Effects of dietary phosphorus and calcium-to-phosphorus ratio on calcium and bone metabolism in healthy 20- to 43-year-old Finnish women

Dietary habits have changed during the past decades towards an increasing consumption of processed foods, which has notably increased not only total dietary phosphorus (P) intake, but also intake of P from phosphate additives. While the intake of calcium (Ca) in many Western countries remains below recommended levels (800 mg/d), the usual daily P intake in a typical Western diet exceeds by 2- to 3-fold the dietary guidelines (600 mg/d). The effects of high P intake in healthy humans have been investigated seldom. In this thesis healthy 20- to 43-year-old women were studied. In the first controlled study (n = 14), we examined the effects of P doses, and in a cross-sectional study (n = 147) the associations of habitual P intakes with Ca and bone metabolism. In this same cross-sectional study, we also investigated whether differences exist between dietary P originating from natural P sources and phosphate additives. The second controlled study (n = 12) investigated whether by increasing the Ca intake, the effects of a high P intake could be reduced. The associations of habitual dietary calcium-to-phosphorus ratios (Ca:P ratio) with Ca and bone metabolism were determined in a cross-sectional study design (n = 147). In the controlled study, the oral intake of P doses (495, 745, 1245 and 1995 mg/d) with a low Ca intake (250 mg/d) increased serum parathyroid hormone (S-PTH) concentration in a dose-dependent manner. In addition, the highest P dose decreased serum ionized calcium (S-iCa) concentration and bone formation and increased bone resorption. In the second controlled study with a dietary P intake of 1850 mg/d, by increasing the Ca intake from 480 mg/d to 1080 mg/d and then to 1680 mg/d, the S-PTH concentration decreased, the S-iCa concentration increased and bone resorption decreased dose-dependently. However, not even the highest Ca intake could counteract the effect of high dietary P on bone formation, as indicated by unchanged bone formation activity. In the cross-sectional studies, a higher habitual dietary P intake (>1650 mg/d) was associated with lower S-iCa and higher S-PTH concentrations. The consumption of phosphate additive-containing foods was associated with a higher S-PTH concentration. Moreover, habitual low dietary Ca:P ratios (≤0.50, molar ratio) were associated with higher S-PTH concentrations and 24-h urinary Ca excretions, suggesting that low dietary Ca:P ratios may interfere with homeostasis of Ca metabolism and increase bone resorption. In summary, excessive dietary P intake in healthy Finnish women seems to be detrimental to Ca and bone metabolism, especially when dietary Ca intake is low. The results indicate that by increasing dietary Ca intake to the recommended level, the negative effects of high P intake could be diminished, but not totally prevented. These findings imply that phosphate additives may be more harmful than natural P. Thus, reduction of an excessively high dietary P intake is also beneficial for healthy individuals.

Relação Cálcio/Fósforo Disponível em Rações para Tilápia do Nilo (Oreochromis niloticus)

The objective of this work was to evaluate the effect of Ca: available P (P-a) ratio in the diets on performance and bone mineral depositions of juvenile Nile tilapia (2.5 +/- 0.5g). Seven isoproteic and isoenergetic diets (28% CP and 3100 Kcal of DE/Kg of diet), with similar crude fiber and sulfur aminoacids content, were used. The diets had 0.50 and 0.25; 0.50 and 0.50; 0.50 and 0.75; 0.80 and 0.40; 0.80 and 0.80; and 0.80 and 1.20% of Ca and P-a which corresponded to Ca/P-a ratios of 2:1;1:1 and 1:1.5, respectively. An additional control diet, with low levels of Ca and Pa (0.02 and 0.12%, respectively) was used. A completely randomized design with a 2'3 factorial arrangement (Ca level and Ca:P-a ratio) on treatments, plus the additional control diet and three replications was used. Five fishes per aquaria were randomly allotted to 21 fiberglass aquaria (80L). The temperature of the water was maintained close to 26degreesC, and the oxygen, pH and ammonia levels of the water were monitored. The results showed that it was necessary a minimum dietary level of 0.25% of P-a for a satisfactory bone mineral depositions, and that the best performance results were achieved using diets with Ca: P-a ratios between 1:1 and 1:1.5.

Calcium and available phosphorus levels for laying hens in second production cycle

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Monitoring of Urinary Calcium and Phosphorus Excretion in Preterm Infants - Comparison of two Methods

OBJECTIVES: Premature babies require supplementation with calcium and phosphorus to prevent metabolic bone disease of prematurity. To guide mineral supplementation, two methods of monitoring urinary excretion of calcium and phosphorus are used: urinary calcium or phosphorus concentration and calcium/creatinine or phosphorus/creatinine ratios. We compare these two methods in regards to their agreement on the need for mineral supplementation. METHODS: Retrospective chart review of 230 premature babies with birthweight <1500 g, undergoing screening of urinary spot samples from day 21 of life and fortnightly thereafter. Hypothetical cut-off values for urine calcium or phosphorus concentration (1 mmol/l) and urine calcium/creatinine ratio (0.5 mol/mol) or phosphorus/creatinine ratio (4 mol/mol) were applied to the sample results. The agreement on whether or not to supplement the respective minerals based on the results with the two methods was compared. Multivariate general linear models sought to identify patient characteristic to predict disagreeing results. RESULTS: 24.8% of cases disagreed on the indication for calcium supplementation, 8.8% for phosphorus. Total daily calcium intake was the only patient characteristic associated with discordant results. CONCLUSIONS: With the intention to supplement the respective mineral, comparison of urinary mineral concentration with mineral/creatinine ratio is moderate for Calcium and good for Phosphorus. The results do not allow to identify superiority of either method on the decision which babies require calcium and/or phosphorus supplements.

Effect of dietary supplementation of vitamins A, D-3, E, and C on yearling rice field eel, Monopterus albus: Serum indices, gonad development, and metabolism of calcium and phosphorus

The objective of this study was to determine the effect of dietary vitamins A, D-3, E, and C on the gonad development, lipid peroxidation, and immune response of yearling rice field eel, Monopterus albus. A 6-wk feeding trial was designed according to an L-16(4(5)) orthogonal design, in which four vitamins, each at four supplementation levels, were arranged. Sixteen diets were mixed with the different vitamin levels and randomly assigned to 16 groups of fish. Increasing dietary vitamin E supplementation level significantly (P <= 0.05) increased the gonadosomatic index and lowered the serum content of malondialdehyde of rice field eel. Increasing dietary vitamin A and C levels also showed similar effect, but the differences were not statistically significant. Serum immunoglobulin M content increased significantly (P <= 0.01) as dietary vitamin C supplementation levels increased. The concentrations of calcium in bones showed significant (P <= 0.05) trend with vitamin D-3 and A supplementation levels, but the bone phosphorus content was not affected by the dietary vitamin levels.

Variations and possible source of potentially available phosphorus in a Chinese shallow eutrophic lake

Surface, overlying, and interstitial waters were collected at monthly intervals at three experimental stations in a shallow Chinese eutrophic lake (Lake Donghu) to assess the occurrence, distribution, and status of UV-sensitive phosphorus compounds (UVSP) and phosphatase hydrolyzable phosphorus (PHP), coupled with kinetics of alkaline phosphatase activity (APA). Orthophosphate (o-P) concentrations were generally the highest at Station 1, where chlorophyll a (chl a) was a function of o-P at temporal scale. The V-max/K-m of APA obtained by Michaelis-Menten approach paralleled the chlorophyll data at two stations. These facts imply that the development of phytoplankton may be attributed to APA induced by PHP. The potentially available UVSP and PHP peaked in interstitial, overlying, and surface water simultaneously sometimes in 1995 to 1996 and 1997 to 1999. It is postulated that they may arise from the bottom. UVSP peaked in interstitial water at the 12-16 cm layers in sediment cores. Moreover, in interstitial water, UV irradiation resulted in an elevated o-P concentration and decreased APA in a timeseries analysis. Therefore, the mechanism that APA involved in the process of photorelease of o-P was not demonstrated. UVSP is most likely a functional group of labile phosphorus distinct from the enzymatic substrate in this shallow eutrophic lake.

Broiler chicken ileal apparent digestibility of calcium and phosphorus from microalgae spirulina maxima.

2016

Response of organically managed grassland to available phosphorus and potassium in the soil and supplementary fertilization: field trials using grass-clover leys cut for silage

Effective use and recycling of manures together with occasional and judicious use of supplementary fertilizing materials forms the basis for management of phosphorus (P) and potassium (K) within organic farming systems. Replicated field trials were established at three sites across the UK to compare the supply of P and K to grass-clover swards cut for silage from a range of fertilizing materials, and to assess the usefulness of routine soil tests for P and K in organic farming systems. None of the fertilizing materials (farmyard manure, rock phosphate, Kali vinasse, volcanic tuff) significantly increased silage yields, nor was P offtake increased. However, farmyard manure and Kali vinasse proved effective sources of K to grass and clover in the short to medium term. Available P (measured as Olsen-P) showed no clear relationship with crop P offtake in these trials. In contrast, available K (measured by ammonium nitrate extraction) proved a useful measurement to predict K availability to crops and support K management decisions.

Spatial correlation between the composition of the clay fraction and contents of available phosphorus of an Oxisol at hillslope scale

Relief is regarded as the abiotic factor most strongly influencing pedogenic processes at a local scale. The spatial correlations between the composition of the clay fraction (iron - Fe and aluminum - Al oxides, kaolinite and organic matter - OM) and contents of available phosphorus (P) of an Oxisol were evaluated at hillslope scale under sugarcane cultivation. A total of 119 samples were collected at intersection points on a 100. ×. 100. m georeferenced grid of regularly spaced points 10. m apart in the 0.2-0.4. m depth in an area consisting of two landform components namely: component I (an area with a linear hillslope curvature), and component II (one with a concave-convex hillslope curvature). Soil OM and available P contents were subjected to descriptive statistics and geostatistical analyses in order to assess their variability and spatial dependence. All attributes studied were spatially dependent. Available phosphorus had positive spatial correlation with high crystalline goethite, hematite and gibbsite. Identifying small hillslope curvatures is useful with a view to better understanding their relationships with soil organic matter and available phosphorus, as well as kaolinite and Fe and Al oxide attributes. A simple correlation analysis by itself is inadequate to relate attributes, which requires a supplemental, geostatistical technique. © 2012 Elsevier B.V..

Salmonella enteritidis in the eggs of Japanese quails (coturnix coturnix Japonica - Temminck & Schlegel, 1849) fed diets with different calcium and phosphorus levels

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Eliminating exposure to aqueous solvents is necessary for the early detection and ultrastructural elemental analysis of sites of calcium and phosphorus enrichment in mineralizing UMR106-01 osteoblastic cultures

The mechanism underlying the mineralization of bone is well studied and yet it remains controversial. Inherent difficulties of imaging mineralized tissues and the aqueous solubility of calcium and phosphate, the 2 ions which combine to form bone mineral crystals, limit current analyses of labile diffusible, amorphous, and crystalline intermediates by electron microscopy. To improve the retention of calcium and phosphorus, we developed a pseudo nonaqueous processing approach and used it to characterize biomineralization foci, extracellular sites of hydroxyapatite deposition in osteoblastic cell cultures. Since mineralization of UMR106-01 osteoblasts is temporally synchronized and begins 78 h after plating, we used these cultures to evaluate the effectiveness of our method when applied to cells just prior to the formation of the first mineral crystals. Our approach combines for the first time 3 well-established methods with a fourth one, i.e. dry ultrathin sectioning. Dry ultrathin sectioning with an oscillating diamond knife was used to produce electron spectroscopic images of mineralized biomineralization foci which were high-pressure frozen and freeze substituted. For comparison, cultures were also treated with conventional processing and wet sectioning. The results show that only the use of pseudo nonaqueous processing was able to detect extracellular sites of early calcium and phosphorus enrichment at 76 h, several hours prior to detection of mineral crystals within biomineralization foci.

Nutritional value of some small indigenous fish species (SIS) of Bangladesh

Twenty three small indigenous fish species (SIS) in the size range of 3-18 cm were analyzed for proximate composition and minerals (Ca and P) content to evaluate their nutritive value. The moisture content of different species ranged between 71.00 and 81.94%. In general, small sized fishes showed higher moisture content. The muscle protein content among the species varied widely (16.16-22.28%). In general, the muscle protein content of fishes showed higher value than the whole carcass protein content. The carcass lipid content varied between 1.87 and 9.55% and showed an inverse relationship with the moisture content. The gross energy content ranged from 19.51-27.30 KJ/g on dry matter basis. In the present study, the calcium and phosphorus contents ranged between 0.85-3.20% and 1.01-3.29% respectively. The calcium and phosphorus ratio (Ca/P) varied between 0.44 and 2.00. From the nutritional point of view, it shows that the SIS are good source of protein and minerals especially calcium and phosphorus

Dietary phosphorus requirement of juvenile black seabream, Sparus macrocephalus

A growth trial was conducted to estimate the optimum requirement of dietary available phosphorus (P) for black seabream (Sparus macrocephalus) in indoor net cages (1.5x1.0x1.0 m). Triplicate groups of black seabream (11.45 +/- 0.02 g) were fed diets containing graded levels (0.18, 0.36, 0.54, 0.72, 0.89 and 1.07%) of available P to satiation for 8 weeks. The basal diet (diet 1), containing 0.18% available P, was supplemented with graded levels of monosodium phosphate (NaH2PO4 2H(2)O) to formulate five experimental diets. The fish were fed twice daily (08:00 h and 16:00 h) and reared in seawater (salinity, 26-29 g l(-1)) at a temperature of 28 +/- 1 degrees C. Dissolved oxygen during the experiment was above 5 mg l(-1). The specific growth rate (SGR), weight gain (WG), feed efficiency (FE) and protein efficiency ratio (PER) were all significantly improved by dietary phosphorus up to 0.54% (P<0.05) and then leveled off beyond this level. Hepatosomatic index (HSI) was inversely correlated with dietary phosphorus levels (P< 0.05). Efficiency of P utilization stabled in fish fed diets containing 0.18%-0.54% available P and then decreased dramatically with further supplementation of dietary phosphorus. Body composition analysis showed that the whole-body lipid, ash, calcium and phosphorus contents were all significantly affected by dietary available P concentration (P<0.05), however, no significance were found in whole-body calcium/phosphorus (Ca/P) ratios among all the treatments (P>0.05). Dietary phosphorus levels also affected the mineralization of vertebrae, skin and scale (P<0.05). Ca/P ratios in vertebrae and scale were not influenced by dietary P supplementation, while skin Ca/P ratio increased statistically with dietary available P levels (quadratic effect, P<0.001). The blood chemistry analysis showed that dietary available P had distinct effects on enzyme activities of alkaline phosphatase (ALP) and plasma lysozyme (LSZ), as well as contents of triacyglycerol (TG) and total cholesterol (T-CHO) (P<0.05). Broken-line analysis showed maximum weight gain (WG) was obtained at dietary available P concentrations of 0.55%. Quadratic analysis based on P contents in whole fish, vertebrae or scale indicated that the requirements were 0.81, 0.87 and 0.88%, respectively. Signs of phosphorus deficiency were characterized by poor growth, slightly reduced mineralization and an increase in body lipid content. (C) 2008 Published by Elsevier B.V.