Benefits of milk powder supplementation on bone accretion in Chinese children

Association of dietary carbohydrate intake with bone mineral density, osteoporosis and fractures among adults without diabetes: Evidence from National Health and Nutrition Examination Survey

Background

The impact of dietary carbohydrate intake on bone health remains a subject of controversy, potentially influenced by individuals with diabetic osteoporosis who exhibit normal or elevated bone mineral density (BMD). The cross-sectional study was conducted to explore the association between carbohydrate intake and BMD, osteoporosis and fractures among adults without diabetes, based on the National health and nutrition examination survey (NHANES).

Methods

Participants were from the NHANES 2005-2010, excluding individuals with diabetes and those with incomplete data. The association between carbohydrate intake and BMD was analyzed using Spearman correlation, linear regression analysis and subgroup analysis, respectively. The association between carbohydrate intake and osteoporosis/fractures was analyzed using weighted logistic regression analysis.

Results

A total of 7275 adult participants were included and their dietary carbohydrate intake was inversely associated with BMD in the total femur [β = -0.20 95%CI (-0.30, -0.10); p < 0.001], femoral neck [β = -0.10 95%CI (-0.20, -0.00); p = 0.002], and lumbar spine [β = -0.10 95%CI (-0.20, -0.00); p = 0.004]. Stratified analysis indicated that individuals aged 65 and over, women, and non-Hispanic whites were more likely to have lower BMD. Furthermore, a higher intake of dietary carbohydrates was associated with an increased risk of osteoporosis [OR = 1.001 95%CI (1.001, 1.001); p < 0.001] and fractures at the hip [OR = 1.005 95%CI (1.005, 1.005); p < 0.001], wrist [OR = 1.001 95%CI (1.001, 1.001), p < 0.001], and spine [OR = 1.003 95%CI(1.003, 1.003); p < 0.001].

Conclusions

A higher carbohydrate diet is associated with lower BMD and a higher risk of osteoporosis and fractures among adults without diabetes, and a higher carbohydrate consumption show a stronger effect in individuals aged 65 and over, women, and non-Hispanic whites.

Impact of dairy supplementation on bone acquisition in children's limbs: a 12-month cluster-randomized controlled trial and meta-analysis

The impact of milk on bone health in rural preschoolers is under-researched. This study, through a clinical trial and a meta-analysis, finds that milk supplementation enhances forearm and calcaneus bone acquisition in children, supporting the benefits of daily milk consumption.

PURPOSE

This study evaluated the impact of dairy supplementation on bone acquisition in children's limbs through a cluster-randomized controlled trial and a meta-analysis.

METHODS

The trial involved 315 children (4-6 year) from Northwest China, randomized to receive either 390 ml of milk daily (n = 215) or 20-30 g of bread (n = 100) over 12 months. We primarily assessed bone mineral density (BMD) and content (BMC) changes at the limbs, alongside bone-related biomarkers, measured at baseline, the 6th and 12th months. The meta-analysis aggregated BMD or BMC changes in the forearm/legs/calcaneus from published randomized trials involving children aged 3-18 years supplemented with dairy foods (vs. control group).

RESULTS

Of 278 completed the trial, intention-to-treat analysis revealed significant increases in BMD (4.05% and 7.31%) and BMC (4.69% and 7.34%) in the left forearm at the 6th and 12th months in the milk group compared to controls (P < 0.001). The calcaneus showed notable improvements in BMD (2.01%) and BMC (1.87%) at 6 months but not at 12 months. Additionally, milk supplementation was associated with beneficial changes in bone resorption markers, parathyroid hormone (- 12.70%), insulin-like growth factor 1 (6.69%), and the calcium-to-phosphorus ratio (2.22%) (all P < 0.05). The meta-analysis, encompassing 894 children, indicated that dairy supplementation significantly increased BMD (SMD, 0.629; 95%CI: 0.275, 0.983) and BMC (SMD, 0.616; 95%CI: 0.380, 0.851) (P < 0.05) in the arms, but not in the legs (P > 0.05).

CONCLUSION

Milk supplementation significantly improves bone health in children's forearms, underscoring its potential as a strategic dietary intervention for bone development. Trial registration NCT05074836.

The Impact of Whole Egg Consumption on Bone Accrual in Healthy Children: A Randomized Controlled Trial

Dietary interventions designed to examine the role of nutrition on childhood bone accrual have often focused on the role of individual micronutrients (eg, calcium, vitamin D, and zinc) and macronutrients (eg, protein). The osteogenic benefits of whole foods, such as eggs, are not well understood despite eggs being a source of high-quality nutrients and bioactive compounds known to positively influence bone. A significant positive cross-sectional association between whole egg consumption and tibia cortical bone mass has recently been shown in young children; however, randomized controlled trials (RCTs) have not been conducted. This study is a double-blind RCT in male and female children ages 9-13 years of different ancestries, designed to determine if consuming food products with whole eggs (equivalent to 8-10 eggs/wk) versus foods with milk or gelatin (placebo) over a 9-month period will improve measures of bone strength. Total body less head (TBLH) and lumbar spine bone mineral content (BMC) and areal bone mineral density (aBMD) were assessed using dual-energy X-ray absorptiometry (DXA). DXA Z-scores were computed using published pediatric growth charts and were adjusted for height-for-age Z-score (HAZ). Mid-tibia cortical volumetric BMD, BMC, cortical area, total bone area, cortical thickness, and strength strain index were measured using peripheral quantitative computed tomography. Overall, there were no significant intervention effects for any bone outcomes. The increase in spine BMCHAZ Z-score in the egg group versus the gelatin group approached significance (p = 0.07). Significant time effects in TBLH aBMDHAZ Z-score occurred as all groups decreased over 9 months (p < 0.03). Most tibia cortical bone outcomes increased over time (all p < 0.02), but changes did not differ across intervention groups. Whole eggs provide important nutritional benefits for children, but the bone responses to consumption of 8-10 eggs/wk over a period of 9 months in children entering the early stages of puberty were small. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

The Effects of Dairy Product Supplementation on Bone Health Indices in Children Aged 3 to 18 Years: A Meta-Analysis of Randomized Controlled Trials

Childhood and adolescence are critical periods for optimizing skeletal growth. Dairy products are valuable sources of bone-beneficial nutrients, particularly calcium and protein. A random-effects meta-analysis of published randomized controlled trials was performed to quantitatively assess the effects of dairy supplementation on bone health indices in children and adolescents. The PubMed and Web of Science databases were searched. Dairy supplementation increased whole-body bone mineral content (BMC) (+25.37 g) and areal bone mineral density (aBMD) (+0.016 g/cm2), total hip BMC (+0.49 g) and aBMD (+0.013 g/cm2), femoral neck BMC (+0.06 g) and aBMD (+0.030 g/cm2), lumbar spine BMC (+0.85 g) and aBMD (+0.019 g/cm2), and height (0.21 cm). When expressed as a percentage difference, whole-body BMC was increased by 3.0%, total hip BMC by 3.3%, femoral neck BMC by 4.0%, lumbar spine BMC by 4.1%, whole-body aBMD by 1.8%, total hip aBMD by 1.2%, femoral neck aBMD by 1.5%, and lumbar spine aBMD by 2.6%. Dairy supplementation increased serum insulin-like growth factor I concentrations (19.89 nmol/L) and reduced concentrations of urinary deoxypyridinoline (-1.78 nmol/mmol creatinine) and serum parathyroid hormone (-10.46 pg/mL) but did not significantly affect the serum concentrations of osteocalcin, bone alkaline phosphatase, and C-terminal telopeptide of type 1 collagen. Serum 25-hydroxyvitamin D concentrations (+4.98 ng/mL) increased with vitamin D-fortified dairy supplementation. The positive effects on bone mineral mass parameters and height were generally consistent across subgroups defined by sex, geographical region, baseline calcium intake, calcium from the supplementation, trial duration, and Tanner stages. In summary, dairy supplementation during growth leads to a small but significant increase in bone mineral mass parameters, and these findings are generally supported by the changes in several biochemical parameters related to bone health.

Twelve weeks of a diet and exercise intervention alters the acute bone response to exercise in adolescent females with overweight/obesity

Introduction: Exercise and consumption of dairy foods have been shown to improve bone mineralization. However, little is known about the magnitude and timing of their synergistic effects on markers and regulators of bone metabolism in response to acute exercise in adolescent females with obesity, a population susceptible to altered bone metabolism and mineral properties. This study examined the influence of twelve weeks of exercise training and nutritional counselling on the bone biochemical marker response to acute exercise and whether higher dairy consumption could further influence the response. Methods: Thirty adolescent females (14.3 ± 2.0 years) with overweight/obesity (OW/OB) completed a 12-week lifestyle modification intervention involving exercise training and nutritional counselling. Participants were randomized into two groups: higher dairy intake (RDa; 4 servings/day; n = 14) or low dairy intake (LDa; 0-2 servings/d; n = 16). Participants performed one bout of plyometric exercise (5 circuits; 120 jumps) both pre- and post-intervention. Blood samples were taken at rest, 5 min and 1 h post-exercise. Serum sclerostin, osteocalcin (OC), osteoprotegerin (OPG), receptor activator nuclear factor kappa B ligand (RANKL), and C-terminal telopeptide of type 1 collagen (βCTX) concentrations were measured. Results: While there was an overall increase in sclerostin pre-intervention from pre to 5 min post-exercise (+11% p = 0.04), this response was significantly decreased post-intervention (-25%, p = 0.03) independent of dairy intake. The OPG:RANKL ratio was unresponsive to acute exercise pre-intervention but increased 1 h post-exercise (+2.6 AU; p < 0.001) post-intervention. Dairy intake did not further influence these absolute responses. However, after the 12-week intervention, the RDa group showed a decrease in the relative RANKL post-exercise response (-21.9%; p < 0.01), leading to a consistent increase in the relative OPG:RANKL ratio response, which was not the case in the LDa group. There was no influence of the intervention or dairy product intake on OC, OPG, or βCTX responses to acute exercise (p > 0.05). Conclusion: A lifestyle modification intervention involving exercise training blunts the increase in sclerostin and can augment the increase in OPG:RANKL ratio to acute exercise in adolescent females with OW/OB, while dairy product consumption did not further influence these responses.

The effect of calcium supplementation in people under 35 years old: A systematic review and meta-analysis of randomized controlled trials

Background:

The effect of calcium supplementation on bone mineral accretion in people under 35 years old is inconclusive. To comprehensively summarize the evidence for the effect of calcium supplementation on bone mineral accretion in young populations (≤35 years).

Methods:

This is a systematic review and meta-analysis. The Pubmed, Embase, ProQuest, CENTRAL, WHO Global Index Medicus, Clinical Trials.gov, WHO ICTRP, China National Knowledge Infrastructure (CNKI), and Wanfang Data databases were systematically searched from database inception to April 25, 2021. Randomized clinical trials assessing the effects of calcium supplementation on bone mineral density (BMD) or bone mineral content (BMC) in people under 35 years old.

Results:

This systematic review and meta-analysis identified 43 studies involving 7,382 subjects. Moderate certainty of evidence showed that calcium supplementation was associated with the accretion of BMD and BMC, especially on femoral neck (standardized mean difference [SMD] 0.627, 95% confidence interval [CI] 0.338–0.915; SMD 0.364, 95% CI 0.134–0.595; respectively) and total body (SMD 0.330, 95% CI 0.163–0.496; SMD 0.149, 95% CI 0.006–0.291), also with a slight improvement effect on lumbar spine BMC (SMD 0.163, 95% CI 0.008–0.317), no effects on total hip BMD and BMC and lumbar spine BMD were observed. Very interestingly, subgroup analyses suggested that the improvement of bone at femoral neck was more pronounced in the peripeak bone mass (PBM) population (20–35 years) than the pre-PBM population (<20 years).

Conclusions:

Our findings provided novel insights and evidence in calcium supplementation, which showed that calcium supplementation significantly improves bone mass, implying that preventive calcium supplementation before or around achieving PBM may be a shift in the window of intervention for osteoporosis.

Funding:

This work was supported by Wenzhou Medical University grant [89219029].

Osteoporosis and bone fractures are common problems among older people, particularly older women. These conditions cause disability and reduce quality of life. Progressive loss of bone mineral density is usually the culprit. So far, strategies to prevent bone weakening with age have produced disappointing results. For example, taking calcium supplements in later life only slightly reduces the risk of osteoporosis or fracture. New approaches are needed.

Bone mass increases gradually early in life and peaks and plateaus around 20-35 years of age. After that period, bone mass slowly declines. Some scientists suspect that increasing calcium intake during this period of peak bone mass may reduce osteoporosis or fracture risk later in life.

A meta-analysis by Liu, Le et al. shows that boosting calcium intake in young adulthood strengthens bones. The researchers analyzed data from 43 randomized controlled trials that enrolled 7,382 participants. About half the studies looked at the effects of taking calcium supplements and the other half analyzed the effects of a high calcium diet. Boosting calcium intake in people younger than age 35 improved bone mineral density throughout the body. It also increased bone mineral density at the femoral neck, where most hip fractures occur. Calcium supplementation produced larger effects in individuals between the ages of 20 and 35 than in people younger than 20.

Both high calcium diets and calcium supplements with doses less than 1000 mg/d boosted bone strength. Higher dose calcium supplements did not provide any extra benefits. The analysis suggests people should pay more attention to bone health during early adulthood. Large randomized clinical trials are needed to confirm the long-term benefits of boosting calcium intake during early adulthood. But if the results are validated, taking calcium supplements, or eating more calcium-rich foods between the ages of 20 and 35 may help individuals build healthier bones and prevent fractures and osteoporosis later in life.

Dairy products and bone health

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.

The Effects of Milk Supplementation on Bone Health Indices in Adults: A Meta-Analysis of Randomized Controlled Trials

Milk contains a number of bone-beneficial nutrients. However, milk, due to the D-galactose content, might have unfavorable effects on bone health. A meta-analysis of randomized controlled trials (RCTs) was performed to clarify the effects of milk supplementation on bone mineral density (BMD), bone turnover markers [N-terminal telopeptide of type I collagen (NTx), C-terminal telopeptide of type 1 collagen (CTx), osteocalcin, bone alkaline phosphatase (BALP), and procollagen type 1 N-propeptide (P1NP)], and hormonal indices related to bone metabolism [parathyroid hormone (PTH), 25-hydroxyvitamin D [25(OH)D], and insulin-like growth factor 1 (IGF-1)] in adults. The PubMed and Web of Science databases were searched. A random-effects model was used to estimate the pooled effect sizes. A total of 20 RCTs were included. The trial duration ranged from 1 mo to 36 mo. Milk supplementation resulted in a small but significant increase in BMD at the hip (+0.004 g/cm2; n = 9 RCTs) and lumbar spine (+0.025 g/cm2; n = 7), but did not significantly affect whole-body BMD (n = 3) and femoral neck BMD (n = 7). Milk supplementation reduced the concentrations of P1NP (-5.20 ng/mL; n = 9), CTx (-0.16 ng/mL; n = 9), and NTx (-8.66 nmol bone collagen equivalents/mmol creatinine; n = 3). The concentrations of osteocalcin (n = 9) and BALP (n = 3) were not affected by milk supplementation. Reduced parathyroid hormone PTH (-1.01 pg/mL; n = 13) concentrations and increased IGF-1 (+1.79 nmol/l; n = 4) concentrations were observed with milk supplementation. 25(OH)D (+3.73 ng/mL; n = 11) concentrations were increased with vitamin-D fortified milk supplementation. The addition of milk to the diet may potentially increase the likelihood of preventing bone loss by restoring bone homeostasis through the modulation of the calcium-vitamin D-PTH axis, bone remodeling rate, and growth hormone/IGF-1 axis.

A critical review of the role of milk and other dairy products in the development of obesity in children and adolescents

Existing reviews suggest that milk and other dairy products do not play a role in the development of obesity in childhood, but they do make an important contribution to children's nutrient intake. It is thus curious that public health advice on the consumption of dairy products for children is often perceived as unclear. The present review aimed to provide an overview of the totality of the evidence on the association between milk and other dairy products, and obesity and indicators of adiposity, in children. Our search identified forty-three cross-sectional studies, thirty-one longitudinal cohort studies and twenty randomised controlled trials. We found that milk and other dairy products are consistently found to be not associated, or inversely associated, with obesity and indicators of adiposity in children. Adjustment for energy intake tended to change inverse associations to neutral. Also, we found little evidence to suggest that the relationship varied by type of milk or dairy product, or age of the children, although there was a dearth of evidence for young children. Only nine of the ninety-four studies found a positive association between milk and other dairy products and body fatness. There may be some plausible mechanisms underlying the effect of milk and other dairy products on adiposity that influence energy and fat balance, possibly through fat absorption, appetite or metabolic activity of gut microbiota. In conclusion, there is little evidence to support a concern to limit the consumption of milk and other dairy products for children on the grounds that they may promote obesity.

Effects of Dairy Product Consumption on Height and Bone Mineral Content in Children: A Systematic Review of Controlled Trials

There is a physiological basis for the roles of selected nutrients, especially proteins, calcium, and vitamin D, in growth and development, which are at a maximum during the pediatric period. Milk and dairy products are particularly rich in this group of nutrients. The present systematic review summarizes the available evidence relating dairy product intake with linear growth and bone mineral content in childhood and adolescence. A search was conducted in the MEDLINE (via PubMed) and SCOPUS databases following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and included intervention-controlled clinical trials with dairy products in children from 1 January, 1926 to 30 June, 2018. The risk of bias for each study was assessed using the Cochrane methodology. The number of study participants, the type of study and doses, the major outcomes, and the key results of the 13 articles included in the review are reported. The present systematic review shows that supplementing the usual diet with dairy products significantly increases bone mineral content during childhood. However, the results regarding a possible relation between dairy product consumption and linear growth are inconclusive.

Lactose Intolerance and Bone Health: The Challenge of Ensuring Adequate Calcium Intake

Calcium is an important nutrient with impact upon many biological systems, most notably bone. Ensuring adequate calcium intake throughout the lifespan is essential to building and maintaining bone. Lactose intolerance may predispose individuals to low calcium intake as the number of lactose-free, calcium-rich food sources is limited. In this review, we summarize data from human and animal studies on the influence of lactose and lactase deficiency on calcium absorption and bone health. Based on the available evidence, neither dietary lactose nor lactase deficiency have a significant impact on calcium absorption in adult humans. However, lactose intolerance may lead to reduced bone density and fragility fractures when accompanied by decreased intake or avoidance of dairy. Recently published human trials and meta-analyses suggest a weak but significant association between dairy consumption and bone health, particularly in children. Given the availability of simple dietary approaches to building lactose tolerance and the nutritional deficiencies associated with dairy avoidance, multiple public health organizations recommend that all individuals—including those that are lactose intolerant—consume three servings of dairy per day to ensure adequate nutrient intakes and optimal bone health.

Dairy foods and bone health throughout the lifespan: a critical appraisal of the evidence

The consumption of high-Ca, high-protein dairy foods (i.e. milk, cheese, yogurt) is advocated for bone health across the lifespan to reduce the risk of low-trauma fractures. However, to date, the anti-fracture efficacy of dairy food consumption has not been demonstrated in randomised controlled trials but inferred from cross-sectional and prospective studies. The anti-fracture efficacy of dairy food consumption is plausible, but testing this requires a robust study design to ensure outcomes are suitably answering this important public health question. The evidence of skeletal benefits of dairy food consumption is equivocal, not because it may not be efficacious but because the study design and execution are often inadequate. The key issues are compliance with dietary intervention, dropouts, sample sizes and most importantly lack of deficiency before intervention. Without careful appraisal of the design and execution of available studies, precarious interpretations of outcomes may be made from these poorly designed or executed studies, without consideration of how study design may be improved. Dairy food interventions in children are further hampered by heterogeneity in growth: in particular sex and maturity-related differences in the magnitude, timing, location and surface-specific site of bone accrual. Outcomes of studies combining children of different sexes and maturity status may be masked or exaggerated by these differences in growth, so inaccurate conclusions are drawn from results. Until these critical issues in study design are considered in future dairy food interventions, the anti-fracture efficacy of dairy food consumption may remain unknown and continue to be based on conjecture.

How Milk and Its Proteins Affect Growth, Bone Health, and Weight

Milk has long been recognized to constitute a complete, well-balanced source of the nutrients and energy required to ensure the proper postnatal growth and development of infants. A growing body of evidence suggests the positive effects of dairy products and particularly of milk proteins on linear growth also in older children, both healthy or during recovery from malnutrition. This evidence led the way to the performance of extensive research aimed to delineate the components of milk and the mechanisms acting to make milk so effective. The present review summarizes the current knowledge regarding the influence of milk and its proteins on linear growth in healthy and malnourished children, focusing also on other important aspects of healthy growth, including bone health, weight status, and body composition.
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Dairy products and bone health: how strong is the scientific evidence?

The relevance of dairy produce for the diminishment of osteoporotic risk is still a matter of scientific debate due to the outcome of a few single observational studies. This review will address the most robust point estimate on the role of dairy products, as reported in systematic reviews and meta-analyses on randomised controlled trials in the case of bone mineralisation or prospective studies in the case of fracture risk. Plain dairy products or those fortified with Ca and/or vitamin D improve total body bone mineral content (BMC) by 45-50 g over 1 year when the daily baseline Ca intake is lower than 750 mg in Caucasians and Chinese girls. In Caucasian and Chinese women, Ca from (fortified) dairy products increases bone mineral density (BMD) by 0·7-1·8 % over 2 years dependent on the site of measurement. Despite the results on BMC, there are currently no studies that have investigated the potential of dairy products to reduce fracture risk in children. In adult Caucasian women, daily intake of 200-250 ml of milk is associated with a reduction in fracture risk of 5 % or higher. In conclusion, the role of dairy products for BMC or BMD has been sufficiently established in Chinese and Caucasian girls and women. In Caucasian women, drinking milk also reduces fracture risk. More research on the role of dairy products within the context of bone health-promoting diets is needed in specific ethnicities, other than Chinese and Caucasians, and in men.

Effects of Dairy Consumption on Body Composition and Bone Properties in Youth: A Systematic Review

Background: According to previous reviews, there is no clear evidence on the effects of dairy consumption on body composition and bone properties in pediatric populations. There is a need for further assessment of existing findings and the methodologic quality of studies before summarizing the evidence. Objective: The aim of the study was to assess the quality, methodologies, and substantive findings of randomized controlled trials (RCTs) that examined the effects of dairy consumption on body size, body composition, and bone properties in children and adolescents. Methods: After searching PubMed and Google Scholar up to December 2016, 15 RCTs were retained and included in this systematic review for further analysis. The quality of the included studies was assessed via the Jadad scale; detailed methodologic and statistical characteristics were evaluated, and the main findings were summarized. Results: The effects of dairy consumption were found to be significant for bone structure and nonsignificant for body size and composition. Eight of the 11 RCTs that assessed bone found significant effects (P < 0.05) for bone mineral content and bone mineral density (BMD), with an average 8% increase in BMD after 16 mo of dairy consumption. Conversely, significant effects (P < 0.05) were found only in 2 of the 14 RCTs that focused on body size (i.e., height and weight) and in only 1 of the 11 RCTs that focused on body composition (i.e., lean mass). Conclusions: The systematic consumption of dairy products may benefit bone structure and development, but it does not appear to affect body composition or body size in children and adolescents. On the basis of the Jadad scale, the methodologic quality of the 15 RCTs was rated as good overall. However, there were methodologic disparities and limitations that may have led to nonsignificant results, particularly for body size and composition. Future RCTs designed to address these limitations are warranted.

The effect of increasing dairy calcium intake of adolescent girls on changes in body fat and weight

Background: Overweight is epidemic in adolescents and is a major concern because it tracks into adulthood. Evidence supports the efficacy of high-calcium, high-dairy diets in achieving healthy weight in adults. However, no randomized controlled trials of the effect of dairy food on weight and body fat in adolescents have been reported to our knowledge.Objective: The aim was to determine whether increasing calcium intake to recommended amounts with dairy foods in adolescent girls with habitually low calcium intakes would decrease body fat gain compared with girls who continued their low calcium intake. Participants had above-the-median body mass index (BMI; in kg/m²).Design: We enrolled 274 healthy postmenarcheal 13- to 14-y-old overweight girls who had calcium intakes of ≤600 mg/d in a 12-mo randomized controlled trial. Girls were randomly assigned in a 1:1 ratio to 1 of 2 groups within each of 3 BMI percentiles: 50th to <70th, 70th to <85th, and 85th to <98th. The assignments were 1) dairy, which included low-fat milk or yogurt servings providing ≥1200 mg Ca/d or 2) control, which included the usual diet of ≤600 mg Ca/d.Results: We failed to detect a statistically significant difference between groups in percentage of body fat gain over 12 mo (mean ± SEM: dairy 0.40% ± 0.53% > control; P < 0.45). The effect of the intervention did not differ by BMI percentile stratum. There was no difference in weight change between the 2 groups.Conclusion: Our findings that the dairy group gained body fat similar to the control group provide no support for dairy food as a stratagem to decrease body fat or weight gain in overweight adolescent girls. This trial was registered at clinicaltrials.gov as NCT01066806.

Calcium revisited, part III: effect of dietary calcium on BMD and fracture risk

Food can be an excellent source of calcium. Dietary calcium is in general as well absorbed as calcium supplements, and exerts the same effects on bone. The main sources are dairy products, but also some vegetables and fruits contain considerable amounts of calcium. Mineral water can serve as a supplement. Cross-sectional, longitudinal and some interventional trials have shown positive effects on bone metabolism, bone density and bone loss. But the effect on fracture incidence is less certain, and that of milk, the most studied dairy product, still unproven.

Nutritional aspects of bone health

Bone mass, geometry and microstructure, and bony tissue material level properties determine bone strength, hence the resistance to fracture. At a given age, all these variables are the consequence of the amount accumulated and of the structure developed during growth, up to the so-called peak bone mass, and of the bone loss and microstructure degradation occurring later in life. Genetic factors primarily contribute to the variance of the determinants of bone strength. Nutritional intakes are environmental factors that influence both processes, either directly by modifying modelling and remodelling, or indirectly through changes in calcitropic hormone secretion and action. Some effects of nutrition on the offspring bone could take place during foetal life. There are interplays between genetic factors, nutritional intakes and physical exercise. Among the nutrients, sufficient dietary intakes of calcium and protein are necessary for bone health in childhood and adolescence as well as later in life.

The phenomenon of micronutrient deficiency among children in China: a systematic review of the literature

OBJECTIVE

The present study aimed to review the literature on micronutrient deficiency and other factors influencing a deficiency status among children living in China.

DESIGN

A systematic review was performed to analyse the literature.

SETTING

Studies were identified through a search of PubMed and secondary references.

SUBJECTS

Children living in China aged less than 18 years.

RESULTS

Sixty-one articles were included. The prevalence of vitamin A deficiency decreased to approximately 10 % in 1995-2009. It increased with age but no significant difference was found between genders. The prevalence of thiamin and vitamin B12 deficiency was 10·5 % in Yunnan and 4·5 % in Chongqing provinces, respectively. Higher vitamin D deficiency rates were seen in spring and winter. The incidence of bleeding due to vitamin K deficiency was 3·3 % in 1998-2001 and more prevalent in rural areas. Both iodine deficiency and excess iodine intake were observed. Goitre rates were reported in Tibet, Jiangxi, Gansu and Hong Kong (3·5-46 %). Anaemia rates ranged from 20 % to 40 % in 2007-2011. High Se deficiency rates were found in Tibet, Shaanxi and Jiangsu. High Zn deficiency rates were also found (50-70 %) in 1995-2006. Few studies reported Ca deficiency rates (19·6-34·3 %). The degrees of deficiency for vitamin A, vitamin B12, Fe and Zn were more substantial in rural areas compared with urban areas.

CONCLUSIONS

The prevalence of micronutrient deficiency rates varied. Socio-economic status, environmental factors and the Chinese diet may influence micronutrient deficiency. Public health policies should consider implementing programmes of supplementation, food fortification and nutrition education to address these deficiencies among Chinese children.

Effects of milk salt supplementation on bone mineral gain in pubertal Chinese adolescents: a 2-year randomized, double-blind, controlled, dose-response trial

BACKGROUND/OBJECTIVE

Adequate calcium intakes may enhance bone mineral accumulation during childhood. Little is known about the optimal calcium intake in Chinese adolescents. We examined the effects of three levels of calcium intake on bone mineral accretion in adolescents.

METHODS

This was a 2-year randomized, double-blind, controlled trial. The subjects were randomly assigned to receive 40 g of milk powder containing 300 mg of calcium and 200 IU of vitamin D (Low-Ca group), or same milk powder additionally fortified with 300 mg of calcium (Mid-Ca group) or 600 mg of calcium (High-Ca group) for 2 years. The subjects' bone mineral density (BMD) and bone mineral content (BMC) at the total body, lumbar spine and left hip were determined by dual-energy X-ray absorptiometry at baseline and after the second year of treatment. Of the 111 girls and 109 boys (aged 12-14 years) enrolled, 91 girls and 91 boys completed the trial.

RESULTS

The girls in the High-Ca group (1,110 mg/d) had 2.3%, 2.7% and 2.6% greater BMD accretion at the total hip, femoral neck and shaft (P<0.05) but not at total body less head and spine than those in the Low-Ca group (655 mg/d). A significant effect of higher calcium intake was also observed for percentage change of size-adjusted BMC at femur neck (P=0.047). Bonferroni tests indicated no significant differences in the percentage changes in BMD, BMC or size-adjusted BMC between the Mid- and Low-Ca groups and between the High- and Mid-Ca groups. Extra calcium had no observable additional effect in the boys (P>0.05).

CONCLUSION

An intake of 1000 mg/d or more might be helpful in maximizing bone mineral accretion in the hip for girls. But further large studies are required to identify its long-term effects and the optimal calcium intake for boys.

Dairy products, yogurts, and bone health

Fracture risk is determined by bone mass, geometry, and microstructure, which result from peak bone mass (the amount attained at the end of pubertal growth) and from the amount of bone lost subsequently. Nutritional intakes are an important environmental factor that influence both bone mass accumulation during childhood and adolescence and bone loss that occurs in later life. Bone growth is influenced by dietary intake, particularly of calcium and protein. Adequate dietary calcium and protein are essential to achieve optimal peak bone mass during skeletal growth and to prevent bone loss in the elderly. Dairy products are rich in nutrients that are essential for good bone health, including calcium, protein, vitamin D, potassium, phosphorus, and other micronutrients and macronutrients. Studies supporting the beneficial effects of milk or dairy products on bone health show a significant inverse association between dairy food intake and bone turnover markers and a positive association with bone mineral content. Fortified dairy products induce more favorable changes in biochemical indexes of bone metabolism than does calcium supplementation alone. The associations between the consumption of dairy products and the risk of hip fracture are less well established, although yogurt intake shows a weakly positive protective trend for hip fracture. By consuming 3 servings of dairy products per day, the recommended daily intakes of nutrients essential for good bone health may be readily achieved. Dairy products could therefore improve bone health and reduce the risk of fractures in later life.

The Importance of Milk and other Animal-Source Foods for Children in Low-Income Countries

Background

Milk and other animal-source foods are concentrated dietary sources of macro- and micronutrients. Despite a global increase in milk production and consumption over the past decades, milk and other animal-source foods are often lacking in the diets of children in developing countries.

Objective

To evaluate the importance of milk and other animal-source food intake in promoting the growth, development, and health of children in low-income countries.

Methods

Original research articles describing observational and intervention studies with unfortified milk, fortified milk, and other animal-source foods in children were identified by searching the PubMed database.

Results

Consumption of milk and other animal-source foods by undernourished children improves anthropometric indices and cognitive function and reduces the prevalence of biochemical and functional nutritional deficiencies, reducing morbidity and mortality. Unfortified and fortified milk used in supplementation trials has been well tolerated and widely accepted by parents and children.

Conclusions

To improve the dietary quality of children in low-income countries and further the effort to eradicate extreme poverty and hunger in accordance with the United Nations Millennium Development Goals, additional research is necessary to identify and implement programs and policy supporting increased intake of milk and other animal-source foods.

The Role of Dairy Products in Healthy Weight and Body Composition in Children and Adolescents

Overweight and obesity are major public health concerns with approximately 32% and 17% of U.S. children aged 2 – 19 being classified as overweight or obese, respectively. While the cause of overweight and obesity is multi-factorial, changes in eating habits and physical activity patterns have been proposed as contributing factors to the obesity epidemic. For example, the displacement of nutrient rich foods and beverages with non-nutrient dense items may be influencing childhood obesity. Many children do not consume the recommended servings of the Food Groups to Encourage, i.e. low-fat and fat-free dairy foods, fruits, vegetables, and whole grains identified by the 2005 Dietary Guidelines for Americans which results in low intakes of calcium, potassium, fiber, magnesium, and vitamin E. While attention has focused primarily on reducing energy intake and/or increasing energy expenditure for weight maintenance, a promising beneficial role for dairy products in weight management has emerged. Most research has focused on adults, but there is evidence in children and adolescents indicating either a beneficial or neutral effect of dairy food consumption on body weight or body composition. The current review provides and assessment of the scientific evidence on the effects of dairy food consumption on body weight and body composition in children and adolescents.

Maximizing bone mineral mass gain during growth for the prevention of fractures in the adolescents and the elderly

Bone mass is a key determinant of fracture risk. Maximizing bone mineral mass during childhood and adolescence may contribute to fracture risk reduction during adolescence and possibly in the elderly. Although more than 60% of the variance of peak bone mass (PBM), the amount of bone present in the skeleton at the end of its maturation process, is genetically determined, the remainder is likely influenced by factors amenable to positive intervention, such as adequate dietary intake of dairy products as a natural source of calcium and proteins, vitamin D, and regular weight-bearing physical activity. Low calcium and vitamin D intakes are associated with negative effects on bone, including suboptimal PBM acquisition. As suggested by intervention studies, regular intake of dairy products may have positive and possibly sustained effects on bone mineral mass gain, contributing thereby to fracture risk reduction. Further evidence from intervention studies suggests that weight-bearing physical activities, such as jumping, may contribute to bone mineral mass gain in children. Optimizing PBM acquisition through dietary and physical exercise measures may represent a valuable primary method for the prevention of fractures.

Randomized trials assessing calcium supplementation in healthy children: relationship between industry sponsorship and study outcomes

Objective

To explore the relationship between industry sponsorship of Ca supplementation studies in healthy children and study outcomes.

Design

An electronic search for published randomized controlled trials (RCT) was conducted. We collected data on study design features aimed at reducing bias, statistical significance of results, authors’ conclusions and financial sponsorship of study. We used Fischer’s exact test to examine associations between sponsorship and study results and conclusions.

Subjects

Healthy children between the ages of 9 and 18 years.

Results

Nineteen trials met our inclusion criteria. Seventeen out of nineteen studies reported a statistically significant improvement of supplementation on bone mineral density. Subjects in eight of the seventeen studies had a baseline daily Ca intake of 800–1300 mg. There was no significant association between study design features and the results or conclusions of the studies. Three studies received government funding, two of which (66·7 %) concluded in favour of additional supplementation. Sixteen studies were either industry-funded or had mixed industry funding, thirteen (81·3 %) of which had a conclusion supporting Ca supplementation in children. There was no significant association between study sponsorship and authors’ conclusions.

Conclusions

The majority of RCT assessing the effects of Ca supplementation in healthy children are industry-funded and support Ca supplementation. The clinical significance of the outcomes measured in Ca supplementation studies should be considered when examining associations between study design and results. Further non-industry funded research is needed to thoroughly assess the impact of funding on authors’ conclusions in nutrition research.

Nutrition: its role in bone health

At a given age, bone mass is determined by the amount of bone accumulated at the end of skeletal growth (the so-called peak bone mass), and by the amount of bone lost subsequently. Nutritional intake is an environmental factor that influences both bone capital accumulation, which is fully achieved by the end of the second decade of life, and bone loss, which occurs during the second half of existence. Nutrients may act directly by modifying bone turnover, or indirectly via changes in calciotropic hormone secretion. The study of the association between nutrition and a bone phenotypic expression may provide inconsistent results, in part because of the low accuracy and reproducibility of the various tools used to assess dietary intakes. Sufficient dietary calcium and protein are necessary for bone health during growth as well as in the elderly.

Impact of dairy products and dietary calcium on bone-mineral content in children: results of a meta-analysis

OBJECTIVE

Although calcium is essential for maintaining bone health in children, the optimum dietary intake of calcium in this age group, particularly in the form of dairy foods, is not well defined. A meta-analysis was conducted to examine the impact of dietary calcium/dairy supplementation on bone mineral content in this age group.

METHODS

Data were pooled from randomized controlled intervention trials and observational studies using previously described methods. The outcome of interest was a summary mean difference bone mineral content. Sensitivity analyses were employed to evaluate any observed statistical heterogeneity and to examine the influence of specific study characteristics on the summary estimate of effect.

RESULTS

Initially combining data from twenty-one randomized controlled trials (RCTs) using total body bone mineral content (TB-BMC) as the outcome of interest, yielded a non-statistically significant increase in TB-BMC of 2 g (supplemented versus controls). These data demonstrated substantial statistical heterogeneity with sensitivity analyses revealing that among study subjects with normal or near normal baseline dietary calcium/dairy intakes, supplemental dairy/calcium showed little impact on bone mineral content. Sensitivity analyses suggested that baseline calcium intake could potentially account for the statistical heterogeneity. Pooling the three reports utilizing low intake subjects yielded a statistically significant summary mean BMC of 49 g (24.0-76-6). Pooling two RCTs using calcium/dairy supplement plus vitamin D was also associated with an increase in lumbar spine BMC of, on average, 35 g (-6.8-41.8). The lack of data using BMC measurements at other anatomic sites as well as sparse data from non-randomized studies, precluded further statistical pooling.

CONCLUSION

Increased dietary calcium/dairy products, with and without vitamin D, significantly increases total body and lumbar spine BMC in children with low base-line intakes.

Dairy and weight loss hypothesis: an evaluation of the clinical trials

This review evaluates evidence from clinical trials that assessed the effect of dairy product or calcium intake, with or without concomitant energy restriction, on body weight and adiposity. Of 49 randomized trials assessing the effect of dairy products or calcium supplementation on body weight, 41 showed no effect, two demonstrated weight gain, one showed a lower rate of gain, and five showed weight loss. Four of 24 trials report differential fat loss. Consequently, the majority of the current evidence from clinical trials does not support the hypothesis that calcium or dairy consumption aids in weight or fat loss.

Fractures during growth: potential role of a milk-free diet

Dietary calcium deficiency may increase fracture risk. In girls, 29.4% of fracture cases and 11.8% of controls without fracture had a history of milk-free diet. The odds ratio (OR) for fracture with a milk-free diet in girls was 4.6, p < 0.01. In boys, 23% of cases and 19% of controls had a history of a milk-free diet; OR = 1.3, NS). A milk-free diet due to cow's milk allergy is associated with increased fracture risk in girls.

INTRODUCTION

An intake of calcium below the reference daily intake (RDI) of 800-1200 mg/day during growth is thought to increase fracture risk even though convincing evidence for this view is scarce. The paucity of evidence may be partly due to many trial participants being calcium replete. Children and adolescents with cow's milk allergy (CMA) avoid milk and have a calcium intake below the RDI. The aim of this study was to examine the association between consumption of a milk-free diet and fracture risk.

METHODS

In this case-control study conducted in Poland, 57 boys and 34 girls aged 2.5-20 years with fractures (cases) were randomly matched by age and sex with 171 boys and 102 girls without fractures (controls). Weight and height were examined using standard methods. Bone mineral density (BMD) and body composition were measured using dual-energy X-ray absorptiometry. Conditional logistic regression and Bayesian analyses were used to determine the proportion of the fracture risk attributable to a milk-free diet.

RESULTS

In girls, 29.4% of cases and 11.8% of controls had a history of milk-free diet producing an odds ratio (OR) for fracture associated with a milk-free diet of 4.6 (95% confidence interval [CI]: 1.4-15.5, p < 0.01). In boys, 23% of cases and 19% of controls had a history of a milk-free diet; OR = 1.3 (95% CI: 0.6-2.7, NS). If the prevalence of CMA in the population is 5%, only 6.7% of the fractures occurring are attributable to CMA and the associated nutritional deficit.

CONCLUSIONS

Cow's milk allergy is associated with increased fracture risk in girls. Whether this association is due to the illness, calcium deficit or a deficit in other milk nutrients is uncertain. These data suggest that the contribution of milk-free diet to fracture liability among children and adolescents is modest.

Milk Supplementation and Bone Health in Young Adult Chinese Women

BACKGROUND

Milk is potentially beneficial for bone health, particularly for Chinese populations where consumption of dairy products is low. There are few data about milk consumption by Chinese women aged 20-35 years. This study examines whether milk supplement over 2 years caused increased bone mineral density (BMD) in Chinese women aged 20-35 years.

METHODS

Four hundred forty-one community-living women living in Hong Kong SAR (221) and Beijing (220) China were randomized to receive milk supplement or nothing. The supplement consisted of two sachets of milk powder (1000 mg calcium, 80 microg vitamin K(1)), for 24 months. BMD at total hip, total spine, and whole body was measured at baseline and at 6, 12, 18, and 24 months; blood specimens were analyzed at baseline and at 3 and 24 months for biochemical indices of bone turnover and vitamin K. Urine samples also were collected. Analysis was by intention to treat as well as per protocol. Differences in change from baseline between the milk and control groups were analyzed using the mixed models approach to repeated measures, including the baseline value as a covariate.

RESULTS

Both groups had an increase in BMD and a decrease in bone turnover markers over time, as an indicator of the process of attainment of peak bone mass during this period. Apart from a higher total spine BMD at 6 months in the milk group using per protocol analysis, there was little significant difference observed between the milk group and the control group.

CONCLUSIONS

Age-related bone metabolism and lack of compliance most likely explain the lack of consistent changes in BMD or bone biochemical measures in response to milk supplementation for 2 years in Chinese women aged 20-35 years.

Skeletal benefits from calcium supplementation are limited in children with calcium intakes near 800 mg daily

INTRODUCTION AND HYPOTHESIS

Calcium supplementation enhances bone mass accrual during administration, with a sustained benefit observed using milk-based calcium but not calcium salts. We tested the hypothesis that calcium from milk minerals but not calcium carbonate will be sustained after supplementation was discontinued.

METHODS

Ninety-nine pre-pubertal boys and girls aged 5-11 years were followed for 12 months after being randomized to receive 800 mg/day of calcium from milk minerals (MM) or calcium carbonate (CC), or a placebo (Pla) in a 10-month double blind study. Total body and regional BMC, and femoral shaft bone dimensions were measured using dual energy x-ray absorptiometry. Group differences were determined using ANCOVA.

RESULTS

In the intention to treat analysis of the entire sample, no group differences were observed in increments in BMC or bone dimensions during or after supplementation. In those children who remained pre-pubertal, greater gains in pelvis BMC in the milk mineral group than controls were sustained (37.9 versus 29.3% respectively, p<0.02).

CONCLUSION

In healthy children consuming about 800 mg calcium daily, calcium supplementation with milk minerals or calcium carbonate does not appear to be produce biologically meaningful benefits to skeletal health. A benefit of calcium supplementation in pre-pubertal was evident, but inconclusive, with the biological significance of the effect of calcium supplementation at the pelvis, and the longevity of this effect to be determined.

Calcium supplementation for improving bone mineral density in children

BACKGROUND

Clinical trials have shown that calcium supplementation in children can increase bone mineral density (BMD) although this effect may not be maintained. There has been no quantitative systematic review of this intervention.

OBJECTIVES

. To determine the effectiveness of calcium supplementation for improving BMD in children. . To determine if any effect varies by sex, pubertal stage, ethnicity or level of physical activity, and if any effect persists after supplementation is ceased.

SEARCH STRATEGY

We searched CENTRAL, (Cochrane Central Register of Controlled Trials) (Issue 3, 2005), MEDLINE (1966 to 1 April 2005), EMBASE (1980 to 1 April 2005), CINAHL (1982 to 1 April 2005), AMED (1985 to 1 April 2005), MANTIS (1880 to 1 April 2005) ISI Web of Science (1945 to 1 April 2005), Food Science and Technology Abstracts (1969 to 1 April 2005) and Human Nutrition (1982 to 1 April 2005). Conference abstract books (Osteoporosis International, Journal of Bone and Mineral Research) were hand-searched.

SELECTION CRITERIA

Randomised controlled trials of calcium supplementation (including by food sources) compared with placebo, with a treatment period of at least 3 months in children without co-existent medical conditions affecting bone metabolism. Outcomes had to include areal or volumetric BMD, bone mineral content (BMC), or in the case of studies using quantitative ultrasound, broadband ultrasound attenuation and ultrasonic speed of sound, measured after at least 6 months of follow-up.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data including adverse events. We contacted study authors for additional information.

MAIN RESULTS

The 19 trials included 2859 participants, of which 1367 were randomised to supplementation and 1426 to placebo. There was no heterogeneity in the results of the main effects analyses to suggest that the studies were not comparable. There was no effect of calcium supplementation on femoral neck or lumbar spine BMD. There was a small effect on total body BMC (standardised mean difference (SMD) +0.14, 95% CI+0.01, +0.27) and upper limb BMD (SMD +0.14, 95%CI +0.04, +0.24). Only the effect in the upper limb persisted after supplementation ceased (SMD+0.14, 95%CI+0.01, +0.28). This effect is approximately equivalent to a 1.7% greater increase in supplemented groups, which at best would reduce absolute fracture risk in children by 0.1-0.2%per annum. There was no evidence of effect modification by baseline calcium intake, sex, ethnicity, physical activity or pubertal stage. Adverse events were reported infrequently and were minor.

AUTHORS' CONCLUSIONS

While there is a small effect of calcium supplementation in the upper limb, the increase in BMD which results is unlikely to result in a clinically significant decrease in fracture risk. The results do not support the use of calcium supplementation in healthy children as a public health intervention. These results cannot be extrapolated to children with medical conditions affecting bone metabolism.

Growth, bone mass, and vitamin D status of Chinese adolescent girls 3 y after withdrawal of milk supplementation

BACKGROUND

A 2-y school milk intervention trial showed that 330 mL of a dietary milk supplement (fortified with calcium alone or with both calcium and vitamin D) enhanced the growth and bone mineral accretion of Chinese girls aged 10 y at baseline. Girls who received milk fortified with both calcium and vitamin D also had better vitamin D status than did girls who received nothing or girls who received milk fortified only with calcium.

OBJECTIVE

The aim was to evaluate whether these effects were sustained 3 y after supplement withdrawal.

DESIGN

Anthropometric measures and dietary intake were reassessed in 501 of the 698 girls whose data had been studied at the end of the intervention. As in the intervention phase, total-body bone mineral content and bone mineral density and serum 25-hydroxyvitamin D concentrations were measured in half of these subjects.

RESULTS

At follow-up, 99% of girls had reached menarche, at a mean (+/-SD) menarcheal age of 12.1 +/- 1.1 y. No significant differences in the timing of menarche were observed between the 3 groups (P = 0.6). No significant differences in the changes of total-body bone mineral content and bone mineral density since baseline were observed between the groups. The group receiving calcium-fortified milk had significantly greater gains in sitting height (0.9 +/- 0.3%; P = 0.02) than did the control group. The group that received calcium- and vitamin D-fortified milk had 17.1 +/- 6.7% lower serum 25-hydroxyvitamin D concentrations than did the control group (P = 0.04), but the difference was attenuated by additional adjustment for physical activity level (14.2 +/- 6.7%; P = 0.08).

CONCLUSION

Milk supplementation during early puberty does not have long-lasting effects on bone mineral accretion.

Determinants of bone mass and bone size in a large cohort of physically active young adult men

The determinants of bone mineral density (BMD) at multiple sites were examined in a fit college population. Subjects were 755 males (mean age = 18.7 years) entering the United States Military Academy. A questionnaire assessed exercise frequency and milk, caffeine, and alcohol consumption and tobacco use. Academy staff measured height, weight, and fitness. Calcaneal BMD was measured by peripheral dual-energy x-ray absorptiometry (pDXA). Peripheral-quantitative computed tomography (pQCT) was used to measure tibial mineral content, circumference and cortical thickness. Spine and hip BMD were measured by DXA in a subset (n = 159). Mean BMD at all sites was approximately one standard deviation above young normal (p < 0.05). African Americans had significantly higher hip, spine and heel BMD and greater tibial mineral content and cortical thickness than Caucasians and Asians. In Caucasians (n = 653), weight was a significant determinant of BMD at every skeletal site. Prior exercise levels and milk intake positively related to bone density and size, while caffeine had a negative impact. There was an apparent interaction between milk and exercise in BMD at the heel, spine, hip and tibial mineral content and cortical thickness. Our data confirm the importance of race, body size, milk intake and duration of weekly exercise as determinants of BMD and bone size.

Effects of calcium, dairy product, and vitamin D supplementation on bone mass accrual and body composition in 10-12-y-old girls: a 2-y randomized trial

BACKGROUND

Little is known about the relative effectiveness of calcium supplementation from food or pills with or without vitamin D supplementation for bone mass accrual during the rapid growth period.

OBJECTIVE

The purpose was to examine the effects of both food-based and pill supplements of calcium and vitamin D on bone mass and body composition in girls aged 10-12 y.

DESIGN

This placebo-controlled intervention trial randomly assigned 195 healthy girls at Tanner stage I-II, aged 10-12 y, with dietary calcium intakes <900 mg/d to 1 of 4 groups: calcium (1000 mg) + vitamin D3 (200 IU), calcium (1000 mg), cheese (1000 mg calcium), and placebo. Primary outcomes were bone indexes of the hip, spine, and whole body by dual-energy X-ray absorptiometry and of the radius and tibia by peripheral quantitative computed tomography.

RESULTS

With the use of intention-to-treat or efficacy analysis, calcium supplementation with cheese resulted in a higher percentage change in cortical thickness of the tibia than did placebo, calcium, or calcium + vitamin D treatment (P = 0.01, 0.038, and 0.004, respectively) and in higher whole-body bone mineral density than did placebo treatment (P = 0.044) when compliance was >50%. With the use of a hierarchical linear model with random effects to control for growth velocity, these differences disappeared.

CONCLUSIONS

Increasing calcium intake by consuming cheese appears to be more beneficial for cortical bone mass accrual than the consumption of tablets containing a similar amount of calcium. Diverse patterns of growth velocity may mask the efficacy of supplementation in a short-term trial of children transiting through puberty.