Osteoporosis and adipose tissue are closely related with many contradictions. Visfatin is an adipokine that is related to osteoporosis and adiposity. This nutrigenomics study examined the interaction between visfatin genotypes and dietary fat intake, with regard to bone mineral density (BMD) among an obese population. In this cross-sectional study, 336 subjects were enrolled; the mean age was 38·25 (sd 11·69) years and the mean BMI was 31·79 (sd 4·77) kg/m2. Laboratory measurements were lipid profile, insulin and fasting blood sugar. Bone density measurements were assessed by dual-energy X-ray absorptiometry. Dietary data were collected through a 3-d 24-h dietary recall. Genotyping for visfatin gene SNP (rs2110385) was performed by the PCR-restriction fragment length polymorphism method. The frequency of GG, GT and TT genotypes were 33·92 48·51 and 17·54 %, respectively, and 86·6 % of participants were women. The results showed that subjects with TT genotypes had significantly higher lumbar BMD, T score and z score (P<0·0001). After categorisation by percentage of fat intake (30 % of total energy content as a cut-off point), no interaction was found, but when categorised by fat types, we found an interaction between visfatin genotypes and dietary PUFA intake in terms of the hip T score and z score (P=0·043, B= −0·08; P=0·04, B= −0·078, respectively). There was a significant relationship between high PUFA intake and lower energy and protein intake. When participants were categorised by median PUFA intake (22·8 g), it was concluded that subjects with GG genotype who had high PUFA-intake diets had lower hip z scores and T scores, unlike the other genotypes.

A high Ca intake has been recommended for osteoporosis prevention; however, little research has examined the relationship between dietary Ca and bone health in men. We examined associations between dietary Ca intake, bone mineral density (BMD) and change in BMD at the total body, hip and spine over 2 years in a cohort of men (mean age 57 years, BMI 26 kg/m2) from a trial. Data from the total cohort (n 323) were used in the analysis of Ca intake and BMD at baseline, and data from the placebo group (n 99) were used in the longitudinal analysis of Ca intake and change in BMD. Parathyroid hormone (PTH) and the markers of bone turnover serum total alkaline phosphatase activity, serum C-telopeptide and serum procollagen type-1 N-terminal propeptide were measured in a subset of participants at baseline (n 150), and associations with dietary Ca at baseline were examined. Mean Ca intake was 870 mg/d. Baseline BMD was not related to dietary Ca intake at any site, before or after adjustment for covariables. Similarly, bone loss over 2 years was not related to Ca intake at any site, before or after adjustment. Dietary Ca intake was inversely correlated with PTH at baseline (r −0·19, P=0·02), but was not associated with the markers of bone turnover. BMD and rates of bone loss were unrelated to Ca intake in these men. This suggests that strategies to increase Ca intake are unlikely to impact on the prevalence of and morbidity from male osteoporosis.

Cod liver oil is a traditional source of vitamin D in Iceland, and regular intake is recommended partly for the sake of bone health. However, the association between lifelong consumption of cod liver oil and bone mineral density (BMD) in old age is unclear. The present study attempted to assess the associations between intake of cod liver oil in adolescence, midlife, and old age, and hip BMD in old age, as well as associations between cod liver oil intake in old age and serum 25-hydroxyvitamin D (25(OH)D) concentration. Participants of the Age, Gene/Environment Susceptibility–Reykjavik Study (age 66–96 years; n 4798), reported retrospectively cod liver oil intake during adolescence and midlife, as well as the one now in old age, using a validated FFQ. BMD of femoral neck and trochanteric region was measured by volumetric quantitative computed tomography, and serum 25(OH)D concentration was measured by means of a direct, competitive chemiluminescence immunoassay. Associations were assessed using linear regression models. No significant association was seen between retrospective cod liver oil intake and hip BMD in old age. Current intake of aged men was also not associated with hip BMD, while aged women with daily intakes had z-scores on average 0·1 higher, compared with those with an intake of < once/week. Although significant, this difference is small, and its clinical relevance is questionable. Intake of aged participants was positively associated with serum 25(OH)D: individuals with intakes of < once/week, one to six time(s)/week and daily intake had concentrations of approximately 40, 50 and 60 nmol/l respectively (P for trend < 0·001).

Some epidemiological evidence suggests that diets high in omega 3 fatty acids (n-3 FAs) may be beneficial for skeletal health. The aim of this systematic review was to determine if randomized controlled trials (RCTs) support a positive effect of n-3 FAs on osteoporosis. A systematic search was performed in PubMed and EMBASE databases. We included RCTs with skeletal outcomes conducted in adults or children (> = 1 year old) using n-3 FA fortified foods, diets or supplements alone or in combination with other vitamins/minerals, versus placebo. Primary outcomes were incident fracture at any site and bone mineral density (BMD) in g/cm2. Secondary outcomes included bone formation or resorption markers and bone turnover regulators. A total of 10 RCTs met inclusion criteria. Effect sizes with 95 % confidence intervals were estimated to compare studies across various treatments and outcome measures. No pooled analysis was completed due to heterogeneity of studies and small sample sizes. No RCTs included fracture as an outcome. Four studies reported significant favorable effects of n-3 FA on BMD or bone turnover markers. Of these, three delivered n-3 FA in combination with high calcium foods or supplements. Five studies reported no differences in outcomes between n-3 FA intervention and control groups; one study included insufficient data for effect size estimation. Strong conclusions regarding n-3 FAs and bone disease are limited due to the small number and modest sample sizes of RCTs, however, it appears that any potential benefit of n-3 FA on skeletal health may be enhanced by concurrent administration of calcium.

Laying hens have a unique bone turnover due to the daily egg laying cycle. Laying hens have three distinctive kinds of bones related to egg formation: cortical, cancellous, and medullary bones. Cortical bone is a compact structural bone, whereas cancellous bone is the three-dimensional lattice-like honeycomb architecture at the end of long bones. Medullary bone is a highly labile woven bone lying in the marrow cavities. Medullary bone acts as Ca storage for egg shell formation. Thus, bone quality is closely related with egg production and eggshell quality. During the daily egg laying cycle, medullary bone osteoclasts alternately cease and accelerate bone resorption. Although osteoclast numbers are not changed during the daily egg laying cycle, considerable morphological changes in osteoclasts occur along with changes in calcium requirements for egg shell formation. Furthermore, the selection of proper methods is critical to obtain precise bone evaluation data, and include bone ashing, densitometric techniques, mechanical testing, or histomorphometry to evaluate bone status in laying hens. Since bone metabolism in laying hens is related to economic and animal welfare issues, better understanding of bone metabolism in laying hens would be important to enhance productivity and improve animal welfare.

Phyto-oestrogens have been associated with a decreased risk for osteoporosis, but results from intervention and observational studies in Western countries have been inconsistent. In the present study, we investigated the association between habitual phyto-oestrogen intake and broadband ultrasound attenuation (BUA) of the calcanaeum as a marker of bone density. We collected 7 d records of diet, medical history and demographic and anthropometric data from participants (aged 45–75 years) in the European Prospective Investigation into Cancer-Norfolk study. Phyto-oestrogen (biochanin A, daidzein, formononetin; genistein, glycitein; matairesinol; secoisolariciresinol; enterolactone; equol) intake was determined using a newly developed food composition database. Bone density was assessed using BUA of the calcanaeum. Associations between bone density and phyto-oestrogen intake were investigated in 2580 postmenopausal women who were not on hormone replacement therapy and 4973 men. Median intake of total phyto-oestrogens was 876 (interquartile range 412) μg/d in postmenopausal women and 1212 (interquartile range 604) μg/d in men. The non-soya isoflavones formononetin and biochanin A were marginally significant or significantly associated with BUA in postmenopausal women (β = 1·2; P < 0·1) and men (β = 1·2; P < 0·05), respectively; enterolignans and equol were positively associated with bone density in postmenopausal women, but this association became non-significant when dietary Ca was added to the model. In the lowest quintile of Ca intake, soya isoflavones were positively associated with bone density in postmenopausal women (β = 1·4; P < 0·1). The present results therefore suggest that non-soya isoflavones are associated with bone density independent of Ca, whereas the association with soya or soya isoflavones is affected by dietary Ca.

Considerable research on osteoporosis has recently focused on the prevention of bone loss in the later years. Researchers and clinicians are now able to accurately measure the effects of therapies and preventive strategies on the skeleton. It has been suggested that regular physical activity will be one of the valuable strategies in maintaining bone density and preventing osteoporosis. This paper will review the quantitative techniques available for bone density assessment and provide an overview of the recent cross-sectional and longitudinal studies related to the potential benefits of physical activity on the aging skeleton.

Controversy continues over the relationship between calcium intake and bone density in women. Epidemiological evidence does not strongly support the conclusion that high levels of dietary calcium during the postmenopausal years influence the extent or rate of bone loss. Dietary calcium in the growing years may be a determinant of peak adult bone density attained at maturity. Experimental trials do not appear to support the contention that calcium supplementation will restore lost bone in healthy or osteoporotic postmenopausal women. However, an increased calcium intake to an optimal individual level may slow the rate of bone loss in postmenopausal women. The cross-sectional and controlled investigations regarding the relationship between calcium intake and bone density will be discussed in this review.

New strategies to improve Ca absorption and bone health are needed to address the current state of osteoporosis prevention and management. Inulin-type fructans have shown great promise as a dietary intervention strategy, but have not yet been tested in a young female model. Our objective was to investigate the effect of long chain (LC) inulin on bone mineralization and density in growing, female rats, as well as the quality of growth. Weanling Sprague–Dawley rats were assigned to inulin or cellulose treatments for either 4 or 8 weeks. Growth was measured weekly and quality of growth assessed using fat pad weights and dual-energy X-ray absorptiometry (DXA). Whole body (WB) and selected regions were analysed for bone mineral density (BMD) and body composition by DXA. Serum markers of bone turnover were assessed by enzyme-linked immunosorbent assays. Ca and P concentrations were determined in excised femurs by inductively coupled plasma spectrometry. Feeding inulin resulted in 4 % higher femoral weight (adjusted for body weight) and 6 % less feed intake. Inulin did not affect WB or regional BMD, but was associated with a 28 % lower parametrial fat pad mass, 21 % less WB fat mass and 5 % less WB mass. In summary, LC-inulin lowered body fat mass, without consequence to bone density in growing female rats.

Deficiency of oestrogen at menopause decreases intestinal Ca absorption, contributing to a negative Ca balance and bone loss. Mg deficiency has also been associated with bone loss. The purpose of the present investigation was to test the hypothesis that treatment with a spray-dried mixture of chicory oligofructose and long-chain inulin (Synergy1; SYN1) would increase the absorption of both Ca and Mg and alter markers of bone turnover. Fifteen postmenopausal women (72·2 (sd 6·4) years) were treated with SYN1 or placebo for 6 weeks using a double-blind, placebo-controlled, cross-over design. Fractional Ca and Mg absorption were measured using dual-tracer stable isotopes before and after treatment. Bone turnover markers were measured at baseline, 3 and 6 weeks. Fractional absorption of Ca and Mg increased following SYN1 compared with placebo (P < 0·05). Bone resorption (by urinary deoxypyridinoline cross-links) was greater than baseline at 6 weeks of active treatment (P < 0·05). Bone formation (by serum osteocalcin) showed an upward trend at 3 weeks and an increase following 6 weeks of SYN1 (P < 0·05). Closer examination revealed a variation in response, with two-thirds of the subjects showing increased absorption with SYN1. Post hoc analyses demonstrated that positive responders had significantly lower lumbar spine bone mineral density than non-responders (dual X-ray absorptiometry 0·887 ± 0·102 v. 1·104 ± 0·121 g/cm2; P < 0·01), and changes in bone turnover markers occurred only in responders. These results suggest that 6 weeks of SYN1 can improve mineral absorption and impact markers of bone turnover in postmenopausal women. Further research is needed to determine why a greater response was found in women with lower initial spine bone mineral density.

Osteophagia, variable serum calcium (Ca) and phosphorus (P) concentration, high serum alkaline phosphatase activity, a high growth rate, and a large skeletal mass, all suggest that Ca and P requirements and availability are finely balanced in giraffes. The mineral content of some marker bones in skeletons obtained from adult male giraffes (browsers) and adult male African buffaloes (grazers of similar body mass) were compared to assess the idea of critical Ca and P balance. Our results show that the P concentration of plasma varies more than Ca concentration, and that the Ca content of giraffe bones (0.196±0.01 g/g) and buffalo (0.202±0.006 g/g) varies more than P content (0.095±0.002 in both). The average Ca and P content of the bones analysed was similar in both species (Ca=∼20.0%, P=∼9.5%). Giraffe skeletons, however, contain three times more Ca and P than do buffalo skeletons. This translates into a 1.5–2.0 fold higher Ca requirement for giraffes, with which they seem to cope effectively by selection for Ca-rich, dicotyledonous, browse. Sources of P to meet requirements are not obvious and a seasonal deficiency of P is a more likely cause of observed osteophagia than Ca deficiency. Giraffe rib P density, the best measure of P balance, of 0.142±0.01 g/cm3 is, however, above the deficiency threshold. Bone mineral content (Ca and P) correlates well with bone density and shows only slight differences between adult males of the two species.

Bovine milk has been shown to contain bioactive components with bone-protective properties. Earlier studies on bovine milk whey protein showed that it suppressed bone resorption in the female ovariectomised rat. A new osteotropic component was subsequently identified in the whey basic protein fraction, but bone bioactivity may also be associated with other whey fractions. In the present study, we investigated whether acidic protein fractions isolated from bovine milk whey could prevent bone loss in mature ovariectomised female rats. Six-month-old female rats were ovariectomised (OVX) or left intact (sham). The OVX rats were randomised into four groups. One group remained the control (OVX), whereas three groups were fed various whey acidic protein fractions from milk whey as 3g/kg diet for 4 months. Outcomes were bone mineral density, bone biomechanics and markers of bone turnover. Bone mineral density of the femurs indicated that one of the whey AF over time caused a recovery of bone lost from OVX. Plasma C-telopeptide of type I collagen decreased significantly in all groups except OVX control over time, indicating an anti-resorptive effect of whey acidic protein. Biomechanical data showed that the AF may affect bone architecture as elasticity was increased by one of the whey AF. The femurs of AF-supplemented rats all showed an increase in organic matter. This is the first report of an acidic whey protein fraction isolated from milk whey that may support the recovery of bone loss in vivo.

Unique features of giraffe Giraffa camelopardalis anatomy are its long neck and slender long limbs. Its neck vertebrae should be light and have low density to make it manoeuvrable while the limb bones should have high density to provide the strength to support the giraffe's mass. Giraffes also have a very high vertical growth rate, a diet with a high Ca:P ratio, and a skeleton that constitutes a high proportion of its body mass. To investigate whether the giraffe skeleton is affected by its anatomy and biology, giraffe bone density and morphology were compared with those of African buffalo Syncerus caffer, an artiodactyl of similar mass, more conventional anatomy, a lower vertical growth rate, and different diet. Our results show that except for minor differences the density of giraffe bones is the same as that of buffaloes. Giraffe limb bones have a slightly greater diameter and much thicker walls than equivalent bones in buffaloes. Giraffe cervical vertebrae, unlike those in buffaloes, decrease in mass with cranial distance. We conclude that giraffe biology and anatomy do not affect bone deposition or density. However, other characteristics of their skeletons seem to be adaptations to their unique anatomy.