Calcium-vitamin D Research Articles

Long-term effects of exercise and calcium–vitamin D3 supplementation on biochemical markers of bone turnover and their association with changes in BMD in older men

Long-term effects of exercise and calcium–vitamin D3 supplementation on biochemical markers of bone turnover and their association with changes in BMD in older men

Long-term effect of calcium-vitamin D3 fortified milk on blood pressure and serum lipid concentrations in healthy older men

Some epidemiological and clinical studies have shown that increased dairy consumption or calcium and/or vitamin D supplementation can have a beneficial effect on blood pressure, and lipid and lipoprotein concentrations. The aim of this study was to assess the long-term effects of calcium-vitamin D(3) fortified milk on blood pressure and lipid-lipoprotein concentrations in community-dwelling older men. This is a substudy of a 2-year randomized controlled trial in which 167 men aged >50 years were assigned to receive either 400 ml per day of reduced fat (approximately 1%) milk fortified with approximately 1000 mg of calcium and 800 IU of vitamin D(3) or to a control group receiving no additional fortified milk. Weight, blood pressure, lipid and lipoprotein concentrations were measured every 6 months. Participants on lipid-lowering (n=32) or antihypertensive medication (n=39) were included, but those who commenced, increased or decreased their medication throughout the intervention were excluded (n=27). In the 140 men included in this study (milk, n=73; control, n=67), there were no significant effects of the calcium-vitamin D(3) fortified milk on weight, systolic or diastolic blood pressure, total cholesterol, high-density lipoprotein or low-density lipoprotein cholesterol or triglyceride concentrations at any time throughout the intervention. Similar results were observed after excluding men taking antihypertensive or lipid-lowering medication or limiting the analysis to those with baseline calcium intakes <1000 mg per day and/or with hypovitaminosis D (25(OH)D <75 nmol/l). Supplementation with reduced-fat calcium-vitamin D(3) fortified milk did not have a beneficial (nor detrimental) effect on blood pressure, lipid or lipoprotein concentrations in healthy community-dwelling older men.

Vascular calcification and atherosclerosis in hemodialysis patients: what can we learn from the routine clinical practice?

Hemodialysis (HD) patients are at increased risk for arterial intimal (AIC) and medial calcification (AMC). In a cross-sectional study on 153 HD patients we evaluated the presence of AIC and AMC using plain radiography of the pelvis and the presence of atherosclerotic lesions using high-resolution B-mode ultrasonography of the common carotid arteries (CCA). The radiography of the pelvis confirmed the frequent presence of AIC (35.3%) and AMC (35.9%) in our HD patients. Arterial calcification was absent (non calcified-NC) in a minority of patients (28.8%). Patients with AIC had significantly higher prevalence of atherosclerotic plaques on CCA (78.6%) compared with both other groups and a higher number of documented atherosclerotic complications, such as cardiovascular (85.2%), cerebrovascular (33.3%) and peripheral arterial disease (38.9%) in comparison with the NC patients. According to the 1-year calculated data from patient records, there were no significant differences in the specific HD risks, such as the dose of prescribed calcium carbonate and vitamin D3, serum levels of calcium, phosphate, calcium-phosphate product and intact parathyroid hormone. All four bone metabolism markers within the range proposed by K/DOQI guidelines were achieved in 9.3%, 14.5% and 20.4% in the AIC, AMC and NC group, respectively. Patients with AIC and AMC are frequently found in the HD population. Screening for arterial calcifications in chronic kidney disease patients is suggested even in the early pre-dialysis period. The highest proportion of patients within the guidelines proposed range for bone and mineral metabolism markers was observed in the NC group. A longer period of data analysis is required in order to evaluate the possible role of some traditional and HD-specific risk factors for the development of arterial calcifications. The achievement of the K/DOQI guidelines is an important issue in the prevention of those conditions.

322 Does calcium-vitamin D3 fortified milk enhance the effects of exercise on bone structure and strength in older men? An 18 month community based RCT

322 Does calcium-vitamin D3 fortified milk enhance the effects of exercise on bone structure and strength in older men? An 18 month community based RCT

Long-term effects of calcium–vitamin-D 3-fortified milk on bone geometry and strength in older men

The long-term effects of calcium and vitamin D supplementation on bone material and structural properties in older men are not known. The aim of this study was to examine the effects of high calcium (1000 mg/day)- and vitamin-D 3 (800 IU/day)-fortified milk on cortical and trabecular volumetric BMD (vBMD) and bone geometry at the axial and appendicular skeleton in men aged over 50 years. One hundred and eleven men who were part of a larger 2-year randomized controlled trial had QCT scans of the mid-femur and lumbar spine (L 1–L 3) to assess vBMD, bone geometry and indices of bone strength [polar moment of inertia ( I polar)]. After 2 years, there were no significant differences between the milk supplementation and control group for the change in any mid-femur or L 1–L 3 bone parameters for all men aged over 50 years. However, the mid-femur skeletal responses to the fortified milk varied according to age, with a split of ≤ 62 versus > 62 years being the most significant for discriminating the changes between the two groups. Subsequent analysis revealed that, in the older men (> 62 years), the expansion in mid-femur medullary area was 2.8% ( P < 0.01) less in the milk supplementation compared to control group, which helped to preserve cortical area in the milk supplementation group (between group difference 1.1%, P < 0.01). Similarly, for mid-femur cortical vBMD and I polar, the net loss was 2.3 and 2.8% less in the milk supplementation compared to control group ( P < 0.01 and < 0.001, respectively). In conclusion, calcium–vitamin-D 3-fortified milk may represent an effective strategy to maintain bone strength by preventing endocortical bone loss and slowing the loss in cortical vBMD in elderly men.

Prophylaxis against bone loss in Kock reservoir patients with reduced glomerular filtration rate

We investigated whether treatment with calcium carbonate and vitamin D3 can improve the bone mineral content of patients with ileal reservoirs for continent urinary diversion and a reduced glomerular filtration rate (GFR). Twenty-six patients with Kock reservoirs were included in the study. Bone mineralization was determined using dual-energy X-ray absorptiometry. Kidney function was estimated from Cr-EDTA clearance and serum cystatin C concentration. Osteocalcin and parathyroid hormone in serum were also measured. Patients with reduced GFR were treated with calcium carbonate and vitamin D3 perorally. Bone mineral density in the femur neck and hip increased in the treatment group, as reflected by an improved T score. Patients with ileal reservoirs for continent urinary diversion and reduced kidney function should be supplemented with calcium carbonate and vitamin D3 in order to reduce the long-term risk of osteoporosis.

THE EFFECT OF OESTROGEN AND OR CALCIUM VITAMIN D3 ON THE MANDIBULAR HEIGHT OF POST OVARIECTOMIZED WISTAR RATS

One of the major health problems in elderly women is osteoporosis post menopause. Dentists must be aware of the disease since its involvement on the jaw. Nowadays, there are a lot of researches on correlation of osteopororsis and mandible but only few concentrate on hormonal substitution therapy and/or Calcium-vitamin D3 (Ca-Vit D3). This research is to evaluate the effect of hormonal substitiution therapy and/or Ca-vit D3 on mandibular height. Forty five rats used in this research and divided into nine groups: one control group, two ovariectomized (OVX) groups, two OVX groups treated with estrogen, two OVC groups treated with Ca-vit D3, two OVC groups treated with estrogen and Ca-vit D3. All of the rats except the control group were ovariectomized as model for postmenopausal estrogen deficiency state. The treatment was done in two or four weeks. The animals were killed with cervical dislocation, the mandible were excised and soaked on Hydrogen Peroxide 10%. Then the mandible's heights on right buccal side were measured from the manduble base to the alveolar crest. It is concluded that hormonal substitution therapy and combination of the hormonal substitution therapy and Ca-vit D3 can maintain the normal mandibular height. Mandibular height of groups with therapy using Ca-vit D3 have slightly lower means compared to control group but without significant difference statistically. The best therapy is combination of hormonal substitution therapy and Ca-vit D3.

Implications of phytic acid and supplemental microbial phytase in poultry nutrition: a review

Phytic acid or phytate is a naturally occurring organic complex found in plants. As a reactive anion, it forms a wide variety of insoluble salts with divalent and trivalent cations. Phytic acid is also known to complex with proteins and consequently reduce their availability. Recent studies indicate that phytic acid reduces the activity of pepsin, trypsin and α-amylase. Because of a lack of endogenous phytase, which hydrolyses phytic acid, phytate phosphorus is biologically less available to poultry. Because of the complex factors influencing phytate hydrolysis, such as dietary calcium content, inorganic phosphorus and vitamin D3, and the age and genotype of birds, there is wide disagreement concerning the ability of poultry to utilize phytate phosphorus. Data suggest that the amount of endogenous phytase is extremely low in young birds but that it increases with age. Cereal based poultry diets supplemented with microbial phytase result in increased digestibility and availability of phytate bound phosphorus, calcium, zinc and copper. Microbial phytase supplementation has also been shown to increase ileal digestibility of crude protein and amino acids in female broiler chickens and in female turkeys, but curiously not in male chickens. There is no report to date of such a study in male turkeys. While the efficacy of supplemental microbial phytase depends on its rate of inclusion, on the calcium and phytate phosphorus contents and on the dietary calcium:phosphorus ratio, clear benefits have been shown in terms of increased availability of phytate-bound minerals and crude protein, and reduced environmental pollution through lower levels of phosphorus and nitrogen excretion. To maximize the benefit from the addition of microbial phytase, future research should focus on determining the optimum dietary conditions for it to work.

Effects of dietary calcium and vitamin D3 on tumor promotion in mouse skin

The effects of low, adequate, and supplemental intake of calcium and vitamin D3 on 12-O-tetradecanoylphorbol-13-acetate (TPA) skin tumor promotion were examined. Administration of the experimental diets was started one week before the first TPA application to the 7,12-dimethylbenz[a]anthracene-initiated dorsal skin of female Sencar mice. Neither dietary calcium in a range from 0.15% to 2.0% of the diet as calcium carbonate nor vitamin D3 ranging from 200 to 4,000 IU/kg diet resulted in modulation of the skin papilloma response in terms of incidence, number per mouse, or size distribution of tumors. There were also no effects of the varied levels of calcium or vitamin D3 on mouse body weights, serum calcium, or TPA induction of epidermal ornithine decarboxylase activity. These results indicate that dietary administration of a wide range of doses of calcium or vitamin D does not alter the serum calcium levels and, therefore, does not appear capable of altering skin tumor promotion. These results are in contrast to reports that demonstrate antineoplastic activity for both calcium ion and active hormonal vitamin D, either in control of epidermal cell proliferation and/or differentiation or inhibition of carcinogenesis.

Thyrocalcitonin Activity in Hypercalcemia Produced by Calcium Salts, Parathyroid Hormone and Vitamin D

To investigate the relation between the hypocalcemic activity of thyrocalcitonin and the rate of bone resorption, the quantitative effect of exogenous thyrocalcitonin was studied in rats in which the rate of bone resorption was altered by thyroparathyroidectomy and by the administration of calcium salts, parathyroid extract or vitamin D3. In sham-operated rats made hypercalcemic by the oral administration of CaCl3, thyrocalcitonin had no significant hypocalcemic activity. In thyroparathyroidectomized rats given oral CaCl2, a full Hypocalcemic response to thyrocalcitonin, of 1.49 mEq/1, occurred. In sham-operated and thyroparathyroidectomized rats made hypercalcemic by the administration of parathyroid extract, thyrocalcitonin caused mean decreases in the plasma concentration of calcium of 0.83 and 1.47 mEq/1, respectively. In hypercalcemia produced by the administration of a single dose of 105 USP U of vitamin D3, sham-operated and thyroparathyroidectomized rats showed mean decreases in the plasma concent...