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Nutrients Dec 2021This article reviews physicochemical aspects of calcium absorption from foods. Notable differences are observed between different food products in relation to calcium... (Review)
Review
This article reviews physicochemical aspects of calcium absorption from foods. Notable differences are observed between different food products in relation to calcium absorption, which range from <10% to >50% of calcium in the foods. These differences can be related to the interactions of calcium with other food components in the food matrix, which are affected by various factors, including fermentation, and how these are affected by the conditions encountered in the gastrointestinal tract. Calcium absorption in the intestine requires calcium to be in an ionized form. The low pH in the stomach is critical for solubilization and ionization of calcium salts present in foods, although calcium oxalate complexes remain insoluble and thus poorly absorbable. In addition, the rate of gastric transit can strongly affect fractional absorption of calcium and a phased release of calcium into the intestine, resulting in higher absorption levels. Dairy products are the main natural sources of dietary calcium in many diets worldwide, which is attributable to their ability to provide high levels of absorbable calcium in a single serving. For calcium from other food products, lower levels of absorbable calcium can limit contributions to bodily calcium requirements.
Topics: Calcium; Calcium, Dietary; Eating; Food; Food Analysis; Gastric Acid; Gastrointestinal Tract; Hydrogen-Ion Concentration; Intestinal Absorption; Ions; Nutritional Physiological Phenomena; Nutritional Requirements; Solubility
PubMed: 35011055
DOI: 10.3390/nu14010180 -
American Journal of Physiology. Renal... Mar 2019Dietary oxalate is plant-derived and may be a component of vegetables, nuts, fruits, and grains. In normal individuals, approximately half of urinary oxalate is derived... (Review)
Review
Dietary oxalate is plant-derived and may be a component of vegetables, nuts, fruits, and grains. In normal individuals, approximately half of urinary oxalate is derived from the diet and half from endogenous synthesis. The amount of oxalate excreted in urine plays an important role in calcium oxalate stone formation. Large epidemiological cohort studies have demonstrated that urinary oxalate excretion is a continuous variable when indexed to stone risk. Thus, individuals with oxalate excretions >25 mg/day may benefit from a reduction of urinary oxalate output. The 24-h urine assessment may miss periods of transient surges in urinary oxalate excretion, which may promote stone growth and is a limitation of this analysis. In this review we describe the impact of dietary oxalate and its contribution to stone growth. To limit calcium oxalate stone growth, we advocate that patients maintain appropriate hydration, avoid oxalate-rich foods, and consume an adequate amount of calcium.
Topics: Calcium; Calcium Oxalate; Calcium, Dietary; Diet; Humans; Kidney Calculi; Oxalates
PubMed: 30566003
DOI: 10.1152/ajprenal.00373.2018 -
Aging Clinical and Experimental Research Jan 2022Bone mineral mass, geometry and microstructure, hence determinants of fracture risk, result bone accrual during growth and bone loss later in life. Peak bone mass, which... (Review)
Review
Bone mineral mass, geometry and microstructure, hence determinants of fracture risk, result bone accrual during growth and bone loss later in life. Peak bone mass, which is reached by the end of the second decade of life, is mainly determined by genetic factors. Among other factors influencing bone capital, dietary intakes, particularly calcium and protein, play a significant role in peak bone mass attainment. Both nutrients are provided in dairy products, which accounts for 50-60% and 20-30% of the daily calcium and protein intakes, respectively. Children avoiding dairy products are at higher risk of fracture, as are adults or older individuals following a diet devoid of dairy products, like vegans. Various intervention trials have shown some beneficial effects of dairy products on bone capital accumulation during growth and on bone turnover in adults. In observational studies, dairy products intake, particularly the fermented ones, which also provide probiotics in addition to calcium, phosphorus and protein, appear to be associated with a lower risk of hip fracture.
Topics: Bone Density; Bone and Bones; Calcium, Dietary; Dairy Products; Humans; Osteoporosis
PubMed: 34494238
DOI: 10.1007/s40520-021-01970-4 -
Iranian Journal of Kidney Diseases Sep 2016Hypertension is the most important, modifiable risk factor for cardiovascular disease and mortality. High salt intake may predispose children to develop hypertension... (Review)
Review
Hypertension is the most important, modifiable risk factor for cardiovascular disease and mortality. High salt intake may predispose children to develop hypertension later. A modest reduction in population salt intake worldwide would result in a major improvement in public health. Regarding smoking as another risk factor, there are various strategies that can be used to promote smoking cessation. Physicians are in an excellent position to help their patients stop smoking. Targeted weight loss interventions in population subgroups might be more effective for the prevention of hypertension than a general-population approach. A diet rich in high-potassium fruit and vegetables is strongly recommended. Fresh products are best; normal potassium content is reduced when foods are canned or frozen. Calcium supplementation reduces blood pressure in hypertensive individuals during chronic nitric oxide synthase inhibition and high calcium diet enhances vasorelaxation in nitric oxide-deficient hypertension. Magnesium should be considered by anyone seeking to prevent or treat high blood pressure. The foundation for a healthy blood pressure consists of a healthy diet, adequate exercise, stress reduction, and sufficient amounts of potassium and magnesium, but further investigations are required before making definitive therapeutic recommendations on magnesium use. Alcohol usage is a more frequent contributor to hypertension than is generally appreciated. For hypertensive patients in whom stress appears to be an important issue, stress management should be considered as an intervention. Individualized cognitive behavioral interventions are more likely to be effective than single-component interventions.
Topics: Calcium, Dietary; Diet Therapy; Diet, Sodium-Restricted; Dietary Supplements; Exercise; Fruit; Humans; Hypertension; Life Style; Magnesium; Smoking; Smoking Cessation; Vegetables; Weight Loss
PubMed: 27721223
DOI: No ID Found -
The American Journal of Clinical... Jun 2017: Considerable attention has recently focused on dietary protein's role in the mature skeleton, prompted partly by an interest in nonpharmacologic approaches to maintain... (Meta-Analysis)
Meta-Analysis Review
: Considerable attention has recently focused on dietary protein's role in the mature skeleton, prompted partly by an interest in nonpharmacologic approaches to maintain skeletal health in adult life. The aim was to conduct a systematic review and meta-analysis evaluating the effects of dietary protein intake alone and with calcium with or without vitamin D (Ca±D) on bone health measures in adults. Searches across 5 databases were conducted through October 2016 including randomized controlled trials (RCTs) and prospective cohort studies examining ) the effects of "high versus low" protein intake or ) dietary protein's synergistic effect with Ca±D intake on bone health outcomes. Two investigators independently conducted abstract and full-text screenings, data extractions, and risk of bias (ROB) assessments. Strength of evidence was rated by group consensus. Random-effects meta-analyses for outcomes with ≥4 RCTs were performed. Sixteen RCTs and 20 prospective cohort studies were included in the systematic review. Overall ROB was medium. Moderate evidence suggested that higher protein intake may have a protective effect on lumbar spine (LS) bone mineral density (BMD) compared with lower protein intake (net percentage change: 0.52%; 95% CI: 0.06%, 0.97%, : 0%; = 5) but no effect on total hip (TH), femoral neck (FN), or total body BMD or bone biomarkers. Limited evidence did not support an effect of protein with Ca±D on LS BMD, TH BMD, or forearm fractures; there was insufficient evidence for FN BMD and overall fractures. Current evidence shows no adverse effects of higher protein intakes. Although there were positive trends on BMD at most bone sites, only the LS showed moderate evidence to support benefits of higher protein intake. Studies were heterogeneous, and confounding could not be excluded. High-quality, long-term studies are needed to clarify dietary protein's role in bone health. This trial was registered at www.crd.york.ac.uk as CRD42015017751.
Topics: Bone Density; Bone Density Conservation Agents; Calcium; Calcium, Dietary; Dietary Proteins; Female; Fractures, Bone; Humans; Lumbar Vertebrae; Male; Osteoporosis; Vitamin D
PubMed: 28404575
DOI: 10.3945/ajcn.116.145110 -
Journal of Clinical Hypertension... Jun 2017Over the past decade, the number of individuals taking calcium supplementation worldwide has been on the rise, especially with the emergence of new pharmaceutical... (Review)
Review
Over the past decade, the number of individuals taking calcium supplementation worldwide has been on the rise, especially with the emergence of new pharmaceutical companies specialized in the marketing of dietary supplements; with calcium supplementation being their main business axis. This is mostly because of the established role of calcium in the prevention and treatment of osteoporosis and, to a lesser extent, its role in the prevention of fractures. Recently, a rising body of evidence on the adverse effect of calcium supplementation on nonskeletal, especially cardiovascular, health has been a cause for concern. In fact, a significant number of studies have reported an association between calcium supplementation and adverse cardiovascular events, even though high dietary calcium intake was shown to have a protective effect. The mechanism by which calcium supplementation could cause a cardiovascular event was still unclear until a recent study published in the Journal of the American Heart Association. Combining this recent finding with available data associating calcium supplementation with cardiovascular mortality and all-cause mortality, we call on the need for an evidence-based approach to calcium supplementation, while stressing on the safety of dietary calcium intake over the former on cardiovascular health.
Topics: Aged; Blood Pressure; Calcium; Calcium, Dietary; Cardiovascular Diseases; Dietary Supplements; Female; Fractures, Bone; Humans; Hypertension; Male; Middle Aged; Osteoporosis; Randomized Controlled Trials as Topic; Risk Factors
PubMed: 28466573
DOI: 10.1111/jch.13010 -
BMJ (Clinical Research Ed.) Sep 2015To examine the evidence underpinning recommendations to increase calcium intake through dietary sources or calcium supplements to prevent fractures. (Meta-Analysis)
Meta-Analysis Review
OBJECTIVE
To examine the evidence underpinning recommendations to increase calcium intake through dietary sources or calcium supplements to prevent fractures.
DESIGN
Systematic review of randomised controlled trials and observational studies of calcium intake with fracture as an endpoint. Results from trials were pooled with random effects meta-analyses.
DATA SOURCES
Ovid Medline, Embase, PubMed, and references from relevant systematic reviews. Initial searches undertaken in July 2013 and updated in September 2014.
ELIGIBILITY CRITERIA FOR SELECTING STUDIES
Randomised controlled trials or cohort studies of dietary calcium, milk or dairy intake, or calcium supplements (with or without vitamin D) with fracture as an outcome and participants aged >50.
RESULTS
There were only two eligible randomised controlled trials of dietary sources of calcium (n=262), but 50 reports from 44 cohort studies of relations between dietary calcium (n=37), milk (n=14), or dairy intake (n=8) and fracture outcomes. For dietary calcium, most studies reported no association between calcium intake and fracture (14/22 for total, 17/21 for hip, 7/8 for vertebral, and 5/7 for forearm fracture). For milk (25/28) and dairy intake (11/13), most studies also reported no associations. In 26 randomised controlled trials, calcium supplements reduced the risk of total fracture (20 studies, n=58,573; relative risk 0.89, 95% confidence interval 0.81 to 0.96) and vertebral fracture (12 studies, n=48,967. 0.86, 0.74 to 1.00) but not hip (13 studies, n=56,648; 0.95, 0.76 to 1.18) or forearm fracture (eight studies, n=51,775; 0.96, 0.85 to 1.09). Funnel plot inspection and Egger's regression suggested bias toward calcium supplements in the published data. In randomised controlled trials at lowest risk of bias (four studies, n=44,505), there was no effect on risk of fracture at any site. Results were similar for trials of calcium monotherapy and co-administered calcium and vitamin D. Only one trial in frail elderly women in residential care with low dietary calcium intake and vitamin D concentrations showed significant reductions in risk of fracture.
CONCLUSIONS
Dietary calcium intake is not associated with risk of fracture, and there is no clinical trial evidence that increasing calcium intake from dietary sources prevents fractures. Evidence that calcium supplements prevent fractures is weak and inconsistent.
Topics: Aged; Bone Density; Calcium, Dietary; Dietary Supplements; Fractures, Bone; Frail Elderly; Humans; Middle Aged; Randomized Controlled Trials as Topic
PubMed: 26420387
DOI: 10.1136/bmj.h4580 -
Nutrients Aug 2022Vitamin D is a critical regulator of calcium and bone homeostasis. While vitamin D has multiple effects on bone and calcium metabolism, the regulation of intestinal... (Review)
Review
Vitamin D is a critical regulator of calcium and bone homeostasis. While vitamin D has multiple effects on bone and calcium metabolism, the regulation of intestinal calcium (Ca) absorption efficiency is a critical function for vitamin D. This is necessary for optimal bone mineralization during growth, the protection of bone in adults, and the prevention of osteoporosis. Intestinal Ca absorption is regulated by 1,25 dihydroxyvitamin D (1,25(OH) D), a hormone that activates gene transcription following binding to the intestinal vitamin D receptor (VDR). When dietary Ca intake is low, Ca absorption follows a vitamin-D-regulated, saturable pathway, but when dietary Ca intake is high, Ca absorption is predominately through a paracellular diffusion pathway. Deletion of genes that mediate vitamin D action (i.e., VDR) or production (CYP27B1) eliminates basal Ca absorption and prevents the adaptation of mice to low-Ca diets. Various physiologic or disease states modify vitamin-D-regulated intestinal absorption of Ca (enhanced during late pregnancy, reduced due to menopause and aging).
Topics: Animals; Calcium; Calcium, Dietary; Female; Intestinal Absorption; Mice; Pregnancy; Receptors, Calcitriol; Vitamin D; Vitamins
PubMed: 36014856
DOI: 10.3390/nu14163351 -
Women's Health (London, England) Nov 2014Osteoporosis affects one out of three postmenopausal women. Their remaining lifetime risk of fragility fractures exceeds that of breast cancer. The risk of osteoporosis... (Review)
Review
Osteoporosis affects one out of three postmenopausal women. Their remaining lifetime risk of fragility fractures exceeds that of breast cancer. The risk of osteoporosis and/or fragility fractures can be reduced through healthy lifestyle changes. These include adequate dietary intakes of calcium, vitamin D and protein, regular weight-bearing exercise, reduction in alcohol intake and smoking cessation. European guidance for the diagnosis and management of osteoporosis in postmenopausal women recommends a daily intake of at least 1000 mg/day for calcium, 800 IU/day for vitamin D and 1 g/kg body weight of protein for all women aged over 50 years. The development of programs that encourage lifestyle changes (in particular balanced nutrient intakes) are therefore essential for the reduction of osteoporosis risk.
Topics: Aged; Bone Density; Calcium, Dietary; Diet; Female; Fractures, Bone; Humans; Middle Aged; Osteoporosis, Postmenopausal; Vitamin D Deficiency
PubMed: 25482487
DOI: 10.2217/whe.14.40 -
Annals of the New York Academy of... Jun 2022Dietary calcium deficiency is considered to be widespread globally, with published estimates suggesting that approximately half of the world's population has inadequate...
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.
Topics: Calcium; Calcium, Dietary; Female; Humans; Malnutrition; Outcome Assessment, Health Care; Pregnancy; Prevalence
PubMed: 35247225
DOI: 10.1111/nyas.14758