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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 -
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 -
The American Journal of Clinical... May 2000The evidence that calcium plays a role in the etiology, prevention, and treatment of pregnancy-induced hypertension (PIH) is reviewed. The precise factors involved in... (Review)
Review
The evidence that calcium plays a role in the etiology, prevention, and treatment of pregnancy-induced hypertension (PIH) is reviewed. The precise factors involved in the pathogenesis of PIH are unclear, but several alterations in calcium metabolism have been identified. Epidemiologic data suggest an inverse correlation between dietary calcium intake and incidence of PIH. Although evidence suggests a possible beneficial effect of supplemental calcium, contradictions persist in clinical trials of pregnant women. Presently, there is insufficient evidence to support routine calcium supplementation of all pregnant women. However, high-risk groups, such as pregnant teens, populations with inadequate calcium intake, and women at risk of developing PIH, may benefit from consuming additional dietary calcium.
Topics: Calcium, Dietary; Dietary Supplements; Eclampsia; Female; Humans; Hypertension; Infant, Newborn; Pregnancy; Pregnancy Complications, Cardiovascular; Pregnancy Outcome
PubMed: 10799415
DOI: 10.1093/ajcn/71.5.1371s -
Nutrition in Clinical Practice :... Jun 2007Most Americans do not meet the adequate intake (AI) for calcium; calcium supplements can help meet requirements. Calcium supplementation has been found to be beneficial... (Review)
Review
Most Americans do not meet the adequate intake (AI) for calcium; calcium supplements can help meet requirements. Calcium supplementation has been found to be beneficial for bone health in children, young adults, and menopausal women. In addition to calcium, vitamin D is necessary for bone health and is generally deficient in the industrialized world. Calcium from carbonate and citrate are the most common forms of calcium supplements. Calcium carbonate, the most cost-effective form, should be taken with a meal to ensure optimal absorption. Calcium citrate can be taken without food and is the supplement of choice for individuals with achlorhydria or who are taking histamine-2 blockers or protein-pump inhibitors. Calcium lactate and calcium gluconate are less concentrated forms of calcium and are not practical oral supplements. Research on hydroxyapatite as a source of calcium is limited, so this form of calcium is not recommended. The maximum dose of elemental calcium that should be taken at a time is 500 mg. U.S. Pharmacopeia-verified calcium supplements meet vigorous manufacturing and quality requirements. Absorption from calcium-fortified beverages varies and in general is not equal to that of milk. Potential adverse effects of calcium supplementation include gastrointestinal complaints. Renal calculi in most studies have not been associated with calcium supplementation. The risk of advanced and fatal prostate cancer has been associated with calcium intakes from food or supplements in amounts >1500 mg/d.
Topics: Age Factors; Biological Availability; Bone Density Conservation Agents; Calcium; Calcium, Dietary; Dietary Supplements; Dose-Response Relationship, Drug; Food, Fortified; Humans; Intestinal Absorption; Nutrition Policy; Nutritional Requirements; Osteoporosis; Sex Factors
PubMed: 17507729
DOI: 10.1177/0115426507022003286 -
Nutrients Dec 2021Obesity is declared as a chronic multifaceted health problem, and young adults may be particularly vulnerable to weight gain. This study aims to identify the role of...
Obesity is declared as a chronic multifaceted health problem, and young adults may be particularly vulnerable to weight gain. This study aims to identify the role of dietary calcium intake and the muscle strength index in handling excess of fat mass in young adults and to examine if the relationship between dietary calcium intake and fat mass percentage is mediated by muscle strength. A cross-sectional study including 355 Spanish college students (aged 21.05 ± 3.11) was performed during the 2017-2018 academic year. Pearson correlation coefficients were estimated to determine the relationship between dietary calcium intake, fat mass percentage, body mass index, muscle strength components, and total energy intake. ANCOVA models were used to analyze the differences in the muscle strength index by total dietary calcium intake categories, as well as the differences in % fat mass by total dietary calcium intake and muscle strength index categories, controlling for different sets of confounders. A mediator analysis was conducted to test if the relationship between dietary calcium intake and fat mass percentage was explained by muscle strength. Data on the fat mass percentage, dietary calcium intake, and muscle strength index as the sum of the standardized z-score of the standing long jump and z-score of handgrip/weight were collected. The muscle strength index was significantly better in young adults with higher dietary calcium intake. Moreover, the fat mass percentage was significantly lower in those with a higher dietary calcium intake and a better muscle strength index. Finally, the relationship between dietary calcium intake and fat mass percentage was fully mediated by muscle strength (z = -1.90; < 0.05), explaining 33.33% of this relationship. This study suggests that both a major dietary calcium intake and muscle strength are associated with fat mass percentage. Moreover, muscle strength mediates the link between dietary calcium intake and fat mass percentage. Therefore, both high dietary calcium intake and exercise activities aimed at improving muscle strength levels may help to prevent the cardiometabolic risk associated with an excess of fat mass in young people.
Topics: Adipose Tissue; Analysis of Variance; Body Composition; Body Mass Index; Calcium, Dietary; Cross-Sectional Studies; Diet; Diet Surveys; Energy Intake; Female; Hand Strength; Humans; Male; Mediation Analysis; Muscle Strength; Nutritional Physiological Phenomena; Spain; Young Adult
PubMed: 34960051
DOI: 10.3390/nu13124498 -
Hypertension (Dallas, Tex. : 1979) Apr 1994More than 80 studies have reported lowered blood pressure after dietary calcium enrichment in experimental models of hypertension. The evidence presented here suggests... (Review)
Review
More than 80 studies have reported lowered blood pressure after dietary calcium enrichment in experimental models of hypertension. The evidence presented here suggests that dietary calcium may act concurrently through a number of physiological mechanisms to influence blood pressure. The importance of any given mechanism may vary depending on the experimental model under consideration. Supplemental dietary calcium is associated with reduced membrane permeability, increased Ca(2+)-ATPase and Na,K-ATPase, and reduced intracellular calcium. These results suggest that supplemental calcium may limit calcium influx into the cell and improve the ability of the VSMC to extrude calcium. This could be a direct effect of calcium on the VSMC or an indirect effect mediated hormonally. The calcium-regulating hormones have all been found to have vasoactive properties and therefore may influence blood pressure. Furthermore, CGRP and the proposed parathyroid hypertensive factor are both vasoactive substances that are responsive to dietary calcium. Therefore, diet-induced variations in calcium-regulating hormones may influence blood pressure. Modulation of the sympathetic nervous system is another important way that dietary calcium can influence blood pressure. There is evidence of altered norepinephrine levels in the hypothalamus as a consequence of manipulations of dietary calcium as well as changes in central sympathetic nervous system outflow. Dietary calcium has also been shown to specifically modify alpha 1-adrenergic receptor activity in the periphery. In some experimental models of hypertension, dietary calcium may alter blood pressure by changing the metabolism of other electrolytes. For example, the ability of calcium to prevent sodium chloride-induced elevations in blood pressure may be attributed to natriuresis. However, natriuresis does not account for all of the interactive effects of calcium and sodium chloride on blood pressure. Sodium chloride-induced hypertension may be due in part to calcium wasting and subsequent elevation of calcium-regulating hormones. Chloride is an important mediator of this effect because it appears that sodium does not cause calcium wasting when it is not combined with chloride. More attention to the central nervous system effects of dietary calcium is needed. Not only can calcium itself influence neural function, but many of the calcium-regulating hormones appear to affect the central nervous system. The influence of calcium and calcium-regulating hormones on central nervous system activity may have important implications for blood pressure regulation and also may extend to other aspects of physiology and behavior.
Topics: Animals; Blood Pressure; Calcium, Dietary; Disease Models, Animal; Humans; Hypertension; Rats
PubMed: 8144221
DOI: 10.1161/01.hyp.23.4.513 -
The American Journal of Clinical... Sep 1999To achieve adequate dietary calcium intake, several choices are available that accommodate a variety of lifestyles and tastes. Liberal consumption of dairy products in... (Review)
Review
To achieve adequate dietary calcium intake, several choices are available that accommodate a variety of lifestyles and tastes. Liberal consumption of dairy products in the diet is the approach of most Americans. Some plants provide absorbable calcium, but the quantity of vegetables required to reach sufficient calcium intake make an exclusively plant-based diet impractical for most individuals unless fortified foods or supplements are included. Also, dietary constituents that decrease calcium retention, such as salt, protein, and caffeine, can be high in the vegetarian diet. Although it is possible to obtain calcium balance from a plant-based diet in a Western lifestyle, it may be more convenient to achieve calcium balance by increasing calcium consumption than by limiting other dietary factors.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Biological Availability; Caffeine; Calcium, Dietary; Child; Child, Preschool; Diet, Vegetarian; Dietary Proteins; Female; Humans; Infant; Infant, Newborn; Middle Aged; Nutritional Requirements; Pregnancy; Sodium Chloride, Dietary
PubMed: 10479229
DOI: 10.1093/ajcn/70.3.543s -
Archives of Physiology and Biochemistry Aug 2022The antiobesity effect of dietary calcium by preventing fat accumulation and weight gain was well established from several epidemiological and animal studies.
CONTEXT
The antiobesity effect of dietary calcium by preventing fat accumulation and weight gain was well established from several epidemiological and animal studies.
OBJECTIVE
To evaluate the effect of dietary calcium against obesity-associated with renal injury in high fat diet induced obese rats. Materials and Methods: Obesity was induced by high fat diet (HFD) and then given either low or high calcium HFD (0.25% and 1.0%) for another 30 days.
RESULTS
The results showed that 1.0% high calcium group was effective in reducing renal lipogenesis activity, lipid accumulation, fatty acid synthase (FAS) activity, acetyl coenzyme A carboxylase (ACC) expression, oxidative stress, inflammation and increased the adenosine monophosphate kinase (AMPK) expression.
DISCUSSION AND CONCLUSION
Downregulation of renal lipid accumulation by high calcium diet through AMPK mediated lipogenesis activity, oxidative stress and the inflammatory response seemed to prevent the renal injury in high fat diet (HFD) induced obese rats.
Topics: AMP-Activated Protein Kinases; Animals; Calcium; Calcium, Dietary; Diet, High-Fat; Inflammation; Kidney; Lipid Metabolism; Lipids; Lipogenesis; Liver; Obesity; Oxidative Stress; Rats
PubMed: 32255372
DOI: 10.1080/13813455.2020.1746812 -
Ecology of Food and Nutrition 2021Calcium is a requisite nutrient in maintaining bone health. High calcium intake has been recommended for osteoporosis prevention. However, the relationship of dietary...
Calcium is a requisite nutrient in maintaining bone health. High calcium intake has been recommended for osteoporosis prevention. However, the relationship of dietary calcium intake with bone mineral density (BMD) in the elderly remained controversial. We aimd to evaluate the association between them in older adults. Using data from the Nutrition and Health Examination Survey (NHANES, 2001-2006), we conducted multivariate logistic regression analyses to explore the association of dietary calcium intake with lumbar BMD in older adults. Subgroup analyses were also performed. We included 2904 older adults aged ≥ 60 (43.63% men) for analysis. Higher dietary calcium intake was associated with greater lumbar BMD after adjusting for other covariates. In the subgroup analysis stratified by sex, this positive association existed in women, but not in men. In conclusion, for older adults aged ≥ 60, higher dietary calcium intake is associated with a higher lumbar BMD in women, but not in men.
Topics: Aged; Bone Density; Calcium, Dietary; Cross-Sectional Studies; Female; Humans; Male; Middle Aged; Nutrition Surveys; Sex Characteristics
PubMed: 32779476
DOI: 10.1080/03670244.2020.1801432 -
Journal of the American Dietetic... Mar 1989Calcium supplements have become big business in the United States. The sale of calcium supplements increased sevenfold from 1980 to 1985, with +130,000,000 being spent... (Review)
Review
Calcium supplements have become big business in the United States. The sale of calcium supplements increased sevenfold from 1980 to 1985, with +130,000,000 being spent on calcium supplements during 1985. The median daily dietary calcium intake for women in the United States is 574 mg and for men is 826 mg. The average American diet contains 389 mg calcium per 1,000 kcal. The Recommended Dietary Allowance (RDA) of 800 mg calcium may be insufficient to meet the needs of women who are "poor absorbers" of calcium. Research linking calcium intake with bone density is confounded by the type of bone measured, the variation in efficiency of calcium absorption among individuals, and the methodology for measuring calcium intake. Although calcium supplements will retard cortical bone loss in some postmenopausal women and are generally safe, they are not so effective as estrogen.
Topics: Adolescent; Adult; Aged; Bone Resorption; Bone and Bones; Calcium; Calcium, Dietary; Female; Humans; Male; Middle Aged; Nutritional Requirements; Osteoporosis
PubMed: 2646349
DOI: No ID Found