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Nutrition is tightly associated with the risk of stone events. A part from genetic predisposition, a correct and balanced diet might prevent incident kidney stones. Several studies analyzed each dietary component and different diets to better understand their impact on stone recurrence. Fluids: High fluids intake is the most important factor for preventing kidney stones disease and for every 200 mL of water, the risk of stones is reduced by 13%. Soft drinks seems to be associated to a greater risk of stone events, whereas caffeine and citrus fruits juice are not. Calcium: Normally calcium intake with diet does not exceed 1.2 g/day. A balanced consumption of dairy products is capable of reducing oxalate intestinal absorption and urinary excretion compared to low calcium diet, being protective for stone disease. Oxalate: The exact amount of oxalate contained in different foods is difficult to estimate for its variability, even in the same aliment. In addition, the amount of oxalate consumed was shown to be only a minor risk factor for stone disease, whereas its intestinal absorption is strongly influenced by external factors, such as calcium intake. Dietary oxalate restriction is advisable only in patients with known elevated consumption. Sodium: High sodium intake is both associated with hypertension, heart disease and stone risk. Increased sodium consumption is directly associated to hypercalciuria in both calcium stone formers and healthy subjects. Although dietary sodium restriction to recommended values is always desirable in stone formers, it is difficult to achieve for its broad use in food preparation. Proteins: Animal proteins are associated to increased risk for stone formation, whereas vegetable and dairy proteins are not. Increased meat intake was associated to acidic urine pH, negative calcium balance and reduced anti-lithogenic urinary solutes excretion.Fruits and vegetables: Alkalizing foods are one of the most important factors for stone protection. Their consumption increases anti-lithogenic solutes as citrate, potassium and magnesium. A diet rich in fruits and vegetables is strongly recommended for stone formers. Uric acid: Elevated meat consumption is either associated to increased purine metabolism and acid load, favoring uric acid nephrolithiasis by reducing urine pH and increasing urinary excretion of uric acid, especially in patients affected by metabolic syndrome and diabetes.In conclusion, the most effective diet for stone protection is rich in fruits and vegetables, low in animal proteins and salt, with balanced dairy product consumption and obviously, with elevated fluid intake. These characteristics make vegetarian and Mediterranean diets protective and useful for stone formers, whereas western diet is at risk for stone formation.

During food thermal treatment Maillard's reaction may occur, which implicates mainly the carbonyl groups of reductory sugars and amino protein groups. Maillard's reaction products (MRP) may interfere with mineral bioavailability because of modifications of their physical-chemical moiety in the food or the lumen, disrupting the absorption process or its normal metabolism. In this study, we sought to investigate MRP influence on issues related to Ca bioavailability in vitro and in vivo. Equimolar mixtures of glucose-lysine (GL) and glucose-methionine (GM) (40% moisture) were heated at 150 degrees C for 90 minutes (samples GL90 and GM90, respectively). In vitro solubility was measured by additioning each samples to a 3.75 mM Ca solution at intestinal pH and ionic strength; after shaking and centrifugation, soluble and insoluble calcium was determined. Three percent of GL90 and GM90 were individually added to the AIN93-G diet to obtain D-GL90 and D-GM90 diets. Three Wistar rats groups were fed for 21 days with both diets and with AIN93-G as control, carrying out calcium balance during last week and extirpating various organs after sacrifice. GM90 did not affect calcium solubility; GL90 reduced it slightly, remaining in both cases more than 94% soluble. D-GL90 and D-GM90 did not modify calcium bioavailability, with as effective usage as with the control diet (57.6 +/- 1.3%, 57.8 +/- 2.3% and 63.9 +/- 2.6% in control diet, D-GL90 and D-GM90, respectively). MRP intake produced, however, metabolic changes that decreased bone calcium, accumulating compensatorily in other organs.

Background and Objective: Due to recent medical advances, patients with cystic fibrosis (CF) can expect longer survival rates and, as a result, face previously unreported complications such as osteoporosis. Our goal was to determine the mineral bone density in young adult patients with CF attended in the adult CF Unit, and correlate these findings with other clinical variables of interest in this patient population., Patients and Method: We carried out a transversal study from 1999 to 2002 of 34 patients with CF (19 males and 15 females. Mean age 23 years). Upon enrollment in the study, patient gender and age were recorded along with Schwachman and Brasfield scores, pulmonary function test results (spirometry) and sputum analysis, phosphorus and calcium balance, vitamin D intake, and dual energy X-ray absorptiometry (DEXA) findings of the spinal column (L2-L4) and femur., Results: 54.5% of all study patients were found to have an abnormal mineral bone density. Fifteen patients met criteria for osteopenia and 3 for osteoporosis. Age, treatment with inhaled corticosteroids, and pulmonary function test results correlated with bone density., Conclusions: DEXA scans should be performed in young adults with CF at least once during the course of their illness on the basis of the high prevalence of mineral bone density abnormalities in this population.

Phosphorus is involved in the pathogenesis of hyperparathyroidism in Chronic Renal Failure (CRF) and in extra-osseous calcifications. Therefore, it is directly related with the morbi-mortality of these patients. The control of phosphorus is of the utmost importance and is often extremely difficult to achieve. A quick overview of the drugs that can bind phosphorus is given in this paper. Iron salts are beginning to come through as a viable possibility in the near future; nevertheless, calcium salts continue to be the most widespread. The problem is the ease with which a positive calcium balance can be produced, as extra-osseous calcifications (and above all, vascular calcifications) can appear and morbid-mortality increases. As a result of all this, calcium-free binders such as lanthanum carbonate and sevelamer are eagerly awaited. The lanthanum is as of yet little and not very well known. Sevelamer possesses good phosphorus-binding properties, as it is insoluble, does not cause intestinal degradation, does not contain traces of other elements and its use has few side effects. Long-term studies and accumulated experience have demonstrated its efficacy as a binder, plus additional advantages such as an improvement in the lipid profile, with a decrease in LDL--and an increase in HDL-cholesterol. As to whether these new binders--or any other compounds that could appear-will be of any real use only time will tell.

Unlabelled: Impaired phosphate excretion resulting in hyperphosphatemia is one of the earliest consequences of chronic renal failure. To control serum phosphate levels, we can use the following therapies: 1) Restriction of dietary phosphate (but on CAPD, obligatory protein losses via peritoneal fluid makes impractical any reduction of phosphate diet. 2) Reduction of phosphate absorption, using phosphate binders. 3) Peritoneal phosphate removal., Objective: 1) To evaluate the factors affecting peritoneal phosphate removal such as plasma phosphate, peritoneal membrane transport type, peritoneal dialysis modality prescription (CAPD or APD) and daily dialysate volume. 2) To test the best calcium concentration in the peritoneal dialysis fluid (5, 6 or 7 mg/dl) in order to permit the use of calcium carbonate or acetate without the risk of hypercalcemia or hyperparathyroidism., Method: Phosphate was measured in seventy 24-hour dialysate collections, 33 from patients on CAPD and 37 from patients on APD. 24-hour peritoneal phosphate removal (mg/24 hours) and weekly peritoneal phosphate clearance was calculated (L/week). The peritoneal membrane was studied by the peritoneal equilibrium test (PET), using a 2.27% glucose. We calculated also the peritoneal calcium balance in 25 daily peritoneal fluid collections from patients using a calcium dialysate concentration of 5, 6 or 7 mg/dl each one. IPTH levels and doses of vitamin D were compared at 6 months in patients using a calcium concentration of 5, 6 or 7 mg/dl from the beginning of peritoneal dialysis (5 patients of each calcium dialysate concentration)., Results: Weekly peritoneal phosphate clearance (WPC) were higher or APD than on CAPD (51 +/- 21 vs 41 +/- 14, p < 0.005). Daily dialysate volume was also higher on APD (14 +/- 4 vs 7.8 +/- 1.8 L/day, p < 0.001). WPC was higher on APD when a mild-day exchange was done (61 +/- 23 vs 45 +/- 15, p < 0.005), instead an equal total daily volume of the dialysate. Peritoneal calcium balance was significantly more negative in patients using a calcium in the dialysis fluid of 5 than 6 or 7 mg/dl (-125 +/- 7 vs -18 +/- 41 vs -11 +/- 49, p < 0.001). At 6 months, patients using a calcium fluid concentration of 5 mg/dl increased iPTH levels (from 160 +/- 101 to 332 +/- 153, p < 0.001) and vitamin D needs (from 0 to 1.87 +/- 0.37 mcg/week, p < 0.001). In summary, peritoneal phosphate clearance depends on plasma phosphate levels, daily volume of dialysate prescribed and peritoneal membrane transport characteristics. It can be improved by increasing the total peritoneal fluid. On APD, a mild-day exchange may improve phosphate clearance, without total volume increase. The risk of secondary hyperparathyroidism can be decreased with a calcium fluid concentration of 6 mg/dl, which was shown to be better than 5 mg/dl when calcium phosphate binders are not correctly taken.

During lactation the main source of the breast-milk calcium seems to be maternal bone. The women who breast-fed, lost bone mineral content, which is recovered once breast-feeding ceased. Breast-milk calcium do not depend on an increase in calcium intake by the lactating mother. Calcium demand during lactation is associated with adjustments in the calcium metabolism, such as a decrease in urinary calcium excretion and mobilization of calcium from maternal bone. The classical calciotropic hormones concentrations (PTH and 1,25-dihydroxyvitamin D) are not associated with bone turnover markers or with changes in bone mineral content in the lactating women. However, serum estradiol is strongly associated with calcium balance, bone loss and calcium milk content.

The effects of aluminum on growth have been studied in rats chronically poisoned with aluminum hydroxide (80 mg/kg b.w.-i.p.-three times a week, during 6 months) and in control rats, between 3 and 26 weeks of age. The growth data was evaluated according to Parks 'theory of feeding an growth. At the end of the poisoning period, the calcium metabolism was studied through a balance of calcium and the determination of bone Ca++ accretion and resorption rates with the aid of 45Ca++. The parathyroid glands function was studied using an indirect method. Treated rats showed a significant decrease in asymptotic weights and in the initial efficiency of food conversion into biomass regarding controls. No differences were observed in food intake between both group. Aluminum affected neither the peak growth rate nor the time necessary to attain maturity. The calcium balance in treated rats was significantly less than in the control group. This was accompanied by a significant increase in the calcium excreted by faces, caused perhaps by a less intestinal absorption. An important amount of aluminum on the surface of the trabecular bone and a reduction in the skeletal Ca++ mass, was observed in all treated rats. Nevertheless there are no differences in the latter when expressed for 100 g of body weight. The rate of skeletal Ca++ accretion was found to be significantly decreased in treated group with respect to controls, without any changes in the bone Ca resorption rate. The reduction in bone turnover revealed by the decrease of Vo+/Vo- was accompanied by less recovery velocity of calcemia in the aluminum treated group, being indirectly related to the parathyroid gland response to calcium depletion. In the model that we studied the decreased bone turnover could have been caused by deposits of aluminum in bone; however there could exist associated factors such as dysfunction in the secretion of PTH, or less affinity between its receptors at the bone level.

Patients with celiac disease present a high prevalence of osteopenia and osteoporosis which globally jeopardize the skeleton. The pathogenesis of this bone disease is related to an accelerated bone change in which catabolism predominates. The metabolic studies coincide in a negative calcium balance with consequent secondary hyperparathyroidism. Diagnosis requires evaluation of bone mineral density by precise, reliable methods to which all adult celiac patients should be submitted. Finally, specific treatment with a gluten-free diet leads to significant bone remineralization.

The absorption of calcium pidolate is studied in 10 females suffering from osteoporosis by oral overload compared to the results of the glucono-lactate-carbonate. 405 mq of Ca pidolate produced a higher excretion of calcium by urine and an increase of Ca levels in blood than that produced by 1000 mq of Ca glucono-lactate-carbonate. The tolerance and the lack of side effects were the common feature in both salts. There were no effects on parathyroid glands nor bone resorption. We concluded that calcium pidolate is a safe and efficient treatment for osteoporosis because of easy absorption, which is very helpful in maintaining the calcium balance.