Daily Phosphorus Intake Research Articles

Impact of Restricted Phosphorus, Calcium-adjusted Diet on Musculoskeletal and Mental Health in Hypophosphatasia.

Impairments in musculoskeletal and mental health are common in adults with Hypophosphatasia (HPP). Restricted phosphorus intake has been suggested to positively affect symptoms in HPP, but there is a lack of interventional evidence. This work aimed to evaluate the effect of a phosphorus-restricted, calcium-adjusted diet on musculoskeletal and mental health in HPP. A prospective, noncontrolled, single-center interventional study (NuSTEPS II) was conducted among outpatients at the Osteology Department, University of Wuerzburg, Germany. A total of 26 adults with an established HPP diagnosis received a standardized diet with a defined daily intake of phosphorus (1160-1240 mg/d) and calcium (870-930 mg/d) over 8 weeks. Main outcome measures were functional testing and patient-reported outcome measures. At 8 weeks, significant improvements were observed in usual gait speed (P = .028) and the chair-rise test (P = .019), while no significant changes were seen in the 6-minute walk test (P = .468) and the timed up-and-go test (P = .230). Pain was not significantly reduced according to the visual analog scale (VAS) (P = .061), pain subscale of the 36-Item Short-Form Health Survey (SF-36) (P = .346), and Pain Disability Index (P = .686). Further, there was a significant improvement in the SF-36 vitality subscale (P = .022) while all other subscales as well as the Lower Extremity Functional Scale (P = .670) and the Fatigue Assessment Scale (P = .392) did not change significantly. Adjustments of mineral intake were not associated with relevant alterations regarding the intake of energy and energy-supplying nutrients or body composition. Adjusting phosphorus and calcium intake may positively affect individual symptoms in adults with HPP, but overall clinical effectiveness regarding major issues like pain and endurance appears limited.

Influence of Dietary Phosphorus on the Growth, Feed Utilization, Proximate Composition, Intestinal Enzymes, and Oxidation Resistance of Sea Cucumber Apostichopus japonicus.

Six experimental diets (crude protein 12.58%, crude fat 1.93%, and total energy 10.72 kJ/kg) containing 0.24%, 0.37%, 0.51%, 0.62%, 0.77%, and 0.89% phosphorus were formulated to evaluate dietary phosphorus requirement for sea cucumber Apostichopus japonicus. The feeding trial was conducted in 18 fiberglass tanks (220 L) for 63 days. Each diet was randomly assigned to triplicate tanks of 50 sea cucumbers (9.99 g) and fed once daily. With the increase of dietary phosphorus level, weight gain (WG), specific growth rate (SGR), daily feed intake (DFI), feces production ratio, the activities of amylase, alkaline phosphatase, phosphofructokinase, succinate dehydrogenase, and glutathione peroxidase as well as the contents of glutathione and glutathione oxidized significantly increased and then decreased afterwards (P < 0.05). A. japonicus fed diet with 0.63%, 0.63%, and 0.55% dietary phosphorus was estimated to yield the highest WG (11.39 g), SGR (1.09%/d), and DFI (2.55%/d) according to the quadratic regression analysis of WG, SGR, and DFI against dietary phosphorus level, respectively. The apparent digestibility of dry material and energy followed an opposite tendency. Feed efficiency, the contents of whole-body phosphorus, initially increased and then plateaued, fitting piecewise-linear models with breakpoint at 0.57% and 0.55% dietary phosphorus. Daily phosphorus intake, pyruvate kinase activity, and the ratio of glutathione and glutathione oxidized increased (P < 0.05) but the apparent digestibility of phosphorus, the activities of alkaline protease, aspartate transaminase, and phosphoenolpyruvate carboxykinase decreased (P < 0.05), responding to the increasing dietary phosphorus. Considering the present results, the optimal dietary phosphorus for A. japonicus is 0.57-0.63%.

Optimal Administration of Phosphorus Adsorbents When Using Medical Nutritional Supplements for Tube-fed Patients.

All medical enteral nutrition products contain phosphorus and when administered to patients with chronic kidney disease (CKD) and on dialysis, they lead to the risk of elevated serum phosphorus levels. Thus, serum phosphorus levels should be monitored, and phosphorus adsorbents should be used in cases of high serum phosphorus levels. In this study, we investigated the effect of phosphorus adsorbents on enteral nutrition, using Ensure Liquid®, a medical nutritional formula, for patients with CKD and those on dialysis. Additionally, we compared the effects of the simple suspension method, in which various phosphorus-adsorbing agents are suspended and mixed directly with the nutritional formula for tube administration (hereafter referred to as the "pre-mix method"), and the conventional method, in which only the phosphorus-adsorbing agents are administered separately from the nutritional formula for tube administration (hereafter referred to as the "normal administration method"). The administration of various phosphorus adsorbents using the pre-mix technique resulted in a phosphorus removal rate of 8-15% (approximately 12% on average). Therefore, through the pre-mix method, maintaining the phosphorus content of Ensure Liquid® below the daily phosphorus intake standard was possible for patients on dialysis. The pre-mix method via the simple suspension method of administering phosphorus adsorbent with Ensure Liquid® resulted in less drug adsorption to the injector and tube and a higher phosphorus removal rate than the normal administration method.

FC 102: Daily Phosphorus Intake, its Source and Mortality in Adults on Hemodialysis: The Diet-Hd Study

Abstract BACKGROUND AND AIMS Elevated serum phosphorus is associated with increased mortality in dialysis patients. Since the bioavailability of dietary phosphorus intake (DPI) varies based on its source and might contribute to serum phosphorus differently, the aim of the study is to investigate the association between total DPI and DPI from different sources with mortality in patients treated with hemodialysis. METHOD DPI (plant, animal and other sources) was ascertained by the Global Allergy and Asthma European Network food frequency questionnaire within the DIET-HD study, a multinational cohort study of European and South American adults on maintenance hemodialysis. Adjusted Cox regression analyses were conducted to evaluate the association between total and source-specific DPI (both as tertiles and continuous in fraction or in absolute amount) with all-cause and cardiovascular mortality. RESULTS A total of 8110 patients were followed for a median of 3.8 years (26 074 person-years). There were 2953 deaths, of which 1160 were cardiovascular-related. The median (interquartile range) DPI was 1388 (961–1994) mg/day, with only 12% (995/8110) of participants consuming the recommend range of DPI (800–1000 mg/day). Each standard deviation (SD, 896 mg/day) increase in total DPI was associated with higher all-cause mortality [hazard ratio (HR) 1.14; 95% confident interval (95% CI) 1.02–1.27] and cardiovascular mortality (1.45; 95% CI 1.08–1.96). Each SD (17%) increase in the fraction of DPI from plant sources was associated with lower all-cause mortality (HR 0.92; 95% CI 0.85–0.99) and marginally in cardiovascular mortality (HR 0.93; 95% CI 0.85–1.01). Each SD (9%) increase in the fraction of DPI from other source [HR: 1.06; 95%CI 1.02–1.10)] was associated with higher all-cause mortality. In contrast, each SD (17%) increase in the fraction of DPI from animal source was not associated either all-cause (HR: 1.02; 95% CI 0.96–1.07) or cardiovascular mortality (HR 1.07; 95% CI 0.98–1.16). Increased absolute amount of DPI from animal or other source were associated with both all-cause and cardiovascular mortality. CONCLUSION A higher total DPI is associated with increased all-cause and cardiovascular death. This positive association is driven by the DPI from animal and other sources, while higher DPI fraction from plant associated with reduced all-cause mortality.

Mineral Balance and Metabolic Syndrome in Adolescents: Focus on Calcium and Phosphorus Intake.

The incidence of metabolic syndrome, a chronic disease, tends to increase in adolescence, but has not been a high priority in delivery of health services. This study was to investigate the relationship between metabolic syndrome prevalence and mineral balance such as calcium and phosphorus intake among Korean adolescents. This study is a cross-sectional descriptive study using data from the 7th Korean national health and nutrition examination survey (KNHANES) VII-3 (2018) and the 8th KNHANES VII-1 (2019). A total of 895 adolescents aged 12 to 18 who filled in mineral intake questionnaires were analyzed using SPSS. According to their responses, only 2.9% of the subjects had a calcium: phosphorus intake ratio of 1:1, which is the recommended ratio. Daily phosphorus intake was significantly correlated with systolic blood pressure (r = 0.448, p < 0.001), waist circumference (r = 0.115, p = 0.001), HDL cholesterol (r = −0.113, p = 0.002), and daily calcium intake (r = 0.697, p = 0.001). And, as the serum creatinine increased by 1, the risk of metabolic syndrome increased 16.5 times (OR: 16.452, 95% CI: 1.701–159.136, p < 0.05). Excessive phosphorus intake and high creatinine levels may increase the risk of metabolic syndrome in adolescents. Therefore, education is necessary to encourage adolescents to follow a balanced diet that contains essential minerals. In addition, it is suggested to expand the metabolic syndrome prevention education, which has been largely targeted towards adults.

Phosphorus Content of Commonly Prescribed Medications Among Patients With Chronic Kidney Disease

This study aimed to build a brand-specific library of phosphorus content in medications and to determine the median daily phosphorus intake from medications among chronic kidney disease (CKD) patients in Singapore.This is a single-center, cross-sectional study conducted in 200 patients with CKD Stages 3-5D. Package inserts of medications commonly used by the CKD patients were reviewed to identify brands containing phosphorus. Drug manufacturers were contacted to obtain phosphorus content of products. The median daily phosphorus intake from medications of the 200 patients was then calculated using the information.A total of 399 formulations of 204 medications and supplements were reviewed (March 2020). Fifty-eight (15%) formulations were found to contain phosphorus. Forty-three (11%) formulations had missing information regarding the phosphorus content. Based on available information, the median daily phosphorus intake from medications was 1.28 mg (interquartile range = 0.006-16.08) across the CKD stages. Patients with CKD Stage 5D had a higher median intake of 4.09 mg (P = .009). A dose-independent variation in phosphorus content of excipients between generic and branded formulations was noted in this study. We have developed a library of phosphorus content in medications.The inorganic phosphorous content in frequently prescribed medications for CKD patients is generally low, with excipients (as opposed to the active ingredient or counterions) being the main source of phosphorus. Although this may seem almost negligible in comparison to the recommended dietary intake, prescribers should still exercise care, given the wide range of phosphorus content possible between different brands of the same medication, and the unpredictable absorption of inorganic phosphate in CKD patients.

POS-286 ASSESSMENT OF PHOPSHATE INTAKE AND IMPLEMENTATION OF PARENTAL STRUCTURED DIETARY PHOSPHATE EDUCATION IN PEDIATRIC CKD-A PROSPECTIVE STUDY

Hyperphosphatemia is an important co morbidity of chronic kidney disease (CKD) with long term implications on cardiovascular health. The KDOQI 2008 guidelines based on dietary references intakes (DRI) and PRNT [Pediatric Renal Nutrition task force] 2020 guidelines based on suggested daily intakes (SDI) provide recommendations for phosphorus(P) intake in children with CKD. Besides, differences in food culture demands detailed assessment of dietary intake of phosphorus and its sources in children across regions. Data on dietary phosphorus intake and sources in Indian children with CKD has not been systematically studied. The aim of this study was to evaluate for dietary intake and sources of phosphorus with reference to KDOQI and PRNT guidelines and assess the impact of parental structured phosphate education in the management of hyperphosphatemia. This prospective study included children aged 2-18yrs with stage2-5DCKD[calculated sample size 58] recruited from April 2018 to November 2019. Phosphorus intake was assessed by 24 hour dietary recall, analysed using food processor software (version7.4,1999, ESHA,Portland,OR,USA) and interpreted based on KDOQI 2008 and PRNT recommendations. No change in phosphate binders were made during the study period. Parents of those with hyperphosphatemia were subjected to a structured phosphate education comprising of pamphlets in regional languages describing the importance of dietary phosphorus control. A phosphorus pyramid based on Indian foods and phosphorus lowering techniques was formulated (Figure 1) for the parental education. Serum phosphate was monitored once in 2 months for 6 months. Figure 2 depicts the study flow. Seventy of the 75 children screened were recruited [mean age 9.4±3.4 years, CKD2-4:49% (n=34), CKD5/5D:51% (n=36), 27/36 on peritoneal dialysis, 20% vegetarians] with median duration of CKD being 3.8 [IQR2,6] years. The mean daily phosphorus intake was comparable between children with and without hyperphosphatemia [908±279 mg vs 814±302 mg, p=0.1]. Dairy and bakery products were main dietary sources of phosphorus. Based on DRI of KDOQI and SDI of PRNT recommendations, high phosphorus intake was observed in 51%and 64% of the cohort and in 58% and 100% of those with hyperphosphatemia respectively. Hyperphosphatemia was observed in 51% (Stage 2 to 4 CKD:33%; CKD5:67%; CKD5D:55% p=0.6). In 36 parents who received phosphate education, 29 children completed 6 months follow up and serum phosphate levels reduced to normal in 66%. Reduction in serum phosphate was independent of age, stage of CKD, dietary intake of phosphorus or intake of phosphate binders. In children with CKD2-5D,dietary intake of phosphorus is comparable in those with and without hyperphosphatemia. DRI based KDOQI2008 recommendation underestimated dietary phosphate intake compared to SDI based PRNT recommendations. In the majority, parental structured phosphate education using the phosphorus pyramid, is useful in the management of hyperphosphatemia.

Diet Controls Uranium Intake and Aggravates Health Hazards

Uranium (U) is ubiquitously abundant in the environment. Significant amounts of U are applied on agricultural soils with mineral phosphorus fertilizers; thus, entering the food chain. The daily intake of U with solid food varies only slightly. It is lowest with a mixed standard diet (1.3 µg/day U) and highest with a vegan diet (2.0 µg/day U). It is the U content of tap and mineral water which determines the total U intake (1.7 – 7.1 µg/day U). Next to U speciation and amount of U entering the human body, an oversupply with phosphorus, and a critical supply with calcium and iron may amplify negative health effects. Kidneys are the prime target of a high P intake and U toxicity. The additional daily phosphorus intake by food phosphates peaked to 1000 mg/day in the last 20 years. This may add on an average 1.2 µg/day U and worst case 11 µg/day U to the solid diet. Toxicological studies suggest that damages of kidneys can be expected when the U content is as low as 0.1-0.4 µg/g U. The study provides a comprehensive overview of potential health hazards caused by dietary uranium intake in relation to nutritional habits.

Habitual dietary phosphorus intake and urinary excretion in chronic kidney disease patients: a 3-day observational study.

Hyperphosphatemia in chronic kidney disease (CKD) is associated with vascular calcification, cardiovascular morbidity and mortality. The aim of this study was to estimate the daily dietary phosphorus intake compared with recommendations in CKD patients and to evaluate the reproducibility of the 24-h urinary phosphorus excretion. Twenty CKD patients stage 3-4 from the outpatient clinic, collected 24-h urine and kept dietary records for 3 consecutive days. The mean daily phosphorus intake was 1367±499, 1642±815 and 1426±706 mg/day, respectively (P=0.57). The mean urinary phosphorus excretion was 914±465, 954±414 and 994±479 mg/day, respectively (P=0.21). In this population of CKD patients stage 3-4 the daily phosphorus intake was above the recommended. Twenty-four-hour urinary phosphorus excretion was reproducible and the data indicate that a single 24-h urine collection is sufficient to estimate the individual phosphorus excretion.

A Preliminary Investigation Into the Mineral Intake of Horses in the UK

The diet of the domesticated horse is influenced by both internal and external variables, such as age, breed, discipline, and workload, as well as the feed brand preference of the owner. With a range of products and feeds available to the horse owner, this has the potential to lead to inappropriate feeding management. The aim of this study was to evaluate the current mineral intakes of horses in the UK. An online questionnaire was used to collect data on horse and owner demographics and feed rations. Total daily intakes of phosphorus, calcium, sodium, and potassium were calculated based on forage, concentrate, and supplement information given in the questionnaire. Estimated mineral intakes were compared to recommended levels using a Wilcoxon signed-rank test. Intakes of phosphorus, calcium, sodium, and potassium were found to be significantly (P < .001) higher than NRC recommendations, with most estimated mineral intakes originating from the forage component of the diet. However, the calcium to phosphorus ratio was calculated at 2.07:1, which is close to the recommended ratio limits. Excess intakes of calcium, phosphorus, sodium, and potassium have the potential to influence the metabolism of additional macro and micro minerals and, therefore, further research into this area is recommended.

Associations of Dietary Phosphorus Intake, Urinary Phosphate Excretion, and Fibroblast Growth Factor 23 With Vascular Stiffness in Chronic Kidney Disease

Elevated serum phosphate concentrations are established risk factors for cardiovascular disease and mortality in chronic kidney disease (CKD). Independent associations of other indices of phosphorus metabolism, such as phosphorus intake, urinary phosphate excretion, or hormones that regulate these systems, like fibroblast growth factor 23 (FGF23), with markers of cardiovascular disease in CKD, have been studied in less detail. Cross-sectional study. Seventy-four adult CKD patients with mean creatinine clearance of 51 ± 19 mL/minute. Augmentation index (AI)--a surrogate marker of arterial stiffness. Although serum phosphate varied little across quartiles of creatinine clearance, average daily phosphorus intake and 24-hour urinary phosphate excretion decreased from highest to lowest quartile (by 31% and 60%, respectively, P for trend <.05). FGF23 was associated with serum phosphate (r = 0.24, P = .03) and creatinine clearance (r = -0.4, P = .001), but not with dietary phosphorus or 24-hour urinary phosphate excretion (P > .05 for both). Older age, higher systolic blood pressure, female gender, and black race were independently associated with increased AI. In contrast, there were no associations of serum phosphate, dietary phosphorus intake, urinary phosphate excretion, or FGF23 with AI in multivariate-adjusted models. In this sample of patients with CKD, established risk factors for arterial stiffness, but not mediators of phosphorus metabolism, were associated with increased AI. In addition, there were no significant associations between FGF23 and dietary phosphorus or urinary phosphate excretion. Future studies are needed to determine the main factors associated with elevations in FGF23 in CKD and to further assess the association of disordered phosphorus metabolism with subclinical markers of vascular disease.

Diet-Dependent Net Endogenous Acid Load of Vegan Diets in Relation to Food Groups and Bone Health-Related Nutrients: Results from the German Vegan Study

Background/Aims:Dietary composition has been shown to affect acid-base homeostasis and bone health in humans. We investigated the potential renal acid load (PRAL) and the estimated diet-dependent net acid load (net endogenous acid production, NEAP) in adult vegans and evaluated the relationships between NEAP, food groups and intake of bone health-related nutrients. Methods: The German Vegan Study (GVS) is a cross-sectional study. Data from healthy men (n = 67) and women (n = 87), aged 21–75 years, who fulfilled the study criteria (vegan diet for ≧1 year prior to study start; age ≧18 years, and no pregnancy/childbirth during the last 12 months) were included in the analysis. NEAP values were calculated from diet composition using two models: one based on the protein/potassium quotient and another taking into account an anthropometry-based loss of urinary organic anions. Results:Mean daily intakes of phosphorus, potassium, sodium, magnesium and vitamin C were above, and vitamin D and calcium below Dietary Reference Intake (DRI). Regardless of the model used, the diet in the GVS was characterized by a nearly neutral NEAP. A strong correlation was observed between the NEAP values of the two models (r_s = 0.873, p < 0.001). Only the consumption of fruits decreased constantly across the increasing quartiles of NEAP. Conclusions: It can be hypothesized that vegan diets do not affect acid-base homeostasis. With respect to bone health, the significance of this finding needs further investigation.

Nutritional Contributions of Pork to the Diets of the US Population

A typical 3‐oz serving of pork is an excellent source of protein, and a good or excellent source of several vitamins and minerals. Many cuts of pork, including several cuts of chops and ham, meet the USDA criteria for lean meat. Data from the 2003–06 NHANES were used to estimate pork consumption by the US population age 2 years and older and the nutritional contributions of pork to the diet. More than 50% of the US population reported eating pork, either alone or in a mixed dish. Processed pork was most commonly consumed, with 58% of the population consuming it, while 16% of the population reported eating fresh pork. Lean (fresh or processed) pork was consumed by 28% of the population. Two‐day mean intakes by consumers were 38 g for lean (fresh or processed) pork, 38 g for all fresh pork and 45 g for all processed pork. Analyses of usual intake (using C‐Side) of nutrients from pork indicate that pork provides on average 11 to 18% of the total daily intake of protein, thiamin, selenium, vit B6, vit B12, niacin, zinc and phosphorus on the days people consume pork. Analyses of 2‐day intake data show that lean pork cuts account for 10% of total protein and 3% of total energy, fat and saturated fat in the diets of lean pork consumers, along with 7 to 14% of consumers’ daily intake of phosphorus, zinc, selenium, thiamin, niacin and vit B6. These results indicate that pork is an important source of several key nutrients. Supported by the National Pork Board.

Exigência de fósforo disponível para suínos machos castrados selecionados para deposição de carne magra, dos 30 aos 60kg

Realizou-se um experimento para determinar a exigência de fósforo disponível para suínos machos castrados (Agroceres-Pic) utilizando-se 60 animais, distribuídos em delineamento experimental de blocos ao acaso, com cinco tratamentos -0,1; 0,2; 0,3; 0,4 e 0,5% de fósforo disponível, seis repetições e dois animais por unidade experimental. Os animais foram sangrados por punção do plexo venoso orbitário aos 21 dias e ao final do experimento, em jejum, para obtenção dos valores da atividade da fosfatase alcalina no soro (AFAS) e fósforo no soro. Observou-se efeito quadrático dos níveis de fósforo disponível sobre o ganho de peso diário, consumo diário de ração, fósforo no soro aos 21 dias, fósforo no soro ao final do experimento e conversão alimentar, que melhorou até o nível de 0,39% de fósforo disponível. Houve efeito linear sobre o consumo diário de fósforo, AFAS aos 21 dias e AFAS ao final do experimento. Concluiu-se que a exigência de fósforo disponível para suínos machos castrados selecionados para deposição de carne magra na carcaça, de 30 a 60kg, é de 0,39%, correspondendo ao consumo de 9,11g/dia.

Average daily intake of phosphorus in 3- to 5-year-old Japanese children as assessed by the duplicate-diet technique

The present study aimed to determine whether there is excessive mean daily intake of phosphorus in 3- to 5-year-old Japanese children and to ascertain relationships between phosphorus intake and various food and beverage groups. Subjects comprised of 90 children, with 15 boys and 15 girls in each age group from 3 to 5 years. The duplicate-diet technique was used to ascertain total dietary intake, including snacks and beverages over a 24-h period on 3 separate days from summer 1999 to winter 2000. After wet ashing food samples, phosphorus was quantified by colourimetry using a spectrophotometer. Median and 25th-75th percentile daily phosphorus intake for 3- to 5-year-old Japanese children was 674 mg (534-890 mg), and phosphorus intake correlated with the intake of many food groups and was closely correlated with total daily intake of food and beverage (rs=0.64). In addition, phosphorus intake correlated with the intake of magnesium and calcium (rs>=0.6, p<0.001). When assessed based on dietary reference intakes for the US, maximum intake did not exceed the tolerable upper intake level in any of the young children, but phosphorus intake was not more than the estimated average requirement (EAR) in 4.4% of subjects, which exceeded the target of 2.5% for the US EAR. We concluded that there is a risk of insufficient phosphorous intake, rather than excessive intake, for 4.4% of 3- to 5-year-old Japanese children.

Salivary Phosphorus Binding

Hyperphosphatemia as a complication of chronic kidney disease (CKD) was recognized nearly a century ago.1 The central role of altered phosphate metabolism in CKD as a cause of secondary hyperparathyroidism and renal osteodystrophy was exposed as part of the elegant experimental studies that provided the basis of the “intact nephron hypothesis.”2 The association of high serum phosphorus levels and increased mortality of patients with ESRD first noted in 19903 has since been confirmed and extensively studied.4,5 There is now considerable evidence, convincing on balance, that elevated serum phosphorus levels are a surrogate marker of cardiovascular disease (coronary, aortic, valvular, and vascular calcification) and hard clinical outcomes (cardiovascular and all-cause hospitalization and mortality) in CKD.4–6 Accrued evidence on the systemic complications of altered phosphate homeostasis in CKD has led to the proposal of a new syndrome of mineral and bone disorders (MBD) of CKD, termed CKD-MBD, which encompasses biochemical alterations, bone abnormalities, and vascular calcification.7 Renewed interest in the detrimental consequences of elevated serum phosphorus and the difficulties of its management in CKD has become the center of much recent debate and controversy fueled, at least in part, by the pharmaceutical industry. Approximately two thirds of the daily phosphorus intake is absorbed in the small intestines, and normal phosphorus homeostasis is maintained by its subsequent appropriate excretion by the kidney.8 With decreasing kidney function, the initial adaptive changes for maintenance of …

PHOSPHORUS METABOLISM AND MANAGEMENT IN CHRONIC KIDNEY DISEASE: Phosphorus Homeostasis in Normal Health and in Chronic Kidney Disease Patients with Special Emphasis on Dietary Phosphorus Intake

AbstractElevated serum phosphorus has been identified as a cardiovascular risk factor in chronic kidney disease (CKD) patients and a clear understanding of phosphorus homeostasis is very important for practicing nephrologists. At any particular point, serum phosphorus levels reflect the balance between movements of this mineral from and into the intestine, bone, intracellular space, and kidneys. We briefly review here all these exchanges with a particular emphasis on dietary phosphorus intake. Despite all the oral phosphorus binders currently available in the market, dietary restriction of this mineral remains a cornerstone for the prevention and treatment of hyperphosphatemia. An effective restriction of dietary intake of phosphorus requires prescription of a moderate protein intake (0.9–1.0 g/kg/day) and restricted consumption of highly processed fast and convenience foods. Phosphorus added during food processing is an important source of this mineral because of its magnitude and high bioavailabilty. Moreover, as food manufacturers are not required to label the amount of phosphorus added during food processing, a significant amount of the current daily phosphorus intake remains unaccounted when estimating phosphorus intake in CKD patients. The recent development of low phosphorus‐containing food products represents a very useful addition for CKD patients.

Inadequate dietary intake but not renal tubular acidosis is associated with bone demineralization in primary biliary cirrhosis

Metabolic bone disease associated with primary biliary cirrhosis (PBC) is inadequately characterized. Renal tubular acidosis (RTA) may lead to bone loss through chronic mobilization of skeletal calcium salts to buffer increased acid load. To evaluate the prevalence of RTA in PBC and establish the relationships among bone mineral density (BMD), renal function and nutritional status. We enrolled 69 female patients with compensated PBC and 35 control patients with chronic hepatitis C. RTA was searched in all patients, and 24-h dietary recalls were collected at enrolment. BMD was measured by dual-energy X-ray absorptiometry at the femur neck, lumbar spine and radius ultradistalis sites. No patients received a diagnosis of RTA. BMD values (Z-scores) showed only little deviation from normal population with no difference between PBC and controls. Osteopoenic PBC patients (T-score < 1) showed significantly lower daily phosphorus intake [median: 672 (288-1374) vs. 921 (253-1923) mg/day; P = 0.037], with a trend towards lower caloric intake than their nonosteopoenic counterparts. Renal tubular acidosis is uncommon in compensated PBC. Cholestasis is not associated with an increased risk of bone demineralization. Inadequate dietary intake may be a preventable factor contributing to bone loss in PBC.

Relationship between nutrient factors and osteo-sono assessment index in calcaneus of young Japanese women

The aim of our study was to investigate the association between nutrient factors and the osteo-sono assessment index (OSI) for calcaneus of young Japanese women. The subjects consisted of 965 young women aged from 18 to 22 years studying at the Department of Food and Nutrition at Nakamura-Gakuen University. The OSI was measured by ultrasonic bone absorptiometry. We found that age, weight, height, exercise, as well as the daily intakes of calcium, phosphorus, protein, energy and sodium were the main factors related to OSI in young women. Positive associations were observed between the OSI and the weight, exercise and daily intakes of calcium, protein and energy, whereas while negative associations were seen between the OSI and the age, height and daily intakes of phosphorus and sodium. In addition, all of these factors were also independently related to the OSI.

Changing Phosphorus Content of the U.S. Diet: Potential for Adverse Effects on Bone

The dietary intake of phosphorus in the United States is high relative to calcium. Intake estimates from the 1989–1991 Continuing Surveys of Food Intakes by Individuals conducted by the U.S. Department of Agriculture show that for both men and women, median calcium intakes do not meet the 1989 Recommended Dietary Allowances (RDAs) for most age groups over 10 y of age, whereas phosphorus intakes exceed the RDAs for most age groups. The use of phosphorus-containing food additives in the processing of foods contributes substantially to the daily phosphorus intake, and their use is increasing. Because much of the phosphorus through food additive use is not reflected in the estimates of phosphorus intakes derived from national food consumption surveys, these estimates underestimate true dietary intakes of phosphorus. High phosphorus intake has been shown to cause secondary hyperparathyroidism and bone loss in several animal models. High phosphorus, low calcium consumption consistent with current observed intake levels resulted in changes in calcium-regulating hormones that were not conducive to optimizing peak bone mass in young women. Evidence that such high phosphorus intakes may impair synthesis of the active metabolite of vitamin D and disrupt calcium homeostasis particularly in older women are discussed.