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Cell Metabolism Jan 2015Dietary potassium deficiency, common in modern diets, raises blood pressure and enhances salt sensitivity. Potassium homeostasis requires a molecular switch in the...
Dietary potassium deficiency, common in modern diets, raises blood pressure and enhances salt sensitivity. Potassium homeostasis requires a molecular switch in the distal convoluted tubule (DCT), which fails in familial hyperkalemic hypertension (pseudohypoaldosteronism type 2), activating the thiazide-sensitive NaCl cotransporter, NCC. Here, we show that dietary potassium deficiency activates NCC, even in the setting of high salt intake, thereby causing sodium retention and a rise in blood pressure. The effect is dependent on plasma potassium, which modulates DCT cell membrane voltage and, in turn, intracellular chloride. Low intracellular chloride stimulates WNK kinases to activate NCC, limiting potassium losses, even at the expense of increased blood pressure. These data show that DCT cells, like adrenal cells, sense potassium via membrane voltage. In the DCT, hyperpolarization activates NCC via WNK kinases, whereas in the adrenal gland, it inhibits aldosterone secretion. These effects work in concert to maintain potassium homeostasis.
Topics: Animals; Blood Pressure; Cell Line; Chlorides; Electrolytes; Humans; Kidney Tubules, Distal; Membrane Potentials; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Knockout; Minor Histocompatibility Antigens; Potassium; Potassium Channels, Inwardly Rectifying; Potassium, Dietary; Protein Serine-Threonine Kinases; Pseudohypoaldosteronism; Sodium Chloride, Dietary; Solute Carrier Family 12, Member 3; WNK Lysine-Deficient Protein Kinase 1
PubMed: 25565204
DOI: 10.1016/j.cmet.2014.12.006 -
Nutrition & Dietetics: the Journal of... Feb 2020The potential renal acid load (PRAL) has been described in relation to different health outcomes. Outcomes over time and conclusions made are often based on baseline...
AIM
The potential renal acid load (PRAL) has been described in relation to different health outcomes. Outcomes over time and conclusions made are often based on baseline dietary intake values. However, to study reliable long-term associations, parameters calculated based on dietary intake data, such as PRAL, must be stable over time. Therefore, the aim of the present study was to assess the stability of PRAL and its components over a 10-year time period.
METHODS
PRAL values of three-day dietary intake data from 197 women and 373 men on two assessment moments (2002-2004 and 2012-2014) were calculated. Pearson correlation and intra-class correlation coefficients were used for assessing the stability of PRAL and its components. Level of agreement between the two assessment moments was estimated after splitting up subjects in quintiles of PRAL, calculating kappa values and changes of quintiles over time.
RESULTS
No significant differences in mean PRAL over time were found. Stability of PRAL and its components was low. Poor agreement between the first and second assessment was shown by low kappa values and change of most of the subjects to an adjacent and non-adjacent quintile after 10 years.
CONCLUSIONS
Based on nutrition assessments carried out using three-day dietary records, stability of PRAL over a 10-year time period could not be confirmed, even though no significant difference between mean PRAL and its components over time was found. Therefore, interpretation of longitudinal outcomes based on PRAL and its component calculated at baseline should be interpreted with caution.
Topics: Adolescent; Adult; Aged; Body Mass Index; Calcium, Dietary; Databases, Factual; Diet; Diet Records; Dietary Proteins; Female; Follow-Up Studies; Humans; Hydrogen-Ion Concentration; Kidney; Longitudinal Studies; Male; Middle Aged; Nutrition Assessment; Phosphorus, Dietary; Potassium, Dietary; Young Adult
PubMed: 29732678
DOI: 10.1111/1747-0080.12432 -
Kidney International Feb 2017Dietary potassium intake is inversely related to blood pressure and mortality. Moreover, the sodium-chloride cotransporter (NCC) plays an important role in blood...
Dietary potassium intake is inversely related to blood pressure and mortality. Moreover, the sodium-chloride cotransporter (NCC) plays an important role in blood pressure regulation and urinary potassium excretion in response to potassium intake. Previously, it was shown that NCC is activated by the WNK4-SPAK cascade and dephosphorylated by protein phosphatase. However, the mechanism of NCC regulation with acute potassium intake is still unclear. To identify the molecular mechanism of NCC regulation in response to potassium intake, we used adult C57BL/6 mice fed a 1.7% potassium solution by oral gavage. We confirmed that acute potassium load rapidly dephosphorylated NCC, which was not dependent on the accompanying anions. Mice were treated with tacrolimus (calcineurin inhibitor) and W7 (calmodulin inhibitor) before the oral potassium loads. Dephosphorylation of NCC induced by potassium was significantly inhibited by both tacrolimus and W7 treatment. There was no significant difference in WNK4, OSR1, and SPAK expression after high potassium intake, even after tacrolimus and W7 treatment. Another phosphatase, protein phosphatase 1, and its endogenous inhibitor I-1 did not show a significant change after potassium intake. Hyperkaliuria, induced by high potassium intake, was significantly suppressed by tacrolimus treatment. Thus, calcineurin is activated by an acute potassium load, which rapidly dephosphorylates NCC, leading to increased urinary potassium excretion.
Topics: Animals; Calcineurin; Calcineurin Inhibitors; Calcium-Calmodulin-Dependent Protein Kinases; Hydrogen-Ion Concentration; Kidney; Male; Mice, Inbred C57BL; Phosphorylation; Potassium, Dietary; Protein Kinase Inhibitors; Protein Phosphatase 1; Protein Serine-Threonine Kinases; Renal Elimination; Signal Transduction; Solute Carrier Family 12, Member 3; Sulfonamides; Tacrolimus; Time Factors; Transcription Factors
PubMed: 28341239
DOI: 10.1016/j.kint.2016.09.001 -
Nutrients Dec 2021Potassium supplementation has been associated with reduced urinary calcium (Ca) excretion and increased Ca balance. Dietary interventions assessing the impact of... (Randomized Controlled Trial)
Randomized Controlled Trial
Potassium supplementation has been associated with reduced urinary calcium (Ca) excretion and increased Ca balance. Dietary interventions assessing the impact of potassium on bone are lacking. In this secondary analysis of a study designed primarily to determine blood pressure effects, we assessed the effects of potassium intake from potato sources and a potassium supplement on urinary Ca, urine pH, and Ca balance. Thirty men ( = 15) and women ( = 15) with a mean ± SD age and BMI of 48.2 ± 15 years and 31.4 ± 6.1 kg/m, respectively, were enrolled in a cross-over, randomized control feeding trial. Participants were assigned to a random order of four 16-day dietary potassium interventions including a basal diet (control) of 2300 mg/day (~60 mmol/day) of potassium, and three phases of an additional 1000 mg/day (3300 mg/day(~85 mmol/day) total) of potassium in the form of potatoes (baked, boiled, or pan-heated), French fries (FF), or a potassium (K)-gluconate supplement. Calcium intake for all diets was approximately 700-800 mg/day. Using a mixed model ANOVA there was a significantly lower urinary Ca excretion in the K-gluconate phase (96 ± 10 mg/day) compared to the control (115 ± 10 mg/day; = 0.027) and potato (114 ± 10 mg/day; = 0.033). In addition, there was a significant difference in urinary pH between the supplement and control phases (6.54 ± 0.16 vs. 6.08 ± 0.18; = 0.0036). There were no significant differences in Ca retention. An increased potassium intake via K-gluconate supplementation may favorably influence urinary Ca excretion and urine pH. This trial was registered at ClinicalTrials.gov as NCT02697708.
Topics: Adult; Aged; Aged, 80 and over; Calcium; Calcium, Dietary; Cross-Over Studies; Dietary Supplements; Female; Gluconates; Humans; Hydrogen-Ion Concentration; Hypertension; Male; Middle Aged; Potassium, Dietary; Solanum tuberosum; Young Adult
PubMed: 34959951
DOI: 10.3390/nu13124399 -
Journal of Renal Nutrition : the... Oct 2006To determine analytically the amount of potassium in raw tuberous root vegetables (TRV); to estimate the amount of potassium that can be leached from raw TRV by soaking... (Comparative Study)
Comparative Study
OBJECTIVES
To determine analytically the amount of potassium in raw tuberous root vegetables (TRV); to estimate the amount of potassium that can be leached from raw TRV by soaking in water; and to determine whether the duration of soaking and the cooking method selected affect potassium extraction.
DESIGN
Fresh TRV (ie, fresh and sweet batata, cocomalanga, dasheen, eddo, black yam, white yam, yellow yam, yampi, malanga, red yautia, white yautia, and yuca) were obtained from an ethnic market. Five experimental conditions with variations in soak time and cooking method were applied. Potassium was extracted from the ash of dried samples. The potassium content of aqueous extractions was determined through atomic absorption spectrophotometry.
RESULTS
Mean potassium content was highest in raw cocomalanga and lowest in raw dasheen. All of the raw TRV, except for dasheen, had a potassium content >200 mg (5.1 mEq)/100 g sample. Soaking was not effective in the leaching of significant amounts of potassium from most TRV. The double cooking (DC) method (ie, boil, rinse, boil again) leached more potassium from most TRV than did the normal cooking (NC) method (ie, boil), except with dasheen and yellow yam. More vegetables retained a potassium content >200 mg (5.1 mEq)/100 g following NC versus DC (92% versus 54%).
CONCLUSIONS
The potassium content of raw TRV varied considerably, with most tubers retaining a moderate or high potassium content following the leaching procedures. However, this study showed that DC appears to be more effective than NC for leaching potassium from TRV.
Topics: Chronic Disease; Cooking; Culture; Dioscorea; Ethnicity; Food Analysis; Hot Temperature; Humans; Kidney Diseases; Manihot; Plant Tubers; Potassium; Potassium, Dietary; Vegetables; Water
PubMed: 17046614
DOI: 10.1053/j.jrn.2006.07.012 -
Nature Sep 1962
Topics: Anions; Hydrogen-Ion Concentration; Ions; Potassium; Protons; Sodium
PubMed: 14496422
DOI: 10.1038/195908a0 -
Hypertension (Dallas, Tex. : 1979) Sep 1993It has recently been proposed that in rat models of genetic hypertension, supplemental dietary potassium preserves release of endothelium-derived relaxing factor...
It has recently been proposed that in rat models of genetic hypertension, supplemental dietary potassium preserves release of endothelium-derived relaxing factor independently of its capacity to either attenuate hypertension or increase plasma potassium. To test this hypothesis in Dahl salt-sensitive rats given sodium chloride (4%) for 3 weeks, we supplemented dietary potassium (2.1%) with either KCl (n = 16) or KHCO3 (n = 16). Compared with unsupplemented rats (n = 16), rats supplemented with either potassium salt had a lower mean arterial pressure and a greater release of endothelium-derived relaxing factor, as assessed from acetylcholine-induced relaxation of precontracted aortic rings. However, the maximum relaxation response to acetylcholine correlated inversely with blood pressure (r = -.82, P < .001), not only in the KCl (r = -.68, P < .002) and KHCO3 (r = -.77, P < .001) groups but also in unsupplemented rats (r = -.86, P < .001). With potassium supplementation, plasma potassium concentrations measured between 4 and 6 PM did not increase, but those measured between 4 and 6 AM did increase (P < .05). In isolated ring segments, aortic compliance was greater in both the KCl and KHCO3 groups than in unsupplemented rats (0.015 and 0.017 vs 0.009 mm2/mm Hg) (P < .01). This greater compliance could not be related to differences in blood pressure, plasma potassium, or collagen or elastin content of the aortic wall.(ABSTRACT TRUNCATED AT 250 WORDS)
Topics: Acetylcholine; Animals; Bicarbonates; Blood Pressure; Compliance; Hypertension; Male; Nitric Oxide; Potassium; Potassium Chloride; Potassium Compounds; Potassium, Dietary; Rats; Rats, Inbred Strains; Vasodilation
PubMed: 8349324
DOI: 10.1161/01.hyp.22.3.315 -
Journal of the American College of... Jun 2006Sodium, in the form of sodium chloride, elevates urinary calcium excretion and, at prevailing calcium intakes, evokes compensatory responses that may lead to increased... (Review)
Review
Sodium, in the form of sodium chloride, elevates urinary calcium excretion and, at prevailing calcium intakes, evokes compensatory responses that may lead to increased bone remodeling and bone loss. The calciuria is partly due to salt-induced volume expansion, with an increase in GFR, and partly to competition between sodium and calcium ions in the renal tubule. Potassium intakes in the range of current recommendations actually reduce or prevent sodium chloride-induced calciuria. At calcium intakes at or above currently recommended levels, there appear to be no deleterious effects of prevailing salt intakes on bone or the calcium economy, mainly because adaptive increases in calcium absorption offset the increased urinary loss. Such compensation is likely to be incomplete at low calcium intakes. Limited evidence suggests equivalent bone-sparing effects of either salt restriction or augmented calcium intakes. Given the relative difficulty of the former, and the ancillary benefits of the latter, it would seem that the optimal strategy to protect the skeleton is to ensure adequate calcium and potassium intakes.
Topics: Animals; Bone Remodeling; Calcium; Humans; Osteoporosis; Potassium, Dietary; Sodium, Dietary
PubMed: 16772639
DOI: 10.1080/07315724.2006.10719577 -
Current Opinion in Nephrology and... May 2017Patients with chronic kidney disease (CKD) have an increased risk of hyperkalemia that increases both short-term and long-term mortality. Historically, managing... (Review)
Review
PURPOSE OF REVIEW
Patients with chronic kidney disease (CKD) have an increased risk of hyperkalemia that increases both short-term and long-term mortality. Historically, managing hyperkalemia has relied upon dietary modifications, augmentation of urinary potassium excretion and enhanced enteral potassium elimination. This review discusses current treatments and their limitations and summarizes the evidence supporting novel agents for potassium lowering in patients with CKD.
RECENT FINDINGS
The introduction of two novel ion exchange resins represents the first new pharmacologic therapies for hyperkalemia in the last 50 years. Patiromer, which was recently approved for use in the United States, has been shown to be well tolerated and effective for decreasing serum potassium in patients with CKD when taken for up to a year. Sodium zirconium cyclosilicate for which approval is pending has also shown promise in treating both acute and chronic hyperkalemia in patients with CKD. Both medications have been well tolerated with minimal adverse events in relatively short-term follow-up.
SUMMARY
Novel ion exchange resins have the potential to provide new strategies for safely and effectively managing hyperkalemia in the CKD population. This may decrease morbidity and mortality associated with hyperkalemia and allow more broad use of medications whose use is otherwise limited by hyperkalemia.
Topics: Humans; Hyperkalemia; Ion Exchange Resins; Polymers; Potassium; Potassium, Dietary; Renal Insufficiency, Chronic; Silicates
PubMed: 28212180
DOI: 10.1097/MNH.0000000000000320 -
Praxis Mar 2015The optimal diet for chronic kidney disease (CKD) is an issue frequently brought up by patients and/or their relatives during outpatient visits. For patients without... (Review)
Review
The optimal diet for chronic kidney disease (CKD) is an issue frequently brought up by patients and/or their relatives during outpatient visits. For patients without malnutrition who are motivated and supported by an experienced multidisciplinary team, the optimal protein intake of 0,6 g/kg of ideal body weight/day is recommended to halt the progression of CKD. A calorie intake of 30 to 35 kcal/kg of ideal body weight/day is necessary to reduce the risk of malnutrition from a low protein diet and to maintain a neutral nitrogen balance. A low-salt diet, namely 5 to 6 g/d, is useful to optimize the treatment of hypertension associated with CKD and to limit fluid overload. At the advanced stage of CKD, it is also necessary to restrict the intake of phosphorus and sometimes potassium. Given the complexity of optimal renal diet, coordination between general practitioners, nephrologists and dietitians is essential to foster optimal care.
Topics: Calcium, Dietary; Diet, Protein-Restricted; Diet, Sodium-Restricted; Energy Intake; Humans; Kidney Failure, Chronic; Nutritional Requirements; Phosphates; Potassium, Dietary; Water-Electrolyte Balance
PubMed: 25804779
DOI: 10.1024/1661-8157/a001959