The growing years and prevention of osteoporosis in later life

Dietary acidity and bone mass in minority children and adolescents: a cross-sectional analysis from the MetA-Bone trial

Dietary acid load could be associated with bone mass, but there are limited and conflicting results. This secondary cross-sectional analysis evaluated these associations among 123 children/adolescents, mostly Hispanics. Dietary acid load seems to be associated with bone mass in boys, but these results should be confirmed through long-term studies.

BACKGROUND

Childhood/adolescence is key for developing strong bones. With the continuing rise in osteoporosis rates in Western societies, attention has turned to the possible impact of diets that create high levels of acid in the body. Some studies have shown an association between dietary acid load and bone mass, but there are limited studies in children/adolescents and none in Hispanics.

OBJECTIVE

This study aimed to evaluate the associations between dietary acid load (assessed as dietary potential renal acid load, PRAL, and protein to potassium ratio) and whole-body bone mineral content (BMC) and density (BMD) in a sample of 123 children and adolescents of predominantly Hispanic ethnicity.

DESIGN

This study is a secondary cross-sectional analysis.

RESULTS

Dietary PRAL was positively associated with BMC and BMD overall (p < 0.05) and with BMC in boys (p < 0.05) when adjusted for energy misreporting only. The vegetable protein to potassium ratio was inversely associated with BMC (p = 0.004) in boys only, after adjusting for important factors.

CONCLUSIONS

Dietary acid load seems to be associated with BMC in boys in this sample of primarily Hispanic children. Long-term studies are needed to confirm these results and to understand the importance of protein intake in relation to other key nutrients in bone mass acquisition among Hispanic boys.

The Temporal Change in Ionised Calcium, Parathyroid Hormone and Bone Metabolism Following Ingestion of a Plant-Sourced Marine Mineral + Protein Isolate in Healthy Young Adults

Background: An increase in plant-sourced (PS) nutrient intake is promoted in support of a sustainable diet. PS dietary minerals and proteins have bioactive properties that can affect bone health and the risk of fracture. Methods: In a group randomised, cross-over design, this study evaluated the post-ingestion temporal pattern of change in arterialised ionised calcium (iCa), parathyroid hormone (PTH), C-terminal crosslinked telopeptide of type I collagen (CTX) and procollagen type 1 amino-terminal propeptide (P1NP) for 4 h following ingestion of a novel supplement (SUPP) containing a PS marine multi-mineral + PS protein isolate. A diurnally matched intake of mineral water was used as a control (CON). Results: Compared to baseline, the change in iCa concentration was 0.022 (95% CI, 0.006 to 0.038, p = 0.011) mmol/l greater in SUPP than CON, resulting in a -4.214 (95% CI, -8.244 to -0.183, p = 0.042) pg/mL mean reduction in PTH, a -0.64 (95% CI, -0.199 to -0.008, p = 0.029) ng/mL decrease in the biomarker of bone resorption, CTX, and no change in the biomarker of bone formation, P1NP. Conclusions: When used as a dietary supplement, or incorporated into a food matrix, the promotion of PS marine multi-mineral and PS protein isolates may contribute to a more sustainable diet and overall bone health.

Calcium Deficiency Decreases Bone Mass without Affecting Adiposity in Ovariectomized Rats Fed a High-Fat Diet

Obesity induced by a high-fat (HF) diet increases bone resorption and/or decreases bone formation, resulting in reduced bone mass and strength in various animal models. Studies showed that Ca intake is a modifiable factor for osteoporosis and obesity. This study investigated whether Ca deficiency affects bone structure and adiposity in ovariectomized (OVX) rats fed a HF diet. We hypothesized that Ca deficiency further decreases bone mass and increases fat mass in HF-fed OVX rats. Forty-seven OVX at 6-month-old were randomly assigned to four groups in a 2 × 2 factorial design: normal-fat (NF, 10% fat as energy) or HF (45% fat as energy) diet with either low Ca (LC, 1 g/4057 kcal) or normal Ca (NC, 6 g/4057 kcal). In addition, 12 sham-operated rats at 6 months old were fed a NFNC diet as a control for the OVX procedure. Rats were fed the respective diet for 4 months. Dietary Ca content did not affect body weight, fat mass, lean mass, food intake, energy intake, and serum cytokines. Compared to NC, LC resulted in lower tibial bone volume/total volume (BV/TV, p < 0.01), connectivity density (p < 0.01), trabecular number (Tb.N, p = 0.01), bone mineral density (BMD, p < 0.01), and femur weight (p < 0.01), femur content of Ca (p < 0.01), Cu (p = 0.03), Zn (p < 0.01), and greater trabecular separation (Tb.Sp, p < 0.01) at proximal tibia indicating bone structure deterioration. Compared to rats on the NF diet, animals fed the HF had lower BV/TV (p = 0.03) and Tb.N (p < 0.01) with greater body weight (p < 0.01), fat mass (p < 0.01), Tb.Sp (p = 0.01), the content of Ca, Cu, and Zn in the femur, and serum leptin (p < 0.01). There were no significant interactions between Ca and fat for body composition and bone structural parameters. Compared to Sham, OVX resulted in greater body weight and fat mass. The trabecular bone structure of the tibia, but not the cortical bone, was significantly impaired by the OVX procedure. These data indicate that inadequate Ca intake and a high-fat diet have independent negative effects on bone structure and that Ca deficiency does not affect adiposity in OVX rats.

Adequacy of calcium and vitamin D nutritional status in a nationally representative sample of Irish teenagers aged 13-18 years

CONTEXT AND PURPOSE

In light of the key roles of vitamin D and calcium in adolescent bone health, there is a critical need for representative data on nutritional status for both micronutrients in teenagers. The present work used data from the recent representative National Teens' Food Survey II (2019-2020) to assess calcium and vitamin D intakes of teenagers in Ireland, including adequacy of such intakes, as well as, for the first time, to characterise serum 25-hydroxyvitamin D (25(OH)D) concentrations and their determinants.

METHODS

Usual calcium and vitamin D intake estimates were generated using food intake data (via 4-day weighed food records) from a nationally representative sample of teenagers aged 13-18 years in Ireland (n 428). Serum 25(OH)D was measured (via LC-MS/MS) in the 57.5% (n 246) who provided a blood sample.

RESULTS

Sixty-seven and 94% of Irish teenagers had intakes of calcium and vitamin D below the respective Estimated Average Requirements values, reflecting a high degree of inadequacy of intake for both micronutrients (and higher in girls than boys; P < 0.001). In addition, 21.7% and 33.1% of teenagers had serum 25(OH)D < 30 nmol/L (risk of vitamin D deficiency) and 30-49.9 nmol/L (inadequacy), respectively. Extended winter sampling, being aged 16-18 years, low total vitamin D intake, being overweight/obese or being of non-white skin type were significant (P < 0.05) predictors of serum 25(OH)D < 30 nmol/L.

CONCLUSIONS

There was a high prevalence of inadequacy of intake of calcium and vitamin D in Irish teenagers, and a fifth were at increased risk of vitamin D deficiency.

Is breakfast consumption among Brazilian schoolchildren associated with an ultra-processed food dietary pattern?

Omission of breakfast starts at school age and can be explained as a reflection of the independent behaviour acquired in this phase of life. Breakfast has been investigated for its association with healthier diet quality, but few studies have investigated this relationship in schoolchildren aged 7 to 13 years. The objective of this study was to assess breakfast consumption in schoolchildren aged 7 to 13 years and to examine associations with dietary patterns (DPs). It was a cross-sectional study carried out in 2017 with 1069 students in Florianopolis, southern Brazil. Previous-day food consumption, physical activity and screen activities were self-reported. Factor analysis was used to identify DPs. Associations between breakfast consumption and overall DPs were evaluated using multivariate linear regression. Breakfast consumption was reported by 85% of the children, with the highest proportion observed among students on the afternoon school shift. Five DPs were identified explaining 41% of the total variance in daily food consumption: Ultra-processed, Mixed, Traditional Brazilian Lunch, Healthy + Sweets and Traditional Brazilian Breakfast. Breakfast consumption was directly associated with a Traditional Brazilian Breakfast DP (β = 0.335; 95% CI = 0.227, 0.442), a Mixed DP (β = 0.241; 95% CI = 0.160, 0.323), and a Healthy + Sweets DP (β = 0.160; 95% CI = 0.061, 0.260), and inversely associated with an Ultra-processed DP (β = -0.116; 95% CI = -0.207, -0.026). Breakfast consumption was associated with overall DPs, suggesting the importance of eating this meal by schoolchildren. We emphasise the relevance of offering a healthy breakfast at public schools for students who do not take this meal at home, contributing to health promotion.

Soluble Corn Fiber Increases Calcium Absorption Associated with Shifts in the Gut Microbiome: A Randomized Dose-Response Trial in Free-Living Pubertal Females

BACKGROUND

Soluble corn fiber (SCF; 12 g fiber/d) is shown to increase calcium absorption efficiency, associated with shifts in the gut microbiota in adolescent males and females who participated in a controlled feeding study.

OBJECTIVE

We evaluated the dose response of 0, 10, and 20 g fiber/d delivered by PROMITOR SCF 85 (85% fiber) on calcium absorption, biochemical bone properties, and the fecal microbiome in free-living adolescents.

METHODS

Healthy adolescent females (n = 28; aged 11-14 y) randomly assigned into a 3-phase, double-blind, crossover study consumed SCF for 4 wk at each dose (0, 10, and 20 g fiber/d from SCF) alongside their habitual diet and were followed by 3-d clinical visits and 3-wk washout periods. Stable isotope ((44)Ca and (43)Ca) enrichment in pooled urine was measured by inductively coupled plasma mass spectrometry. Fecal microbial community composition was assessed by high-throughput sequencing (Illumina) of polymerase chain reaction-amplified 16S rRNA genes. Mixed model ANOVA and Friedman analysis were used to determine effects of SCF on calcium absorption and to compare mean microbial proportions, respectively.

RESULTS

Calcium absorption increased significantly with 10 (13.3% ± 5.3%; P = 0.042) and 20 g fiber/d (12.9% ± 3.6%; P = 0.026) from SCF relative to control. Significant differences in fecal microbial community diversity were found after consuming SCF (operational taxonomic unit measures of 601.4 ± 83.5, 634.5 ± 83.8, and 649.6 ± 75.5 for 0, 10, and 20 g fiber/d, respectively; P < 0.05). Proportions of the genus Parabacteroides significantly increased with SCF dose (1.1% ± 0.8%, 2.1% ± 1.6%, and 3.0% ± 2.0% for 0, 10, and 20 g fiber/d from SCF, respectively; P < 0.05). Increases in calcium absorption positively correlated with increases in Clostridium (r = 0.44, P = 0.023) and unclassified Clostridiaceae (r = 0.40, P = 0.040).

CONCLUSIONS

SCF, a nondigestible carbohydrate, increased calcium absorption in free-living adolescent females. Two groups of bacteria may be involved, one directly fermenting SCF and the second fermenting SCF metabolites further, thereby promoting increased calcium absorption. This trial was registered at clinicaltrials.gov as NCT01660503.

Field testing a questionnaire assessing parental psychosocial factors related to consumption of calcium-rich foods by Hispanic, Asian, and Non-Hispanic white young adolescent children

Intervention strategies to increase calcium intake of parents and young adolescent children could be improved by identifying psychosocial factors influencing intake. The objective was to develop a tool to assess factors related to calcium intake among parents and Hispanic, Asian, and non-Hispanic white young adolescent children (10-13 years) meeting acceptable standards for psychometric properties. A parent questionnaire was constructed from interviews conducted to identify factors. Parents (n = 166) in the United States completed the questionnaire, with seventy-one completing it twice. Two constructs (Attitudes/Preferences and Social/Environmental) were identified and described by eighteen subscales with Cronbach's alpha levels from .50 to .79. Test-retest coefficients ranged from .68 to .85 (p < .001). Several subscales were statistically significantly associated with parent characteristics consistent with theory and published literature. This tool shows promise as a valid and reliable measure of factors associated with calcium-rich food intake among parents and young adolescent children.

Is Healthy Eating Behaviour Common Among School Adolescents in Mauritius?

Adolescents eating behaviours have come in the limelight because of the unconventional meals, fast-food intake, and snacking. This study was therefore undertaken to appraise and understand eating behaviours of secondary school adolescents in Mauritius. Data were collected randomly from a representative sample (n=384) of adolescents via a self-administered questionnaire and analysed statistically to examine associations, if any, between socio-demographic factors and eating behaviours. Breakfast was the most frequently (68%) missed meal, attributed mainly to lack of time (79.2%). No significant difference was observed between common socio-demographic variables and breakfast skipping. Adolescents tend to consume healthy food items such as breakfast cereals, fruits and vegetables while fast food consumption was universally present but higher among low income groups. Snacking was highly prevalent (84%) and occurred more often in female teens, urban residents and middle and higher income groups. However, snacking pattern revealed a healthy trend with 76% adolescents reporting drinking water and fruits appeared to be the most popular snack (Popularity Score: 5.57). This study shows that there has been an improvement in the eating behaviour of school adolescents in Mauritius compared to previous local studies.

Alternative therapies for the prevention and treatment of osteoporosis

Osteoporosis is a medical condition that affects millions of men and women. People with this condition have low bone mass, which places them at increased risk for bone fracture after minor trauma. The surgeries and treatments required to repair and heal bone fractures involve long recovery periods and can be expensive. Because osteoporosis occurs frequently in the elderly, the financial burden it places on society is likely to be large. In the United States, the Food and Drug Administration has approved several drugs for use in the prevention and treatment of osteoporosis. However, all of the currently available agents have severe side effects that limit their efficacy and underscore the urgent need for new treatment options. One promising approach is the development of alternative (nonpharmaceutical) strategies for bone maintenance, as well as for the prevention and treatment of osteoporosis. This review examines the currently available nonpharmaceutical alternatives that have been evaluated in in vitro and in vivo studies. Certain plants from the following families have shown the greatest benefits on bone: Alliceae, Asteraceae, Thecaceae, Fabaceae, Oleaceae, Rosaceae, Ranunculaceae, Vitaceae, Zingiberaceae. The present review discusses the most promising findings from studies of these plant families.

The effect of polyunsaturated fatty acids on bone health

The essential polyunsaturated fatty acids (PUFAs) are divided into two classes, n-3 (ω-3) and n-6 (ω-6) and their dietary precursors are α-linolenic (ALA) and linoleic acid (LA), respectively. PUFAs are precursors of a wide range of metabolites, for example eicosanoids like prostaglandins and leukotrienes, which play critical roles in the regulation of a variety of biological processes, including bone metabolism.

A large body of evidence supports an effect of PUFA on bone metabolism which may be mediated by regulation of osteoblastogenesis and osteoclast activity, change of membrane function, decrease in inflammatory cytokines, such as interleukin-1 (IL-1), interleukin-6 (IL-6), and tumour necrosis factor alpha (TNF-α), modulation of peroxisome proliferators-activated receptor γ (PPARγ) and influence in NO secretion and NO synthase.

Animal studies have shown that a higher dietary omega-3/omega-6 fatty acids ratio is associated with beneficial effects on bone health. Human studies conducted in elderly subjects suggest that omega-3 instead of omega-6 has a positive effect on bone metabolism. In spite of increasing evidence, studies conducted in humans do not allow us to draw a definitive conclusion on the usefulness of PUFAs in clinical practice.

Factors affecting calcium balance in Chinese adolescents

Chinese dietary reference intakes (DRIs) for calcium were developed mainly from studies conducted amongst Caucasians, yet a recent review showed that reference calcium intakes for Asians are likely to be different from those of Caucasians (Lee and Jiang, 2008). In order to develop calcium DRIs for Chinese adolescents, it is necessary to explore the characteristics and potential influencing factors of calcium metabolic balance in Chinese adolescents. A total of 80 students (15.1+/-0.8 years) were recruited stratified by gender from a 1-year calcium supplementation study. Subjects were randomly designed to four groups and supplemented with calcium carbonate tablets providing elemental calcium at 63, 354, 660, and 966 mg/day, respectively. Subjects consumed food from a 3-day cycle menu prepared by staff for 10 days. Elemental calcium in samples of foods, feces, and urine was determined in duplicates by inductively coupled plasma atomic emission spectrometry. The total calcium intake ranged from 352 to 1323 mg/day. The calcium apparent absorption efficiency and retention in boys were significantly higher than that in girls (68.7% vs. 46.4%, 480 mg/day vs. 204 mg/day, P<0.05). Calcium retention increased with calcium intakes, but did not reach a plateau. Calcium absorption efficiency in boys increased with calcium intake up to 665 mg/day, and decreased after that. In girls, calcium absorption efficiency decreased with calcium intake. Calcium absorption efficiency increased within 1 year after first spermatorrhea in boys, but decreased with pubertal development in girls. Sex, calcium intake, age, and pubertal development were the most important determinants of calcium absorption (R(2)=0.508, P<0.01) and retention (R(2)=0.745, P<0.05). This study indicates that sex, calcium intake, age, and pubertal development are important factors for calcium retention and absorption during growth, which should be considered for the development of calcium DRIs for Chinese adolescents.

Dairy and bone health

Bone health is the resultant of bone mass, bone architecture, and body mechanics. Nutrition supports all three components, with the principal nutrients concerned being calcium, protein, and vitamin D. Potassium, magnesium, zinc, and several vitamins are also involved to varying extents. Given modern food sources, it is difficult to devise a diet that is "bone healthy" without including three servings of dairy per day, not just because of dairy calcium, but dairy protein and potassium as well.

Neonatal exposure to daidzein, genistein, or the combination modulates bone development in female CD-1 mice

Neonatal exposure to genistein (GEN), an isoflavone abundant in soy, favorably modulates bone mineral density (BMD) and bone strength in mice at adulthood. The study objective was to determine whether early exposure to a combination of the soy isoflavones daidzein (DAI) and GEN that naturally exists in soy protein-based infant formula results in greater benefits to bone at adulthood than either treatment alone. Male and female CD-1 mice (n = 8-16 pups per group per gender) were randomized to subcutaneous injections of DAI (2 mg x kg body weight(-1) x d(-1)), GEN (5 mg x kg body weight(-1) x d(-1)), DAI+GEN (7 mg x kg body weight(-1) x d(-1)), diethylstilbesterol (DES; positive control) (2 mg x kg body weight(-1) x d(-1)), or control (CON) from postnatal d 1-5 and were studied to 4 mo of age. BMD, biomechanical bone strength, and bone microarchitecture were assessed at the femur and lumbar vertebrae (LV). Females treated with DAI, GEN, DAI+GEN, or DES had greater (P < 0.05) BMD at the LV compared with CON and vertebra in the DAI and DES group were more resistant to compression fractures. Microstructural analyses demonstrated that treatment with DAI and GEN resulted in greater (P < 0.05) trabecular connectivity and trabecular thickness, respectively, than the CON. In conclusion, neonatal exposure to DAI and/or GEN had a positive effect on the skeleton of female mice at adulthood, but, compared with individual treatments, DAI+GEN did not have a greater benefit to bone in females or males.

A Mediterranean dietary style improves calcium utilization in healthy male adolescents

OBJECTIVE

To examine the effects of consuming a diet based on the Mediterranean patterns on calcium availability and metabolism in male adolescents.

DESIGN

A longitudinal study divided into two periods: a 3-day basal period, during which the subjects (n = 20; 12.9 +/- 1.14 years) consumed their usual diet (basal diet, BD), and a 28-day nutritional intervention period, in which an intervention Mediterranean-type diet - was consumed (ID).

METHODS

Dietary calcium utilization was assessed by means of calcium intake in food and calcium output in feces and urine as measured by flame absorption spectrophotometry. In addition, markers of calcium metabolism (serum Ca, parathyroid hormone and total alkaline phosphatase) and bone resorption (urine deoxypiridinoline) were measured.

RESULTS

No differences in total calcium intake were found between the two diets, but food sources of dietary calcium varied significantly. Compared with the BD, the consumption of the ID resulted in significant increases in calcium absorption (approximately 40%, p = 0.04) and retention (approximately 80%, p = 0.008), and a considerable decrease in urinary calcium excretion (approximately 40%, p = 0.01).The variations observed in bone markers reflected a higher bone turnover rate after the ID consumption.

CONCLUSIONS

A varied diet based on Mediterranean diet patterns during adolescence greatly improves dietary calcium utilization, which may help to maximize the peak bone mass and prevent related diseases, such as osteoporosis.

Vitamin D: a growing perspective

Vitamin D deficiency has been widely reported in all age groups in recent years. Rickets has never been eradicated in developed countries, and it most commonly affects children from recent immigrant groups. There is much evidence that current vitamin D guidelines for the neonatal period, 5-10 microg (200-400 IU)/day, prevent rickets at the typical calcium intakes in developed countries. The annual incidence of vitamin D-deficiency rickets in developed countries ranges between 2.9 and 7.5 cases per 100,000 children. The prevalence of vitamin D deficiency in mothers and their neonates is remarkable, and the results of one study suggest that third-trimester 25-hydroxyvitamin D (25(OH)D) is associated with fetal bone mineral accrual that may affect prepubertal bone mass accumulation. Beyond infancy, the evidence indicates that 5 microg (200 IU)/day of vitamin D has little effect on vitamin D status as measured by the serum 25(OH)D concentration. Two randomized clinical trials show that higher vitamin D intake improves one-year gain in bone density in adolescent girls. The functions of vitamin D extend beyond bone to include immune system regulation and anti-proliferative effects on cells. Early life vitamin D inadequacy is implicated in the risk of bone disease, autoimmune disease, and certain cancers later in life; however, long-term interventional studies do not exist to validate the widespread implementation of greater vitamin D consumption. Here we review the available data concerning vitamin D status and health effects of vitamin D in pregnancy through to and including adolescence.

Altered bone metabolism in inflammatory disease: role for nutrition

Osteoporosis is a major public health problem, and as life expectancy and the world's population continue to increase will become even more important. Thus, there is an urgent need to develop and implement nutritional approaches and policies for the prevention and treatment of osteoporosis. Patients with some chronic inflammatory diseases appear to be more likely to develop osteopenia, and in some cases earlier in life, which is of particular concern as the incidence of inflammatory diseases in the Western world is increasing. While the cause of bone loss in patients with inflammatory disease is multifactorial, nutrition may have a role. Many of these patients may have one or more nutritional deficiencies, which can lead to altered rates of bone metabolism. On the other hand, some nutritional factors may attenuate the inflammatory process itself, and thus may indirectly benefit bone metabolism and bone health in patients with inflammatory disease. The present review will consider these issues, particularly in the context of inflammatory bowel disease, coeliac diease and atherosclerosis.

Interactions between effects of estrogen receptor gene polymorphisms on BMD and experiences of the first spermorrhea in Chinese Han boys

OBJECTIVE

To study the interaction between polymorphisms of estrogen receptor (ER) gene and puberty on bone mineral density (BMD).

METHODS

One hundred and forty-six boys aged 13-17 years were divided into two groups according to their first spermorrhea. DNA was analyzed for Xba I and Pvu II genotypes by PCR-RFLP. BMD of the total body, forearm and lumbar spine was measured by dual-energy X-ray absorptiometry (DXA). The relationship between polymorphisms of ER gene and BMD in these two groups was analyzed.

RESULTS

The BMD at all sites in the spermorrhea group was significantly higher than that in the un-spermorrhea group. The independent contribution of ER genotypes to BMD at two pubertal stages was analyzed after adjusting co-variables. In the un-spermorrhea group, the BMD at distal 1/10 and 1/3 forearm of those carrying pp genotype was significantly higher than that of the non-carries, whereas in the spermorrhea group BMD in those carrying the same genotype was significantly lower than that in the non-carriers. Similar results were obtained by haplotype analysis. Multiple stepwise regression analysis showed that body weight, age and the first spermorrehea were the dominant determinants for BMD. BMD at forearm might be influenced by interaction between ER genotype and the first spermorrehea.

CONCLUSION

The polymorphisms of ER gene play a different role in BMD influenced by the first spermorrhea. Chinese boys carrying p or x allele should pay more attention to their bone mass.

Independent and combined effect of nutrition and exercise on bone mass development

Food intake provides the necessary components for adequate metabolic functions in bone. Calcium, phosphorus, vitamin D, magnesium, proteins, and fluoride are some of the most important nutrients in this regard. These have different effects on bone mass. Additionally, exercise has been shown to elicit osteogenic responses in bone development; indeed, it seems to potentiate, for example, the effect of calcium supplementation on bone mass. However, the nutrition-exercise-bone mass relationship is complex and needs further in-depth investigation. As a first step, therefore, we reviewed current knowledge about the role of nutrition on the development of bone tissue and how physical activity affects the nutrient-bone relationship.

Diet, nutrition, and bone health

Osteoporosis is a debilitating disease that affects many older people. Fragility fractures are the hallmark of osteoporosis. Although nutrition is only 1 of many factors that influence bone mass and fragility fractures, there is an urgent need to develop and implement nutritional approaches and policies for the prevention and treatment of osteoporosis that could, with time, offer a foundation for population-based preventive strategies. However, to develop efficient and precocious strategies in the prevention of osteoporosis, it is important to determine which modifiable factors, especially nutritional factors, are able to improve bone health throughout life. There are potentially numerous nutrients and dietary components that can influence bone health, and these range from the macronutrients to micronutrients as well as bioactive food ingredients. The evidence-base to support the role of nutrients and food components in bone health ranges from very firm to scant, depending on the nutrient/component. This article initially overviews osteoporosis, including its definition, etiology, and incidence, and then provides some information on possible dietary strategies for optimizing bone health and preventing osteoporosis. The potential benefits of calcium, vitamin D, vitamin K(1), phytoestrogens, and nondigestible oligosaccharides are briefly discussed, with particular emphasis on the evidence base for their benefits to bone. It also briefly considers some of the recent findings that highlight the importance of some dietary factors for bone health in childhood and adolescence.

Calcium intake, calcium bioavailability and bone health

Calcium accounts for 1–2 % of adult human body weight. Over 99 % of total body Ca is found in the teeth and bones. Therefore, in addition to the obvious structural role of the skeleton, it also serves as a reservoir for Ca. Dietary Ca intake has an important impact on bone metabolism and bone health. Chronic Ca deficiency resulting from inadequate intake or poor intestinal absorption is one of several important causes of reduced bone mass and osteoporosis. It is vital, therefore, that adequate dietary Ca is consumed at all stages of life — in early life so that the genetically programmed peak bone mass can be reached and in later adulthood so that the skeletal mass can be maintained and age-related bone loss minimised. Unfortunately, there is wide variation in the estimates of daily Ca requirements made by different expert authorities. Furthermore, there is evidence that many individuals are not consuming these recommended levels. The consequence of this for bone health will be discussed in the present review. Besides the amount of Ca in the diet, the absorption of dietary Ca in foods is also a critical factor in determining the availability of Ca for bone development and maintenance. Thus, there is a need to identify food components and/or functional food ingredients that may positively influence Ca absorption in order to ensure that Ca bioavailability from foods can be optimised. This approach may be of particular value in individuals who fail to achieve the dietary recommended level of Ca.

Inulin-type fructans and bone health: state of the art and perspectives in the management of osteoporosis

If the primary role of diet is to provide sufficient nutrients to meet the metabolic requirements of an individual, there is an emerging rationale to support the hypothesis that, by modulating specific target functions in the body, it can help achieve optimal health. Regarding osteoporosis prevention, since Ca is most likely to be inadequate in terms of dietary intake, every strategy targeting an improvement in Ca absorption is very interesting. Actually, this process may be susceptible to manipulation by fermentable substrates. In this light, inulin-type fructans are very interesting, even if we need to gather more data targeting bone metabolism before health professionals can actively advocate their consumption to prevent senile osteoporosis. Besides targeting the prevention of postmenopausal osteoporosis, inulin-type fructans still remain a source for putative innovative dietary health intervention. Indeed, given in combination with isoflavones, they may have a potential for maintaining or improving the bone mass of human subjects, by modulating the bioavailability of phyto-oestrogens.

Differences in the quantitative and qualitative performance of a calcium-specific food frequency questionnaire across age and sex

OBJECTIVE

To examine putative differences in the quantitative and qualitative performance of a food frequency questionnaire (FFQ) for assessing dietary calcium intake across age and sex in the Greek population.

MATERIALS AND METHODS

A total of 351 children (189 girls and 162 boys, aged 11.9 +/- 1.2 years), 260 adults (192 women and 68 men, aged 29.6 +/- 2.7 years) and 390 elderly individuals (317 women and 73 men, aged 68.6 +/- 4.6 years) were recruited. Estimates of calcium intake from the 30-item FFQ were compared with those from a multi-pass 24-h recall.

RESULTS

The FFQ significantly underestimated mean calcium intake in all age groups and both sexes (P < 0.05). The magnitude of underestimation, however, was greater in adults (-207 +/- 344 mg day(-1)), less in the elderly (-137 +/- 310 mg day(-1)) and even less in children (-74 +/- 340 mg day(-1); P < 0.025), with no differences between sexes. Calcium intakes by the two methods were positively and significantly correlated in all study groups (r = 0.536-0.739, P < 0.001). Cohen's weighted kappa statistic ranged from 0.39 to 0.57, indicating moderate agreement between the two methods. The 95% limits of agreement were comparably wide across age and sex (boys: -762, 585 mg day(-1); girls: -747, 624 mg day(-1); adult men: -972, 505 mg day(-1); adult women: -867, 412 mg day(-1); elderly men: -858, 486 mg day(-1); elderly women: -732, 480 mg day(-1)). A significant association between age, sex and the classification of individuals as true/false positive/negative was detected (P < 0.001), implying that sensitivity, specificity, positive and negative predictive values of the FFQ were not independent of the age and sex of the participants. Gross misclassification by the FFQ ranged from 0% to 4.2%, whereas 75.3-87.3% of the subjects were correctly classified. In this respect, the FFQ performed similarly across the study groups (P = 0.065). Without controlling for age, however, gross misclassification appeared to be higher in females than in males (3.2% versus 0.7%, respectively, P = 0.048).

CONCLUSIONS

There may be several significant differences in the quantitative and qualitative performance of a calcium-specific FFQ across age and sex. This should be taken into account when attempting to evaluate dietary calcium intake in men and women or in different age groups, as some of the differences between study groups may actually be due to the different response of these groups to the FFQ.

Dietary calcium utilization among a group of Spanish boys aged 11-14 years on their usual diets

Adolescence constitutes a period of nutritional vulnerability due to increased dietary requirements for growth and development and special dietary habits. A pilot trial was performed to evaluate the dietary calcium utilization among a sample of Spanish boys on their usual diets, in which the calcium intake and consumption of dairy products were as well examined. Nutrient and food intake was recorded using a 24-h dietary recall and a 2-d food consumption record for 21 subjects aged 11-14 years. Dietary calcium utilization was assessed by means of calcium intake in food and calcium output in faeces and urine as measured by flame atomic absorption spectrophotometry. Overall intake of dairy products was 399.3 +/- 22.1 g/d, and the single most consumed item was milk (72% of the total). An inverse relationship was found between dairy product consumption at breakfast (55% of the total) and BMI (p = 0.016, r = -0.5168). Dairy products contributed the majority of dietary calcium (66.9%). Mean calcium intake was 881.7 +/- 39.9 mg/d, 88% of the recommended value for Spanish adolescents. Net calcium absorption (271.7 +/- 51.7 mg/d) and retention (170.6 +/- 50.9 mg/d) seemed not to be sufficient to meet growth demands during puberty. The results shown that adolescents of the study absorbed 31% of dietary calcium and retained nearly 20% of the total intake, but dietary calcium intake and consumption of dairy products failed to meet recommended values. Optimizing calcium intake is of crucial importance among adolescents, to maximize calcium retention and to help prevent osteoporosis in later life.

Development and validation of a food frequency questionnaire for assessing dietary calcium intake in the general population

The aim of this study was to develop and evaluate a food frequency questionnaire (FFQ) for assessing dietary calcium intake in the general population, since all available questionnaires at present are age- and/or gender-specific. A total of 1001 individuals (including children, adults, and elderly people of both genders) were randomly recruited throughout Greece. Estimates of calcium intake from the 30-item FFQ were compared with those from a multi-pass 24-h recall. The FFQ underestimated mean calcium intake compared to the 24-h recall by (mean+/-SD) -133+/-333 mg/day or -5.4+/-47.6% (P<0.001). The two methods were strongly correlated (r=0.639, P<0.001), but the 95% limits of agreement for individual assessment were rather wide, as the FFQ could provide estimates of calcium intake from 533 mg/day above to 799 mg/day below the 24-h recall. Actual values for surrogate FFQ quartiles manifested a progressive increase, with significant differences between mean calcium intakes (P<0.001). The FFQ could identify individuals who consumed less calcium than 800 mg/day or less than the age-specific adequate intake with a relatively high sensitivity (82.8 and 95.5%, respectively), but low specificity (54.9 and 34.1%, respectively). Cross-classification analysis indicated that only 17 subjects (1.7%) were grossly misclassified (lowest quartile for one method and highest quartile for the other), while 827 subjects (82.6%) were correctly classified (into the same or adjacent quartiles). The FFQ could be used in population-based epidemiological studies or screening programs involving individuals of all ages and both genders, where the discrimination of subjects with relatively low (<500 mg/day) and relatively high (>1000 mg/day) calcium intakes is of primary interest. Results, however, do not support its use for the quantitative assessment of individual calcium intakes.

Adolescents’ Low-Carbohydrate-Density Diets Are Related to Poorer Dietary Intakes

This study was undertaken to assess how low-carbohydrate-density diets below the acceptable macronutrient distribution range relate to food and micronutrient intake and sociodemographic and health-related characteristics. The multistage stratified cluster design in the 1990 Ontario Health Survey was used. There were 5,194 subjects, 12 to 18 years of age, in sampled households. Dietary data were collected via a food frequency questionnaire. Low-carbohydrate-density diets were consumed by 27.6% of males and 24.1% of females. Low-carbohydrate-density diets were related (P < .05) to reduced sufficiency of vegetables and fruit and higher consumption of meat and alternatives and added fats. The low-carbohydrate-density diet resulted in intakes lower in vitamin C and fiber and higher in cholesterol and total fat. The low-carbohydrate-density diet was directly associated with being Canadian-born (odds ratio [OR] = 1.78, 95% confidence interval [CI] = 1.27 to 2.50), overweight status (OR = 1.27, 95% CI = 1.02 to 1.57), smoking (OR = 1.53, 95% CI = 1.23 to 1.90), alcohol use (OR = 1.46, 95% CI = 1.21 to 1.75), and poorer self-rated health (OR = 1.47, 95% CI = 1.01 to 2.14). Use of the acceptable macronutrient distribution range identified adolescents with low-carbohydrate-density diets whose food choices and nutrient intake may impact negatively on short- and long-term health.

The Nutritional Impact of Dairy Product Consumption on Dietary Intakes of Adults (1995–1996): The Bogalusa Heart Study

OBJECTIVE

To examine the nutritional impact of dairy product consumption on the dietary intakes of adults.

DESIGN

Dietary intakes of adults who participated in a cross-sectional survey (1995-1996) in Bogalusa, LA.

SUBJECTS

Dietary intake data were collected on 1,266 adults (61% women, 39% men; 74% white, 26% African American) in Bogalusa, LA.

STATISTICAL ANALYSIS

Analysis of covariance was used to examine the mean nutrient intake differences among four dairy consumption groups. Significance tests in multiple comparisons between any two groups were conducted using Tukey's procedure.

RESULTS

Forty-eight percent of adults consumed one serving or less of dairy products, 32% consumed two servings, 12% consumed three servings, and 8% consumed four or more servings. Overall mean intake of dairy was higher in whites (mean=1.63) compared with African Americans (mean=1.22) (P<.0001), especially the consumption of milk and cheese. No differences were found in overall mean intake of dairy servings by sex after adjusting for energy intake. However, women consumed significantly more servings of cheese (P<.0001) and yogurt (P<.01) than men. There were higher intakes of total energy, saturated fat, total protein, animal protein, and lactose (P<.0001), with greater number of servings of dairy products consumed. There were lower intakes of monounsaturated and polyunsaturated fatty acids (P<.0001), vegetable protein (P<.0001), total carbohydrates (P<.01), sucrose (P<.001), fructose (P<.0001), and fiber (P<.001). The percentage of energy from saturated fat (P<.0001) and protein (P<.001) increased with increasing number of dairy servings consumed. Intakes of calcium; magnesium; potassium; zinc; sodium; folate; thiamin; riboflavin; and vitamins B-6, B-12, A, D, and E were higher with greater number of dairy servings consumed. There was lower consumption of sweetened beverages (P<.001), specifically regular soft drinks (P<.0001), with greater consumption of milk products.

CONCLUSIONS

Dairy product consumption by adults has a major influence on their vitamin and mineral intakes. The higher intakes of saturated fat, total energy, and animal protein and lower intake of fiber suggest that it may be useful to consume lower-fat dairy products and/or modify eating patterns to optimize the nutritional contributions of dairy products. Public health organizations and dietetics professionals need to educate adults on practical strategies for increasing dairy product consumption for improving the nutritional quality of adults' diets.

Breakfast habits, nutritional status, body weight, and academic performance in children and adolescents

Breakfast has been labeled the most important meal of the day, but are there data to support this claim? We summarized the results of 47 studies examining the association of breakfast consumption with nutritional adequacy (nine studies), body weight (16 studies), and academic performance (22 studies) in children and adolescents. Breakfast skipping is highly prevalent in the United States and Europe (10% to 30%), depending on age group, population, and definition. Although the quality of breakfast was variable within and between studies, children who reported eating breakfast on a consistent basis tended to have superior nutritional profiles than their breakfast-skipping peers. Breakfast eaters generally consumed more daily calories yet were less likely to be overweight, although not all studies associated breakfast skipping with overweight. Evidence suggests that breakfast consumption may improve cognitive function related to memory, test grades, and school attendance. Breakfast as part of a healthful diet and lifestyle can positively impact children's health and well-being. Parents should be encouraged to provide breakfast for their children or explore the availability of a school breakfast program. We advocate consumption of a healthful breakfast on a daily basis consisting of a variety of foods, especially high-fiber and nutrient-rich whole grains, fruits, and dairy products.

Dairy products do not lead to alterations in body weight or fat mass in young women in a 1-y intervention

BACKGROUND

Previous results suggested that increased intake of dairy calcium is associated with reduced weight and fat mass.

OBJECTIVE

The purpose of this study was to determine whether long-term increases in consumption of dairy calcium alter body weight and fat mass in young, healthy women.

DESIGN

We used a randomized, 1-y intervention for dairy calcium. Subjects were 155 young (aged 18-30 y), healthy, normal-weight women with intake of dietary calcium < 800 mg/d and energy intake </= 2200 kcal/d. Women were randomly assigned to 1 of 3 groups: 1) control: continue established dietary intake; 2) medium dairy: substitute dairy products to achieve intake of calcium of approximately 1000-1100 mg/d and maintain isocaloric intake; 3) high dairy: substitute dairy products to achieve intake of calcium of 1300-1400 mg/d and maintain isocaloric intake. The main outcome measures were 1-y changes in body weight (in kg) and fat mass (in kg). One hundred thirty-five women completed the trial.

RESULTS

Mean intakes of calcium during the intervention were 742.4 +/- 321.5, 1026.4 +/- 311.3, and 1131.29 +/- 337.2 mg/d for the control, medium-dairy, and high-dairy groups, respectively (P < 0.0001). No significant differences were observed in the mean 1-y change in body weight between the control, medium-dairy, and high-dairy groups (0.8 +/- 2.8, 0.7 +/- 3.0, and 1.5 +/- 4.1 kg, respectively; P = 0.45). No significant differences were observed in the mean 1-y change in fat mass between the control, medium-dairy, and high-dairy groups (-0.5 +/- 2.5, 0.3 +/- 2.7, and 0.5 +/- 3.5 kg, respectively; P = 0.26).

CONCLUSION

Increased intake of dairy products does not alter body weight or fat mass in young, healthy women over 1 y.

Parental pressure, dietary patterns, and weight status among girls who are "picky eaters"

OBJECTIVE

To determine whether mothers' fruit and vegetable intake and mothers' use of pressure in the feeding domain when their daughters were 7 years old predicted picky eating and dietary intake when their daughters were 9 years old, and to examine diet and weight status in picky and nonpicky eaters.

DESIGN/SUBJECTS

Participants were 173 9-year-old non-Hispanic white girls and their mothers. A longitudinal analysis was used to assess maternal influences on picky eating and diet. A cross-sectional analysis was used to examine diet and weight status between picky and nonpicky eaters. Measures included maternal feeding practices, daughters' pickiness, mothers' fruit and vegetable intake, daughters' food intake, and weight status.

STATISTICAL ANALYSES

t tests examined differences between picky and nonpicky eaters. Structural equation modeling examined relationships among mothers' fruit and vegetable intake; child feeding practices; daughters' pickiness; and fruit, vegetable, micronutrient, and fiber intakes.

RESULTS

Mothers consuming more fruits and vegetables were less likely to pressure their daughters to eat and had daughters who were less picky and consumed more fruits and vegetables. Picky eaters consumed fewer fruits and vegetables, but also fewer fats and sweets. All girls consumed low amounts of vitamin E, calcium, and magnesium, but more picky girls were at risk for not meeting recommendations for vitamins E and C and also consumed significantly less fiber. In addition, picky eaters were less likely to be overweight.

CONCLUSIONS

Mothers influenced daughters' fruit and vegetable intake via their own patterns of fruit and vegetable intake and by influencing their daughters' tendencies to be picky eaters. Both picky and nonpicky eaters had aspects of their diets that did not meet recommendations. Taken together, these findings suggest that parents should focus less on "picky eating" behavior and more on modeling fruit and vegetable consumption for their children.

Meeting calcium recommendations during middle childhood reflects mother-daughter beverage choices and predicts bone mineral status

BACKGROUND

Longitudinal data regarding the influence of beverage intakes on calcium adequacy are lacking.

OBJECTIVE

This study evaluated calcium intake from ages 5 to 9 y as a function of mother-daughter beverage choices and as a predictor of bone mineral status.

DESIGN

Intakes of energy, calcium, milk, sweetened beverages, fruit juices, and non-energy-containing beverages were measured with the use of three 24-h dietary recalls in 192 non-Hispanic white girls aged 5, 7, and 9 y and their mothers. Calcium intakes from ages 5 to 9 y were categorized as either meeting or falling below recommended adequate intakes (AIs). The girls' bone mineral status was assessed with dual-energy X-ray absorptiometry at age 9 y.

RESULTS

The mean 5-y calcium intake was related to bone mineral density at age 9 y (beta = 0.27, P < 0.001). The girls who met the AI for calcium were not heavier (P = 0.83) but had higher energy intakes (P < 0.0001) than did the girls who consumed less than the AI. Compared with the girls who consumed less than the AI, the girls who met the AI consumed, on average, almost twice as much milk (P < 0.0001), had smaller decreases in milk intake (P < 0.01), and consumed 18% less sweetened beverages (P < 0.01) from ages 5 to 9 y; the 2 groups did not differ significantly in juice and non-energy-containing beverage intakes. The girls who met the AI were also served milk more frequently than were the girls who consumed less than the AI (P < 0.0001) and had mothers who drank milk more frequently (P < 0.01) than did the mothers of the girls who consumed less than the AI.

CONCLUSIONS

These findings provide new longitudinal evidence that calcium intake predicts bone mineral status during middle childhood and reflects mother-daughter beverage choice patterns that are established well before the rapid growth and bone mineralization observed in adolescence.

Protective role of n-3 lipids and soy protein in osteoporosis

It is well established that bone loss due to estrogen deficiency after menopause is greater in women consuming higher quantities of animal protein than in women consuming vegetable protein, particularly soy protein. Besides the dietary protein source altering bone loss, it has also been postulated recently that the source of a higher n-6/n-3 ratio in dietary oils is implicated in causing osteoporosis. Both animal and human studies have indicated that an increased intake of n-6 fatty acids from vegetable oils elevates prostaglandin E(2) levels as well as pro-inflammatory cytokines such as IL-1, IL-6 and TNF-alpha. Interestingly, it has been found that lack of estrogen also increases the production of these cytokines by immune cells and thereby activates osteoclasts during the peri-menopausal period. We speculated that the use of n-3 fatty acids and soy protein, which are known to act as anti-inflammatory and down regulate pro-inflammatory cytokines, may also protect against bone loss by decreasing osteoclast activation and bone resorption. Similar to the results of others, our ongoing studies indeed show that the bone loss in ovariectomized mice is significantly attenuated by feeding diets enriched with either fish oil or soy protein when compared to corn oil and casein-fed mice. One of the mechanisms appears to be decreasing the activation of receptor activator of NF-kappaB ligand (RANKL) on T cells, which has been found to increase osteoclast activation along with increasing pro-inflammatory cytokines in OVX mice. Since hormone replacement therapy has been found to cause adverse effects, further both animal and human studies are required with moderate soy protein and fish oil supplements in understanding the mechanisms involved in altering immune function and bone loss during menopause in women and aging in men.