Racial differences in the effect of early milk consumption on peak and postmenopausal bone mineral density

Causal relationship between childhood obesity and osteoporosis: A STROBE two-sample Mendelian randomization study

The causal relationship between childhood obesity and osteoporosis is not yet clear. Two-sample randomized Mendelian analysis was applied to examine the causal relationship between childhood obesity and osteoporosis. This study employs a two-sample Mendelian randomization (MR) approach. The single-nucleotide polymorphisms associated with childhood obesity and summary-level data for osteoporosis were selected from publicly published genome-wide association study. The childhood obesity dataset includes individuals under the age of 18 with a body mass index exceeding the 95th percentile, representing both male and female European children. The osteoporosis dataset includes individuals with osteoporosis from the European population (age 0-70), encompassing both genders. MR analysis was primarily conducted via inverse-variance weighted analysis. Quality of our study was assessed according to STROBE-MR guidelines. MR analysis revealed a statistically significant association between childhood obesity and osteoporosis via the inverse-variance weighted method (odds ratio 0.9985, 95% CI [0.9974, 0.9996], P = .0087). Other MR analysis methods also confirmed this result. The heterogeneity analysis and sensitivity analysis show the accuracy and robustness of our results. Our MR study revealed a significant causal relationship between childhood obesity and osteoporosis, indicating that childhood obesity can reduce the incidence of osteoporosis.

New insights into dairy management and the prevention and treatment of osteoporosis: The shift from single nutrient to dairy matrix effects-A review

Dairy is recognized as a good source of calcium, which is important for preventing osteoporosis. However, the relationship between milk and bone health is more complex than just calcium supplementation. It is unwise to focus solely on observing the effects of a single nutrient. Lactose, proteins, and vitamins in milk, as well as fatty acids, oligosaccharides, and exosomes, all work together with calcium to enhance its bioavailability and utilization efficiency through various mechanisms. We evaluate the roles of dairy nutrients and active ingredients in maintaining bone homeostasis from the perspective of the dairy matrix effects. Special attention is given to threshold effects, synergistic effects, and associations with the gut-bone axis. We also summarize the associations between probiotic/prebiotic milk, low-fat/high-fat milk, lactose-free milk, and fortified milk with a reduced risk of osteoporosis and discuss the potential benefits and controversies of these dairy products. Moreover, we examine the role of dairy products in increasing peak bone mass during adolescence and reducing bone loss in old age. It provides a theoretical reference for the use of dairy products in the accurate prevention and management of osteoporosis and related chronic diseases and offers personalized dietary recommendations for bone health in different populations.

A review of dairy food intake for improving health among black geriatrics in the US

The transition to older adulthood is generally marked by progressive declines in body composition, metabolism, cognitive function, and immunity. For socially disadvantaged geriatric populations such as Black Americans, this life stage may also include additional stressors, including dealing with discrimination, poor access to healthcare, and food insecurity. These types of chronic stressors are linked to a higher allostatic load, which is associated with accelerated biological aging, higher rates of adverse health outcomes, and an overall lower quality of life. Of the numerous factors involved in healthy aging, a growing body of research indicates that consuming a higher quality diet that is rich in fruits, vegetables, whole grains, protein foods, and dairy foods, is one of the most potent factors for helping to protect against age-related disease progression. Among the food groups listed above that are recommended by the 2020-2025 Dietary Guidelines for Americans dairy foods are unique in their ability to provide several of the essential nutrients (e.g., high-quality protein, calcium, potassium, vitamin B12, and vitamin D in fortified products) that are most often inadequately consumed by older Black Americans. However, dairy is the most inadequately consumed food group in the US, with older Black adults consuming fewer than half of the 3 daily recommended servings. Therefore, this review examines the current body of evidence exploring the links between dairy intake and age-related disease risk, with a special focus on health and disparities among older Black Americans. Overall, the evidence from most systematic reviews and/or meta-analyses focused on dairy intake and musculoskeletal health suggest that higher dairy intake across the life span, and especially from fermented and fortified products, is associated with better bone and muscle health outcomes in older adults. The evidence on dairy intake and neurocognitive and immune outcomes among older adults holds significant promise for potential benefits, but most of these results are sourced from individual studies or narrative reviews and are not currently corroborated in systematic reviews or meta-analyses. Additionally, most of the research on dairy intake and age-related disease risk has been performed in White populations and can only be extrapolated to Black populations. Nonetheless, older Black populations who do not meet the DGA recommended 3 servings of dairy per day due to lactose intolerance, restrictive dietary patterns, or for other reasons, are likely falling short of several of the nutritional requirements necessary to support healthy aging.

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.

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.

Nutritional intake and bone health

Osteoporotic or fragility fractures affect one in two women and one in five men who are older than 50. These events are associated with substantial morbidity, increased mortality, and an impaired quality of life. Recommended general measures for fragility fracture prevention include a balanced diet with an optimal protein and calcium intake and vitamin D sufficiency, together with regular weight-bearing physical exercise. In this narrative Review, we discuss the role of nutrients, foods, and dietary patterns in maintaining bone health. Much of this information comes from observational studies. Bone mineral density, microstructure-estimated bone strength, and trabecular and cortical microstructure are positively associated with total protein intake. Several studies indicate that fracture risk might be lower with a higher dietary protein intake, provided that the calcium supply is sufficient. Dairy products are a valuable source of these two nutrients. Hip fracture risk appears to be lower in consumers of dairy products, particularly fermented dairy products. Consuming less than five servings per day of fruit and vegetables is associated with a higher hip fracture risk. Adherence to a Mediterranean diet or to a prudent diet is associated with a lower fracture risk. These various nutrients and dietary patterns influence gut microbiota composition or function, or both. The conclusions of this Review emphasise the importance of a balanced diet including minerals, protein, and fruit and vegetables for bone health and in the prevention of fragility fractures.

Calcium: More Than Bone? Implications for Clinical Practice and Theory

Serum calcium is routinely screened, but rarely scrutinized in the context of normal, physiologic functioning. This brief review strives to explore the implications of serum calcium, suggests guidelines for its interpretation, and discusses the implications of high, low, and “normocalcemia” in the clinical setting. We find that serum Ca²⁺ concentrations are a valuable prognostic indicator in routine metabolic workups and advocate for greater attention, on behalf of the provider, to variations in a patient’s calcemic status. Variations in calcemic status are primarily tied to malignancy, impaired parathyroid hormone (PTH) secretion, defects in vitamin D synthesis, insulin-like growth factor 1 (IGF-1) fluctuation, genetic syndromes (DiGeorge syndrome) and calcium-sensing receptor (CaSR) mutation. Prognostic implications for high and low serum Ca²⁺ include, but are not limited to, increased thromboembolic and major adverse cardiovascular event (MACE) risk, cardiac remodeling, hypertension, cognitive decline, and insulin resistance.

Effects of Fermented Milk Products on Bone

Fermented milk products like yogurt or soft cheese provide calcium, phosphorus, and protein. All these nutrients influence bone growth and bone loss. In addition, fermented milk products may contain prebiotics like inulin which may be added to yogurt, and provide probiotics which are capable of modifying intestinal calcium absorption and/or bone metabolism. On the other hand, yogurt consumption may ensure a more regular ingestion of milk products and higher compliance, because of various flavors and sweetness. Bone mass accrual, bone homeostasis, and attenuation of sex hormone deficiency-induced bone loss seem to benefit from calcium, protein, pre-, or probiotics ingestion, which may modify gut microbiota composition and metabolism. Fermented milk products might also represent a marker of lifestyle promoting healthy bone health.

Effects of Proton Pump Inhibitor Administration and Intake of a Combination of Yogurt and Galactooligosaccharides on Bone and Mineral Metabolism in Rats

The aim of this study was to investigate the effects of proton pump inhibitor (PPI), the most potent acid-suppressing drug, administration and intake of a combination of yogurt and galactooligosaccharides (YG) on bone and mineral metabolism in adult rats. Twelve-week-old male Wistar rats were divided into three groups: a control group fed the control diet with vehicle administration, a PPI group fed the control diet with PPI administration and a YG + PPI group fed the YG diet with PPI administration. All of the groups received their respective experimental diets and daily subcutaneous injection of the vehicle or PPI for 12 weeks. The PPI group showed significantly lower bone mineral density (BMD) of the femur and the lumbar vertebrae and serum fibroblast growth factor 23 (FGF23) and significantly higher phosphorus absorption and serum 1,25-dihydroxyvitamin D (1,25(OH)2D) than the control group, although PPI did not affect calcium absorption. The PPI + YG group showed significantly higher BMD and serum FGF23 and significantly lower phosphorus absorption and serum 1,25(OH)2D than the PPI group. Furthermore, the PPI + YG group showed higher calcium absorption than the control group. These results suggest that although PPI administration did not affect calcium absorption, it adversely affected BMD and influenced phosphorus metabolism in adult rats. Furthermore, the YG diet beneficially affected BMD and attenuated the effects of PPI administration on phosphorus metabolism.

A biomechanical sorting of clinical risk factors affecting osteoporotic hip fracture

Osteoporotic fracture has been found associated with many clinical risk factors, and the associations have been explored dominantly by evidence-based and case-control approaches. The major challenges emerging from the studies are the large number of the risk factors, the difficulty in quantification, the incomplete list, and the interdependence of the risk factors. A biomechanical sorting of the risk factors may shed lights on resolving the above issues. Based on the definition of load-strength ratio (LSR), we first identified the four biomechanical variables determining fracture risk, i.e., the risk of fall, impact force, bone quality, and bone geometry. Then, we explored the links between the FRAX clinical risk factors and the biomechanical variables by looking for evidences in the literature. To accurately assess fracture risk, none of the four biomechanical variables can be ignored and their values must be subject-specific. A clinical risk factor contributes to osteoporotic fracture by affecting one or more of the biomechanical variables. A biomechanical variable represents the integral effect from all the clinical risk factors linked to the variable. The clinical risk factors in FRAX mostly stand for bone quality. The other three biomechanical variables are not adequately represented by the clinical risk factors. From the biomechanical viewpoint, most clinical risk factors are interdependent to each other as they affect the same biomechanical variable(s). As biomechanical variables must be expressed in numbers before their use in calculating LSR, the numerical value of a biomechanical variable can be used as a gauge of the linked clinical risk factors to measure their integral effect on fracture risk, which may be more efficient than to study each individual risk factor.

Interventions to Increase Dairy Consumption in Adolescents

Objective. Effective interventions are needed to address the reported inadequacies of dairy product and calcium (Ca) intakes among adolescents. The present review investigated interventions aimed at increasing adolescent dairy and/or Ca intakes and determined the characteristics associated with successful interventions. Design. A PRISMA systematic review search identified 17 interventions, described in 16 publications, between 1993 and 2015 (February). Studies were evaluated for population, delivery, dietary targets and outcomes measures, measure of intervention intensity, use of behavior change techniques, intervention effectiveness, and effect size and quality. Setting. Interventions targeting an increase in dairy food or Ca intake, either exclusively or in combination with other dietary modifications. Subjects. Adolescents, aged 12 to 18 years. Results. Twelve of the 17 interventions were found to be effective. Effective interventions tended to be higher in overall intensity (mean intensity: negative interventions 12.2, positive interventions 14.25), with the most notable difference in the duration category, such that effective interventions tended to be longer in duration. The number of behavior change techniques applied did not differentiate effective and ineffective interventions, but prompting the review of behavioral goals and including interviews or brief counseling appeared to be important for effective interventions. Effective interventions tended to have higher methodological quality, while the majority of ineffective interventions were qualitatively assessed as weak. Conclusions. The current review has identified characteristics of effective interventions that offer insight into promising strategies likely to increase dairy consumption and Ca intakes in countries where adolescent intake is insufficient. These findings may have important implications for future intervention design.

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.

No association between bone mass and prolactin levels among patients with schizophrenia

OBJECTIVE

Decreased bone mineral density has been implicated in schizophrenic patients for long years. The purpose of this study was to assess the relationship between bone mass and prolactin levels in schizophrenic patients.

METHODS

In this study, bone mass was measured using quantitative ultrasound densitometry of the calcaneus in 114 patients (49 males and 65 females). The osteosono-assessment index (OSI) was calculated as a function of the speed of sound and transmission index. Estradiol, testosterone, and prolactin levels were also measured. Factors that influenced prolactin levels and bone mass were determined via multiple linear regression analysis.

RESULTS

Among the female patients, body mass index and estradiol levels were independently and significantly associated with the OSI. Neither prolactin levels nor duration of antipsychotic treatment was associated with bone mass for either gender.

CONCLUSIONS

These findings suggest that prolactin levels do not contribute to poor bone mass, as assessed using the OSI among schizophrenic patients. However, the interpretation of our results was hampered by lack of data including differences in lifestyle and type of antipsychotic medications used in schizophrenic patients. Association between prolactin levels and low bone mineral density was not completely ruled out. Future research exploring prolactin levels and bone mineral density is warranted.

A dairy product fermented by lactobacilli cancels the adverse effects of hypochlorhydria induced by a proton pump inhibitor on bone metabolism in growing rats

The purpose of the present study is to investigate the effects of hypochlorhydria induced by proton pump inhibitor (PPI) administration and intake of a dairy product fermented by lactobacilli (DFL) on bone metabolism in growing rats. Male rats, aged 3 weeks, were divided into two groups: a control group fed a casein-based diet and a group fed a DFL-based diet. Each group was fed its respective experimental diets for 9 d. At day 5 of the feeding period, each group was divided into two subgroups: one that received a saline injection and one that received a PPI injection. Rats were subcutaneously administered saline or PPI for 5 d. Faecal Ca excretion was determined from day 6 to day 9. At the end of the experiment, plasma and femurs were collected. Administration of PPI significantly decreased bone mineral density (shown by X-ray computerised tomography) and bone strength (shown by a three-point bending test) in the control group. Plasma osteocalcin, type I collagen C-telopeptides, 1,25-dihydroxyvitamin D and parathyroid hormone concentrations were elevated by PPI administration in the control group. Faecal Ca excretion and urinary P excretion in the control group were remarkably increased by PPI administration. On the other hand, these adverse effects of PPI were not observed in the DFL group. These results suggest that hypochlorhydria-induced bone loss may result from high bone turnover induced by secondary hyperparathyroidism due to Ca malabsorption and that DFL intake cancels these adverse effects probably via improving Ca malabsorption in growing rats.

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.

The bare bones of race

In this paper I examine claims of racial difference in bone density and find that the use and definitions of race in medicine lack a theoretical foundation. My central argument is that the social produces the biological in a system of constant feedback between body and social experience. By providing a different angle of vision on claimed racial differences I hope to move the conversation away from an ultimately futile discussion of nature versus nurture, where time is held constant and place seen as irrelevant, and begin to build a new paradigm for examining the contributions of geographic ancestry, individual lifecycle experience, race, and gender to varied patterns of health and disease.

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.

Effects of dietary lactose on long-term high-fat-diet-induced obesity in rats

OBJECTIVE

In this study, we examined the effects of lactose on long-term high-fat-diet-induced obesity in rats.

RESEARCH METHODS AND PROCEDURES

A total of 112 Sprague-Dawley strain female rats (6 weeks old) were divided into four groups: a basic control diet group (Cont), 10% lactose diet group (Lac), high-fat diet group (Fat), and high-fat with 10% lactose diet group (Fat+Lac). After 0, 7, 14, and 84 days from starting the experimental diet, the animals were fasted overnight and killed by bleeding from the abdominal aorta under anesthesia (n = 8 or 9/group).

RESULTS

After 84 days, the addition of lactose to the high-fat diet decreased the final body weight, body weight gain, fat accumulation, and the levels of serum leptin, serum triglycerides, and serum glucose significantly (p < 0.05). Although there was no significant difference in the levels of serum calcium and phosphorus between the Fat and Fat+Lac groups, lumbar vertebral bone mineral density was significantly higher in the Fat+Lac group than in the Cont group on Day 82. Interestingly, the level of serum 1alpha, 25-dihydroxyvitamin D(3) in the Fat+Lac group on Day 84 was reduced by 74% compared with the Fat group (p < 0.01), while there was no significant difference in serum parathyroid hormone levels between the Fat and Fat+Lac groups.

DISCUSSION

This is the first study to suggest that the addition of lactose to a long-term high-fat diet may regulate not only calcium metabolism but also fat deposition. Further studies on the mechanism of dietary lactose in the regulation of adiposity would provide valuable data for the prevention of long-term high-fat-diet-induced obesity.

Magnesium intake from food and supplements is associated with bone mineral density in healthy older white subjects

OBJECTIVES

To determine whether magnesium intake from supplemental and dietary sources is associated with bone mineral density (BMD) in older men and women.

DESIGN

Cross-sectional.

SETTING

Memphis, Tennessee, and Pittsburgh, Pennsylvania.

PARTICIPANTS

Two thousand thirty-eight older black and white men and women aged 70 to 79 at baseline enrolled in the Health, Aging and Body Composition Study.

MEASUREMENTS

Dietary intake of magnesium was assessed using a semiquantitative food frequency questionnaire, and supplement data were collected based on a medication inventory. BMD of the whole body was obtained using a fan-beam densitometer. Additional covariates included age, body mass index (BMI), smoking status, alcohol use, physical activity, estrogen use, and supplemental calcium (Ca) and vitamin D use.

RESULTS

In white, but not black, men and women, magnesium intake was positively associated with BMD of the whole body after adjustment for age, self-report of osteoporosis or fracture in adulthood, caloric intake, Ca and vitamin D intake, BMI, smoking status, alcohol intake, physical activity, thiazide diuretic use, and estrogen use in women (P=.05 for men and P=.005 for women). BMD was 0.04 g/cm2 higher in white women and 0.02 g/cm2 higher in white men in the highest than in the lowest quintile of magnesium intake.

CONCLUSION

Greater magnesium intake was significantly related to higher BMD in white women and men. The lack of association observed in black women and men may be related to differences in Ca regulation or in nutrient reporting.

Socioeconomic influences on bone health in postmenopausal women: findings from NHANES III, 1988-1994

Our objectives were (1) to examine the associations of education and income with bone health in non-Hispanic White, non-Hispanic Black and Mexican-American postmenopausal women, (2) to determine if any observed associations can be explained by behavioral factors such as calcium intake and physical activity and (3) to determine if government food assistance and education are associated with increased calcium intake among low-income women. Cross-sectional data were gathered by the Third National Health and Nutrition Examination Survey, 1988-1994 (NHANES III) using a stratified multistage probability design. Bone health was indicated by total hip bone mineral density (BMD, g/cm2). Multiple linear regression was used to evaluate the associations of education, income and behavioral factors with BMD. There were 2,905 postmenopausal women with acceptable DXA scans and complete relevant data selected from a nationally representative sample of the civilian non-institutionalized population aged 2 months and older. Education and income were positively associated with BMD in Black and White women, respectively, but not in Mexican-American women. When behavioral factors were included in the analyses, associations with education and income were eliminated. Instead, positive associations with estrogen use, calcium intake and physical activity, and a negative association with smoking, were noted in White women. Among low-income women, education was associated with increased calcium intake, while participation in the Food Stamp Program was associated with increased calcium intake in Black women. We conclude that education and/or income are positively associated with BMD among Black and White postmenopausal women, and that efforts to promote bone health among low-income women are warranted.

Does milk make children grow? Relationships between milk consumption and height in NHANES 1999-2002

In the United States, milk (usually cow's milk) is widely considered an "essential food" to support bone growth among post-weaning age children, as evident in government-sponsored nutrition policies that mandate milk for children. Milk contains calories, protein, and calcium, among other nutrients, and bioactive components such as insulin-like growth factor-I (IGF-I), all of which may facilitate bone growth. There is a large literature on milk and/or calcium intake and its effects on bone density, but one aspect of bone mass--height--is not well studied in relation to milk consumption. Limited experimental studies show no consistent relationship across populations. To investigate this linkage among American children, analysis of the NHANES 1999-2002 was undertaken. NHANES data allow two hypotheses to be tested: (1) reported frequency of childhood milk consumption will be positively related to adult height and (2) height of children 5-18 years will be predicted by the reported frequency of milk consumption and/or milk intake from a 24-h dietary recall. Results indicate that adult height was positively associated with milk consumption at ages 5-12 and 13-17, after controlling for sex, education, and ethnicity. Among contemporary children, milk consumption had no effect on the height of 5-11 year olds after controlling for age, birthweight, energy intake, and ethnicity. In contrast, milk consumption frequency and milk intake (measured as grams of milk, or protein or calcium from milk) were significant predictors of the height of 12-18 year olds, along with age, sex, household income, and ethnicity. The greatest ethnic contrasts were between Mexican Americans and non-Hispanic whites and blacks, and milk variables remained significant predictors of height in these comparisons. Thus NHANES data show substantial variability in the effects of milk consumption on height.

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.

Two-year changes in bone and body composition in young children with a history of prolonged milk avoidance

No previous longitudinal studies of calcium intake, anthropometry and bone health in young children with a history of avoiding cow's milk have been undertaken. We report the 2-year changes of a group of 46 Caucasian children (28 girls, l8 boys) aged 8.1+/-2.0 years (mean +/- SD) who had low calcium intakes at baseline and were short in stature, with elevated body mass index, poor skeletons and lower Z scores for both areal bone mineral density (BMD, in grams per square centimeter) and volumetric density (bone mineral apparent density, BMAD, in grams per cubic centimeter), compared with a reference population of milk drinkers. At follow-up, adverse symptoms to milk had diminished and modest increases in milk consumption and calcium intake had occurred. Total body bone mineral content (BMC) and bone area assessed by dual energy X-ray absorptiometry had increased (P<0.05), and calcium intake from all sources was associated with both these measures (P<0.05). However, although some catch-up in height had taken place, the group remained significantly shorter than the reference population (Z scores -0.39+/-1.14), with elevated body mass index (Z scores 0.46+/-1.0). The ultradistal radius BMC Z scores remained low (-0.31+/-0.98). The Z scores for BMD had improved to lie within the normal range at predominantly cortical sites (33% radius, neck of femur and hip trochanter) but had worsened at predominantly trabecular sites (ultradistal radius and lumbar spine), where values lay below those of the reference group (P<0.05). Similarly, although volumetric BMAD Z scores at the 33% radius had normalized, BMAD Z scores at the lumbar spine remained below the reference population at follow-up (-0.67+/-1.12, P<0.001). Our results demonstrate persisting height reduction, overweight and osteopenia at the ultradistal radius and lumbar spine in young milk avoiders over 2 years of follow-up.

Resting Energy Expenditure: A Better Marker than BMI for BMD in African-American Women

PURPOSE

African-American women tend to be more overweight and to have lower resting energy expenditures (REE) compared with Caucasian women. Weight is associated with bone mineral density (BMD), but the relation between BMD and REE has not been reported.

METHODS

Four hundred postmenopausal African-American women aged 45-87 (yr) from San Diego, CA participated in this community-based cross-sectional study. Body composition (fat mass, lean body mass), bone mineral content (BMC) and BMD of the lumbar spine, hip (femoral neck, greater trochanter, intertrochanter), and total body were measured using dual energy x-ray absorptiometry (DXA). REE was calculated using the Harris-Benedict equation; grip strength was measured by isometric dynamometry.

RESULTS

REE (r range: 0.32-0.79) showed the strongest correlation with spine, total hip, and total body BMC and BMD. In stepwise multiple linear regressions adjusted for age and grip strength, REE explained 15% of the variance in spine BMD, 33% of the variance in total hip, and 32% of the total body BMD variance. REE explained 63% of the total body BMC variance. When body weight replaced REE in the models, weight became the strongest covariate of BMC and BMD but explained 1% less of the variance in spine BMD, 5% less of the variance in total hip BMD, 4% less of the variance in total body BMD, and 3% less of the variances in spine, total hip, and total body BMC than did REE.

CONCLUSION

In this cohort of African-American women, weight explained less of the BMC and BMD variance than REE. Poor energy economy may contribute to being overweight and may explain the lower rates of osteoporosis observed in African-American women.