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Although the implications of long-term high Ca intakes have been well documented in growing dogs, the health consequences of Ca excess in adult dogs remain to be established. To evaluate the impact of feeding a diet containing 7·1 g/4184 kJ (1000 kcal) Ca for 40 weeks on Ca balance and health parameters in adult dogs, eighteen neutered adult Labrador Retrievers, (nine males and nine females) aged 2·5-7·4 years were randomised to one of two customised diets for 40 weeks. The diets were manufactured according to similar nutritional specifications, with the exception of Ca and P levels. The diets provided 1·7 and 7·1 g/4184 kJ (1000 kcal) (200(SD26) and 881(SD145) mg/kg body weight0·75 per d, respectively) Ca, respectively, with a Ca:P ratio of 1·6. Clinical examinations, ultrasound scans, radiographs, health parameters, metabolic effects and mineral balance were recorded at baseline and at 8-week intervals throughout the study. Dogs in both groups were healthy throughout the trial without evidence of urinary, renal or orthopaedic disease. In addition, there were no clinically relevant changes in any of the measures made in either group (all P>0·05). The high-Ca diet resulted in a 3·3-fold increase in faecal Ca excretion (P0·05). Ca intakes of up to 7·1 g/4184 kJ (1000 kcal) are well tolerated over a period of 40 weeks, with no adverse effects that could be attributed to the diet or to a high mineral intake.

Fructus Ligustri Lucidi (FLL) is a commonly prescribed herb in many kidney-tonifying Traditional Chinese Medicinal formulae for the treatment of osteoporosis. The present study aimed to identify the active fractions in FLL and to characterise its effects on Ca balance, calciotropic hormone levels as well as bone properties in mature female rats fed diets containing different levels of Ca. In the present study, 4-month-old Sprague-Dawley female rats were treated with either FLL ethanol extract (EE), ethyl acetate-soluble fraction of EE (EAF), water-soluble fraction of EE (WF) or their vehicle for 12 weeks on a medium-Ca diet (MCD, 0·6 % Ca, 0·65 % P). Then, the Sprague-Dawley female rats treated with WF or its vehicle for 12 weeks were fed diets containing different levels of dietary Ca (low-Ca diet (LCD), 0·1 % Ca, 0·65 % P; MCD; high-Ca diet (HCD), 1·2 % Ca, 0·65 % P). The results demonstrated that WF from EE but not EAF exerted a prominent effect on Ca balance by inhibiting urinary and faecal Ca excretion. WF significantly increased Ca balance in rats fed MCD or HCD with an associated increase in serum parathyroid hormone (PTH) levels. WF did not alter bone mineral density or bone mineral content of the tibia in all the rats fed with different levels of dietary Ca. In conclusion, WF was responsible for the positive actions of FLL on Ca absorption and balance. The regulation of Ca balance by WF might involve its action in stimulating PTH production in the mature female rats.

The present study was conducted to investigate the effect of dietary protein on urinary Ca excretion, apparent Ca absorption and Ca balance in young and elderly subjects. Young adults (n 29) and elderly persons (n 26) consumed diets containing 12% (diet A) and 21% (diet B) of total energy as protein for 3 weeks according to a randomized crossover design. Results showed no differences between the two age groups with respect to the interaction between protein intake and Ca excretion (both in urine and in faeces), apparent Ca absorption and Ca balance. Therefore analyses were done for both age groups separately and also for the whole group. In elderly persons and in the whole group the Ca excretion in faeces (as a percentage of Ca intake) was lower during the higher protein intake (elderly: diet A, 106 (SEM 7)%; diet B, 86 (SEM 7)%; P = 0.018; whole group: diet A, 99 (SEM 4)%; diet B, 84 (SEM 4)%; P = 0.003). In young adults faecal Ca excretion tended to be lower when they consumed diet B (diet A: 94 (SEM 5)%; diet B: 83 (SEM 6)%; P = 0.093). Relative urinary Ca excretion was greater during the higher protein intake in young adults and in the whole group while relative urinary Ca excretion was not different in the elderly (diet A: 15 (SEM 1)%, 14 (SEM 1)%, 15 (SEM 1)%; diet B: 16 (SEM 1)%, 16 (SEM 1)%, 17 (SEM 2)% for the whole group, the young and elderly subjects respectively, P = 0.019; P = 0.016; P = 0.243). The resulting Ca balance was not influenced by the amount of protein in the diet in young adults. Values for the elderly and for the whole group showed that the Ca balance during diet A was significantly more negative compared with Ca balance during diet B, despite the higher urinary Ca excretion during diet B. It can be concluded that increasing the protein intake from 12 to 21% of total energy intake had no negative effect on Ca balance.

Bioactivity of phosphopeptides yielded after tryptic hydrolysis of casein (CPP) was reported more than 50 years ago when CPP were found to improve calcium balance in rachitic newborns. Several investigations have been carried out to study the effects of CPP mainly on calcium metabolism but also on other minerals like iron and zinc. Most of the experiments were in vitro studies or short-term experiments like the effects of CPP after single meals or their effect on mineral disappearance from intestinal everted sac or ligated loop. Investigations on calcium balance were also mainly short term, i.e. 3–4 weeks, and mainly done in rats. A few experiments have been carried out in minipigs, an animal model that is closer to the human than the rat. Studies in human were rare and short term. To date a variety of other peptides have been isolated after enzymatic hydrolysis, and some have been investigated for bioactivity, with equivocal findings. Bioactivity of phosphopeptides seemed to be more obvious when investigations were done in vitro or short term. Results were less clear in metabolic balance studies, especially under physiological conditions. The composition of the basal diet, i.e. content of calcium and phytate, or the protein source had a significant impact on the effect of phosphopeptides. It was concluded that phosphopeptides revealed positive effects on mineral solubility and absorbability, and bone mineralisation under certain experimental conditions. Accordingly they could have a beneficial effect on bone health for some groups of the population. [ABSTRACT FROM PUBLISHER]

The article reports that Phosphorus requirements of reproducing sows were estimated using 24-h urinary P excretion. Thirty-six multiparous sows were fed one of six maize-soybean meal-based diets with total P ranging from 0·40 to 0·80 % in 0·08 % increments with a constant Ca:total P ratio (1·25:1). Diets were fed from day 7·5 ± 1 after breeding until the end of lactation (day 26 ± 1).

A high dose of whey protein hydrolysate fed with milk minerals rich in calcium (Capolac®) results in enhanced glucagon-like peptide-1 (GLP-1) concentrations in lean individuals; however, the effect of different calcium doses ingested alongside protein is unknown. The present study assessed the dose response of calcium fed alongside 25 g whey protein hydrolysate on GLP-1 concentrations in individuals with overweight/obesity. Eighteen adults (mean ± sd: 8M/10F, 34 ± 18 years, 28·2 ± 2·9 kgm−2) completed four trials in a randomised, double-blind, crossover design. Participants consumed test solutions consisting of 25 g whey protein hydrolysate (CON), supplemented with 3179 mg (LOW), 6363 mg (MED) or 9547 mg (HIGH) Capolac® on different occasions, separated by at least 48 h. The calcium content of test solutions equated to 65, 892, 1719 and 2547 mg, respectively. Arterialised-venous blood was sampled over 180 min to determine plasma concentrations of GLP-1TOTAL, GLP-17–36amide, insulin, glucose, NEFA, and serum concentrations of calcium and albumin. Ad libitum energy intake was measured at 180 min. Time–averaged incremental AUC (iAUC) for GLP-1TOTAL (pmol·l−1·min−1) did not differ between CON (23 ± 4), LOW (25 ± 6), MED (24 ± 5) and HIGH (24 ± 6). Energy intake (kcal) did not differ between CON (940 ± 387), LOW (884 ± 345), MED (920 ± 334) and HIGH (973 ± 390). Co-ingestion of whey protein hydrolysate with Capolac® does not potentiate GLP-1 release in comparison with whey protein hydrolysate alone. The study was registered at clinical trials (NCT03819972). [ABSTRACT FROM AUTHOR]

Improvement of vitamin D status of the general population has been a challenge for policymakers. We conducted a meta-analysis to evaluate whether vitamin D-fortified products can be a suitable solution for tackling vitamin D deficiency. Our secondary objective was to determine the effect of some variables including age, latitude and BMI on efficacy of this strategy. MEDLINE, PubMed, Embase, Cochrane Library and Google Scholar were searched and 231 studies were found in a preliminary search. After screening of titles and abstracts, 23 studies were selected. Pooled data comparing fortification with vitamin D +/- Ca with control showed statistically significant effect on total 25(OH)D concentrations (2002 participants, mean difference (MD): 25·4 nmol/l, (95 % CI 19·5, 31·3)). The subgroup analysis by duration of intervention (less than 12 weeks v. more than 12 weeks) and type of vehicle (dairy product, juice, grain product, oil and combination of dairy and grain products), isoform of the vitamin (D3v. D2) and dose of the fortificant (≥ 1000 IU/d v. < 1000 IU/d) also indicated significant effect of fortification with vitamin D on serum 25(OH)D concentrations. In conclusion, the circulating 25(OH)D response to vitamin D-fortified food consumption is influenced by age, BMI and the baseline 25(OH)D concentrations. Notwithstanding, an average of 2 nmol/l increase in circulating 25(OH)D concentration for each 100 IU vitamin D intake per d is expected for general adult population. These findings can be informative for policymakers to tackle vitamin D deficiency through food fortification strategy. [ABSTRACT FROM AUTHOR]

The relationships between both dietary and empty body fatty acid composition and the morphometry, densitometry, geometry and biomechanical properties of the femur of growing pigs were analysed. A total of thirty-two pigs aged 115 d were divided into four groups (n 8 per group). The pigs were fed either a control diet (group C) or a diet supplemented with linseed oil (rich in α-linolenic acid (C18 : 3 n -3), group L), fish oil (rich in EPA (C20 : 5 n -3) and DHA (C22 : 6 n -3), group F) and beef tallow (rich in SFA, group T). The diets differed in n -3 PUFA contents (0·63–18·52 g/kg) and n -6: n -3 PUFA ratios (0·91–14·51). At 165 d of age, the pigs were slaughtered and the fatty acids in the empty body were determined. Moreover, the left femur was dissected. The cortical wall thickness, cross-sectional area, cortical index, bone mineral content, bone mineral density, maximum elastic strength and maximum strength were lower (P <0·05) in the femurs of pigs from groups C and T than in those from groups F and L. Significant positive correlations were found between the densitometry, geometry and biomechanical properties of the femur and both dietary and empty body n -3 PUFA content, whereas significant negative correlations were observed between the same properties and both dietary and empty body n -6: n -3 PUFA ratio. The results of the present study suggest that in growing pigs α-linolenic acid has a similar positive effect on bone health to that of EPA and DHA. [ABSTRACT FROM AUTHOR]

Phosphorus is present in diets as naturally occurring P from raw materials or added as an inorganic salt. However, little is known about postprandial kinetics of P absorption in cats. Here, we describe several studies quantifying postprandial kinetics following the ingestion of diets of varying composition. Briefly, cats were fed a meal consisting of 50 % of their metabolic energy requirement in a randomised crossover design. A pre-meal baseline blood sample was taken via cephalic catheter and repeated measurements taken regularly up to 6 h post-meal to assess the whole blood ionised Ca, plasma P and parathyroid hormone concentrations. A diet containing 4·8 g total P/4184 kJ (1000 kcal), 3·5 g P from sodium dihydrogen phosphate (NaH2PO4)/4184 kJ (1000 kcal) and Ca:P 0·6 caused a marked increase in plasma P from baseline to a peak of 1·976 (95% CI 1·724, 2·266) mmol/l (P <0·001), whereas a diet containing 3·38 g total P/4184 kJ (1000 kcal), no added inorganic P and Ca:P 1·55 resulted in a postprandial decrease in plasma P (P = 0·008). Subsequent data indicate that added inorganic P salts in the diet above 0·5 g P/4184 kJ (1000 kcal) cause an increase in plasma P in cats, while diets below this do not. The data presented here demonstrate that sources of added inorganic P salts cause a temporary postprandial increase in plasma P in a dose-dependent manner, prolonged in diets with Ca:P <1·0. Dietary P derived from natural food ingredients (e.g. meat or vegetable matter) does not appear to have any effect on postprandial plasma P. [ABSTRACT FROM AUTHOR]

Renal disease has a high incidence in cats, and some evidence implicates dietary P as well. To investigate this further, two studies in healthy adult cats were conducted. Study 1 (36 weeks) included forty-eight cats, stratified to control or test diets providing 1·2 or 4·8 g/1000 kcal (4184 kJ) P (0 or approximately 3·6 g/1000 kcal (4184 kJ) inorganic P, Ca:P 1·2, 0·6). Study 2 (29 weeks) included fifty cats, stratified to control or test diets, providing 1·3 or 3·6 g/1000 kcal (4184 kJ) P (0 or approximately 1·5 g/1000 kcal (4184 kJ) inorganic P, Ca:P 1·2, 0·9). Health markers, glomerular filtration rate (GFR) and mineral balance were measured regularly, with abdominal ultrasound. Study 1 was halted after 4 weeks as the test group GFR reduced by 0·4 (95 % CI 0·3, 0·5) ml/min per kg, and ultrasound revealed changes in renal echogenicity. In study 2, at week 28, no change in mean GFR was observed (P >0·05); however, altered renal echogenicity was detected in 36 % of test cats. In agreement with previous studies, feeding a diet with Ca:P <1·0, a high total and inorganic P inclusion resulted in loss of renal function and changes in echogenicity suggestive of renal pathology. Feeding a diet containing lower total and inorganic P with Ca:P close to 1·0 led to more subtle structural changes in a third of test cats; however, nephrolithiasis occurred in both diet groups, complicating data interpretation. We conclude that the no observed adverse effects level for total dietary P in adult cats is lower than 3·6 g/1000 kcal (4184 kJ), however the effect of inorganic P sources and Ca:P require further investigation. [ABSTRACT FROM AUTHOR]

The article discusses research on the effects of elevated fruit and vegetable intake on serum bone turnover markers, and it mentions plasma carotenoid levels, bone resorption marker C-terminal telopeptide of type 1 collagen, and lower bone formation marker alkaline phosphatase.

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. [ABSTRACT FROM PUBLISHER]

A 12-month, dose–response, randomised, intervention trial was conducted to determine adequate Ca intake levels for Chinese adolescents by investigating the effect of Ca supplementation on bone mineral accretion. A total of 220 Han adolescents (111 girls and 109 boys) aged 12–14 years were recruited. All subjects were randomly divided into three groups. The bone mineral content (BMC) and bone mineral density (BMD) of the whole body, lumbar spine (L1–L4), left hip and femoral neck were measured by dual-energy X-ray absorptiometry. Girls in the high-Ca group (actual Ca intake: 1243 (sd 193) mg/d) exhibited greater increases in the femoral neck BMC compared with those in the low-Ca group (9·7 v. 6·4 %, P =0·04) over the 1-year intervention period. The increases in femoral neck BMC were greater in boys in the high-Ca and medium-Ca groups (actual Ca intake: 985 (sd 168) mg/d) than in those in the low-Ca group (15·7 v. 11·7 %, P =0·03; 15·8 v. 11·7 %, P =0·03). Ca supplementation had significant effects on the whole-body BMC and BMD in subjects with physical activity levels>34·86 metabolic equivalents and on the spine BMD and BMC and BMD of most sites in subjects with Tanner stage < 3. Increasing Ca intake levels with Ca supplementation enhanced femoral neck mineral acquisition in Chinese adolescents. Furthermore, high physical activity levels and low Tanner stage appeared to significantly contribute to the effect of Ca supplementation on bone mass. Whether this is a lasting beneficial effect leading to the optimisation of peak bone mass needs to be determined in other long-term prospective studies. [ABSTRACT FROM PUBLISHER]

Soluble maize fibre (SCF) has been found to significantly improve bone mineral density and strength in growing rats compared with several other novel prebiotic fibres. The objective of the present study was to investigate the effect of SCF on Ca absorption and retention in pubertal children by studying the potential absorption mechanisms of the intestinal microbiota. A total of twenty-four adolescent boys and girls (12–15 years) participated in two 3-week metabolic balance studies testing 0 g/d SCF (control (CON) treatment) and 12 g/d SCF (SCF treatment) in a random order by inclusion in a low-Ca diet (600 mg/d). Fractional Ca absorption was measured at the end of the two intervention periods using a dual-stable isotope method. Diet composites and faecal and urine samples were collected daily and analysed for Ca content. Ca retention was calculated as dietary Ca intake minus Ca excretion in faeces and urine over the last 2 weeks. Microbial community composition in the faecal samples collected at the beginning and end of each session was determined by 454 pyrosequencing of the PCR-amplified 16S ribosomal RNA gene. Fractional Ca absorption was 12 % higher (41 mg/d) after the SCF treatment compared with that after the CON treatment (0·664 (sd 0·129) and 0·595 (sd 0·142), respectively; P= 0·02), but Ca retention was unaffected. The average proportion of bacteria of the phylum Bacteroidetes was significantly greater in the participants after the SCF treatment than after the CON treatment. These results suggest that moderate daily intake of SCF, a well-tolerated prebiotic fibre, increases short-term Ca absorption in adolescents consuming less than the recommended amounts of Ca. [ABSTRACT FROM PUBLISHER]

For decades, it has been debated whether high protein intake compromises bone mineralisation, but no long-term randomised trial has investigated this in children. In the family-based, randomised controlled trial DiOGenes (Diet, Obesity and Genes), we examined the effects of dietary protein and glycaemic index (GI) on biomarkers of bone turnover and height in children aged 5–18 years. In two study centres, families with overweight parents were randomly assigned to one of five ad libitum-energy, low-fat (25–30 % energy (E%)) diets for 6 months: low protein/low GI; low protein/high GI; high protein/low GI; high protein/high GI; control. They received dietary instructions and were provided all foods for free. Children, who were eligible and willing to participate, were included in the study. In the present analyses, we included children with data on plasma osteocalcin or urinary N-terminal telopeptide of collagen type I (U-NTx) from baseline and at least one later visit (month 1 or month 6) (n 191 in total, n 67 with data on osteocalcin and n 180 with data on U-NTx). The level of osteocalcin was lower (29·1 ng/ml) in the high-protein/high-GI dietary group than in the low-protein/high-GI dietary group after 6 months of intervention (95 % CI 2·2, 56·1 ng/ml, P= 0·034). The dietary intervention did not affect U-NTx (P= 0·96) or height (P= 0·80). Baseline levels of U-NTx and osteocalcin correlated with changes in height at month 6 across the dietary groups (P< 0·001 and P= 0·001, respectively). The present study does not show any effect of increased protein intake on height or bone resorption in children. However, the difference in the change in the level of osteocalcin between the high-protein/high-GI group and the low-protein/high-GI group warrants further investigation and should be confirmed in other studies. [ABSTRACT FROM PUBLISHER]

The nutritional acid load hypothesis of osteoporosis is reviewed from its historical origin to most recent studies with particular attention to the essential but overlooked role of the kidney in acid–base homeostasis. This hypothesis posits that foods associated with an increased urinary acid excretion are deleterious for the skeleton, leading to osteoporosis and enhanced fragility fracture risk. Conversely, foods generating neutral or alkaline urine would favour bone growth and Ca balance, prevent bone loss and reduce osteoporotic fracture risk. This theory currently influences nutrition research, dietary recommendations and the marketing of alkaline salt products or medications meant to optimise bone health and prevent osteoporosis. It stemmed from classic investigations in patients suffering from chronic kidney diseases (CKD) conducted in the 1960s. Accordingly, in CKD, bone mineral mobilisation would serve as a buffer system to acid accumulation. This interpretation was later questioned on both theoretical and experimental grounds. Notwithstanding this questionable role of bone mineral in systemic acid–base equilibrium, not only in CKD but even more in the absence of renal impairment, it is postulated that, in healthy individuals, foods, particularly those containing animal protein, would induce ‘latent’ acidosis and result, in the long run, in osteoporosis. Thus, a questionable interpretation of data from patients with CKD and the subsequent extrapolation to healthy subjects converted a hypothesis into nutritional recommendations for the prevention of osteoporosis. In a historical perspective, the present review dissects out speculation from experimental facts and emphasises the essential role of the renal tubule in systemic acid–base and Ca homeostasis. [ABSTRACT FROM PUBLISHER]

The present study evaluated the prebiotic effect of a standardised aqueous extract of Anoectochilus formosanus (SAEAF) and its effects on osteoporosis in ovariectomised (OVX) rats. The OVX rats were randomly divided into five groups and orally treated with water, SAEAF (200 and 400 mg/kg daily) and inulin (400 mg/kg daily) for 12 weeks. The sham group was orally treated with water. The SAEAF treatment enhanced the number of faecal bifidobacteria in OVX rats. The results of a Ca-balance experiment showed that SAEAF increased apparent Ca absorption and retention. The OVX rats were killed after SAEAF treatment lasting 12 weeks. The SAEAF decreased the caecal pH values and increased the caecal wall weight, caecal mucosa calbindin-D9k mRNA expression, free-Ca concentration and levels of SCFA in the caecum. The mineral content, density and biomechanical strength of bones were lower in OVX rats than the sham group, but these bone losses were prevented by SAEAF administration. Microtomography scanning showed that the SAEAF-treated rats had higher trabecular bone volume than the OVX rats. These results suggest that SAEAF prevented bone loss associated with ovarian hormone deficiency in the rats. [ABSTRACT FROM AUTHOR]

The effects of dietary capsanthin, the main carotenoid in paprika (Capsicum annuum), on lipid metabolism were examined. Young male Wistar rats were fed diets containing paprika powder, paprika organic solvent extract, residue of paprika extract, and purified capsanthin. Administration of purified capsanthin for 2 weeks resulted in a significant increase in plasma HDL-cholesterol (P < 0·05) without detectable differences in plasma total cholesterol and TAG concentrations. A statistically significant correlation (r 0·567; P < 0·001) was found between dietary capsanthin concentrations and plasma HDL-cholesterol concentrations. Animals receiving diets containing two different capsanthin concentrations exhibited dose-dependent increases in plasma HDL-cholesterol (r 0·597; P < 0·005). While capsanthin was absent in the liver of animals fed the basal diet, it increased markedly in capsanthin-fed animals (P < 0·001). Quantitative analyses of hepatic mRNA levels revealed that capsanthin administration resulted in up-regulation of mRNA for apoA5 and lecithin cholesterol acyltransferase (LCAT), without significant differences in other mRNA levels related to HDL-cholesterol metabolism. These results suggest that capsanthin had an HDL-cholesterol-raising effect on plasma, and the potential to increase cholesterol efflux to HDL particles by increasing apoA5 levels and/or enhancement of LCAT activity. [ABSTRACT FROM PUBLISHER]

Both K and Ca supplementation may have beneficial effects on bone through separate mechanisms. K in the form of citrate or bicarbonate affects bone by neutralising the acid load caused by a high protein intake or a low intake of alkalising foods, i.e. fruits and vegetables. Ca is known to decrease serum parathyroid hormone (S-PTH) concentration and bone resorption. We compared the effects of calcium carbonate, calcium citrate and potassium citrate on markers of Ca and bone metabolism in young women. Twelve healthy women aged 22–30 years were randomised into four controlled 24 h study sessions, each subject serving as her own control. At the beginning of each session, subjects received a single dose of calcium carbonate, calcium citrate, potassium citrate or a placebo in randomised order. The diet during each session was identical, containing 300 mg Ca. Both the calcium carbonate and calcium citrate supplement contained 1000 mg Ca; the potassium citrate supplement contained 2250 mg K. Markers of Ca and bone metabolism were followed. Potassium citrate decreased the bone resorption marker (N-terminal telopeptide of type I collagen) and increased Ca retention relative to the control session. Both Ca supplements decreased S-PTH concentration. Ca supplements also decreased bone resorption relative to the control session, but this was significant only for calcium carbonate. No differences in bone formation marker (bone-specific alkaline phosphatase) were seen among the study sessions. The results suggest that potassium citrate has a positive effect on the resorption marker despite low Ca intake. Both Ca supplements were absorbed well and decreased S-PTH efficiently. [ABSTRACT FROM PUBLISHER]

Lactation is known to be associated with a transient loss of bone mineral density (BMD) during 3–6 months post-partum. Bone changes during lactation in women consuming low dietary calcium are not sufficiently studied. The present longitudinal study examined the BMD changes during lactation in undernourished women and the relationship of bone changes to the nutritional status. Whole-body bone mineral content and BMD at hip, lumbar spine and forearm were assessed using dual-energy X-ray absorptiometry in thirty-six lactating women from the low socio-economic group at four time points – within 1 month after delivery (baseline), and at 6, 12 and 18 months after delivery. Maternal body composition and biochemical parameters of bone metabolism were estimated at the same time. It was observed that femoral neck BMD reduced by 4·6 % at 6 months, but recovery to the baseline was incomplete at 18 months with a deficit of 2 %. Hip BMD reduction at 6 months was transient. Lumbar spine BMD did not show significant loss at 6 months and BMD increased by 3·6 and 6·3 % at 12 and 18 months, respectively. Regression analyses indicated that baseline lean mass was the most important determinant of bone preservation at femoral neck, hip as well as whole body, whereas baseline body weight was the most important determinant of per cent gain in lumbar spine. Maternal nutritional status as indicated by body weight and lean mass appears to influence the lactation-related BMD changes in undernourished women from the low socio-economic group in India. [ABSTRACT FROM PUBLISHER]

The consumption of mineral waters is increasing in industrialised countries. High intakes of Ca and other alkalising cations as well as a low acid intake are beneficial to bone. We examined which components of mineral waters are conditioning their Ca content and their alkalinising power, in order to define the optimal profile. European mineral waters were randomly selected on the Internet: 100 waters with less than 200 mg Ca/l (9·98 mEq/l) and fifty with more than 200 mg/l, all with complete data for SO4, P, Cl, Na, K, Mg and Ca, and most also for HCO3. For comparison, forty North American mineral waters were randomly chosen. The potential renal acid load (PRAL) was calculated for each mineral water. North American waters did not reveal significant results because of their low mineralisation. We performed correlations between all eight components in order to explore the properties of the mineral waters. In the European waters, twenty-six out of twenty-eight correlations showed a P value of ≤ 0·01. In waters with PRAL >0 (acidifying waters), PRAL was positively correlated with SO4, Ca, K and Mg (P < 0·001). In those with PRAL < 0 (alkalinising waters), PRAL was negatively correlated with HCO3, Na, Mg, Ca, K, Cl and SO4 (P < 0·001). SO4 and HCO3 were not found together in high quantities in the same water for geochemical reasons. A high Ca content is associated with either a high SO4 or a high HCO3 content. SO4 theoretically increases Ca excretion, while HCO3 and low PRAL values are associated with positive effects on bone. Therefore, the best waters for bone health are rich in both HCO3 and Ca, and by consequence low in SO4. [ABSTRACT FROM PUBLISHER]

The manufacture of garments is the main industry in Bangladesh and employs 1??6 million female workers. Due to the indoor lifestyle and low dietary intake of calcium, we hypothesised that they are at risk of low vitamin D and bone mineral status. Two hundred female garment workers (aged 18???36 years) were randomly selected. Serum 25-hydroxyvitamin D (S-25OHD), serum intact parathyroid hormone (S-iPTH), serum calcium (S-Ca), serum phosphate (S-P) concentration and serum alkaline phosphatase activity (S-ALP) were measured from fasting samples. Bone indexes of hip and spine were measured by dual-energy X-ray absorptiometry. The mean S-25OHD (36??7??nmol/l) was low compared to that recommended for vitamin D sufficiency. About 16??% of the subjects were found to be vitamin D-deficient (S-25OHD??21??ng/l) was associated with progressive reduction in bone mineral density at the femoral neck and lumbar spine. According to the WHO criteria, the mean T-score of the femoral neck and lumbar spine of the subjects were within osteopenic range. We observed that subjects with a bone mineral density T-score??

Evidence exists that a more acidic diet is detrimental to bone health. Although more precise methods exist for measurement of acid???base balance, urine pH reflects acid???base balance and is readily measurable but has not been related to habitual dietary intake in general populations. The present study investigated the relationship between urine pH and dietary acid???base load (potential renal acid load; PRAL) and its contributory food groups (fruit and vegetables, meats, cereal and dairy foods). There were 22??034 men and women aged 39???78 years living in Norfolk (UK) with casual urine samples and dietary intakes from the European Prospective Investigation into Cancer and Nutrition (EPIC)-Norfolk FFQ. A sub-study (n 363) compared pH in casual samples and 24??h urine and intakes from a 7??d diary and the FFQ. A more alkaline diet (low PRAL), high fruit and vegetable intake and lower consumption of meat was significantly associated with a more alkaline urine pH before and after adjustment for age, BMI, physical activity and smoking habit and also after excluding for urinary protein, glucose, ketones, diagnosed high blood pressure and diuretic medication. In the sub-study the strongest relationship was found between the 24??h urine and the 7??d diary. In conclusion, a more alkaline diet, higher fruit and vegetable and lower meat intake were related to more alkaline urine with a magnitude similar to intervention studies. As urine pH relates to dietary acid???base load its use to monitor change in consumption of fruit and vegetables, in individuals, warrants further investigation. [ABSTRACT FROM PUBLISHER]

Himalaya 292 (Hordeum vulgare var. Himalaya 292) is a novel hull-less barley variety lacking activity of a key enzyme of starch synthesis giving a grain containing less total starch, more amylose and higher total dietary fibre. Animal trials have shown that Himalaya 292 contains more resistant starch and has greater positive impact on biomarkers of large-bowel health than comparable wholegrain cereal products. The present study compared the effects of foods made from wholegrain Himalaya 292 with those made from wholegrain wheat on faecal biomarkers of bowel health in human subjects. Seventeen male and female volunteers aged 31???66 years consumed similar quantities of Himalaya 292, whole-wheat or refined cereal foods daily for 4 weeks in a randomised cross-over design. Total dietary fibre intakes from weighed food records were 45, 32 and 21??g/d for the Himalaya 292, whole-wheat and refined cereal periods, respectively. Compared with the refined cereal foods, consumption of Himalaya 292 foods resulted in 33??% higher faecal weight, a lowering of faecal pH from 7??24 to 6??98, a 42??% higher faecal concentration and a 91??% higher excretion of butyrate, a 57??% higher faecal total SCFA excretion and a 33??% lower faecal p-cresol concentration. pH and butyrate concentration and excretion were also significantly different compared with wholemeal wheat. It is concluded that consumption of a diet that included foods made from Himalaya 292 supplied more fibre and improved indices of bowel health compared with refined cereal foods and, for some indices, similar wholemeal wheat foods at equivalent levels of intake. [ABSTRACT FROM PUBLISHER]

A high dietary P intake is suggested to have negative effects on bone through increased parathyroid hormone secretion, as high serum parathyroid hormone (S-PTH) concentration increases bone resorption. In many countries the P intake is 2- to 3-fold above dietary guidelines, whereas Ca intake is too low. This combination may not be optimal for bone health. In a previous controlled study, we found that dietary P dose-dependently increased S-PTH and bone resorption and decreased bone formation. The aim of the present study was to investigate the dose???response effects of Ca intake on Ca and bone metabolism with a dietary P intake higher than recommended. Each of the twelve healthy female subjects aged 21???40 years attended three 24-h study sessions, which were randomized with regard to a Ca dose of 0 (control day), 600 or 1200??mg, and each subject served as her own control. The meals on each study day provided 1850??mg P and 480??mg Ca. S-PTH concentration decreased (P??

Fructus Ligustri Lucidi (FLL), a kidney-tonifying Chinese herb, was shown to regulate Ca balance in ovariectomized (OVX) rats in our previous study. This study investigated whether it could improve bone properties in aged normal and OVX rats and increase osteoblastic differentiation in rat osteoblast-like UMR-106 cells. Ten-month-old aged rats underwent sham-operation or ovariectomy, were orally administered with FLL extracts or its vehicle and fed with diets containing different levels of Ca (LCD, 0·1 % Ca; MCD, 0·6 % Ca; HCD, 1·2 % Ca) for 12 weeks. Ovariectomy induced bone loss at multiple-sites of both tibia and femur in all rats being studied. FLL extract increased bone mineral density and bone mineral content at both tibial and femoral diaphysis as well as the lumbar vertebra (LV-2) in rats fed either LCD or MCD. In addition, FLL increased biomechanical strength of the tibial diaphysis in these rats. Combination of FLL and high-Ca diet significantly improved bone mass of cortical and trabecular bone at appendicular bones and LV-2 and decreased bone loss associated with ovarietomy and low-Ca feeding. Treatment of UMR-106 cells with FLL extracts accelerated the formation of calcified matrix and increased extracellular Ca and P depositions in time- and dose-dependent manner. The level of mineralization reached a maximum by 6 d incubation at the dosage of 10 μg FLL extract/ml. Our study indicated that FLL extract could improve bone properties in aged rats possibly via its direct action on osteoblastic cells by enhancement of the mineralization process. [ABSTRACT FROM PUBLISHER]

Few data have evaluated Zn balance in young children after the first year of life. The objective of the present study was to study the relationships among Zn intake, absorption, endogenous faecal excretion, and retention in a group of healthy children. Thirty children, aged 15???48 months, were studied on a diet representative of their usual daily mineral intake. Zn absorption was assessed using a dual-tracer stable-isotope technique. Endogenous Zn faecal excretion and Cu absorption were determined in a subset of children. We found that Zn intake from the in-patient weighed dietary record (5??0 (sd 2??1) mg/d) was significantly greater than the current estimated average requirement (EAR; 2??5??mg/d; P??0??4, for all). Absolute Zn absorption was significantly related to Zn intake (r2 0??696; P??

Non-digestible oligosaccharides such as inulin and oligofructose have been shown to consistently increase calcium absorption in experimental animals, but data in humans are less clear-cut. The objective of this study was to assess the effect of 8 g/d of oligofructose or a mixture of inulin and oligofructose on calcium absorption in girls at or near menarche. A total of fifty-nine subjects were studied using a balanced, randomized, cross-over design. They received, in random order, 8 g/d placebo (sucrose), oligofructose or the mixture inulin+oligofructose for 3 weeks, separated by a 2-week washout period. Throughout the study, subjects consumed a total of approximately 1500 mg/d dietary calcium, by adding two glasses of calcium-fortified orange juice to their diet. Four grams of placebo, oligofructose or the mixture inulin+oligofructose was added to each glass of orange juice immediately before it was consumed. At the end of each 3-week adaptation period, calcium absorption was measured, using a dual stable isotope technique, from the cumulative fractional excretion of an oral and an intravenous tracer over 48 hours. Calcium absorption was significantly higher in the group receiving the inulin+oligofructose mixture than in the placebo group (38??2??9??8 % v. 32??3??9??8 %; P=0??01), but no significant difference was seen between the oligofructose group and the placebo group (31??8??9??3 % v. 31??8??10??0 %, P=NS). We conclude that modest intakes of an inulin+oligofructose mixture increases calcium absorption in girls at or near menarche. [ABSTRACT FROM PUBLISHER]

Excessive dietary NaCl in association with a paucity of plant foods, major sources of K alkaline salts, is a common feature in Western eating habits which may lead to acid???base disorders and to Ca and Mg wasting. In this context, to evaluate the effects of potato, rich in potassium citrate, on acid???base homeostasis and mineral retention, Wistar rats were fed wheat starch (WS) or cooked potato (CP) diets with a low (0??5 %) or a high (2 %) NaCl content during 3 weeks. The replacement of WS by CP in the diets resulted in a significant urinary alkalinisation (pH from 5??5 to 7??3) parallel to a rise in citrate and K excretion. Urinary Ca and Mg elimination represented respectively 17 and 62% of the daily absorbed mineral in rats fed the high-salt WS diet compared with 5 and 28% in rats fed the high-salt CP diet. The total SCFA concentration in the caecum was 3-fold higher in rats fed the CP diets compared with rats fed the WS diets, and it led to a significant rise in Ca and Mg intestinal absorption (Ca from 39 to 56 %; Mg from 37 to 60 %). The present model of low-grade metabolic acidosis indicates that CP may be effective in alkalinising urine, enhancing citrate excretion and ameliorating Ca and Mg balance. [ABSTRACT FROM PUBLISHER]

The reversibility of osteopenia secondary to isolated Ca deficiency (CaDef) is still not clear. We studied the effect of severe CaDef on Ca homeostasis and bone accrual in a ???hypercalcaemic??? animal, the rabbit, during the post-weaning period and its reversibility on Ca supplementation. Male Belgian 5-week-old rabbit pups were fed CaDef diet (0??026% Ca) for 10 weeks. As compared with those fed with a normal chow diet (0??45% Ca), CaDef pups developed significant hypocalcaemia (P<0??05), hypocalciuria (urinary Ca 76 (sem 12) V 17 (sem 1) mg/l;P<0??005), hypophosphataemia (serum inorganic P 100 (sem 6) V. 65 (sem 4) mg/l; P<0??005), secondary hyperparathyroidism (SHPT) (serum intact parathyroid hormone human equivalent 18??2 (sem 1??4) V. 125??0 (sem 4??5) pg/ml; P<0??001) and elevated serum calcitriol levels (34??0 (sem 3??9) V. 91??0 (sem 1??0) pg/ml; v<0??005). Elevated urinary C-terminal telopeptide of class I collagen (P<0??005) and total serum alkaline phosphatase (P<0??005) suggested increased bone turnover. There was a significantly lower gain in bone mineral density (BMD) and bone mineral content (BMC) in the whole body and lumbar spine in vivo, and various sub-regions of the femur and tibia in vitro.Supplementation of adequate Ca (0??45% Ca) after 15 weeks on the normal diet resulted in rapid catch-up growth, and resolution of SHPT. Rapid gain in various BMD and BMC parameters continued at 30 weeks of age, and both were comparable with those in rabbits on a normal diet. We conclude that Ca deficiency-induced SHPT and poor bone accrual in growing rabbit pups are rapidly reversible with Ca supplementation. The present study indicates that early intervention may be a more appropriate window period for human nutritional corrective measures. [ABSTRACT FROM PUBLISHER]

This study demonstrates that feeding difructose anhydride III (DFAIII) improves bone strength and femoral mineral concentrations in a rat model of oestrogen deficiency. We showed the relationship between Ca, Mg and P absorption and bone characteristics in rats. Two groups of female Sprague-Dawley rats (6 weeks old) underwent bilateral ovariectomy (ovariectomized rats, OVX rats) or bilateral laparotomy (sham rats). At 10 weeks old, OVX and sham rats were divided into three subgroups and fed a control, 1??5 % DFAIII or 3 % DFAIII diet for 8 weeks, respectively. Ca but not Mg absorption rates were lowered by ovariectomy; however, ingestion of the 1??5 % and 3 % DFAIII diets similarly restored the reduced Ca absorption in OVX rats at 4 and 8 weeks after feeding of the test diets. DFAIII increased Mg absorption dose-dependently in sham and OVX rats. The bone strength, femoral Ca and Mg concentrations, and distal bone mineral density in the 3 % DFAIII group were higher than those in the control group in OVX rats. The absorption rates of Ca and Mg were significantly correlated with femoral Ca and Mg concentrations and strength, which suggests that increasing both Ca and Mg absorption improves bone characteristics in OVX rats. There were no differences in any of the variables in the femur between the 1??5 % and 3 % DFAIII groups in OVX rats. In conclusion, feeding of a low dose of DFAIII increased intestinal Ca and Mg absorption, and the promotive effect of DFAIII persisted for over 8 weeks. This effect was associated with prevention of ovariectomy-induced osteopenia. [ABSTRACT FROM PUBLISHER]

It is well known that the intestinal availability of Ca from Ca-rich mineral waters is equivalent to that of milk Ca. However, the effect of associated anions on Ca urinary loss needs to be addressed. The aim of the current study was to compare, under ordinary conditions of consumption, milk and a SO4-rich mineral water as the Ca provider in a large number of subjects consuming the same quantity of Ca from the two sources in a crossover study lasting for an extended period. Thirty-seven healthy women completed a 12-week protocol, divided into four periods of 3 weeks (W). In the first (W1–3) and third (W6–9) periods, dietary Ca intake was restricted to 600 mg/d. In the second (W4–6) and final (W10–12) periods, either 400 ml/d medium-fat milk or 1 litre of a Ca- and SO4-rich mineral water, each providing about 480 mg Ca/d, was added to the diet in a random manner. Dietary evaluation, blood and urinary measures were performed during the last week (W6 and W12) of each Ca supplementation period. The urinary excretion of Ca was higher (0·5 mmol/d more) with water than with milk (P<0·001). An examination of all the dietary factors known to influence calciuria suggested that the acidogenic action of SO4 was responsible for this increased calciuria. Thus, despite an equal Ca intake and assuming an unchanged intestinal absorption, these results suggest that Ca balance is better with milk consumption than with CaSO4-rich water. [ABSTRACT FROM PUBLISHER]

The influence of a high-Na, high-protein (calciuric) diet on Ca and bone metabolism was investigated in postmenopausal women (aged 50???67 years) who were stratified by vitamin D receptor (VDR) genotype. In a crossover trial, twenty-four women were randomly assigned to a diet high in protein (90 g/d) and Na (180 mmol/d) or a diet adequate in protein (70 g/d) and low in Na (65 mmol/d) for 4 weeks, followed by crossover to the alternative dietary regimen for a further 4 weeks. Dietary Ca intake was maintained at usual intakes (about 20 mmol (800 mg)/d). Urinary Na, K, Ca, N and type I collagen cross-linked N-telopeptide (NTx; a marker of bone resorption), plasma parathyroid hormone (PTH), serum 25-hydroxycholecalciferol (25(OH)D3), 1,25-dihydroxycholecalciferol (1,25(OH)2D3), osteocalcin and bone-specific alkaline phosphatase (B-Alkphase) were measured in 24 h urine samples and fasting blood samples collected at the end of each dietary period. The calciuric diet significantly (P<0??05) increased mean urinary Na, N, K, Ca and NTx (by 19 %) compared with the basal diet, but had no effect on circulating 25(OH)D3, 1,25(OH)2D3, PTH, osteocalcin or B-Alkphase in the total group (n 24). There were no differences in serum markers or urinary minerals between the basal and calciuric diet in either VDR genotype groups. While the calciuric diet significantly increased urinary NTx (by 25??6 %, P<0??01) in the f+ VDR group (n 10; carrying one or more (f) Fok I alleles), it had no effect in the f??? VDR group (n 14; not carrying any Fok I alleles). It is concluded that the Na- and protein-induced urinary Ca loss is compensated for by increased bone resorption and that this response may be influenced by VDR genotype. [ABSTRACT FROM PUBLISHER]

Ca absorption has been shown to be unaffected by high luminal concentrations of two commonly consumed soyabean phyto-oestrogens (PO) (genistein and daidzein) in Caco-2 cells grown under oestrogen-depleted conditions. However, these compounds exhibit dose-dependent biphasic effects in some tissues, such as reproductive tissue and bone. Thus, in light of this biphasic activity, the effect of lower concentrations of genistein and daidzein on Ca absorption requires further investigation. Therefore, the aim of the present study was to investigate the effect of a range of concentrations of genistein and daidzein on Ca absorption in the human Caco-2 intestinal-like cell model. Caco-2 cells were seeded onto permeable filter supports and allowed to differentiate into monolayers. On day 21, the Caco-2 monolayers (n 12 per treatment), grown in oestrogen-deplete media, were then exposed to 10 nm-1,25-dihydroxycholecalciferol (1,25 (OH)2D3), or 1, 10 and 50 ??m-genistein or -daidzein for 24 h. After exposure, transepithelial and transcellular transport of 45Ca and fluorescein transport were measured. As expected, 1,25 (OH)2D3 stimulated Ca absorption in Caco-2 cells, by up regulating transcellular transport. Ca absorption was unaffected by either PO at luminal concentrations of 1, 10 or 50 ??m, typical of intakes by Western and Asian populations as well as supplemental levels, respectively. The results of this model suggest that the proposed beneficial effects of supplemental levels of these PO compounds on bone mass in postmenopausal women more probably arise from direct effects on bone cells, and not by an indirect effect of these compounds on Ca absorption. [ABSTRACT FROM PUBLISHER]

Sun-dried raisins are a source of dietary fibre and tartaric acid. The effects of tartaric acid on colon function have not been the focus of extensive research. The purpose of the present study was to evaluate the effects of dietary fibre and tartaric acid from sun-dried raisins on colon function and on faecal bile acid and short-chain fatty acid (SCFA) excretion in healthy adults. Thirteen healthy subjects were fed 120 g sun-dried raisins/d or 5 g cream of tartar (equivalent to the tartaric acid in 120 g sun-dried raisins)/d for 9 weeks, divided into 3-week cycles. The experimental diets were fed in a crossover design after an initial control period. Faeces were collected for the last 4 d of each cycle for analysis of SCFA and bile acids. Intestinal transit time decreased from 42h on the baseline diet to 31h on cream of tartar (P<0??1) and to 28h on sun-dried raisins (P<0??05). Faeces were softer on both sun-dried raisins and cream of tartar, but sun-dried raisins increased faecal wet weight (P<0??05), while cream of tartar did not. Sun-dried raisins caused significant reductions from baseline values in total bile acid concentration (from 1??42 (sd 1??03) to 1??09 (sd 0??76) mg/g, P<0??05), whereas cream of tartar did not (1??40 (sd 1??06) mg/g). Sun-dried raisins also significantly reduced the lithocholic (LC):deoxylithocholic acid (DC) ratio (from 1??63 (sd 0??85) to 1??09 (sd 0??50), P<0??02), whereas cream of tartar reduced the ratio, but to a lesser extent (1??29 (sd 0??79), NS). Both faecal bile acids and the LC:DC ratio are indicators of reduced risk for colon cancer. Sun-dried raisins increased total SCFA excretion (from 5??6 (sd 3??4) to 7??6 (sd 3??0) g/4d, P<0??05), which remained unchanged with cream of tartar (5??6 (sd 3??0) g/4d). Both sun-dried raisins and cream of tartar appear to be good stool softeners and to shorten intestinal transit time, although the fibre in sun-dried raisins has the added benefit of increasing faecal weight. Both sun-dried raisins and cream of tartar modulate the composition of faecal bile acids and SCFA in a way that has potential health benefits. [ABSTRACT FROM PUBLISHER]

The effect of polyunsaturated fatty acids (PUFA), in particular conjugated linoleic acid (CLA), on Ca and bone metabolism is unclear. In a 2 ?? 2 factorial design study, forty male 4-week-old rats were fed a control diet containing 70 g added fat (soyabean oil (SBO; n???6 PUFA-rich diet) or menhaden oil???safflower oil (MSO; n???3 PUFA-rich diet))/kg diet with 0 or 10 g CLA/kg for 8 weeks. Ex vivo prostaglandin E2biosynthesis by bone organ culture was significantly higher (P<0??001) in rats consuming SBO compared with MSO, irrespective of CLA. Addition of the CLA treatment to either diet further lowered (P<0??05) ex vivo prostaglandin E2 production. Neither PUFA type nor CLA altered circulating or femoral mRNA levels of osteocalcin (a marker of bone formation) or insulin-like growth factor-I (a mediator of bone metabolism). While urinary pyridinium crosslinks levels (markers of bone resorption) were unaffected by CLA irrespective of PUFA type, they were significantly higher (P<0??05) in rats consuming SBO compared with MSO irrespective of CLA. Net fractional (%) and absolute (mg) Ca absorption were significantly (P<0??01 and P<0??05 respectively) higher in CLA-supplemented than unsupplemented animals fed on the n???3 PUFA-rich diet, whereas CLA had no effect in animals fed the n???6 PUFA-rich diet. There was no effect of CLA supplementation on bone mineral mass. In conclusion, CLA supplementation over 8 weeks appeared to enhance Ca absorption in young growing rats fed an n???3 PUFA-rich diet, but had no measurable effect on bone metabolism or bone mass over this time frame. [ABSTRACT FROM PUBLISHER]

Recently, dietary phyto-oestrogens (PO) have been suggested as possible alternatives to oestrogen therapy (hormone replacement therapy) as a means of preventing bone loss associated with ovarian hormone deficiency. While PO, which exhibit oestrogen-like activity, act directly on bone cells, their protective effect on bone may be partly due to their ability to enhance Ca absorption. Therefore, the aim of the present study was to investigate the effect of 17??-oestradiol and two commonly consumed soyabean PO (genistein and daidzein) on Ca absorption in the human Caco-2 intestinal-like cell model. Caco-2 cells were seeded onto permeable filter supports and allowed to differentiate into monolayers. On day 21, the Caco-2 monolayers (n 8???18 per treatment), grown in oestrogen-replete or -deplete media, were then exposed to 10 nM-17??-oestradiol, 1 nM-1,25-dihydroxycholecalciferol, or 50 ??M-genistein or -daidzein for 24 h. After exposure, transepithelial and transcellular transport of 45Ca and fluorescein transport (a marker of paracellular diffusion) were measured. As expected, 1,25-dihydroxycholecalciferol stimulated Ca absorption in Caco-2 cells, by up-regulating transcellular transport, whereas 17??-oestradiol had no effect on Ca absorption. Unexpectedly, both PO decreased Ca absorption (by about 17???19 % compared with control, P<0??05), by reducing transcellular Ca transport in Caco-2 cells grown in oestrogen-replete media. This inhibitory effect disappeared when monolayers were grown in oestrogen-deplete media. In conclusion, PO at high luminal concentrations either had no effect or reduced Ca absorption in Caco-2 cells, dependent on oestrogen status. The effect of lower concentrations of these compounds needs to be investigated. [ABSTRACT FROM PUBLISHER]

We investigated the effects of dietary oligofructose and Ca on bone structure in ovariectomized rats, using microradiography and histomorphometry. Ninety-six animals were allocated to seven experimental groups: G1, sham-operated; G2???G7, ovariectomized. Semi-purified diets containing 5 g Ca/kg (recommended content) without oligofructose (G1, G2) or with 25, 50 or 100 g oligofructose/kg (G3, G4, G5) or 10 g Ca/kg (high content) without oligofructose (G6) or with 50 g oligofructose/kg (G7) were fed for 16 weeks. At the recommended level of Ca, high oligofructose (G5) increased femur mineral levels in ovariectomized rats, while medium oligofructose did so at high Ca. Increasing Ca in the absence of oligofructose did not increase femur mineral content. Trabecular bone area (%) analysed in the tibia was 10??3 (SEM 1??2) (G1), 7??7 (SEM 0??6) (G2), 9??3 (SEM 0??7) (G3), 9??4 (SEM 1??0) (G4), 9??5 (SEM 0??7) (G5), 10??2 (SEM 0??8) (G6), and 12??6 (SEM 0??8) (G7). At the recommended level of Ca, 25 g oligofructose/kg prevented loss of trabecular area due to increased trabecular thickness, while 50 or 100 g oligofructose/kg increased trabecular perimeter. At high Ca, oligofructose prevented loss of bone area due to increased trabecular number but similar thickness (G7 v. G6). When Ca was raised in the presence of oligofructose (G7), trabecular area and cortical thickness were highest, while loss of trabecular connectivity was lowest of all groups. At the same time, lumbar vertebra Ca was higher; 44??0 (SEM 0??8) (G7) compared with 41??6 (SEM 0??8) (G2), 41??4 (SEM 0??7) (G4), and 40??5 (SEM 1??0) mg (G6). We conclude that ovariectomy-induced loss of bone structure in the tibia was prevented but with different trabecular architecture, depending on whether dietary Ca was increased, oligofructose was incorporated, or both. Oligofructose was most effective when dietary Ca was high. [ABSTRACT FROM PUBLISHER]

A low Ca intake by both rats and man increases bone resorption, decreases bone mass and increases the risk of osteoporosis. The skeletal effect of high Ca intakes is less clear, particularly during periods of bone mineral accrual. Twenty-four female 5-week-old rats, Wistar strain, were randomized by weight into three groups of eight rats each and fed ad libitum a semi-purified diet containing 2 (Ca-restricted), 5 (normal) or 20 (Ca-supplemented) g Ca/kg for 3 weeks. When compared with the normal Ca diet, urinary Ca excretion was unaffected by the dietary restriction of Ca for 3 weeks, but was greater (P<0??001) in Ca-supplemented rats. Urinary pyridinoline (Pyr) and deoxypyridinoline (Dpyr) levels were significantly greater during weeks 2 (Pyr P<0??05, Dpyr P<0??001) and 3 (Pyr P<0??01, Dpyr, P<0??001) of dietary Ca restriction, but were unaffected by Ca supplementation. Femoral dry weight and the concentration of Mg and P in femora were unaffected by dietary Ca concentration. Femoral Ca concentration was reduced (P<0??05) in the Ca-restricted group compared with the other two groups. In conclusion, these results suggest that increasing dietary Ca intake, well above the recommended level, had no effect on bone mineral composition or bone resorption (as assessed with urinary pyridinium crosslinks) in young growing female rats. In addition, these results confirm the findings of previous studies which have shown that bone Ca content in young growing rats was reduced by dietary Ca restriction and that this reduction results, at least in part, from an increased rate of bone resorption. [ABSTRACT FROM PUBLISHER]

Dietary Ca and osteocalcin (OC), parathyroid hormone (PTH), 25-hydroxyvitamin D (25-OH-D), insulin-like growth factor (IGF)-I and sex hormone binding globulin (SHBG) were assessed simultaneously to bone mineral density (BMD) in 200 adolescent girls (aged 11???15 years) and 100 young women (aged 20???23 years), selected from the lowest and highest end of the Ca intake distribution of a larger population sample. Ca intake was evaluated by food frequency questionnaires, BMD was measured by dual energy x-ray absorptiometry at ultradistal and proximal radius of non-dominant arm, bone age was estimated from x-rays of left hand and wrist according to. Surprisingly, mean Ca intakes were below the dietary reference intakes in the subgroups of girls and women with the highest measured Ca consumption. Postmenarcheal, but not premenarcheal girls showed radial densities as high as the women and in no group was BMD associated with Ca intake. In all adolescents serum PTH was negatively related to dietary Ca. In girls before menarche IGF-I was positively associated with bone age, while in the same subjects the negative relationship between SHBG and BMD pointed to the crucial role of bioavailable sex steroids on bone mass apposition in early puberty. OC levels decreased progressively with age, while serum 25-OH-D significantly increased after menarche. In conclusion, although in adolescents low Ca intake has not been shown to induce any immediate deleterious effect on radial density, the compensatory hypersecretion of PTH supports the need for an adequate Ca intake to achieve peak bone mass. [ABSTRACT FROM PUBLISHER]

The effects of salt (NaCl) supplementation of rat diets (50 g/kg diet), with normal (200 g/kg) or high (500 g/kg) dietary casein content, were studied in 3-week-old male rats over a 3-week period. Weight gain was reduced by dietary salt but was unaffected by dietary casein. Salt-supplemented rats exhibited a two-and three-fold increase in urinary Mg and Ca excretion respectively, irrespective of dietary casein content. Dietary casein had no effect on urinary Ca or Mg. Salt reduced femoral mass but not femoral mass expressed relative to body weight, but neither variable was affected by dietary casein. Femoral Mg and P contents and concentrations were unaffected by dietary salt or casein. While femoral Ca concentration was unaffected by dietary salt, the Ca content was reduced by salt supplementation, irrespective of dietary casein content. Neither the content nor concentration of Ca in femora was affected by dietary casein. Urinary pyridinoline and deoxypyridinoline levels were increased by salt supplementation, irrespective of dietary casein content, but were unaffected by casein. Net Ca absorption was unaffected by dietary salt or casein. In conclusion, these results show that salt supplementation over the short-term increased the rate of bone resorption in rats. This was as a consequence of Na-induced calciuria. On the other hand, a high dietary protein intake had no effect on Ca metabolism, bone composition or bone resorption, nor did it augment the Na-induced calciuria or increased rate of bone resorption. [ABSTRACT FROM PUBLISHER]