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.

Comparative effects of Venlafaxine and Alendronate on Biochemical, Bone mechanical and Anti-inflammatory properties in ovariectomized rats

The drug of choice in the treatment of postmenopausal osteoporosis is alendronate. Antidepressive agents are currently used in combination with alendronate to protect against depression and may affect the condition of osteoporosis. The aim is to study the comparative effects of venlafaxine and alendronate on biochemical, bone mechanical and anti-inflammatory properties in osteoporotic induced rats. 36 female Wistar albino rats were included (6 rats/group). Treated groups were ovariectomized bilaterally to induce osteoporosis. Rats were treated orally with alendronate (3mg/kg/day) and venlafaxine (20mg/kg/day) and combined alendronate and venlafaxine for 28 days. Body weight, serum alkaline phosphates, serum calcium, three point bending test, bone mineral mass and inflammatory cytokines The induction of osteoporosis showed significant elevated serum alkaline phosphatase, decreased serum calcium, body weight, bone mineral mass and inflammatory cytokines. Venlafaxine treatment did not ameliorate the changes in tested parameters, where at end of the experiment alendronate has significant improved with serum alkaline phosphatase, serum calcium, bone mineral mass, bone mineral density. The improvement was not affected by combining venlafaxine with alendronate whereas the venlafaxine treatment alone caused a significant deterioration of tested parameters. Venlafaxine is an anti-depressive agent that inhibits brain serotonin which leads to decrease in bone formation. Hence, from the above findings the combination of alendronate and venlafaxine showed worsen the condition of osteoporosis rats.

Optical Properties on Bone Analysis: An Approach to Biomaterials

The objective of the present study was to investigate the influence of demineralization solution on the optical properties of chicken femoral samples. Biomaterials based on bone have gained importance in clinical applications due to their properties as better osseointegration and biocompatibility. Biomateriais (bone substitute) are essentials to auxiliary in treatment of diseases related to bones such as bone density disorder, low bone mineral mass and the deterioration of bone tissue. Our data shows that integrating sphere technique permits to determinate significant difference in optical properties between healthy and demineralized samples. In this work, the optical properties of bone samples from chicken femur have been measured over the wavelength range 700–1000 nm.

A Dynamic Model of Calcium Metabolism for Predicting the Effects of Treatments on Bone Mineral Mass in Young Growing Rats (P24-046-19)

Objectives Quantifying the long-term effects of nutritional or drug treatments on bone is challenging due to the delay in time between treatment and changes in bone mass. The objective of this study was to develop a dynamic (non-steady state) mathematical model of calcium metabolism in young growing rats as an analogue for human adolescents and to use that model to predict the effects of treatments on calcium mass in bone. Methods A dynamic model of calcium metabolism was developed using kinetic data collected from Sprague-Dawley male rats (n = 54) dosed intraperitoneally with 50 μCi of 45Ca at 4 wk of age. Total calcium and 45Ca levels measured in serum and 24-h urine samples collected periodically for 45 d after treatment were analyzed by compartmental modeling using WinSAAM software. Concurrently, tracer (45Ca) and tracee (total calcium) models, together called the ‘dynamic model’, were developed. Growth of the rats was modeled using a formula based on body weight. Calcium absorption was decreased by about 50% at wk 6 to account for the reduction in bone mineral accretion in late puberty. During the first 40 d after weaning, the model included a 4-fold decrease in bone resorption and a 20-fold decrease in bone formation, consistent with previous findings of studies conducted in growing rats. Data were fitted by iterative least squares regression analysis. To mimic the effects of dietary and drug interventions during adolescence, the absorption efficiency was manipulated in terms of degree, timing, and duration and the subsequent changes in bone mass were quantified. Results The dynamic model predicted that, if absorption decreased by 25% instead of 50% during growth, the rate of bone accretion would be 32% higher and the bone mineral mass at d 50 would be 24% larger, suggesting that a dietary or drug intervention that minimizes the drop in absorption, would result in a higher bone mineral mass. Conclusions A dynamic model of calcium metabolism during growth was developed and used to predict the effect of interventions on bone mass. These predictions would be tested in future studies. Funding Sources Purdue University Graduate School and Amgen, Inc., Thousand Oaks, CA.