Correlation of dietary intakes and biochemical determinates of nutrition in hemodialysis patients

OBJECTIVE: The purpose of this study was to determine the effect of dietary intakes on nutritional indicators of patients on hemodialysis. METHOD: This study was carried out at the hemodialysis unit at the Ministry of Health, Ankara Hospital, from 2003-2004. Sixty-seven patients on regular hemodialysis were enrolled in the study. Nutritional status was assessed by biochemical parameters (urea, uric acid, creatinine, Na, K, Cl, Ca, P, alkaline phosphatase, SGOT, SGPT, cholesterol, total protein, albumin, hemoglobin, hematocrit) and anthropometric measurements (height, dry weight, body mass index), and dietary intakes were calculated. RESULTS: In this study, the mean age of the patients was 45.3 +/- 13.49, and the duration of hemodialysis was 4.9 +/- 3.64 year. Dialysis time was 12.4 +/- 2.7 h/week. The ratio of individuals with BMI of 20 kg/m2 or below this value was 19.4%. Blood hemoglobin and hematocrit levels were below than the recommended level. Mean serum urea (148.0 +/- 27.76 mg/dL) and creatinine (8.8 +/- 2.13 mg/dL) were found to be high, while a significant negative correlation was found between blood urea level and dietary fat (p < 0.01, r = -0.31). A significant positive correlation was found between vitamin B1, vitamin B6, folate, potassium, iron, and magnesium; between uric acid and vitamin D; between blood creatinine level and dietary vitamin B1, vitamin B6, folate, vitamin C, potassium, iron, magnesium; between blood potassium level and dietary vitamin C only; and between blood cholesterol level and dietary vitamin D only (p < 0.01).     

Hyperhomocystinemia and the Prevalence of Symptomatic Atherosclerotic Vascular Disease in Taiwanese Chronic Hemodialysis Patients: A Retrospective Study

Aim.?Hyperhomocystinemia is now recognized as an independent risk factor for atherosclerotic cardiovascular disease in patients with normal renal function. Hyperhomocystinemia is common in patients with chronic renal failure. This aim of this study was designed to look for associations between hyperhomocystinemia and clinically symptomatic atherosclerotic vascular disease (ASVD) in Taiwanese chronic hemodialysis patients. Methods.?Two hundred patients undergoing hemodialysis were enrolled in the study. They had predialysis blood work performed for total homocysteine, serum folate, and vitamin B₁₂ levels. A history of clinically significant ASVD was elicited using information from the patients' questionnaires and verified by careful inpatient and outpatient chart review. Results.?Mean homocysteine concentration was 29.0 µmol/L overall. A total of 196 patients had hyperhomocystinemia and were enrolled in this study. ASVD was present in 24.5% of patients. The mean homocysteine concentration was 31.9 µmol/L and 28.7 µmol/L in patients with (n = 48) and without (n = 148) ASVD, respectively (P = 0.04). There was association hyperhomocystinemia between chronic hemodialysis patients with ASVD and without ASVD. There were significant differences including age, homocysteine level, vitamin B₁₂ level and glucose intolerance in the two groups (P<0.05). Plasma homocysteine concentrations showed significant positive correlations with serum folate or vitamin B₁₂ in majority patients. No patient had serum folate or vitamin B₁₂ deficiency. The adjusted odds ratio for atherosclerotic disease was 2.8 (95%CI, 1.109–7.467) for those subjects with a homocysteine level in the highest quartile compared with the lowest 3 quartiles. Conclusions.?The prevalence of hyperhomocystinemia is 98% among hemodialysis patients. There is a significant association between hyperhomocystinemia and ASVD in Taiwanese chronic hemodialysis patients. There are also associations between homocysteine levels and serum folate/vitamin B₁₂ levels in the majority of the patients. Clinical trials are needed to determine the optimal therapy of folic acid dose for hyperhomocystinemia in Taiwanese chronic hemodialysis patients in the future.     

Dietary intake of trace elements,minerals, and vitamins of patients on chronic hemodialysis

Purpose

We aimed to estimate dietary intakes of trace elements, minerals, and vitamins in hemodialysis patients (HDP) of three centers in one metropolitan and two urban areas of Italy.

Methods

Daily dietary intake was assessed using a 3-day diet diary in 128 HDP.

Results

Mean daily intakes of trace elements were as follows: zinc, 7.6 ± 5.4 mg; copper, 14.3 ± 11.8 mg; selenium, 28.3 ± 18.1 μg; and iron, 7.2 ± 4.1 mg (7.8 ± 2.6 mg in women, 6.9 ± 2.4 mg in men). The distribution of patients by daily intakes of trace elements showed most were under the recommended values, with the exception of copper intake, which was much higher. Mean daily intakes of minerals were as follows: magnesium, 174.4 ± 94.3 mg; phosphorus, 842.6 ± 576.8 mg; calcium, 371.8 ± 363.7 mg; potassium, 1,616.2 ± 897.3 mg; and sodium, 1,350 ± 1,281 mg. Mean daily intakes of vitamins were as follows: vitamin A, 486.1 ± 544.6 μg; vitamin B₁, 0.86 ± 0.7 mg; vitamin B₂, 1.1 ± 0.7 mg; vitamin B₃, 13.3 ± 8.1 mg; vitamin C, 47.8 ± 50.3 mg; and vitamin E, 9.5 ± 3.6 mg. The distribution of patients by daily intakes of vitamins showed most were under the recommended values. Daily intakes of trace elements and vitamins were similar among the three centers and did not differ between dialysis and non-dialysis days.

Conclusions

Many HDP have daily dietary intakes of trace elements and vitamins below the recommended values, whereas the intake of copper is much higher.     

Dietary Intake of Folate,but not Vitamin B<Subscript>2</Subscript> or B<Subscript>12</Subscript>, Is Associated with Increased Bone Mineral Density 5 Years after the Menopause: Results from a 10-Year Follow-Up Study in Early Postmenopausal Women

Folate, vitamin B₂ (riboflavin), and vitamin B₁₂ may affect bone directly or through an effect on plasma homocysteine levels. Previously, a positive association has been found between plasma levels and bone mineral density (BMD) as well as risk of fracture. However, there are limited data on whether dietary intakes affect bone. Our aim was to investigate whether intake of folate, vitamin B_2, and vitamin B₁₂, as assessed by food records affects BMD and fracture risk. In a population-based cohort including 1,869 perimenopausal women from the Danish Osteoporosis Prevention Study, associations between intakes and BMD were assessed at baseline and after 5 years of follow-up. Moreover, associations between intakes and 5- and 10-year changes in BMD as well as risk of fracture were studied. Intakes of folate, vitamin B₂, and vitamin B₁₂ were 417 (range 290–494) μg/day, 2.70 (range 1.70–3.16) mg/day, and 4.98 (range 3.83–6.62) μg/day, respectively, i.e., slightly above the intakes recommended by the United Nations Food and Agriculture Organization. At year 5, but not at baseline, cross-sectional analyses showed positive correlations between daily intake from diet and from diet plus supplements of folate and BMD at the femoral neck (P < 0.01). However, no associations were found between intakes and changes in BMD. During 10 years of follow-up, 360 subjects sustained a fracture. Compared with 1,440 controls, logistic regression analyses revealed no difference in intakes between cases and controls. A high dietary intake of folate, but not vitamin B₂ or B₁₂, exerts positive effects on BMD; but further studies are needed to confirm this association.     

Evaluation of the Relationship Between Homocysteine,Parathormone, Vitamin D3, and Bone Mineral Densitometry in Recipients of Kidney Transplant

PurposeIn this study, we evaluated the relationship between serum homocysteine level and proteinuria, parathyroid hormone, vitamin D, and bone mineral density in kidney transplant recipients (KTR).Materials and methodsA total of 117 stable KTR older than 18 years was followed in our outpatient clinic. Demographic data were recorded. Simultaneously biochemical parameters, including glucose, blood urea nitrogenous, creatinine, calcium, phosphorus, sodium, potassium, albumin, parathormone, vitamin D₃, homocysteine, vitamin B₁₂, folate, and 24-hour urine protein, and bone mineral density of the femoral neck and spine by dual-energy x-ray absorptiometry (DEXA) were measured.ResultsDEXA measurements were normal, osteoporotic, and osteopenic (12.3%, 36.3%, and 51.3%, respectively). There was a relationship between the serum homocysteine and usage of rapamycin (P = .05), statins (P = .057), and beta blockers (P = .01), DEXA measurements were not related with serum homocysteine levels and immunosuppressive drugs used. Serum homocysteine levels correlated negatively with blood urea nitrogen (P = .002), creatinine (P = .001), vitamin B₁₂ (P < .001), and a positively daily proteinuria (rho = 0.203, P = .031). There was a negative relationship between proteinuria and serum level of vitamin D.ConclusionsThe bone mineral density decreased in more than 87% of our KTR. We did not find any relationship between DEXA measurements and levels of homocysteine, vitamin D, parathormone, and immunosuppressive drugs. It should be noted that some drugs used may affect serum homocysteine levels. Interestingly, there was a relationship between proteinuria and serum levels of homocysteine and vitamin D. Therefore, serum levels of homocysteine and vitamin D should be evaluated for preventing renal damage in KTR.     

Effect of Hemodialysis on Cognitive Function in ESRD Patients

Background. Uremia is associated with impairment of different cognitive functions. However the pathogenesis of this cognitive dysfunction is unknown. Objective. In this study, long-latency event related potentials (ERPs) were used to assess changes in cortical function due to hemodialysis treatment. Methods. In this cross-sectional study, we measured event related potentials in 15 end stage renal disease (ESRD) patients maintained on hemodialysis, two hours before and two hours after they underwent hemodialysis and compared their data with a strictly age and sex matched healthy control group. The P3 was elicited by using standard auditory “odd-ball” paradigm and the data obtained was statistically analyzed (Wilcoxon signed ranks, Mann Whitney). Results. Before hemodialysis, the patients' P3 latency (347.73 ± 39.47 ms) was significantly increased as compared with that of healthy control group (308.4 ± 13.73 ms) (p = 0.001). After hemodialysis, P3 latency of the patients showed a significant decrease (347.73 ± 39.47 ms to 325.20 ± 37.15 ms, p = 0.001). P3 latency after dialysis was not significantly different from controls. No significant correlation was noted between various biochemical parameters (hemoglobin, blood urea, creatinine, uric acid and calcium) and P3 latency or amplitude. Conclusions. Removal of uremic toxins by hemodialysis leads to an improvement in cognitive processing.     

Pregnancy Nutritional Indices and Birth Weight After Roux-en-Y Gastric Bypass

Background  Maternal metabolic profile and nutritional course of pregnancy after bariatric interventions is incompletely known. Their impact on birth weight has also not been hitherto addressed. Aiming to document such variables, a retrospective study was undertaken. Methods  Women previously submitted to silastic ring Roux-en-Y gastric bypass, who conceived after 0–5 years (n = 14), were investigated. Intake of selected macro- and micronutrients, representative laboratory measurements, and correlation of these findings with birth weight and time to conception was documented. Results  Mean calorie intake was restricted to about 1,800 kcal/day. Protein (71 ± 17 g/day) and supplementary iron (60 mg/day) were barely adequate, and calcium and vitamin B₁₂ did not meet current recommendations, only folic acid being optimal. Biochemical monitoring reflected these inconsistencies, with occasional low values for serum albumin (4.1 ± 0.4 g/dL), hemoglobin (11.4 ± 1.5 g/dL), iron (78 ± 50 μg/dL) and vitamin B₁₂ (193 ± 102 pg/mL) but not folate. Lipids, glucose, and uric acid were much better than before the anti-obesity intervention. Reduced plasma lipids, glucose, and uric acid were associated with larger birth weight, albeit within the normal range. Conclusions  (1) Anemia as well as additional nutritional deficits during pregnancy were not totally eliminated, despite dietary guidance and micronutrient supplementation; (2) alleviation of metabolic comorbidities was demonstrated, and improved normalization predicted higher birth weight; (3) energy and folate intake was sufficient, but other nutrients probably did not reach ideal levels; (4) recent dietary guidelines for this population represent a step forward, but additional studies are needed.     

Experimental Folate and Vitamin B12 Deficiency Does Not Alter Bone Quality in Rats

Hyperhomocysteinemia (HHCY) has been linked to fragility fractures and osteoporosis. Folate and vitamin B₁₂ deficiencies are among the main causes of HHCY. However, the impact of these vitamins on bone health has been poorly studied. This study analyzed the effect of folate and vitamin B₁₂ deficiency on bone in rats. We used two groups of rats: a control group (Co, n = 10) and a vitamin‐deficient group (VitDef, n = 10). VitDef animals were fed for 12 wk with a folate‐ and vitamin B₁₂–free diet. Co animals received an equicaloric control diet. Tissue and plasma concentrations of homocysteine (HCY), S‐adenosyl‐homocysteine (SAH), and S‐adenosyl‐methionine (SAM) were measured. Bone quality was assessed by biomechanical testing (maximum force of an axial compression test; F_max), histomorphometry (bone area/total area; B.Ar./T.Ar.], and the measurement of biochemical bone turnover markers (osteocalcin, collagen I C‐terminal cross‐laps [CTX]). VitDef animals developed significant HHCY (Co versus VitDef: 6.8 ± 2.7 versus 61.1 ± 12.8 μM, p < 0.001) that was accompanied by a high plasma concentration of SAH (Co versus VitDef: 24.1 ± 5.9 versus 86.4 ± 44.3 nM, p < 0.001). However, bone tissue concentrations of HCY, SAH, and SAM were similar in the two groups. Fmax, B.Ar./T.Ar., OC, and CTX did not differ between VitDef and Co animals, indicating that bone quality was not affected. Folate and vitamin B₁₂ deficiency induces distinct HHCY but has no effect on bone health in otherwise healthy adult rats. The unchanged HCY metabolism in bone is the most probable explanation for the missing effect of the vitamin‐free diet on bone.     

The effect of two different doses comprising the simultaneous administration of intravenous B-complex vitamins and oral folic acid on serum homocysteine levels in hemodialysis patients

Background: Several regimens using different doses of folic acid (FA) alone or supplemented with B-complex vitamins (BCVs) have been tested for their ability to reduce total homocysteine (tHcy) serum levels in hemodialysis (HD) patients. In the present study, we assessed the effect of two different doses comprising the simultaneous administration of intravenous (IV) BCVs and an oral FA supplementation on serum tHCy levels in HD patients. Patients–methods: In a cohort of 49 patients (31 male, 18 female) undergoing chronic HD treatment for a mean of 40.0±40.7 months, serum concentrations of tHcy, folate and vitamin-B12 (vB12) were determined at the end of three sequential periods as follows: 20 weeks without any BCV and/or FA supplementation (period A), 20 weeks with a dose comprising the simultaneous administration of IV BCVs and an oral supplementation of 5 mg of FA once a week (period B), and 20 weeks with a dose comprising the simultaneous administration of IV BCVs and an oral supplementation of 5 mg of FA thrice a week (period C). An IV dose of BCVs consisting of a 5 mL solution containing vitamin B₁ (250 mg), vitamin B₆ (250 mg) and vitamin B₁₂ (1.5 mg) was administered at the end of hemodialysis. Results: Mean serum tHcy levels were significantly higher at the end of period A relative to levels at the end of periods B and C (35.8±23 μmol/L vs. 22.0±17.6 and 15.0±4.5 μmol/L, respectively; p < 0.000001). Mean serum folate levels and mean serum vB12 levels were significantly lower at the end of period A relative to levels at the end of periods B and C (p < 0.000001). Mean serum tHcy levels were lowest at the end of period C (p < 0.000001 in comparison to periods A and B), and 26 of the 49 HD patients (67.3%) possessed tHcy levels below 16 μmol/L. Conclusions: In HD patients, high doses consisting of the simultaneous administration of IV BCVs and an oral FA supplementation resulted in the efficient reduction of serum tHcy levels.     

Acute changes in endothelin after hemodialysis in children

The purpose of this study was to investigate the acute changes in endothelin (ET) levels immediately after hemodialysis and to determine whether these changes vary with the use of different membranes and hemodialysis solutions. Ten children were included in the study. Three different hemodialysis sessions were performed on all patients: session 1, acetate-based dialysate and polycarbonate membrane; session 2, bicarbonate-based dialysate and polycarbonate membrane; session 3, acetate-based dialysate and polysulfone membrane. In all cases blood samples were obtained before and after dialysis. Pre- and post-hemodialysis ET levels of the patients with acetate-based dialysate and polycarbonate membrane were 33.68±11.51 pg/ml and 28.27±12.85 pg/ml, respectively. The fall in ET levels after this session was statistically significant (P = 0.015). We did not observe a statistically significant change in ET levels in the other sessions. Post-dialysis mean arterial pressure values were significantly lower than the pre-dialysis values in all three dialysis sessions (P <0.01). A positive correlation was observed between plasma ET levels and blood urea nitrogen and serum potassium; a negative correlation was observed between plasma ET levels and hematocrit. Received April 1, 1997; received in revised form September 2, 1997; accepted September 9, 1997     

Effect of metabolic acidosis on branched-chain amino acids in uremia

 Fasting plasma concentrations of branched-chain amino acids (BCAA) valine, leucine, and isoleucine were measured in 20 young patients (aged 18±2 years) with end-stage renal disease just before initiation of dialysis and compared with 7 healthy controls (aged 19±1 years). Plasma valine, leucine, and isoleucine were all lower than control values (P<0.01 in all 3 cases). Plasma valine, but not leucine and isoleucine, correlated with venous pH (P<0.02). Plasma valine, leucine, or isoleucine did not correlate with blood urea nitrogen or serum creatinine. Seven patients (aged 18±1 years) on maintenance hemodialysis with metabolic acidosis were then studied before and after 2 weeks of oral sodium bicarbonate (NaHCO₃) treatment to correct the acidosis. To control for the effect of additional sodium, they were also studied after 2 weeks of an equivalent amount of oral sodium chloride (NaCl). Oral NaHCO₃ treatment led to significant increases in venous pH and serum bicarbonate concentrations, but no significant change in total and ionized calcium, phosphate, sodium, potassium, creatinine, blood urea nitrogen, and intact parathyroid hormone concentrations. Oral NaCl did not change any of the biochemical parameters. Fasting plasma concentrations of BCAA were measured. Before treatment of acidosis, uremic patients had low plasma concentrations of valine, leucine, and isoleucine compared with controls. Following 2 weeks of NaHCO₃ treatment, there were significant increases in the plasma concentrations of valine and leucine (P<0.01), although the values did not normalize. There were no changes in plasma concentrations of valine and leucine following 2 weeks of NaCl. The plasma concentration of isoleucine was not different during baseline (acidotic) and treatment periods with NaHCO₃ and NaCl. Thus treatment of metabolic acidosis ameliorated abnormalities in plasma concentrations of valine and leucine in patients with uremia on hemodialysis. Received: 18 February 1998 / Revised: 22 June 1998 / Accepted: 26 June 1998     

Comparison of the nutritional composition of diets of persons with fecal incontinence and that of age- and gender-matched controls

Purpose: In our clinical and research experience, persons with fecal incontinence anecdotally report altered diet intake to avoid incontinence. The purpose of this study was to compare the dietary intake of 39 persons with fecal incontinence living in the community with that of age- and gender-matched control subjects who had normal bowel function. The diets of both groups were compared with recommended dietary allowances (RDAs) for their constituent nutrients.Methods: Subjects prospectively recorded the type, amount, and method of preparing all foods and beverages ingested for 8 consecutive days. Diet records were analyzed using the Nutritionist IV software program.Main outcome measures: The main outcome measures were the amounts and percentage of the RDAs of macronutrients and micronutrients in the subjects' diets.Results: There were no significant differences in the intake of total kilocalories, protein, fat, dietary fiber, caffeine, or lactose by the fecal incontinence and control groups. The fecal incontinence group had a greater intake of carbohydrates, manganese, and vitamin B₁ compared with the control group. Diets of both groups exceeded 100% of the RDA for protein, phosphorus, iron, sodium, potassium, Vitamins B₁, B₂, B₃, B₁₂, and C and folate. Diets of both groups had less than 50% of the RDA for biotin, chromium, copper, and manganese but did not differ significantly. The percentages of the RDA for calcium and vitamin D were 84% ± 6% and 56% ± 8% for the fecal incontinence group and 90 ± 8 (P = .6) and 69 ± 11 for the control group (P = .4).Conclusions: The diets of persons with fecal incontinence were similar to those of control subjects with normal bowel function. Both the fecal incontinence and control groups may improve their nutritional patterns by lowering sodium and protein intake and increasing dietary fiber and monounsaturated fat intake. Calcium and vitamin D supplementation may improve dietary deficiencies and lower disease risks. Including a nutritional assessment and consultation in the care of persons with fecal incontinence to improve their general health and prevent disease is recommended, but consideration must be given to altered diet patterns perceived by the patient to prevent fecal incontinence.     

Are vitamin B12 and folate deficiency clinically important after roux-en-Y gastric bypass?

Although iron, vltamm B₁₂, and folate deficiency have been well documented after gastric bypass operations performed for morbid obesity, there is surprisingly little information on either the natural course or the treatment of these deficiencies in Roux-en-Y gastric bypass (RYGB) patients Durmg a l0-year period, a complete blood count and serum levels of iron, total iron-binding capacity, vltamin B₁₂, and folate were obtained in 348 patients preoperatively and postoperatively at 6-month intervals for the first 2 years, then annually thereafter The principal objectives of this study were to determine how readily patients who developed metabolic deficiencies after Roux-en-Y gastric bypass responded to postoperative supplements of the deficient micronutrient and to learn whether the risk of developmg these deficiencies decreases over time Hemoglobin and hematocrit levels were slgnificantly decreased at all postoperative intervals in comparison to preoperative values Moreover, at each successive interval through 5 years, hemoglobin and hematocrit were decreased signifiantly compared to the preceding interval Folate levels were significantly increased compared to preoperative levels at all time intervals Iron and vltamin B₁₂ levels were lower than preoperative measurements and remained relatively stable postoperatively Half of the low hemoglobin levels were not associated with iron deficiency Taking multivltamin supplements resulted in a lower incidence of folate deficiency but did not prevent iron or vitamin B₁₂ deficiency Oral supplementation of iron and vitamin B₁₂ corrected defiaencies in 43% and 81% of cases, respectively Folate deficiency was almost always corrected with multivitamins alone No patient had symptoms that could be attributed to either vitamin B₁₂ or folate deficiency Conversely, many patients had symptoms of iron deficiency and anenua Lack of symptoms of vitamin B₁₂ and folate deficiency suggests that these deficiencies are not clinically important after RYGB Conversely, iron deficiency and anemia are potentially serious problems after RYGB, particularly in younger women Hence we recommend prophylactic oral iron supplements to premenopausal women who undergo RYGB     

Vitamin E alleviates the oxidative stress of erythropoietin in uremic children on hemodialysis

The efficacy of combined therapy with recombinant human erythropoietin (rhEPO) and vitamin E versus rhEPO alone in the treatment of anemia was examined in children (n=10, aged 15.2±3.2 years) on chronic hemodialysis at the restart of rhEPO therapy after a 4-week interval. The results confirmed that rhEPO induced oxidative stress of the red blood cells as observed during the first rhEPO therapy. Vitamin E (15 mg/kg per day per os) was introduced after 2 weeks of rhEPO monotherapy, when the signs of acute oxidative stress appeared. The level of oxidized glutathione (GSSG) increased from 8.9±3.1 to 26.7±5.7 nmol/g hemoglobin (Hb) by that time. After 2 weeks of simultaneous vitamin E treatment, there was a significant difference in GSSG values compared with rhEPO monotherapy (10.1±3.9 vs. 56.7±15.8 nmol/g Hb, P<0.001). A considerable decrease was observed in the previously high ratio of GSSG/reduced glutathione (GSH), an indicator of oxidative stress, and the level of carboxyhemoglobin, indicating hemolysis. A significant increase in Hb and hematocrit (P<0.01) was achieved within 2 weeks of starting the combined therapy, while similar results occurred only at the 8th and 5th weeks without vitamin E. Antioxidant vitamin E supplementation improved the therapeutic effect of rhEPO in patients with chronic renal failure on hemodialysis. Received: 3 December 1998 / Revised: 20 April 1999 / Accepted: 20 April 1999     

Long-term metabolic effects in patients with urinary diversion

The use of intestinal segments in genitourinary reconstruction could influence vitamin metabolism and affect the skeletal bone and its mineral content in the long term. In 137 patients, serum levels of the vitamins A, B₁, B₂, B₆, B₁₂, D, and E and of folic acid, bile acid, and ammonia as well as levels of intracorpuscular vitamin B₁₂ and folic acid were examined and a red blood cell count was performed. The patients were divided into three groups (≤2 years, >2 to ≤4 years, and >4 years after surgery) as well as into children and adults. In addition, bone mineral density (dual-photon absorptiometry) was measured in 25 patients. Of these, 16 patients were ≈16.8 years s/p rectal reservoir, 6 were ≈20.5 years s/p colonic conduit, two were 6 and 8 years s/p ileocecal pouch, and one adolescent was 5 years s/p ileal bladder augmentation. In all patients the levels of vitamins A, B₁, B₂, B₆, D, and E and of folic acid, bile acid, and ammonia as well as the red blood cell count were within normal ranges. In children (n= 51) there was no significant drop in vitamin B₁₂ levels after the operation. In adults (n= 86), serum vitamin B₁₂ levels dropped significantly from 402 ± 182 ng/l during the first 2 years after the operation to 292 ± 204 ng/l after the 4th year (normal range 240–1,100 ng/l). No significant increase in the intracorpuscular vitamin B₁₂ level was observed during the same period. The bone mineral density was normal in all 25 patients with different types of urinary diversion. In addition to regular examination (sonography, creatinine levels, and base excess), vitamin B₁₂ levels should be determined at 4 years after urinary diversion. It remains unclear whether substitution is necessary. However, substitution is easy to achieve and cheaper than the regular determination of vitamin B₁₂. No decrease in bone mineral content was seen in the long-term follow-up with early correction of the base excess (below −2.5).     

Evaluation of lithogenic elements in urine of healthy newborns

The determination of urinary excretion of lithogenic elements in healthy newborns involves factors ranging from urine collection and data handling to maternal influences, which can cause difficulties in analyzing the results. The objective of this study was to determine normal values of parameters related to lithogenesis, such as calcium, uric acid, citrate, and oxalate, in urine of healthy newborns using isolated samples, focusing on variations according to gender, weight, milk ingestion, and family history of lithiasis. Parameters measured in isolated urine samples from 104 healthy newborns (77 males and 27 females) were corrected by creatinine. The ratios were expressed as milligram/milligram of creatinine: calcium/creatinine of 0.10±0.01 (X±SE), uric acid/ creatinine of 1.10±0.10, citrate/creatinine of 0.56±0.04, and oxalate/creatinine of 0.07±0.01. Differences were observed between males and females, in terms of uric acid (0.80±0.07 vs. 1.10±0.10 mg/mg, P<0.05), citrate (0.05±0.06 vs. 0.17±0.05, P<0.05), sodium (0.17± 0.01 vs. 0.05±0.01, P<0.001), and potassium (0.05± 0.01 vs. 0.20±0.02, P<0.001). Interestingly, the urinary concentration of protector factors such citrate and potassium was higher in females than in males with low sodium excretion. Artificial milk feeding leads to higher calcium (0.10±0.06 vs. 0.06±0.01), uric acid (1.40±0.20 vs. 0.90±0.09, P<0.05), citrate (0.90±0.09 vs. 0.50±0.04, P<0.001), and oxalate (0.17±0.03 vs. 0.05±0.01, P<0.001) excretion when compared with breast feeding. There was higher excretion of calcium and sodium in patients under 3 kg. Children with familial antecedents presented some differences in urinary excretion, with higher uric acid (1.50±0.30 vs. 0.80±0.08, P<0.05) but lower calcium (0.05±0.02 vs. 0.10±0.01, P<0.05) and sodium (0.15±0.02 vs. 0.20±0.02, P<0.05) excretion, respectively. This report provides urinary parameters obtained in healthy newborns and correlates them with factors that could be involved in the genesis of osteopenia, renal stones, and/or nephrocalcinosis. Received: 8 May 2000 / Revised: 7 June 2001 / Accepted: 12 June 2001     

Potassium metabolism in continuous ambulatory peritoneal dialysis patients

Background: Hypokalemia is common and may have contributed to the poor clinical outcome in peritoneal dialysis (PD) patients. In this study, we made a detailed investigation on the potassium metabolism in continuous ambulatory peritoneal dialysis (CAPD) patients and tried to find out the possible factors associated with the high prevalence of hypokalemia in PD patients. Methods: A cross-sectional survey in 243 clinically stable CAPD patients was made in our PD center in 2010. Patients were divided into four groups according to whether they were anuric or not and different dialysis regimens. Patients’ demographic data and data on potassium metabolism including dietary potassium intakes, residual renal potassium, and peritoneal dialysis potassium removal were collected. Results: The average potassium intake in our 243 PD patients was 32.1?±?11.1?mmol/day. The total potassium removal was significantly higher in non-anuric patients as compared to anuric patients (33.2?±?9.1 vs. 23.0?±?4.7?mmol/day for 3 exchanges per day and 35.2?±?8.9 vs. 28.6?±?6.3?mmol/day for 4 exchanges per day, respectively, p?p?p?p?R² linear?=?0.645, p?Conclusions: Our study suggested that if potassium intake was limited in PD patients, we should be aware of the risk of hypokalemia with high doses of PD when patients have good RRF. Our study also suggested that potassium removal in PD patients may not necessarily reflect potassium intake even if serum potassium is normal, the effect of ICW should be considered when evaluating potassium homeostasis.     

Renal function in pediatric patients with β-thalassemia major

In patients with β-thalassemia major, the most important cause of mortality and morbidity is organ failure due to deposits of iron.. In this study, the nature of the kidney injury and possible pathogenetic factors were investigated. Seventy children with β-thalassemia major and 14 age and sex-matched healthy children were involved in the study. Blood and timed urine samples were obtained for hematological and biochemical tests. The mean values of blood urea nitrogen (BUN), serum creatinine, creatinine clearance, serum sodium, urine osmolality, fractional excretion of sodium, potassium, and uric acid were not statistically different between the groups. Serum levels of potassium, phosphorus, and uric acid and the urine volume, high urinary protein to creatinine (U_P/Cr), urinary N-acetyl-β-d-glucosaminidase to creatinine (U_NAG/Cr), and urinary malondialdehyde to creatinine, (U_MDA/Cr) and the tubular phosphate reabsorption (TRP) values were statistically different between two groups (P<0.05). Increased serum levels of potassium, phosphorus, and uric acid in the patient group were attributed to the rapid erythrocyte turnover. The presence of high U_P/Cr, U_NAG/Cr and U_MDA/Cr ratios shows that in these patients with proximal renal tubular damage may be secondary to oxidative lipid peroxidation mediated by the iron overload. Received: 30 September 1999 / Revised: 19 May 2000 / Accepted: 22 May 2000     

Inhibition of Gastric Secretion by Omeprazole and Efficiency of Calcium Carbonate on the Control of Hyperphosphatemia in Patients on Chronic Hemodialysis

Abstract: Contradictions exist in the literature regarding the effect of gastric secretion inhibition on phosphate absorption. In healthy controls, omeprazole would decrease the hyperphosphatemia or the hyperphosphaturia induced by an acute phosphate load, suggesting an inhibition of phosphate absorption. In chronic hemodialysis patients, gastric hypersecretion is associated with hyperphosphatemia, but inhibition of gastric hypersecretion by ranitidine in those receiving calcium carbonate (CaCO₃) as a phosphate binder would paradoxically exacerbate their hyperphosphatemia. Because of these conflicting observations, we performed an open crossover study on 16 chronic stable hemodialyzed patients with a daily mean intake of 9.4 ± 4 g of CaCO₃, and we compared the plasmatic predialysis levels of phosphate, calcium, protides, bicarbonates, intact parathyroid hormone (PTH), urea, and creatininemia during 2 successive periods of 2 months, the first one without omeprazole and the second one with 20 mg omeprazole intake in the morning. Phosphatemia increased with omeprazole but not significantly from 1. 80 ± 0.38 to 1.89 ± 0.42 mM whereas corrected calcemia decreased significantly (p = 0.04) from 2.41 ± 0.18 to 2.36 ± 0.16 mM as did bicarbonatemia from 26.7 ± 3.5 to 25.7 ± 3.1 mM (p < 0.05). No change in creatininemia or in blood urea was observed, suggesting the stable efficiency of dialysis as well as the stable intakes of protein and therefore of phosphate during the two study periods. In conclusion, inhibition of gastric secretion by omeprazole increases the plasmatic phosphate predialytic level but in a nonsignificant way. This increase may be explained by a slight but significant concomitant decrease of calcemia and bicarbonatemia. These results do not support the phosphate binding efficiency of CaCO₃ being decreased by the inhibition of gastric acid secretion.     

Major Nutrient Patterns and Bone Mineral Density among Postmenopausal Iranian Women

Our understanding of the influence of overall nutrient intake on bone mineral density (BMD) is limited because most studies to date have focused on the intakes of calcium, vitamin D, or a few isolated nutrients. Therefore, we examined the association of major nutrient patterns with BMD in a sample of postmenopausal Iranian women. In this cross-sectional study, 160 women aged 50–85 years were studied and their lumbar spine and femoral neck BMDs were measured using dual-energy X-ray absorptiometry. Dietary intakes were assessed using a validated 168-item food frequency questionnaire, and daily intakes of 30 nutrients were calculated. All nutrient intakes were energy adjusted by the residual method and were submitted to principal component factor analysis to identify major nutrient patterns. Overall, three major nutrient patterns were identified, among which only the first pattern, which was high in folate, total fiber, vitamin B₆, potassium, vitamin A (as retinol activity equivalent), vitamin C, β-carotene, vitamin K, magnesium, copper, and manganese, had a significant association with BMD. After controlling for potential confounders, multivariate adjusted mean of the lumbar spine BMD of women in the highest tertile of the first pattern scores was significantly higher than those in the lowest tertile (mean difference 0.08; 95 % confidence interval 0.02–0.15; P = 0.01). A nutrient pattern similar to pattern 1, which is associated with high intakes of fruits and vegetables, may be beneficial for bone health in postmenopausal Iranian women.