Adequate Ca Intake Research Articles

Combined effect of dietary calcium consumption and physical activity on dental caries in children and adolescents: a study of the NHANES database

BackgroundCalcium (Ca) is a nutritional factor that associated with dental caries. A recent study showed that in the case of adequate Ca intake, a higher level of physical activity may contribute to bone mass accumulation. However, the combined effect between Ca intake and physical activity on caries experience is unclear. Herein, we aimed to explore the above combined effect on dental caries in children and adolescents.MethodsData of 5,917 children and adolescents were extracted from the National Health and Nutrition Examination Surveys (NHANES) database in 2015–2020 in this cross-sectional study. The NHANES assessed the dietary Ca intake through the 24-hour dietary recalls, and the physical activity level was self-reported using the questionnaires. Also, the dental caries was diagnosed according to the Decayed, Missing and Filled Teeth/Surfaces (DMFT/S) index. Weighted univariate and multivariate logistic regression analyses were utilized to screen the covariates and to investigate the associations of dietary Ca intake and physical activity with dental caries, respectively, and assess the combined effect between dietary Ca intake and physical activity on dental caries. The evaluation indexes were odd ratios (ORs) and 95% confidence intervals (CIs). Subgroup analyses of age, obesity, and total sugar intake were also performed.ResultsAmong the eligible participants, 2,687 had caries experience. After adjusting for the covariates, we found that children and adolescents who not reach the recommendation level of Ca intake combined with physical activity less than 7 time in 1 week seemed to have higher odds of dental caries [OR = 1.77, 95%CI: (1.38–2.27)], compared with those who reached the standards. In addition, this potential combined effect was also found in age < 12 years old [OR = 1.62, 95%CI: (1.23–2.14)], non-obesity [OR = 1.88, 95%CI: (1.49–2.35)], and total sugar intake (all P < 0.05) subgroups.ConclusionsCa intake and physical activity had a potential combined effect on dental caries in children and adolescents, but the causal relationships between them needed further clarification.

Supplementing Low-Sodium Bicarbonate-Calcic (Lete)® Water: Effects in Women on Bone and Systemic Metabolism.

Calcium (Ca) represents about 40% of the total mineral mass, mainly in the bone, providing mechanical strength to the skeleton and teeth. An adequate Ca intake is necessary for bone growth and development in children and adolescents and for maintaining bone mineral loss in elderly age. Ca deficiency predisposes to osteopenia and osteoporosis. Healthy nutrition, including an adequate intake of Ca-rich food, is paramount to prevent and cure osteoporosis. Recently, several clinical studies have demonstrated that, in conditions of Ca dysmetabolism, Ca-rich mineral water is beneficial as a valuable source of Ca to be used as an alternative to caloric Ca-rich dairy products. Although promising, these data have been collected from small groups of participants. Moreover, they mainly regard the effect of Ca-rich mineral water on bone metabolism. In contrast, an investigation of the effect of Ca supplementation on systemic metabolism is needed to address the spreading of systemic metabolic dysfunction often associated with Ca dysmetabolism. In the present study, we analyzed urine and blood sera of 120 women in perimenopausal condition who were subjected for six months to 2l daily consumption of bicarbonate-calcium mineral water marketed under ®Lete. Remarkably, this water, in addition to being rich in calcium and bicarbonate, is also low in sodium. A complete set of laboratory tests was carried out to investigate whether the specific water composition was such to confirm the known therapeutic effects on bone metabolism. Second, but not least, urine and blood sera were analyzed using NMR-based metabolomic procedures to investigate, other than the action on Ca metabolism, potential system-wide metabolic effects. Our data show that Lete water is a valid supplement for compensating for Ca dysmetabolism and preserving bone health and integrity.

Dairy- and supplement-based calcium intake in adulthood and vertebral dimensions in midlife\u2014the Northern Finland Birth Cohort 1966 Study

SummaryAmong a representative sample of 1064 Northern Finns, we studied the association of dairy- and supplement-based calcium intake in adulthood with vertebral size in midlife. Inadequate calcium intake (< 800 mg/day) from age 31 to 46 predicted small vertebral size and thus decreased spinal resilience among women but not men.IntroductionSmall vertebral size predisposes individuals to fractures, which are common among aging populations. Although previous studies have associated calcium (Ca) intake with enhanced bone geometry in the appendicular skeleton, few reports have addressed the axial skeleton or the vertebrae in particular. We aimed to investigate the association of dairy- and supplement-based Ca intake in adulthood with vertebral cross-sectional area (CSA) in midlife.MethodsA sample of 1064 individuals from the Northern Finland Birth Cohort 1966 had undergone lumbar magnetic resonance imaging at the age of 46, and provided self-reported data on diet and Ca intake (dairy consumption and use of Ca supplements) at the ages of 31 and 46. We assessed the association between Ca intake (both continuous and categorized according to local recommended daily intake) and vertebral CSA, using generalized estimating equation and linear regression models with adjustments for body mass index, diet, vitamin D intake, education, leisure-time physical activity, and smoking.ResultsWomen with inadequate Ca intake (< 800 mg/day) over the follow-up had 3.8% smaller midlife vertebral CSA than women with adequate Ca intake (p = 0.009). Ca intake among men showed no association with vertebral CSA.ConclusionsInadequate Ca intake (< 800 mg/day) from the age of 31 to 46 predicts small vertebral size and thus decreased spinal resilience among middle-aged women. Future studies should confirm these findings and investigate the factors underlying the association of low Ca intake in women but not in men with smaller vertebral size.

Inverse association of calcium intake with abdominal adiposity and C-reactive protein in Brazilian children.

To evaluate Ca intake and its association with cardiometabolic risk factors during childhood. A cross-sectional study with a representative sample. Food consumption was assessed through three 24 h dietary recalls. Anthropometry, body composition and biochemical measurements were also conducted. Viçosa, Minas Gerais, Brazil. Children between 8 and 9 years old (n 350) enrolled in public and private schools in the urban area of the municipality of Viçosa. Almost all children had inadequate intake of Ca (97·4 %), especially those with low income, non-white and who studied in public schools. Foods that contributed most to Ca intake were 'milk' and 'cheeses and yoghurts' (R 2=0·66 and 0·13, respectively), and intake of 'milk' was correlated with 'chocolate milk powder' intake (r=0·538, P<0·01). Children with lower Ca intake had a higher prevalence of increased C-reactive protein (prevalence ratio=2·93; 95 % CI 1·21, 7·07), increased waist circumference (prevalence ratio=2·86; 95 % CI 1·01, 8·13) and a lower prevalence of high LDL cholesterol (prevalence ratio=0·64; 95 % CI 0·41, 0·99). Lower Ca intake was associated with excess abdominal adiposity and subclinical inflammation in Brazilian children. Monitoring of adequate Ca intake is important, especially in poorer communities.

Calcium intake below the recommended dietary allowance is associated with lower tibia bone mineral content and strength in young adults entering initial military training

BackgroundCalcium (Ca), a critical micronutrient for bone health, has been deemed a nutrient of public health concern due to consumption at levels below the recommended dietary allowance (RDA). Stress fracture risk is elevated during initial military training (IMT) and supplemental Ca during IMT reduces stress fracture incidence.ObjectiveTo assess dietary Ca in young adults entering IMT and to determine whether habitual Ca intake is associated with indices of bone health at the tibia, a commonly fractured site.MethodsA retrospective analysis was performed using baseline data from 3 randomized control trials that assessed the efficacy of Ca and vitamin D supplementation for optimizing bone health during IMT in Army, Air Force, and Marine recruits. Ca intake was estimated from a semi‐quantitative food frequency questionnaire and adequacy was based on the age‐specific RDAs. Bone health was evaluated by peripheral quantitative computed tomography (pQCT) of the tibia at the metaphysis and diaphysis. The associations between pQCT parameters and Ca intake adequacy were assessed by multivariate regression (SPSS, v21) controlling for age, sex, race, self‐reported physical activity, BMI, smoking, education level, and use of Depo Provera.ResultsOf the 399 study participants (n=223 females, n=180 males), 251 (62%) did not meet the RDA for Ca. Adequate Ca intake was positively associated with total bone mineral content (BMC; B=.091, p=.005) and strength (B=.084, p=.020) at the metaphysis. When participants were stratified by sex, 70% of females and 52% of the males did not meet the RDA. In the female cohort, adequate Ca intake was positively associated with BMC (B=.169, p=.011) and strength (B=.142, p=.033) at the metaphysis and cortical BMC (B=.134, p=.042) at the diaphysis. There were no associations in the male cohort.ConclusionAdequate Ca intake in young adults is positively associated with measures of tibia BMC and strength. As recruits with Ca intake below the RDA at the start of training may experience diminished bone health potentially leading to greater injury susceptibility, adequate Ca intake should be emphasized prior to initiating military training.Disclaimer: The views expressed in this abstract are those of the authors and do not reflect the official policy of the Department of Army, Department of Defense, or the U.S. Government.Support or Funding InformationResearch supported by USAMRMC, DHP, and in part by an appointment to the Postgraduate Research Participation Program administered by the Oak Ridge Institute for Science and Education.

Adequate calcium intake during long periods improves bone mineral density in healthy children. Data from the Childhood Obesity Project

Bone mineralization can be influenced by genetic factors, hormonal status, nutrition, physical activity and body composition. The association of higher calcium (Ca) intake or Ca supplementation with better bone mineral density (BMD) remains controversial. Furthermore, it has been speculated that maintaining long-term adequate Ca intake rather than having a brief supplementation period is more effective. The aim of the study was to prospectively analyse the influence of adequate Ca intake on BMD at 7 years of age in European children. Data from the Childhood Obesity Project were analysed in a prospective longitudinal cohort trial. Dietary intake was recorded using 3-day food records at 4, 5 and 6 years of age. The probability of adequate intake (PA) of Ca was calculated following the American Institute of Medicine guidelines for individual assessments, with FAO, WHO and United Nations University joint expert consultation dietary recommendations. Children were categorised as having high Ca PA (PA >95%) or not (PA <95%). At 7 years, whole body (WB) and lumbar spine (LS) BMD were measured in the Spanish subsample by dual-energy x-ray absorptiometry. Internal BMD z-scores were calculated; BMD below-1 z-score were considered to indicate osteopenia, and BMD z-scores below-2, "low bone mineral density for age". BMD was measured in 179 children. Ca intake at 6 years was positively correlated with LS BMD at 7 years (R=0.205, p=0.030). A Ca increase of 100mg/day explained 19.4% (p=0.011) of the LS BMD z-score variation, modifying it by 0.089 (0.021, 0.157) units. Children with Ca PA >95% at 5 and 6 or from 4 to 6 years of age showed higher BMD z-scores at the LS and WB levels than children with Ca PA <95% (p<0.001 and p<0.05 for LS and WB BMD, respectively). Ca PA >95% maintained over 2 years explained 26.3% of the LS BMD z-score variation (p<0.001), increasing it by 0.669 (0.202, 1.137). PA >95% maintained over 3 years explained 24.9% of the LS BMD z-score variation, increasing it by 0.773 (0.282, 1.264). The effects of Ca adequacy on WB BMD were similar. Children with PA >95% over 2 years had an Odds ratio of 13.84 and 12 for osteopenia at the LS and WB levels, respectively (p=0.001). Long periods of adequate Ca intake in childhood increase BMD and reduce osteopenia risk. The Childhood Obesity Project clinical trial (CHOP) was registered at clinicaltrials.gov as NCT00338689.

Association Between Phosphorus Intake and Bone Health in the NHANES Population

The objective of this study is to provide reliable estimates of independent associations between intakes of phosphorus (P) and bone mineral content (BMC) and bone mineral density (BMD), as well as the odds ratio (OR) of osteoporosis with quartiles of P intake adjusted for covariates. Data came from males and females aged 13‐99 years who participated in the 2005‐2010 NHANES dietary survey, which includes a representative sample of the non‐institutionalized population of the United States. Our analysis shows that higher calcium (Ca) intake levels are associated with higher P intake and that dietary Ca:P ratios (0.51‐0.62, with an adult population mean of 0.60) were adequate in all age/gender groups. We adjusted for age, gender, BMI, andintakes of calcium, protein, total dairy foods, and vitamin D. Flags were used to denote use of supplemental Ca, vitamin D, and multivitamins/minerals. High consumption of P was positively associated with BMC in female teens (Q4 vs. Q1: BMC, 30.9±1.09 vs. 29.0±0.49 g, P=0.001). High intake of dietary P was also positively associated with BMC and BMD and with reduced risk of osteoporosis in adults older than 20 years (Q4 vs. Q1: OR of osteoporosis, 0.55 [95% confidence interval, 0.39, 0.79] vs. 1.00, P=0.001; BMC, 37.5±0.39 vs. 36.70±0.11 g, P=0.004; BMD, 0.986±0.004 vs. 0.976±0.002 g/cm2, P=0.03). The data support our hypothesis that high P intake not only has no adverse effect on bone metabolism in populations with adequate Ca intake, but also is associated with improved bone parameters in some age/gender groups.

Association between phosphorus intake and bone health in the NHANES population.

The objective of this study was to estimate the independent associations between intake of phosphorus (P) and bone health parameters such as bone mineral content (BMC) and bone mineral density (BMD). It provides odds ratio (OR) of osteoporosis with quartiles of P intake adjusted for covariates (i.e., age, gender, BMI, and consumption of calcium (Ca), protein, total dairy foods, and vitamin D as well as intakes of supplemental Ca, vitamin D, and multivitamins/minerals). Data came from males and females aged 13–99 years who participated in the 2005–2010 National Health and Nutrition Examination Survey (NHANES). Analyses showed that higher P intake was associated with higher Ca intake, and that dietary Ca:P ratios (0.51-0.62, with a mean of 0.60 for adults) were adequate in all age/gender groups. High intake of P was positively associated with BMC in female teenagers (Q4 vs. Q1: BMC, 30.9 ± 1.1 vs. 29.0 ± 0.5 g, P = 0.001). It was also positively associated with BMC and BMD as well as reduced risk of osteoporosis in adults >20 years of age (Q4 vs. Q1: OR of osteoporosis, 0.55; 95% confidence interval [CI], 0.39- 0.79; P = 0.001; BMC, 37.5 ± 0.4 vs. 36.70 ± 0.3 g, P < 0.01; BMD, 0.986 ± 0.004 vs. 0.966 ± 0.005 g/cm2, P < 0.05). The data suggest that high intake of P has no adverse effect on bone metabolism in populations with adequate Ca intake, and that it is also associated with positive bone parameters in some age/gender groups.

Calcium supplementation and bone mineral accretion in Chinese adolescents aged 12-14 years: a 12-month, dose-response, randomised intervention trial.

A 12-month, dose-response, randomised, intervention trial was conducted to determine adequate Ca intake levels for Chinese adolescents by investigating the effect of Ca supplementation on bone mineral accretion. A total of 220 Han adolescents (111 girls and 109 boys) aged 12-14 years were recruited. All subjects were randomly divided into three groups. The bone mineral content (BMC) and bone mineral density (BMD) of the whole body, lumbar spine (L1-L4), left hip and femoral neck were measured by dual-energy X-ray absorptiometry. Girls in the high-Ca group (actual Ca intake: 1243 (sd 193)mg/d) exhibited greater increases in the femoral neck BMC compared with those in the low-Ca group (9·7 v. 6·4%, P=0·04) over the 1-year intervention period. The increases in femoral neck BMC were greater in boys in the high-Ca and medium-Ca groups (actual Ca intake: 985 (sd 168)mg/d) than in those in the low-Ca group (15·7 v. 11·7%, P=0·03; 15·8 v. 11·7%, P=0·03). Ca supplementation had significant effects on the whole-body BMC and BMD in subjects with physical activity levels>34·86 metabolic equivalents and on the spine BMD and BMC and BMD of most sites in subjects with Tanner stage<3. Increasing Ca intake levels with Ca supplementation enhanced femoral neck mineral acquisition in Chinese adolescents. Furthermore, high physical activity levels and low Tanner stage appeared to significantly contribute to the effect of Ca supplementation on bone mass. Whether this is a lasting beneficial effect leading to the optimisation of peak bone mass needs to be determined in other long-term prospective studies.

탈지분유 함유 식이를 섭취하는 흰쥐에서 칼슘과 비타민 D 수준이 무기질 대사에 미치는 영향

The purpose of this study was to investigate the effect of calcium (Ca) and vitamin D (vit. D) levels on metabolism of various minerals such as Ca, P, Mg, Fe, Zn, Cu, and Cr. The comparison was made on the rats that were placed on diet containing powdered skim milk with different Ca and vit. D levels for 5 weeks. A total of 42 5-week-old Sprague-Dawley rats were divided into 7 groups as follows: Control group consisted of normal Ca and normal vit. D (0.5% Ca, 1,000 IU vit. D); Experimental groups were divided into low (0.25%) and high (1.0%) calcium levels; and vit. D group was divided into low (10 IU), normal (1,000 IU), and high (5,000 IU) subgroups. The weight gain and food efficiency ratios of the rats were not significantly different with increasing dietary Ca levels. The absorption rates of 7 minerals (Ca, P, Mg, Fe, Zn, Cu, and Cr) were significantly decreased with increasing dietary Ca levels. Also, fecal excretion of P significantly increased with increasing dietary vit. D levels (p<0.05), and urine excretion of Fe was significantly increased with increasing dietary vit. D levels (p<0.001). The result indicated that higher Ca intake affected on bioavailability of other minerals, due to interactions among minerals in the process of intestinal absorption. However, vitamin D intake had no effect on bioavailability of several minerals. Therefore, it could be suggested that adequate Ca intake is important for balance of the minerals.

Peak bone strength is influenced by calcium intake in growing rats

In this study we investigated the effect of supplementing the diet of the growing male rat with different levels of calcium (from low to higher than recommended intakes at constant Ca/P ratio), on multiple factors (bone mass, strength, size, geometry, material properties, turnover) influencing bone strength during the bone accrual period. Rats, age 28days were supplemented for 4weeks with high Ca (1.2%), adequate Ca (0.5%) or low Ca level (0.2%). Bone metabolism and structural parameters were measured. No changes in body weight or food intake were observed among the groups. As anticipated, compared to the adequate Ca intake, low-Ca intake had a detrimental impact on bone growth (33.63 vs. 33.68mm), bone strength (−19.7% for failure load), bone architecture (−58% for BV/TV) and peak bone mass accrual (−29% for BMD) due to the hormonal disruption implied in Ca metabolism. In contrast, novel, surprising results were observed in that higher than adequate Ca intake resulted in improved peak bone strength (106 vs. 184N/mm for the stiffness and 61 vs. 89N for the failure load) and bone material properties (467 vs. 514mPa for tissue hardness) but these effects were not accompanied by changes in bone mass, size, microarchitecture or bone turnover. Hormonal factors, IGF-I and bone modeling were also evaluated. Compared to the adequate level of Ca, IGF-I level was significantly lower in the low-Ca intake group and significantly higher in the high-Ca intake group. No detrimental effects of high Ca were observed on bone modeling (assessed by histomorphometry and bone markers), at least in this short-term intervention. In conclusion, the decrease in failure load in the low calcium group can be explained by the change in bone geometry and bone mass parameters. Thus, improvements in mechanical properties can be explained by the improved quality of intrinsic bone tissue as shown by nanoindentation. These results suggest that supplemental Ca may be beneficial for the attainment of peak bone strength and that multiple factors linked to bone mass and strength should be taken into account when setting dietary levels of adequate mineral intake to support optimal peak bone mass acquisition.

Calcium and vitamin D intake maintained from preovariectomy independently affect calcium metabolism and bone properties in Sprague Dawley rats.

The interaction of habitual Ca and vitamin D intake from preovariectomy to 4months postovariectomy on bone and Ca metabolism was assessed. Higher Ca intake suppressed net bone turnover, and both nutrients independently benefitted trabecular structure. Habitual intake of adequate Ca and ~50nmol/L vitamin D status is most beneficial. Dietary strategies to benefit bone are typically tested prior to or after menopause but not through menopause transition. We investigated the interaction of Ca and vitamin D status on Ca absorption, bone remodeling, Ca kinetics, and bone strength as rats transitioned through estrogen deficiency. Sprague Dawley rats were randomized at 8weeks to 0.2 or 1.0% Ca and 50, 100, or 1,000IU (1.25, 2.5, or 25μg) vitamin D/kg diet (2 × 3 factorial design) and ovariectomized at 12weeks. Urinary (45)Ca excretion from deep-labeled bone was used to assess net bone turnover weekly. Ca kinetics was performed between 25 and 28weeks. Rats were killed at 29weeks. Femoral and tibiae structure (by μCT), dynamic histomorphometry, and bone Ca content were assessed. Mean 25(OH)D for rats on the 50, 100, 1,000IU vitamin D/kg diet were 32, 54, and 175nmol/L, respectively. Higher Ca intake ameliorated net bone turnover, reduced fractional Ca absorption and bone resorption, and increased net Ca absorption. Tibial and femoral trabecular structures were enhanced independently by higher Ca and vitamin D intake. Tibial bone width and fracture resistance were enhanced by higher vitamin D intake. Dynamic histomorphometry in the tibia was not affected by either nutrient. A Ca × vitamin D interaction existed in femur length, tibial Ca content, and mass of the soft tissue/extracellular fluid compartment. Adequate Ca intake and serum 25(OH)D level of 50nmol/L provided the most benefit for bone health, mostly through independent effects of Ca and vitamin D.

Effects of the amount and source of dietary protein on bone status in rats

This study examined the effects of the dietary amount and source of protein on bone status in rats. 140 male Wistar rats aged 8 weeks were randomly allocated to 4 groups (n = 35) fed normal-protein (NP, 10% richness) or high-protein (HP, 45% richness) diets based on whey protein (WP) or soy protein (SP) sources for 12 weeks. Plasma urea was 46% higher for the HP compared to the NP diet (p < 0.001). Urinary calcium was 65% higher for the HP compared to the NP and 60% higher for the WP compared to the SP diets (all, p < 0.001). Urinary pH was 8% more acidic in the HP compared to the NP diet (p < 0.001) and 4% in the WP compared to the SP diet (p < 0.01). The plasma osteocalcin concentration was 19% higher for the NP compared to the HP (p < 0.05) and 25% for the SP compared to the WP diets (p < 0.01). Femur ash, metaphyseal and diaphyseal cross-sectional, trabecular and cortical areas were 3% higher in the HP compared to the NP diet (all, p < 0.05). Femur diaphyseal periosteal and endocortical perimeters were also 3% higher in the HP compared to the NP diet (both, p < 0.01). Groups fed the SP diet showed 2% higher femur ash percentage, 7% higher calcium content (both, p < 0.001), and 3% higher diaphyseal cortical area and thickness (both, p < 0.05) than those fed the WP diet. Some interactions were found, such as the greater effects of the SP diet on decreasing the higher plasma urea concentration promoted by the intake of the HP diet (p < 0.001). Under adequate Ca intake, HP diets could better maintain bone properties than NP diets, even with increasing some acidity markers, which could be reduced by the intake of SP sources.

The Effects of Mg Supplementation in Diets with Different Calcium Levels on the Bone Status and Bone Metabolism in Growing Female Rats

Previous studies have revealed that magnesium (Mg) plays a significant role in bone health; however, few studies have investigated the effects of Mg supplementation in diets with different calcium (Ca) levels on the bone status and bone metabolism in a growing stage. In this present study, we tested the effects of Mg supplementation on bone status in growing female rats, relative to Ca intake levels. A total of 40 Sprague-Dawley female rats aged 6weeks were divided into the following four groups and fed for 12weeks as indicated: (1) LCaAMg: low Ca (Ca, 0.1% of total diet) and adequate Mg (Mg, 0.05% of total diet), (2) LCaHMg: low Ca and high Mg ( Mg, 0.1% of total diet), (3) ACaAMg: adequate Ca (Ca, 0.5% of total diet) and adequate Mg, and (4) ACaHMg: adequate Ca and high Mg. Our results showed that Mg supplementation with the adequate Ca diet significantly increased the bone mineral contents, bone size (bone area and bone thickness), and bone mineral density of femur or tibia by improving bone metabolism without changing Ca absorption. Mg supplementation significantly increased the serum osteocalcin in the adequate-Ca-diet group (p < 0.05), while the Mg supplementation significantly decreased the serum level of C-telopeptide cross-links of type I collagen in the adequate-Ca-diet group (p < 0.001). This study suggests that Mg supplementation with adequate Ca intake in the growing stage may increase the bone mineral density and bone size by improving bone metabolism.

Calcium from salmon and cod bone is well absorbed in young healthy men: a double-blinded randomised crossover design

BackgroundCalcium (Ca) - fortified foods are likely to play an important role in helping the consumer achieve an adequate Ca intake, especially for persons with a low intake of dairy products. Fish bones have a high Ca content, and huge quantities of this raw material are available as a by-product from the fish industry. Previously, emphasis has been on producing high quality products from fish by-products by use of bacterial proteases. However, documentation of the nutritional value of the enzymatically rinsed Ca-rich bone fraction remains unexplored. The objective of the present study was to assess the bioavailability of calcium in bones of Atlantic salmon (oily fish) and Atlantic cod (lean fish) in a double-blinded randomised crossover design.MethodsCa absorption was measured in 10 healthy young men using 47Ca whole body counting after ingestion of a test meal extrinsically labelled with the 47Ca isotope. The three test meals contained 800 mg of Ca from three different calcium sources: cod bones, salmon bones and control (CaCO3).ResultsMean Ca absorption (± SEE) from the three different Ca sources were 21.9 ± 1.7%, 22.5 ± 1.7% and 27.4 ± 1.8% for cod bones, salmon bones, and control (CaCO3), respectively.ConclusionWe conclude that bones from Atlantic salmon and Atlantic cod are suitable as natural Ca sources in e.g. functional foods or as supplements.

Low calcium:phosphorus ratio in habitual diets affects serum parathyroid hormone concentration and calcium metabolism in healthy women with adequate calcium intake

Excessive dietary P intake alone can be deleterious to bone through increased parathyroid hormone (PTH) secretion, but adverse effects on bone increase when dietary Ca intake is low. In many countries, P intake is abundant, whereas Ca intake fails to meet recommendations; an optimal dietary Ca:P ratio is therefore difficult to achieve. Our objective was to investigate how habitual dietary Ca:P ratio affects serum PTH (S-PTH) concentration and other Ca metabolism markers in a population with generally adequate Ca intake. In this cross-sectional analysis of 147 healthy women aged 31-43 years, fasting blood samples and three separate 24-h urinary samples were collected. Participants kept a 4-d food record and were divided into quartiles according to their dietary Ca:P ratios. The 1st quartile with Ca:P molar ratio < or = 0.50 differed significantly from the 2nd (Ca:P molar ratio 0.51-0.57), 3rd (Ca:P molar ratio 0.58-0.64) and 4th (Ca:P molar ratio > or = 0.65) quartiles by interfering with Ca metabolism. In the 1st quartile, mean S-PTH concentration (P = 0.021) and mean urinary Ca (U-Ca) excretion were higher (P = 0.051) than in all other quartiles. These findings suggest that in habitual diets low Ca:P ratios may interfere with homoeostasis of Ca metabolism and increase bone resorption, as indicated by higher S-PTH and U-Ca levels. Because low habitual dietary Ca:P ratios are common in Western diets, more attention should be focused on decreasing excessively high dietary P intake and increasing Ca intake to the recommended level.

Effects of different levels of calcium and phosphorus intake on calcium homeostasis in exercising horses

Increasing levels of dietary calcium (Ca) and phosphorous (P) might have a negative impact on parathyroid hormone (PTH) response and result in a more pronounced hypocalcaemia during high-speed exercise in horses. In successive order, five trained horses were fed 33 g Ca and 19 g P (approximately 100% NRC, adequate intake), 64 g Ca and 38 g P (moderately high intake) or 96 g Ca and 56 g P (high intake). Each horse was adapted to each diet over a 21 day period before undergoing a standardised exercise test (SET) on a treadmill. The SET comprised 5 steps (each step 4 min duration, 3% incline, first step 5 m/sec, followed by increments of 1 m/sec). Blood samples were taken at defined times. Blood lactate, plasma intact PTH (PTHi) and plasma inorganic P (Pi) increased during exercise (P<0.05), blood pH and blood ionised Ca2+ (Ca2+, adjusted to a pH of 7.4) declined during SETs (P<0.05) whereas total plasma Ca (CaT) and Mg (MgT) remained constant. The most exaggerated drop in Ca2+ and lactate peaks were found for the adequate Ca and P intake at 7, 8, and 9 m/sec during SET (treatment P<0.05). At 120 min after exercise, Ca2+ levels exceeded resting concentrations with higher Ca2+ values for the higher Ca intake (Ca2+: adequate 1.58 +/- 0.07 mmol/, moderately high 1.63 +/- 0.04 mmol/l, high 1.65 +/- 0.02 mmol/l, P<0.05). Concomitantly, 120 min after exercise, PTHi returned to basal concentrations with higher PTH concentrations for the adequate Ca intake than the other two treatments (PTHi: adequate 45.6 +/- 72.8 pg/ml, moderately high 11.6 +/- 13.6 pg/ml, high 2.6 +/- 2.3 pg/ml, P<0.05). During recovery (30 min, 120 min and 24 h after exercise) MgT concentrations were depressed (P<0.05) for the high Ca intake (P<0.05). These results suggest that high dietary Ca and P intake did not impair PTH responses during exercise and recovery, but might depress Mg metabolism. High Ca and P intake might have some potential to increase the availability of blood Ca2+ and Pi in the recovery phase after intensive exercise, but detrimental effects on Mg homeostasis might offset this potential benefit.

A Randomized Controlled Trial for the Primary Prevention of Osteoporosis Among Preadolescent Girl Scouts: 1-Year Outcomes of a Behavioral Program

To provide 1-year outcomes for a randomized controlled trial of a behavioral-educational intervention for the primary prevention of osteoporosis among 247 preadolescent girls. Girl Scout troops were randomly assigned to one of two intervention groups-a group comprising girls only (n = 73) and girls with their mothers (n = 94)-and a healthy-lifestyles control group (n = 80). Multilevel (hierarchical) models were employed to account for clustering of girls within troops. Among girls who met the recommended levels of Ca at baseline, those in the intervention were significantly more likely to maintain or improve their intake at follow-up compared to controls. No significant group differences were found for changes in WBPA. A behavioral intervention for the primary prevention of osteoporosis holds promise for maintaining adequate Ca intake among preadolescent females.

Positive effects of a chicken eggshell powder-enriched vitamin–mineral supplement on femoral neck bone mineral density in healthy late post-menopausal Dutch women

Although bone metabolism is largely under genetic control, the role of nutrition is considerable. The present study evaluates the effects of chicken eggshell powder, a new source of dietary Ca, and purified CaCO3 on bone mineral density (BMD) of the lumbar spine and hip. Besides BMD we also looked at biochemical markers of bone and Ca metabolism. Both Ca sources were provided in combination with minerals and vitamins including Mg, cholecalciferol and phylloquinone. We designed a randomised, double-blind, placebo-controlled study to take place over 12 months. Healthy Caucasian women (n 85), selected by age (≥50 and &lt;70 years), from the databases of general practitioners were recruited by telephone calls. They had to be at least 5 years post-menopausal, with lumbar spine T-score being &gt;-2·5. At baseline, their mean habitual daily Ca intake was adequate. The women were randomly allocated to: eggshell powder-enriched (group A; n 24), purified CaCO3-enriched (group B; n 22), or a placebo product (group C; n 27). BMD was measured at baseline and then after 6 and 12 months of supplementation as were the biochemical markers bone-specific alkaline phosphatase, amino-terminal propeptide extension of type I collagen, deoxypyridinoline, calcitonin, intact parathyroid hormone, calcidiol, and urinary Ca. After 12 months of supplementation, only mean BMD of the femoral neck in group A was significantly increased (P=0·014) by 1·75 % (95 % CI 0·18, 3·32) compared with a decrease of -0·60 % (95 % CI -1·92, 0·72) in group C. This increase coincided with significant decreases in markers of bone resorption and formation. No significant changes were seen in BMD at other sites, including lumbar spine, nor in groups B and C. No differences were found between groups A and B, or B and C. The present study indicates that healthy late post-menopausal women with an adequate Ca intake at baseline may increase BMD of the hip within 12 months following supplementation with the chicken eggshell powder-enriched supplement.

Parathyroid hormone is elevated but bone markers and density are normal in young female subjects who consume inadequate dietary calcium

Dietary Ca and osteocalcin (OC), parathyroid hormone (PTH), 25-hydroxyvitamin D (25-OH-D), insulin-like growth factor (IGF)-I and sex hormone binding globulin (SHBG) were assessed simultaneously to bone mineral density (BMD) in 200 adolescent girls (aged 11-15 years) and 100 young women (aged 20-23 years), selected from the lowest and highest end of the Ca intake distribution of a larger population sample. Ca intake was evaluated by food frequency questionnaires, BMD was measured by dual energy x-ray absorptiometry at ultradistal and proximal radius of non-dominant arm, bone age was estimated from x-rays of left hand and wrist according to Tanner et al. (1983). Surprisingly, mean Ca intakes were below the dietary reference intakes in the subgroups of girls and women with the highest measured Ca consumption. Postmenarcheal, but not premenarcheal girls showed radial densities as high as the women and in no group was BMD associated with Ca intake. In all adolescents serum PTH was negatively related to dietary Ca. In girls before menarche IGF-I was positively associated with bone age, while in the same subjects the negative relationship between SHBG and BMD pointed to the crucial role of bioavailable sex steroids on bone mass apposition in early puberty. OC levels decreased progressively with age, while serum 25-OH-D significantly increased after menarche. In conclusion, although in adolescents low Ca intake has not been shown to induce any immediate deleterious effect on radial density, the compensatory hypersecretion of PTH supports the need for an adequate Ca intake to achieve peak bone mass.