population subgroups in each NHANES survey cycle. Weighted linear or logistic regression models were used to examine the statistical significance of time trends. RESULTS: A total of 48223 U.S. adults were included in this analysis. From 1999 to March 2020, intake of calcium (from 0.94 to 1.02 g/day), magnesium (from 308.07 to 321.85 mg/day), phosphorus (from 1.24 to 1.30 g/day), and sodium (from 3.24 to 3.26 mg/day) from food and beverages (FB) and dietary supplements (DSs) significantly increased, and intake of iron (from 19.17 to 16.38 mg/day), zinc (from 16.45 to 14.19 mg/day), copper (from 1.79 to 1.38 mg/day), and potassium (from 2.65 to 2.50 g/day) from FB + DSs decreased (all FDR < 0.05). Additionally, age-adjusted percentage of participants meeting recommendations for calcium, phosphorus, sodium, and selenium significantly increased, that for iron, potassium, zinc, and copper decreased (all FDR < 0.05). Minerals intake and time trends in minerals intake were highly variable depending on age, gender, race/ethnicity, education, and income. For example, white, higher socioeconomic status participants had a higher minerals intake (e.g. iron, zinc, and copper), but had a greater decrease in minerals intake. Furthermore, the percentage of minerals from milks and DSs decreased, and that from beverages increased. CONCLUSION: From 1999 to March 2020, both minerals intake and their sources experienced a significant alteration among U.S. adults. Many differences in minerals intake and their food sources across sociodemographic characteristics appeared to narrow over time. Although some improvements were observed, important challenges, such as overconsumption of sodium and underconsumption of potassium, calcium, and magnesium, still remained among U.S. adults.

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.

The Women's Health Initiative Randomized Trials and Clinical Practice: A Review.

Importance: Approximately 55 million people in the US and approximately 1.1 billion people worldwide are postmenopausal women. To inform clinical practice about the health effects of menopausal hormone therapy, calcium plus vitamin D supplementation, and a low-fat dietary pattern, the Women's Health Initiative (WHI) enrolled 161 808 postmenopausal US women (N = 68 132 in the clinical trials) aged 50 to 79 years at baseline from 1993 to 1998, and followed them up for up to 20 years. Observations: The WHI clinical trial results do not support hormone therapy with oral conjugated equine estrogens plus medroxyprogesterone acetate for postmenopausal women or conjugated equine estrogens alone for those with prior hysterectomy to prevent cardiovascular disease, dementia, or other chronic diseases. However, hormone therapy is effective for treating moderate to severe vasomotor and other menopausal symptoms. These benefits of hormone therapy in early menopause, combined with lower rates of adverse effects of hormone therapy in early compared with later menopause, support initiation of hormone therapy before age 60 years for women without contraindications to hormone therapy who have bothersome menopausal symptoms. The WHI results do not support routinely recommending calcium plus vitamin D supplementation for fracture prevention in all postmenopausal women. However, calcium and vitamin D are appropriate for women who do not meet national guidelines for recommended intakes of these nutrients through diet. A low-fat dietary pattern with increased fruit, vegetable, and grain consumption did not prevent the primary outcomes of breast or colorectal cancer but was associated with lower rates of the secondary outcome of breast cancer mortality during long-term follow-up. Conclusions and Relevance: For postmenopausal women, the WHI randomized clinical trials do not support menopausal hormone therapy to prevent cardiovascular disease or other chronic diseases. Menopausal hormone therapy is appropriate to treat bothersome vasomotor symptoms among women in early menopause, without contraindications, who are interested in taking hormone therapy. The WHI evidence does not support routine supplementation with calcium plus vitamin D for menopausal women to prevent fractures or a low-fat diet with increased fruits, vegetables, and grains to prevent breast or colorectal cancer. A potential role of a low-fat dietary pattern in reducing breast cancer mortality, a secondary outcome, warrants further study.

Home Meal Replacement Fortified with Eggshell Powder and Vitamin D Prevents Bone Loss in Postmenopausal Women: A Randomized, Double-Blind, Controlled Study.

Calcium and vitamin D deficiencies have been ongoing problems in Koreans due to a lack of food sources of calcium and vitamin D. Postmenopausal women aged 50 to 64 years (n = 25) were randomly assigned to consume three home meal replacements (HMRs)/week with (treatment) and without (control) eggshell powder and vitamin D for 6 months. Additionally, subjects who agreed to continue the study consumed the same three HMRs/week for an additional 6 months in this randomized double-blind study. We confirmed the high compliance of the study participants by analyzing carotenoids, the bioactive substances of HMRs, in the blood. The treatment group consumed an additional 261 mg/d of calcium and 10.3 µg/d of vitamin D from the HMRs, thus meeting the recommended intakes of calcium and vitamin D for Koreans. As a result of consuming fortified HMRs for 6 months, the decline in femoral neck bone density was significantly reduced in the treatment group (p = 0.035). This study indicates that inexpensive eggshell powder may be a good source of calcium for populations with low consumption of milk and dairy products. Additionally, functional HMRs fortified with eggshell powder and vitamin D can be a good dietary strategy for bone health.