Effects of potassium chloride and potassium bicarbonate on endothelial function, cardiovascular risk factors, and bone turnover in mild hypertensives

Klotho is highly expressed in the chief sites of regulated potassium secretion, and it is stimulated by potassium intake

Klotho regulates many pathways in the aging process, but it remains unclear how it is physiologically regulated. Because Klotho is synthesized, cleaved, and released from the kidney; activates the chief urinary K+ secretion channel (ROMK) and stimulates urinary K+ secretion, we explored if Klotho protein is regulated by dietary K+ and the potassium-regulatory hormone, Aldosterone. Klotho protein along the nephron was evaluated in humans and in wild-type (WT) mice; and in mice lacking components of Aldosterone signaling, including the Aldosterone-Synthase KO (AS-KO) and the Mineralocorticoid-Receptor KO (MR-KO) mice. We found the specific cells of the distal nephron in humans and mice that are chief sites of regulated K+ secretion have the highest Klotho protein expression along the nephron. WT mice fed K+-rich diets increased Klotho expression in these cells. AS-KO mice exhibit normal Klotho under basal conditions but could not upregulate Klotho in response to high-K+ intake in the K+-secreting cells. Similarly, MR-KO mice exhibit decreased Klotho protein expression. Together, i) Klotho is highly expressed in the key sites of regulated K+ secretion in humans and mice, ii) In mice, K+-rich diets increase Klotho expression specifically in the potassium secretory cells of the distal nephron, iii) Aldosterone signaling is required for Klotho response to high K+ intake.

Health effects of drinking 100% juice: an umbrella review of systematic reviews with meta-analyses

CONTEXT

Low fruit and vegetable intakes are major modifiable determinants of disease. One hundred percent juice may facilitate intake and deliver essential nutrients and bioactive compounds. However, the position of 100% juice in healthy eating guidelines remains controversial due to its lower dietary fiber and higher free-sugar contents compared with whole fruits and vegetables.

OBJECTIVE

To conduct an umbrella review of systematic literature reviews with meta-analyses (MAs) to summarize the health benefits of drinking 100% fruit and/or vegetable juice.

DATA SOURCES

Four databases (Medline, The Cochrane Library, EMBASE, and CINAHL) were systematically searched for MAs of 100% juice and any health outcomes.

DATA ANALYSIS

Screening, quality, risk of bias, and content overlap tools were applied, and extracted data were narratively synthesized. No eligible studies for vegetable juice were found. Fifteen systematic literature reviews (51 primary MAs, 6 dose-response, and 87 subanalyses; 50-1200 mL/day; hours to years of duration) were included. Ten MAs (19.6%) reported health benefits (4 for blood pressure, 2 for vascular function, 3 for inflammation, 1 for stroke mortality), 3 MAs (5.9%) reported adverse risks (1 each for cardiovascular disease mortality, prostate cancer, type 2 diabetes risk), while most (74.5%) reported no effect (blood lipids, body composition, liver function, metabolic health, cancers, and inflammation). Risks were limited to cohort studies and benefits were found in both cohort and intervention studies.

CONCLUSION

The findings collate evidence showing some potential health benefits associated with 100% juice consumption, with fewer potential risks. The balance of evidence does not support the exclusion of 100% juice from food-based guides to healthy eating, although caution may be warranted in certain groups or individuals, and the body of evidence is not yet conclusive.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42022380588.

Review Article on Molecular Mechanism of Regulation of Hypertension by Macro-elements (Na, K, Ca and Mg), Micro-elements/Trace Metals (Zn and Cu) and Toxic Elements (Pb and As)

Hypertension (HT) is a medical condition arising due to increase in blood pressure (BP) prevalent worldwide. The balanced dietary intakes of macro-elements and micro-elements including Na, K, Ca, Mg, Zn, and Cu have been described to maintain BP in humans by regulating the osmolarity of blood, cells/tissues, prevention of generation of oxidative and nitrosative stress (OANS), and endothelial damage through their functioning as important components of renin-angiotensin-aldosterone system (RAAS), antioxidant enzyme defense system, and maintenance of blood vascular-endothelial and vascular smooth muscle cell (VSMC) functions. However, inadequate/excess dietary intakes of Na/K, Ca/Mg, and Zn/Cu along with higher Pb and As exposures recognized to induce HT through common mechanisms including the followings: endothelial dysfunctions due to impairment of vasodilatation, increased vasoconstriction and arterial stiffness, blood clotting, inflammation, modification of sympathetic activity and higher catecholamine release, increased peripheral vascular resistance, and cardiac output; increased OANS due to reduced and elevated activities of extracellular superoxide dismutase and NAD(P)H oxidase, less nitric oxide bioavailability, decrease in cGMP and guanylate cyclase activity, increase in intracellular Ca2+ ions in VSMCs, and higher pro-inflammatory cytokines; higher parathyroid and calcitriol hormones; activation/suppression of RAAS resulting imbalance in blood Na+, K+, and water regulated by renin, angiotensin II, and aldosterone through affecting natriuresis/kaliuresis/diuresis; elevation in serum cholesterol and LDL cholesterol, decrease in HDL cholesterol due to defect in lipoprotein metabolism. The present study recommends the need to review simple dietary mineral intervention studies/supplementation trials before keeping their individual dietary excess intakes/exposures in consideration because their interactions lead to elevation and fall of their concentrations in body affecting onset of HT.

Dietary calcium, phosphorus, and potassium intake associated with erectile dysfunction in the National Health and Nutrition Examination Survey (NHANES) 2001 to 2004

BACKGROUND

Erectile dysfunction is now a common disorder of sexual function, and its relationship to dietary calcium, phosphorus, and potassium has not been well studied. We set out to determine if dietary intakes of calcium, phosphorus, and potassium are related to erectile dysfunction in U.S. men.

METHODS

For this cross-sectional investigation, we used data from NHANES 2001-2004. To investigate the connection of dietary calcium, phosphorus, and potassium intake with erectile dysfunction, we employed multivariate logistic regression, smoothed curve fitting, and subgroup analysis.

RESULTS

This cross-sectional study comprised 3,556 eligible male subjects in total, with a weighted mean age of 49.93±18.13 years. After controlling for race and age, the greatest tertile of calcium consumption was found to have a 34% lower risk of erectile dysfunction than the lowest tertile (OR = 0.66; 95% CI = 0.52-0.84; p = 0.0006). The risk of erectile dysfunction was found to be reduced by 33% (OR = 0.67; 95% CI = 0.52-0.87; p = 0.0024) for the highest tertile of phosphorus intake compared to the lowest tertile of phosphorus intake and by 35% (OR = 0.65; 95% CI = 0.50-0.83; p = 0.0006) for the highest tertile of potassium intake compared to the lowest tertile of potassium intake in the fully adjusted model.

CONCLUSION

Erectile dysfunction and dietary consumption of calcium, phosphorus, and potassium are inversely associated with the U.S. population. To confirm the accuracy of our findings, additional prospective studies are necessary. Furthermore, it is imperative to do further fundamental research at the molecular level to gain a deeper understanding of the underlying mechanisms.

Potassium - a scoping review for Nordic Nutrition Recommendations 2023

Potassium (K) is an essential mineral that is necessary for normal cell and membrane function and for maintaining both fluid balance and acid-base balance. Potassium is furthermore very important for normal excitation, for example in nerves and muscle. It is widely available in several food products, with the most important dietary sources being potatoes, fruits, vegetables, cereal and cereal products, milk and dairy products, and meat and meat products. Potassium deficiency and toxicity is rare in healthy people, but dietary potassium is associated with other health outcomes. Results from observational studies have shown that a potassium intake above 3500 mg/day (90 mmol/day) is associated with a reduced risk of stroke. Similarly, intervention studies provide evidence that this level of potassium intake has a beneficial effect on blood pressure, particularly among persons with hypertension and in persons with a high sodium intake (>4 g/day, equivalent to >10 g salt/day).

Oral Sodium Bicarbonate and Bone Turnover in CKD: A Secondary Analysis of the BASE Pilot Trial

SIGNIFICANCE STATEMENT

In CKD, metabolic acidosis is commonly treated with alkali in the hope that it will improve bone health. In a post hoc analysis of the Bicarbonate Administration to Stabilize eGFR Pilot Trial, we investigated whether sodium bicarbonate affects serum levels of bone turnover markers and other hormones related to bone health in individuals with CKD who have normal to slightly reduced total CO2 (20-28 mEq/L). Sodium bicarbonate increased serum levels of α-klotho but had no significant effect on other bone health markers, including intact fibroblast growth factor-23 (iFGF-23), intact parathyroid hormone (iPTH), and bone-specific alkaline phosphatase (B-SAP). Further study is needed to determine the effect of bicarbonate administration on clinical aspects of bone health.

BACKGROUND

Treatment with alkali has been hypothesized to improve bone health in CKD by mitigating adverse effects of acid on bone mineral. We investigated the effect of treatment with sodium bicarbonate on bone turnover markers and other factors related to bone metabolism in CKD.

METHODS

This is a post hoc analysis of the Bicarbonate Administration to Stabilize eGFR Pilot Trial in which 194 individuals with CKD and serum total CO2 20-28 mEq/L were randomly assigned to placebo or one of two doses of sodium bicarbonate (0.5 or 0.8 mEq/kg lean body weight per day) for 28 weeks. The following serum measurements were performed at baseline, week 12, and week 28: B-SAP, c-telopeptide, procollagen type I intact N-terminal propeptide, iPTH, iFGF-23, soluble klotho, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, and tartrate-resistant acid phosphatase 5b. The difference (sodium bicarbonate versus placebo) in mean change of each bone biomarker from baseline was determined using linear mixed models.

RESULTS

One hundred sixty-eight participants submitted samples for post hoc investigations. Mean eGFR was 37±10 ml/min per 1.73 m2 and mean total CO2 was 24±3 mEq/L at baseline. Sodium bicarbonate induced a dose-dependent increase in soluble klotho levels compared with placebo. There was no significant effect of treatment with either dose of sodium bicarbonate on any of the other bone biomarkers, including iFGF-23, iPTH, and B-SAP. Effects on bone biomarkers were similar in those with baseline serum total CO2 <24 mEq/L compared with those with total CO2 ≥24 mEq/L.

CONCLUSIONS

In this pilot trial of individuals with CKD and total CO2 20-28 mEq/L, sodium bicarbonate treatment increased serum klotho levels but did not affect other bone health markers over 28 weeks.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

ClinicalTrials.gov, NCT02521181.

Potassium intake: the Cinderella electrolyte

Dietary guidelines recommend intake targets for some essential minerals, based on observational and experimental evidence relating mineral intake levels to health outcomes. For prevention of cardiovascular disease, reducing sodium intake and increasing potassium intake are the principal tools. While reducing sodium intake has received greatest public health priority, emerging evidence suggests that increasing potassium intake may be a more important target for cardiovascular prevention. Increased potassium intake reduces blood pressure and mitigates the hypertensive effects of excess sodium intake, and the recent large Phase III SSaSS trial reported that increasing potassium intake (and reducing sodium intake) in populations with low potassium intake and high sodium intake, through salt substitution (25% KCl, 75%NaCl), reduces the risk of stroke in patients at increased cardiovascular risk. As key sources of potassium intake include fruit, vegetables, nuts, and legumes, higher potassium intake may be associated with healthy dietary patterns. The current review makes the case that increasing potassium intake might represent a more advantageous dietary strategy for prevention of cardiovascular disease. Future research should focus on addressing the independent effect of potassium supplementation in populations with low or moderate potassium intake, and determine effective strategies to increase potassium intake from diet.

Platelet Cyclic GMP Levels Are Reduced in Patients with Primary Aldosteronism

BACKGROUND AND AIM

Nitric oxide inhibits platelet aggregation by increasing the second messenger cyclic guanosine-3',5'-monophosphate (cGMP) through the activation of soluble guanylyl cyclase in target cells. Within this context, the oxidative stress associated with the aldosterone excess impairs the nitric oxide availability. Thus, the aim of the present study was to assess the impact of chronic aldosterone excess on the platelet nitric oxide/cGMP pathway in humans.

METHODS

The levels of cGMP were evaluated in platelets of male patients, 12 with primary aldosteronism (PA) and 32 with uncomplicated essential hypertension (EH), matched for age and blood pressure (BP) values.

RESULTS

PA and EH patients were 52.8 ± 3 years old and 51.6 ± 1.6 years old, respectively. Systolic and diastolic BP were 158 ± 5.0 mmHg and 105.9 ± 2.3 mmHg in PA and did not differ compared to EH patients (156.6 ± 2.4 mmHg and 104.7 ± 1.2 mmHg). Mean aldosterone levels were significantly higher in PA (25.5 ± 8.8 ng/dL) compared toEH (8.11 ± 0.73 ng/dL), whereas potassium was significantly lower in PA (3.52 ± 0.18 mEq/L) compared to EH (4.08 ± 0.04 mEq/L). Aldosterone and potassium were inversely related (r = -0.49, p = 0.0006) in the whole study population (n = 44). Platelet cGMP was significantly lower in PA (5.1 ± 0.36 pM/109 cells) than in EH (7.1 ± 0.53 pM/109 cells), and in the entire study cohort, it was directly related to plasma potassium (r = 0.43, p = 0.0321).

CONCLUSIONS

These results show an impairment of nitric oxide/cGMP signaling in platelets of PA patients. This effect is likely related to the potassium-depleting effect of chronic aldosterone excess. Future studies are needed to understand whether the platelet nitric oxide/cGMP system is involved in the atherothrombotic events in these patients.

Potassium status and the risk of type 2 diabetes, cardiovascular diseases, and mortality: a meta-analysis of prospective observational studies

Epidemiological evidence on the association between potassium and cardiometabolic outcomes remains controversial. This study aimed to examine associations of dietary intake and blood and urinary levels of potassium with risk of type 2 diabetes, cardiovascular disease (CVD), and mortality. Relevant prospective studies were retrieved through a comprehensive search of four electronic databases up to July 1, 2023. Random-effects models were used to pool the study-specific relative risks (RRs) and 95% confidence intervals (CIs). Fifty-six studies were included in this meta-analysis. A higher intake of potassium was significantly associated with a 16% lower risk of CVD (RR: 0.84, 95% CI: 0.78-0.90). Similar inverse associations were also observed between potassium intake and mortality. Each 1.0 g/d increment in potassium intake was associated with a decreased risk of CVD (RR: 0.85, 95% CI: 0.80-0.91) and all-cause mortality (RR: 0.93, 95% CI: 0.88-0.99). For blood and urinary potassium levels, higher level of blood potassium increased the risk of all-cause mortality by 23% (RR: 1.23, 95% CI: 1.11-1.36). The association of blood potassium levels with mortality was nonlinear (Pnon-linearit<0.001). However, urinary potassium levels were inversely associated with the risk of all-cause mortality (RR: 0.84, 95% CI: 0.76-0.93). Our findings support the benefits of moderate potassium consumption for primary prevention of chronic diseases and premature death.

Effects of Zofenopril on Arterial Stiffness in Hypertension Patients

Angiotensin-converting enzyme inhibitors (ACEIs) reduce arterial stiffness beyond their antihypertensive effect. Studies showed that sulfhydryl ACEIs have the antioxidative potential to improve endothelial function, which might have a clinical effect on arterial distensibility. However, there are no studies that directly compare the effects of sulfhydryl (zofenopril) and non-sulfhydryl ACEIs (enalapril) on arterial stiffness. Therefore, this prospective study aims to compare the effects of enalapril and zofenopril on arterial stiffness and oxidative stress in both short- and long-term treatment of arterial hypertension (AH). Baseline and post-treatment peripheral and central arterial pressure indices, augmentation index (Aix), aortic pulse wave velocity (ao-PWV), serum levels of oxidized low-density cholesterol lipoprotein, LDL and uric acid (UA) were measured. The results showed that acute treatment with zofenopril, in contrast to enalapril, significantly decreased peripheral and central Aix (p < 0.001). Chronic treatment with zofenopril showed a superior effect over enalapril on the reduction of the peripheral systolic arterial pressure with reduction of ao-PWV (p = 0.004), as well as a reduction in peripheral Aix (p = 0.021) and central Aix (p = 0.021). Therefore, this study indicates that zofenopril has beneficial effects on the reduction of arterial stiffness compared to enalapril. It has potent clinical efficacy in AH treatment and further studies should compare its safety and long-term efficacy to other AH drugs that would aid clinicians in treating AH and other various cardiovascular diseases that have arterial stiffness as a common denominator.

Association of Dietary Potassium Intake With Abdominal Aortic Calcification and Pulse Pressure in US Adults

OBJECTIVES

Arterial calcification contributes to cardiovascular mortality. Based on a recent animal study, we hypothesized that higher dietary potassium intake was associated with less abdominal aortic calcification (AAC) and lower arterial stiffness among adults in the United States.

METHODS

Cross-sectional analyses were performed on participants over 40 years old from the National Health and Nutrition Examination Survey 2013-2014. Dietary potassium intake was categorized into quartiles (Q1: <1911, Q2: 1911-2461, Q3: 2462-3119, and Q4: >3119 mg/d). Primary outcome AAC was quantified using the Kauppila scoring system. AAC scores were categorized into no AAC (AAC = 0, reference group), mild/moderate (AAC >0 to ≤ 6), and severe AAC (AAC >6). Pulse pressure was used as a surrogate for arterial stiffness and examined as a secondary outcome.

RESULTS

Among 2,418 participants, there was not a linear association between dietary potassium intake and AAC. Higher dietary potassium intake was associated with less severe AAC when comparing dietary potassium intake in Q2 with Q1 (odds ratio 0.55; 95% confidence interval: 0.34 to 0.92; P = .03). Higher dietary potassium intake was significantly associated with lower pulse pressure (P = .007): per 1000 mg/d higher dietary potassium intake, pulse pressure was 1.47 mmHg lower in the fully adjusted model. Compared to participants with dietary potassium intake in Q1, pulse pressure was 2.84 mmHg lower in Q4 (P = .04).

CONCLUSIONS

We did not find a linear association between dietary potassium intake and AAC. Dietary potassium intake was negatively associated with pulse pressure.

A Critical Review on Vasoactive Nutrients for the Management of Endothelial Dysfunction and Arterial Stiffness in Individuals under Cardiovascular Risk

Pathophysiological conditions such as endothelial dysfunction and arterial stiffness, characterized by low nitric oxide bioavailability, deficient endothelium-dependent vasodilation and heart effort, predispose individuals to atherosclerotic lesions and cardiac events. Nitrate (NO₃^-), L-arginine, L-citrulline and potassium (K⁺) can mitigate arterial dysfunction and stiffness by intensifying NO bioavailability. Dietary compounds such as L-arginine, L-citrulline, NO₃^- and K⁺ exert vasoactive effects as demonstrated in clinical interventions by noninvasive flow-mediated vasodilation (FMD) and pulse-wave velocity (PWV) prognostic techniques. Daily L-arginine intakes ranging from 4.5 to 21 g lead to increased FMD and reduced PWV responses. Isolated L-citrulline intake of at least 5.6 g has a better effect compared to watermelon extract, which is only effective on endothelial function when supplemented for longer than 6 weeks and contains at least 6 g of L-citrulline. NO₃^- supplementation employing beetroot at doses greater than 370 mg promotes hemodynamic effects through the NO₃^--NO2-/NO pathway, a well-documented effect. A potassium intake of 1.5 g/day can restore endothelial function and arterial mobility, where decreased vascular tone takes place via ATPase pump/hyperpolarization and natriuresis, leading to muscle relaxation and NO release. These dietary interventions, alone or synergically, can ameliorate endothelial dysfunction and should be considered as adjuvant therapies in cardiovascular diseases.

The Influence of Dietary Interventions on Arterial Stiffness in Overweight and Obese Subjects

Arterial stiffness is often increased in overweight/obese subjects before the development of hypertension. It is also one of the earliest indicators of increased cardiovascular disease risk and can be considered a good predictor of the development of subclinical cardiovascular dysfunction. Arterial stiffness is a significant prognostic factor influencing cardiovascular risk, which dietary habits can modify. Obese patients should use the caloric-restricted diet because it augments aortic distensibility, diminishes pulse wave velocity (PWV), and increases the activity of endothelial nitric oxide synthases. High intake of saturated fatty acids (SFA), trans fats, and cholesterol, typical for the Western diet, impairs endothelial function and raises brachial-ankle PMV. The replacement of SFA with monounsaturated (MUFA) or polyunsaturated fatty acids (PUFA) derived from seafood and plants diminishes the risk of arterial stiffness. The dairy product intake (excluding butter) decreases PWV in the general population. The high-sucrose diet causes toxic hyperglycemia and increases arterial stiffness. Complex carbohydrates with a low glycemic index (including isomaltose) should be recommended to keep vascular health. The high sodium intake (>10 g/day), particularly associated with low potassium consumption, has a deleterious effect on arterial stiffness (↑ baPWV). Since vegetables and fruits are good sources of vitamins and phytochemicals, they should be recommended in patients with high PMV. Thus, the dietary recommendation to prevent arterial stiffness should be similar to the Mediterranean diet, which is rich in dairy products, plant oils, and fish, with a minimal red meat intake and five servings of fruits and vegetables daily.

Effect of Potassium Supplementation on Endothelial Function: A Systematic Review and Meta-Analysis of Intervention Studies

(1) Background: Endothelial dysfunction is an early predictor of cardiovascular diseases. Although a large body of evidence shows an inverse association between potassium intake and cardiovascular risk, the studies on endothelial function provided contrasting results. Thus, we carried out a systematic review and a meta-analysis of the available intervention studies of the potassium supplementation on endothelial function. (2) Methods: A systematic search of the online databases available (up to December 2022) was conducted including the intervention trials that reported flow-mediated dilation (FMD) changes-a non-invasive method of assessing endothelial function-after two different potassium intake regimens. For each study, the mean difference (MD) and 95% confidence intervals were pooled using a random effect model. (3) Results: Five studies met the pre-defined inclusion criteria and provided eight cohorts with 332 participants. In the pooled analysis, potassium supplementation was associated with a significant increase in FMD (MD: 0.74%), with a higher effect for a urinary potassium excretion higher than 90 mmol/day. There was a moderate heterogeneity among studies (I² = 59%), explained by the different amount of potassium supplementation. (4) Conclusions: The results of our meta-analysis indicate that dietary potassium supplement improves endothelial function. This effect is directly associated with the amount of potassium supplement. The findings support the campaigns in favour of an increase in dietary potassium intake to reduce cardiovascular risk.

Introductory Chapter: Potassium in Human Health

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The “FIFTY SHADOWS” of the RALES Trial: Lessons about the Potential Risk of Dietary Potassium Supplementation in Patients with Chronic Kidney Disease

Hyperkalaemia (HK) is one of the most common electrolyte disorders and a frequent reason for nephrological consultations. High serum potassium (K⁺) levels are associated with elevated morbidity and mortality, mainly due to life-threatening arrhythmias. In the majority of cases, HK is associated with chronic kidney disease (CKD), or with the use of renin–angiotensin–aldosterone system inhibitors (RAASis) and/or mineral corticoid antagonists (MRAs). These drugs represent the mainstays of treatment in CKD, HF, diabetes, hypertension, and even glomerular diseases, in consideration of their beneficial effect on hard outcomes related to cardiovascular events and CKD progression. However, experiences in relation to the Randomised Aldactone Evaluation Study (RALES) cast a long shadow that extends to the present day, since the increased risk for HK remains a major concern. In this article, we summarise the physiology of K⁺ homeostasis, and we review the effects of dietary K⁺ on blood pressure and cardiovascular risk in the general population and in patients with early CKD, who are often not aware of this disease. We conclude with a note of caution regarding the recent publication of the SSaSS trial and the use of salt substitutes, particularly in patients with a limited capacity to increase K⁺ secretion in response to an exogenous load, particularly in the context of “occult” CKD, HF, and in patients taking RAASis and/or MRAs.

Dietary Vitamins A, C, and Potassium Intake Is Associated With Narrower Retinal Venular Caliber

INTRODUCTION

The retinal vasculature, a surrogate for the systemic microvasculature, can be observed non-invasively, providing an opportunity to examine the effects of modifiable factors, such as nutrient intake, on microcirculation. We aimed to investigate the possible associations of dietary nutrient intake with the retinal vessel caliber.

METHODS

In this cross-sectional study, a total of 584 participants in a medical survey of Japanese descendants living in Los Angeles in 2015 underwent a dietary assessment, fundus photographic examination, and comprehensive physical and blood examinations. Retinal vessel caliber was measured using fundus photographs with a semi-automated computer system and summarized as central retinal artery and vein equivalents (CRAE and CRVE). The association between dietary nutrient intake and retinal vessel caliber was analyzed using a multivariate linear regression model adjusted for two models including potential confounders. The first model was adjusted for age and sex. The second model was adjusted for age, sex, smoking status, body mass index, hypertension, diabetes, dyslipidemia, history of coronary heart disease, and history of stroke.

RESULTS

After adjustment of potential confounders, compared to the quartile with the lowest intake, the difference in CRVE for the highest quartile was -5.33 μm [95% confidence interval (CI): -9.91 to -0.76, P for trend = 0.02] for vitamin A, -4.93 μm (95% CI: -9.54 to -0.32, P for trend = 0.02) for vitamin C and -3.90 μm (95% CI: -8.48 to 0.69, P for trend = 0.04) for potassium.

CONCLUSIONS

A significant association was observed between higher vitamins A, C and potassium intakes and narrower retinal venular caliber.

Clues and new evidences in arterial hypertension: unmasking the role of the chloride anion

The present review will focus on the role of chloride anion in cardiovascular disease, with special emphasis in the development of hypertensive disease and vascular inflammation. It is known that acute and chronic overload of sodium chloride increase blood pressure and have pro-inflammatory and pro-fibrotic effects on different target organs, but it is unknown how chloride may influence these processes. Chloride anion is the predominant anion in the extracellular fluid and its intracellular concentration is dynamically regulated. As the queen of the electrolytes, it is of crucial importance to understand the physiological mechanisms that regulate the cellular handling of this anion including the different transporters and cellular chloride channels, which exert a variety of functions, such as regulation of cellular proliferation, differentiation, migration, apoptosis, intracellular pH and cellular redox state. In this article, we will also review the relationship between dietary, serum and intracellular chloride and how these different sources of chloride in the organism are affected in hypertension and their impact on cardiovascular disease. Additionally, we will discuss the approach of potential strategies that affect chloride handling and its potential effect on cardiovascular system, including pharmacological blockade of chloride channels and non-pharmacological interventions by replacing chloride by another anion.

Association of Urinary Potassium Excretion with Blood Pressure Variability and Cardiovascular Outcomes in Patients with Pre-Dialysis Chronic Kidney Disease

Dietary potassium intake is a dilemma in patients with chronic kidney disease (CKD). We investigated the association of urine potassium excretion, a surrogate for dietary potassium intake, with blood pressure variability (BPV) and cardiovascular (CV) outcomes in patients with pre-dialysis CKD. A total of 1860 participants from a cohort of pre-dialysis CKD (KNOW-CKD) patients were divided into the quartiles by spot urine potassium-to-creatinine ratio. The first quartile (26.423 ± 5.731 mmol/gCr) was defined as low urine potassium excretion. Multivariate linear regression analyses revealed an independent association of low urine potassium excretion with high BPV (adjusted β coefficient 1.163, 95% confidence interval 0.424 to 1.901). Cox regression analyses demonstrated that, compared to high urine potassium excretion, low urine potassium excretion is associated with increased risk of CV events (adjusted hazard ratio 2.502, 95% confidence interval 1.162 to 5.387) but not with all-cause mortality. In conclusion, low urine potassium excretion is associated with high BPV and increased risk of CV events in patients with pre-dialysis CKD. The restriction of dietary potassium intake should be individualized in patients with pre-dialysis CKD.

Association between the urinary sodium-to-potassium ratio and renal outcomes in patients with chronic kidney disease: a prospective cohort study

A higher urinary sodium-to-potassium (UNa/K) ratio has been reported to be associated with high blood pressure and subsequent cardiovascular events. However, the association between the UNa/K ratio and renal outcomes remains uncertain. We prospectively investigated the association between the UNa/K ratio and renal outcomes in patients with chronic kidney disease (CKD). We enrolled 716 patients with CKD, and 24-h urinary sodium and potassium excretion were measured. Patients were divided into UNa/K ratio tertiles (T1-T3). Endpoints were defined as a composite of doubling of serum creatinine (SCr), end-stage kidney disease (ESKD), or death and a composite of doubling of SCr or ESKD (added as an alternative outcome). We investigated the association between the UNa/K ratio and renal outcomes using a Cox proportional hazards model. During a median follow-up of 2.3 years, doubling of SCr, ESKD, or death and doubling of SCr or ESKD occurred in 332 and 293 patients, respectively. After adjustment for covariates including potentially confounding variables such as plasma renin activity, plasma aldosterone concentration, and B-type natriuretic peptide, the hazard ratios (HRs) (95% confidence intervals [CIs]) for the composite of doubling of SCr, ESKD, or death for T2 and T3 were 1.44 (1.06-1.96) and 1.59 (1.14-2.21), respectively, compared with T1. Additionally, compared with T1, the highest tertile (T3) of the UNa/K ratio was associated with a composite of doubling of SCr or ESKD (HR 1.55, 95% CI 1.09-2.20). A higher UNa/K ratio was independently associated with poor renal outcomes in patients with CKD.

Association of Sodium, Potassium and Sodium-to-Potassium Ratio with Urine Albumin Excretion among the General Chinese Population

Mixed evidence was published regarding the association of sodium, potassium and sodium-to-potassium ratio (Na/K ratio) with renal function impairment. This study was conducted to further explore the relationship between sodium, potassium, NA/K ratio and kidney function in the general adult Chinese population. We performed a cross-sectional analysis using the baseline data from the Action on Salt China (ASC) study. 5185 eligible general adult participants from the baseline investigation of the ASC study were included in this analysis. Sodium, potassium and albumin excretion were examined from 24-h urine collection. Albuminuria was defined as albumin excretion rate (AER) greater than or equal to 30 mg/24-h. Mixed linear regression models, adjusted for confounders, were fitted to analyze the association between sodium, potassium and Na/K ratio, and natural log transformed AER. Mixed effects logistic regression models were performed to analyze the odds ratio of albuminuria at each quintile of sodium, potassium and Na/K ratio. The mean age of the participants was 49.5 ± 12.8 years, and 48.2% were male. The proportion of albuminuria was 7.5%.The adjusted mixed linear models indicated that sodium and Na/K ratio was positively associated with natural log transformed AER (Sodium: β = 0.069, 95%CI [0.050, 0.087], p < 0.001; Na/K ratio: β = 0.026, 95%CI [0.012, 0.040], p < 0.001). Mixed effects logistic regression models showed that the odds of albuminuria significantly increased with the quintiles of sodium (p < 0.001) and Na/K ratio (p = 0.001). No significant association was found between potassium and the outcome indicators. Higher sodium intake and higher Na/K ratio are associated with early renal function impairment, while potassium intake was not associated with kidney function measured by albumin excretion.

Association between serum potassium and risk of all-cause mortality among chronic kidney diseases patients: A systematic review and dose-response meta-analysis of more than one million participants

We aimed to perform a meta-analysis, using prospective cohort studies, to test the association between serum potassium and all-cause mortality among chronic kidney diseases (CKD) patients. A systematic search was performed using PubMed-MEDLINE and Scopus, up to July 2020. Prospective cohort studies which reported risk estimates of all-cause mortality in CKD patients with different serum potassium levels were included in the present meta-analysis. Thirteen studies were included in the analysis. A nonlinear dose-response meta-analysis suggested that there is a J-shaped association between serum potassium levels and the risk of all-cause mortality, with a nadir at serum potassium of 4.5 mmol/L. Subgroup analyses indicated that the strength and shape of the association between serum potassium and all-cause mortality may be influenced by age. Our meta-analysis provides supportive evidence that there is a J-shape association between serum potassium and all-cause mortality among CKD patients.

100% Fruit juice intake and cardiovascular risk: a systematic review and meta-analysis of prospective and randomised controlled studies

PURPOSE

The relationship between 100% fruit juice (100%FJ) consumption and cardiovascular risk is object of debate: indeed, recently published investigations provided new but discrepant evidence on this important question and International dietary guidelines are not in agreement on recommendations about fruit juice consumption. Therefore, we performed a meta-analysis of the prospective studies and the randomised controlled trials (RCTs) that explored the relationship between 100%FJ intake, cardiovascular risk profile and risk of cardiovascular events.

METHODS

We performed a systematic search of publications up to August 2019. Summary relative risks and exploration of linearity of the association were estimated for prospective studies and summary mean differences (MDs) calculated for RCTs.

RESULTS

A total of 21 prospective studies and 35 RCTs met the inclusion criteria. Dose-response analysis detected a significant inverse association between low-moderate 100%FJ consumption and risk of stroke (up to 200 ml/day) or total CV events (up to 170 ml/day) compared with no consumption, with a non-linear relationship (p for non-linearity < 0.05). No significant association was found for coronary heart disease and diabetes risk. In RCTs, a favorable and significant effect of 100%FJ intake was detected on blood pressure (systolic, MD: - 3.14 mmHg; diastolic, MD: - 1.68 mmHg), arterial compliance (carotid-femoral pulse wave velocity, - 0.38 m/s) and endothelial function (flow-mediated dilation, 2.10%). Neutral effects were found on body weight, blood lipids and glucose metabolism.

CONCLUSIONS

The results of these analyses indicate that 100%FJ consumption is not associated with higher CV risk. A non-linear inverse dose-response relationship occurs between 100%FJ consumption and CV disease, in particular for risk of stroke, probably mediated by the decrease in blood pressure.

TRIAL REGISTRATION

PROSPERO registration number (CRD42019135577).

Efficacy of Increased Salt and Water Intake on Pediatric Vasovagal Syncope: A Meta-Analysis Based on Global Published Data

Objective: This study was designed to assess the efficacy of increased salt and water intake in the treatment of pediatric vasovagal syncope (VVS) based on a meta-analysis of global data. Methods: Following the established inclusion criteria, seven databases, Cochrane Library, EMBASE, PubMed, Web of Science, VIP, Wanfang, and China National Knowledge Infrastructure (CNKI), were searched using specific terms. The Cochrane Bias risk assessment tool was used as a quality assessment tool of the included studies, and publication bias was assessed by funnel plots. Review Manager 5.4 software was used to analyze the efficacy of the included studies, taking the negative changing rate of the head-up tilt test (HUTT) and recurrence rate of syncope or presyncope as therapeutic efficacy evaluations. Results: In total, 5 randomized controlled trials (RCTs) were finally obtained, using the negative changing rate of the HUTT as an efficacy evaluation, while in 4 of the studies, the recurrence rate of syncope or presyncope was also evaluated. A total of 233 children with VVS were included in the salt and water intervention group. The cases in the control group were treated with non-medicinal conventional therapy. The results revealed that the negative changing rate of the HUTT in the intervention group (144/233, 61.8%) was higher than that in the control group (48/179, 26.8%), and the difference was significant (P < 0.00001). The recurrence rate of syncope or presyncope in the intervention group (85/195, 43.6%) was lower than that in the control group (86/144, 59.7%), and the difference was significant (P = 0.002). Conclusion: The current findings suggest that increased salt and water intake may increase the negative changing rates of the HUTT and reduce syncope or presyncope recurrence rates in pediatric patients with VVS.

Insulin stimulation reduces aortic wave reflection in adults with metabolic syndrome

Adults with metabolic syndrome (MetS) have increased fasting arterial stiffness and altered central hemodynamics that contribute, partly, to increased cardiovascular disease (CVD) risk. Although insulin affects aortic wave reflections in healthy adults, the effects in individuals with MetS are unclear. We hypothesized that insulin stimulation would reduce measures of pressure waveforms and hemodynamics in people with MetS. Thirty-five adults with obesity (27 women; 54.2 ± 6.0 yr; 37.1 ± 4.8 kg/m²) were selected for MetS (ATP III criteria) following an overnight fast. Pulse wave analysis was assessed using applanation tonometry before and after a 2-h euglycemic-hyperinsulinemic clamp (90 mg/dL, 40 mU/m²/min). Deconvolution analysis was used to decompose the aortic waveform [augmentation index corrected to heart rate of 75 beats/min (AIx@75); augmentation pressure (AP)] into backward and forward pressure components. Aerobic fitness (V̇o_2max), body composition (DXA), and blood biochemistries were also assessed. Insulin significantly reduced augmentation index (AIx@75, 28.0 ± 9.6 vs. 23.0 ± 9.9%, P < 0.01), augmentation pressure (14.8 ± 6.4 vs. 12.0 ± 5.7 mmHg, P < 0.01), pulse pressure amplification (1.26 ± 0.01 vs. 0.03 ± 0.01, P = 0.01), and inflammation [high-sensitivity C-reactive protein (hsCRP): P = 0.02; matrix metallopeptidase 7 (MMP-7): P = 0.03] compared to fasting. In subgroup analyses to understand HTN influence, there were no insulin stimulation differences on any outcome. V̇o_2max, visceral fat, and blood potassium correlated with fasting AIx@75 (r = -0.39, P = 0.02; r = 0.41, P = 0.03; r = -0.53, P = 0.002). Potassium levels were also associated with insulin-mediated reductions in AP (r = 0.52, P = 0.002). Our results suggest insulin stimulation improves indices of aortic reflection in adults with MetS.NEW & NOTEWORTHY This study is one of the first to investigate the effects of insulin on central and peripheral hemodynamics in adults with metabolic syndrome. We provide evidence that insulin infusion reduces aortic wave reflection, potentially through a reduction in inflammation and/or via a potassium-mediated vascular response.

Effect of Acid or Base Interventions on Bone Health: A Systematic Review, Meta-Analysis, and Meta-Regression

Osteoporosis is a global health issue among the aging population. The effect of the acid or base interventions on bone health remains controversial. This study performed a systematic review and meta-analysis to investigate effects of acidic diets and alkaline supplements on bone health simultaneously. We conducted a comprehensive literature search in 5 available databases and 1 registered clinical trial system to identify randomized controlled trials (RCTs) that assessed effects of the acid-base intervention on bone health. Depending on heterogeneity across studies, the pooled effects were calculated by fixed-effects or random-effects models. The present study included 13 acidic diet intervention studies and 13 alkaline supplement studies for final quantitative assessments. The meta-analysis showed that acidic diets significantly increased net acid excretion [NAE; standardized mean difference (SMD) = 2.99; P = 0.003] and urinary calcium excretion (SMD = 0.47, P < 0.00001) but had no significant effect on bone turnover markers and bone mineral density (BMD). On the other hand, alkaline supplement intervention significantly reduced NAE (SMD = -1.29, P < 0.00001), urinary calcium excretion (SMD = -0.44, P = 0.007), bone resorption marker aminoterminal cross-linking telopeptide (NTX; SMD = -0.29, P = 0.003), and bone formation marker osteocalcin (OC; SMD = -0.23, P = 0.02), but did not affect the other bone turnover markers. Furthermore, alkaline supplements significantly increased BMD in femoral neck [mean difference (MD) = 1.62, P < 0.00001, I2 = 0%], lumbar spine (MD = 1.66, P < 0.00001, I2 = 87%), and total hip (MD = 0.98, P = 0.02, I2 = 99%). Subsequently, meta-regression analyses identified 1 study that substantially contributed to the high heterogeneity of BMD in the latter 2 sites, but sensitivity analysis suggested that this study did not affect the significant pooled effects. Despite that, the results should be interpreted with caution and need to be further validated by a larger RCT. In summary, through integrating evidence from RCTs, the present meta-analysis initially suggests that alkaline supplements may be beneficial to bone metabolism and acidic diets may not be harmful to bone health. This work may be clinically useful for both clinicians and patients with osteoporosis.

Mechanisms of Dietary Sodium-Induced Impairments in Endothelial Function and Potential Countermeasures

Despite decades of efforts to reduce sodium intake, excess dietary sodium remains commonplace, and contributes to increased cardiovascular morbidity and mortality independent of its effects on blood pressure. An increasing amount of research suggests that high-sodium diets lead to reduced nitric oxide-mediated endothelial function, even in the absence of a change in blood pressure. As endothelial dysfunction is an early step in the progression of cardiovascular diseases, the endothelium presents a target for interventions aimed at reducing the impact of excess dietary sodium. In this review, we briefly define endothelial function and present the literature demonstrating that excess dietary sodium results in impaired endothelial function. We then discuss the mechanisms through which sodium impairs the endothelium, including increased reactive oxygen species, decreased intrinsic antioxidant defenses, endothelial cell stiffening, and damage to the endothelial glycocalyx. Finally, we present selected research findings suggesting that aerobic exercise or increased intake of dietary potassium may counteract the deleterious vascular effects of a high-sodium diet.

Association between urinary potassium excretion and blood pressure: A systematic review and meta-analysis of observational studies

Background

The evidence base regarding the association between urinary potassium and blood pressure (BP), or risk of hypertension, is inconsistent. Therefore, we sought to conduct a qualitative and quantitative literature review on the association between potassium excretion and BP.

Materials and Methods

Medline, Scopus, Web of Science, Science Direct, and Google Scholar were searched up to June 2020. All observational studies that reported BP and measured potassium excretion in overnight or 24-h urine samples were included. Correlation coefficients, mean urinary potassium excretion, and odds ratio (ORs) of hypertension were extracted from the included studies. There were no language or publication date restrictions.

Results

Overall, twelve observational studies, including 16,174 subjects, were identified for inclusion in the present meta-analysis, and 21 effect sizes were extracted. Pooled mean potassium excretion was 3.46 mmol/24 h higher in normotensive individuals compared with hypertensive subjects (95% confidence interval [CI]: 0.61, 6.31). High urinary potassium excretion was not associated with the risk of hypertension (OR: 0.95; 95% CI: 0.79, 1.13). The pooled correlation coefficient between BP and urinary potassium was not significant (ES: 0.01; 95% CI: -0.03, 0.05). However, a subgroup analysis by age indicated a significant positive correlation between urinary potassium and systolic BP in children (ES: 0.12; 95% CI: 0.04, 0.19).

Conclusion

24 h urinary potassium excretion was not correlated to BP and risk of hypertension. In contrast, mean urinary potassium excretion was higher in normotensive individuals compared with hypertensive counterparts. Future studies should focus on the association between different sources of dietary potassium and BP.

Dietary potassium and the kidney: lifesaving physiology

Potassium often has a negative connotation in Nephrology as patients with chronic kidney disease (CKD) are prone to develop hyperkalaemia. Approaches to the management of chronic hyperkalaemia include a low potassium diet or potassium binders. Yet, emerging data indicate that dietary potassium may be beneficial for patients with CKD. Epidemiological studies have shown that a higher urinary potassium excretion (as proxy for higher dietary potassium intake) is associated with lower blood pressure (BP) and lower cardiovascular risk, as well as better kidney outcomes. Considering that the composition of our current diet is characterized by a high sodium and low potassium content, increasing dietary potassium may be equally important as reducing sodium. Recent studies have revealed that dietary potassium modulates the activity of the thiazide-sensitive sodium-chloride cotransporter in the distal convoluted tubule (DCT). The DCT acts as a potassium sensor to control the delivery of sodium to the collecting duct, the potassium-secreting portion of the kidney. Physiologically, this allows immediate kaliuresis after a potassium load, and conservation of potassium during potassium deficiency. Clinically, it provides a novel explanation for the inverse relationship between dietary potassium and BP. Moreover, increasing dietary potassium intake can exert BP-independent effects on the kidney by relieving the deleterious effects of a low potassium diet (inflammation, oxidative stress and fibrosis). The aim of this comprehensive review is to link physiology with clinical medicine by proposing that the same mechanisms that allow us to excrete an acute potassium load also protect us from hypertension, cardiovascular disease and CKD.

Effects of Potassium or Sodium Supplementation on Mineral Homeostasis: A Controlled Dietary Intervention Study

CONTEXT

Although dietary potassium and sodium intake may influence calcium-phosphate metabolism and bone health, the effects on bone mineral parameters, including fibroblast growth factor 23 (FGF23), are unclear.

OBJECTIVE

Here, we investigated the effects of potassium or sodium supplementation on bone mineral parameters.

DESIGN, SETTING, PARTICIPANTS

We performed a post hoc analysis of a dietary controlled randomized, blinded, placebo-controlled crossover trial. Prehypertensive individuals not using antihypertensive medication (n = 36) received capsules containing potassium chloride (3 g/d), sodium chloride (3 g/d), or placebo. Linear mixed-effect models were used to estimate treatment effects.

RESULTS

Potassium supplementation increased plasma phosphate (from 1.10 ± 0.19 to 1.15 ± 0.19 mmol/L, P = 0.004), in line with an increase in tubular maximum of phosphate reabsorption (from 0.93 ± 0.21 to 1.01 ± 0.20 mmol/L, P < 0.001). FGF23 decreased (114.3 [96.8-135.0] to 108.5 [93.5-125.9] RU/mL, P = 0.01), without change in parathyroid hormone and 25-hydroxy vitamin D3. Fractional calcium excretion decreased (from 1.25 ± 0.50 to 1.11 ± 0.46 %, P = 0.03) without change in plasma calcium. Sodium supplementation decreased both plasma phosphate (from 1.10 ± 0.19 to 1.06 ± 0.21 mmol/L, P = 0.03) and FGF23 (from 114.3 [96.8-135.0] to 108.7 [92.3-128.1] RU/mL, P = 0.02). Urinary and fractional calcium excretion increased (from 4.28 ± 1.91 to 5.45 ± 2.51 mmol/24 hours, P < 0.001, and from 1.25 ± 0.50 to 1.44 ± 0.54 %, P = 0.004, respectively).

CONCLUSIONS

Potassium supplementation led to a decrease in FGF23, which was accompanied by increase in plasma phosphate and decreased calcium excretion. Sodium supplementation reduced FGF23, but this was accompanied by decrease in phosphate and increase in fractional calcium excretion. Our results indicate distinct effects of potassium and sodium intake on bone mineral parameters, including FGF23.

CLINICAL TRIAL REGISTRATION NUMBER

NCT01575041.

Potential of Chlorella as a Dietary Supplement to Promote Human Health

Chlorella is a green unicellular alga that is commercially produced and distributed worldwide as a dietary supplement. Chlorella products contain numerous nutrients and vitamins, including D and B12, that are absent in plant-derived food sources. Chlorella contains larger amounts of folate and iron than other plant-derived foods. Chlorella supplementation to mammals, including humans, has been reported to exhibit various pharmacological activities, including immunomodulatory, antioxidant, antidiabetic, antihypertensive, and antihyperlipidemic activities. Meta-analysis on the effects of Chlorella supplementation on cardiovascular risk factors have suggested that it improves total cholesterol levels, low-density lipoprotein cholesterol levels, systolic blood pressure, diastolic blood pressure, and fasting blood glucose levels but not triglycerides and high-density lipoprotein cholesterol levels. These beneficial effects of Chlorella might be due to synergism between multiple nutrient and antioxidant compounds. However, information regarding the bioactive compounds in Chlorella is limited.

Resistant Hypertension: Where are We Now and Where Do We Go from Here?

Resistant hypertension is an important subtype of hypertension that leads to an increased risk of cerebrovascular, cardiovascular, and kidney disease. The revised guidelines from the American College of Cardiology and American Heart Association now define resistant hypertension as blood pressure that remains above goal despite use of three maximally titrated anti-hypertensive medications including a diuretic or as a hypertensive patient who requires 4 or more agents for adequate BP control. These agents typically include a calcium-channel blocker, a renin-angiotensin system inhibitor, and a diuretic at maximal or maximally tolerated doses. As recognition of resistant hypertension increases, it is important to distinguish pseudo-resistant or apparent hypertension from true resistant hypertension. Etiologies of apparent resistant hypertension include measurement error and medication non-adherence. The prevalence of true resistant hypertension is likely much lower than reported in the literature when accounting for patients with apparent resistant hypertension. Evaluation of patients with true resistant hypertension includes screening for causes of secondary hypertension and interfering medications. Successful management of resistant hypertension includes lifestyle modification and optimization of medical therapy, often including the use of mineralocorticoid receptor antagonists. Looking ahead at developments in hypertension management, a slew of new device-based therapies are under active development. Of these, renal denervation is the closest to routine clinical application. Further study is needed before these devices can be recommended in the routine treatment of resistant hypertension.

Association of urinary sodium and potassium excretion with systolic blood pressure in the Dietary Approaches to Stop Hypertension Sodium Trial

The 2019 National Academy of Science, Engineering and Medicine Dietary Reference Intakes (DRI) for Sodium (Na⁺) and Potassium (K⁺) Report concluded there remains insufficient evidence to establish a K⁺ DRI. This study tested the hypothesis that reduced Na⁺ and increased K⁺ excretion will positively associate with lower blood pressure in salt sensitive (SS) and salt resistant (SR) participants in the Dietary Approaches to Stop Hypertension Sodium Trial (DASH–Sodium). Via the NHLBI BioLINCC we accessed the DASH-Sodium dataset for data on systolic blood pressure (SBP), 24-h urinary Na⁺ and K⁺ excretion at screening (regular patient diet; N = 186, SS N = 222 SR) and post DASH diet (N = 71 SS, N = 119 SR). The relationships between SBP, urinary Na⁺ and K⁺ excretion, and Na⁺/K⁺ ratio were assessed via linear regression. At screening elevated urinary Na⁺ excretion positively associated with SBP in SS (1 g increase in urinary Na⁺ excretion = +1 0 ± 0.4 mmHg) but not SR participants, and urinary K⁺ excretion of <1 g K⁺/day was associated with higher SBP in SS and SR participants. Urinary K⁺ excretion ≥1 g/day, or a decreases in urinary Na⁺/K⁺ ratio, was not associated with lower SBP. Post the DASH–sodium diet intervention, SBP was reduced in SS and SR participants. However, no correlation was observed between reduced SBP and urinary K⁺ excretion or the urinary Na⁺/K⁺ ratio irrespective of the salt sensitivity of blood pressure. Our data support the DRI recommendation not to establish a K⁺ DRI and suggest further evidence is required to support a reduced Na⁺/K⁺ ratio to lower SBP.

Effect of increased potassium intake on the renin-angiotensin-aldosterone system and subcutaneous resistance arteries: a randomized crossover study

BACKGROUND

Increased potassium intake lowers blood pressure (BP) in hypertensive patients. The underlying mechanism is not fully understood but must be complex because increased potassium intake elevates circulating concentrations of the BP-raising hormone aldosterone.

METHODS

In a randomized placebo-controlled crossover study in 25 normotensive men, we investigated the effect of 4 weeks of potassium supplement (90 mmol/day) compared with 4 weeks of placebo on the renin-angiotensin-aldosterone system (RAAS), urine composition and 24-h ambulatory BP. Vascular function was also assessed through wire myograph experiments on subcutaneous resistance arteries from gluteal fat biopsies.

RESULTS

Higher potassium intake increased urinary potassium excretion (144.7 ± 28.7 versus 67.5 ± 25.5 mmol/24-h; P < 0.0001) and plasma concentrations of potassium (4.3 ± 0.2 versus 4.0 ± 0.2 mmol/L; P = 0.0002), renin {mean 16 [95% confidence interval (CI) 12-23] versus 11 [5-16] mIU/L; P = 0.0047}, angiotensin II [mean 10.0 (95% CI 6.2-13.0) versus 6.1 (4.0-10.0) pmol/L; P = 0.0025] and aldosterone [mean 440 (95% CI 336-521) versus 237 (173-386) pmol/L; P < 0.0001]. Despite RAAS activation, systolic BP (117.6 ± 5.8 versus 118.2 ± 5.2 mmHg; P = 0.48) and diastolic BP (70.8 ± 6.2 versus 70.8 ± 6.3 mmHg; P = 0.97) were unchanged. In the wire myograph experiments, higher potassium intake did not affect endothelial function as assessed by acetylcholine [logarithmically transformed half maximal effective concentration (pEC50): 7.66 ± 0.95 versus 7.59 ± 0.85; P = 0.86] and substance P (pEC50: 8.42 ± 0.77 versus 8.41 ± 0.89; P = 0.97) or vascular smooth muscle cell reactivity as assessed by angiotensin II (pEC50: 9.01 ± 0.86 versus 9.02 ± 0.59; P = 0.93) and sodium nitroprusside (pEC50: 7.85 ± 1.07 versus 8.25 ± 1.32; P = 0.25) but attenuated the vasodilatory response of retigabine (pEC50: 7.47 ± 1.16 versus 8.14 ± 0.90; P = 0.0084), an activator of Kv7 channels.

CONCLUSIONS

Four weeks of increased potassium intake activates the RAAS in normotensive men without changing BP and this is not explained by improved vasodilatory responses ex vivo.

Potassium Intake and Blood Pressure: A Dose-Response Meta-Analysis of Randomized Controlled Trials

Background

Epidemiologic studies, including trials, suggest an association between potassium intake and blood pressure (BP). However, the strength and shape of this relationship is uncertain.

Methods and Results

We performed a meta‐analysis to explore the dose‐response relationship between potassium supplementation and BP in randomized‐controlled trials with a duration ≥4 weeks using the recently developed 1‐stage cubic spline regression model. This model allows use of trials with at least 2 exposure categories. We identified 32 eligible trials. Most were conducted in adults with hypertension using a crossover design and potassium supplementation doses that ranged from 30 to 140 mmol/d. We observed a U‐shaped relationship between 24‐hour active and control arm differences in potassium excretion and BP levels, with weakening of the BP reduction effect above differences of 30 mmol/d and a BP increase above differences ≈80 mmol/d. Achieved potassium excretion analysis also identified a U‐shaped relationship. The BP‐lowering effects of potassium supplementation were stronger in participants with hypertension and at higher levels of sodium intake. The BP increase with high potassium excretion was noted in participants with antihypertensive drug‐treated hypertension but not in their untreated counterparts.

Conclusions

We identified a nonlinear relationship between potassium intake and both systolic and diastolic BP, although estimates for BP effects of high potassium intakes should be interpreted with caution because of limited availability of trials. Our findings indicate an adequate intake of potassium is desirable to achieve a lower BP level but suggest excessive potassium supplementation should be avoided, particularly in specific subgroups.

Dietary Potassium Intake Remains Low and Sodium Intake Remains High, and Most Sodium is Derived from Home Food Preparation for Chinese Adults, 1991-2015 Trends

BACKGROUND

Intervention strategies to reduce sodium intake and increase potassium intake may decrease blood pressure; however, most are focused on reducing sodium in processed food globally.

OBJECTIVES

We attempt to fill important gaps in understanding the dynamics of these dietary determinants of hypertension in China.

METHODS

We used data on 29,926 adults aged ≥20 y between 1991 and 2015 from an ongoing cohort, the China Health and Nutrition Survey. We collected detailed diet data with use of weighing methods with 3 consecutive 24-h recalls. With panel data random-effects models, we analyzed factors associated with sodium and potassium intakes and sodium to potassium (Na/K) ratios.

RESULTS

Sodium intake decreased from 6.3 g/d in 1991 to 4.1 g/d in 2015, still twice the tolerable upper intake recommended by the WHO. Potassium intake was 1.7 g/d in 1991 and 1.5 g/d in 2015, below half that recommended by the WHO. The Na/K ratio decreased from 4.1 (ratios in g) in 1991 to 3.1 in 2015, 5 times the recommendation of the WHO. More than two-thirds (67%) of sodium intake was from salt added during food preparation, with 8.8% from processed foods in 2015, up from 5.0% in 1991. The most at-risk populations lived in China's central region and rural areas, were middle aged, had lower educations, or were farmers.

CONCLUSIONS

Sodium intake is very high across all regions in China. As part of sodium reduction efforts, China should target people living in the central region and adults aged above 60 whose sodium intakes are much higher. Strategies to decrease sodium intake and increase potassium intake should be different from those applied in the Western world where the major source is processed food. Reduced sodium higher potassium salts should become a major policy initiative in China.

Dietary Potassium Attenuates the Effects of Dietary Sodium on Vascular Function in Salt-Resistant Adults

The influence of dietary sodium and potassium on blood pressure (BP) has been extensively studied, however their impact on endothelial function, particularly any interactive effects, has received less attention. The purpose of this study was to determine if dietary potassium can offset the deleterious effect of high dietary sodium on endothelial function independent of BP. Thirty-three adults with salt-resistant BP (16 M and 17 F; 27 ± 1 year) completed seven days each of the following diets in a random order: a moderate potassium/low sodium diet (65 mmol potassium/50 mmol sodium; MK/LS), a moderate potassium/high sodium diet (65mmol potassium/300 mmol sodium; MK/HS) and a high potassium/high sodium (120 mmol potassium/300 mmol sodium; HK/HS). On day seven of each diet, 24-h ambulatory BP and a urine collection were performed. Brachial artery flow-mediated dilation (FMD) was measured in response to reactive hyperemia. Between diets, 24-h BP was unchanged confirming salt resistance (p > 0.05). Sodium excretion increased on both HS diets compared to MK/LS (p < 0.05) and potassium excretion was increased on the HK diet compared to MK/LS and MK/HS (p < 0.05) confirming diet compliance. FMD was lower in MK/HS (5.4 ± 0.5%) compared to MK/LS (6.7 ± 0.5%; p < 0.05) and HK/HS (6.4 ± 0.5%), while there was no difference between the MK/LS and HK/HS diets (p > 0.05). These data suggest that dietary potassium provides vascular protection against the deleterious effects of high dietary sodium by restoring conduit artery function.

Kidney Is Essential for Blood Pressure Modulation by Dietary Potassium

Eating more potassium may reduce blood pressure and the occurrence of other cardiovascular diseases by actions on various systems, including the vasculature, the sympathetic nervous system, systemic metabolism, and body fluid volume. Among these, the kidney plays a major role in the potassium-rich diet-mediated blood pressure reduction. PURPOSE OF REVIEW: To provide an overview of recent discoveries about the mechanisms by which a potassium-rich diet leads to natriuresis. RECENT FINDINGS: Although the distal convoluted tubule (DCT) is a short part of the nephron that reabsorbs salt, via the sodium-chloride cotransporter (NCC), it is highly sensitive to changes in plasma potassium concentration. Activation or inhibition of NCC raises or lowers blood pressure. Recent work suggests that extracellular potassium concentration is sensed by the DCT via intracellular chloride concentration which regulates WNK kinases in the DCT. High-potassium diet targets NCC in the DCT, resulting in natriuresis and fluid volume reduction, which are protective from hypertension and other cardiovascular problems.

Hyperkalemia and blood pressure regulation

Hypertension is common in the general population. Management of hypertensive patients at risk of hyperkalemia is challenging due to potential life-threatening complications such as cardiac arrest. Chronic hyperkalemia is often associated with impaired renal ability to excrete excessive potassium ions (K+). This may refer to chronic kidney disease or certain pharmacological interventions, including broadly used renin-angiotensin-aldosterone system and calcineurin inhibitors. Understanding the intrinsic mechanisms permitting kidney adaptations to hyperkalemia is critical for choosing therapeutic strategies. Valuable insights were obtained from the analysis of familial hyperkalemic hypertension (FHHt) syndrome, which became a classic model for coincidence of high blood pressure and hyperkalemia. FHHt can be caused by mutations in several genes, all of them resulting in excessive activity of with-no-lysine kinases (WNKs) in the distal nephron of the kidney. WNKs have been increasingly recognized as key signalling enzymes in the regulation of renal sodium ions (Na+) and K+ handling, enabling adaptive responses to systemic shifts of potassium homoeostasis consequent to variations in dietary potassium intake or disease. The WNK signalling pathway recruits a complex protein network mediating catalytic and non-catalytic effects of distinct WNK isoforms on relevant Na+- or K+-transporting proteins. In this review article, we summarize recent progress in understanding WNK signalling. An update of available models for renal adaptation to hyperkalemic conditions is presented. Consequences for blood pressure regulation are discussed. Pharmacological targeting of WNKs or their substrates offers promising options to manage hypertension while preventing hyperkalemia.

Effect of Dietary Sodium and Potassium Intake on the Mobilization of Bone Lead among Middle-Aged and Older Men: The Veterans Affairs Normative Aging Study

Bone is a major storage site as well as an endogenous source of lead in the human body. Dietary sodium and potassium intake may play a role in the mobilization of lead from bone to the circulation. We examined whether association between bone lead and urinary lead, a marker of mobilized lead in plasma, was modified by dietary intake of sodium and potassium among 318 men, aged 48–93 years, in the Veterans Affairs (VA) Normative Aging Study. Dietary sodium and potassium were assessed by flame photometry using 24-h urine samples, and a sodium-to-potassium ratio was calculated from the resulting measures. Patella and tibia bone lead concentrations were measured by K-shell-x-ray fluorescence. Urinary lead was measured by inductively coupled plasma mass spectroscopy in 24-h urine samples. Linear regression models were used to regress creatinine clearance-corrected urinary lead on bone lead, testing multiplicative interactions with tertiles of sodium, potassium, and sodium-to-potassium ratio, separately. After adjustment for age, body mass index, smoking, vitamin C intake, calcium, and total energy intake, participants in the highest tertile of sodium-to-potassium ratio showed 28.1% (95% CI: 12.5%, 45.9%) greater urinary lead per doubling increase in patella lead, whereas those in the second and lowest tertiles had 13.8% (95% CI: −1.7%, 31.7%) and 5.5% (95% CI: −8.0%, 21.0%) greater urinary lead, respectively (p-for-interaction = 0.04). No statistically significant effect modification by either sodium or potassium intake alone was observed. These findings suggest that relatively high intake of sodium relative to potassium may play an important role in the mobilization of lead from bone into the circulation.

Cross-modal interactions as a strategy to enhance salty taste and to maintain liking of low-salt food: a review

Salt reduction in foods is becoming an important challenge to protect population health from severe diseases as recommended by different health agencies worldwide. Among the reduction strategies already evaluated in order to lower sodium salt content in foods, the use of cross-modal interactions between taste and odour, regardless of saltiness, was revealed to be a very promising method to improve saltiness perception. Cross-modal odour-taste interactions, as means to enhance salty taste in foods, is reviewed. Salt-related odours can enhance salty taste in water solutions containing a low level of sodium chloride through odour-induced changes in taste perception. Odour-induced saltiness perception enhancement (OISE) depends on salt concentration (intensity). OISE was also found to be effective in low salt content solid model cheese but was texture- and composition-dependent. A significant enhancement in saltiness perception induced by Comté cheese and sardine odours was observed only in model foods with soft textures. In ternary odour-sour-salty solutions, sourness additively enhanced saltiness perception with salt-related odours. Finally, in cream-based food systems, a strategy combining OISE and heterogeneous distribution of stimuli was found to compensate for a greater than 35% decrease in salt content without significant loss of acceptability. However, variation in the composition of the food matrix influenced aroma and salt release and consequently the overall saltiness perception. A better knowledge of the mechanisms involved in cross-modal perceptual interactions at the central level should allow for the optimization of their use as salt reduction strategies for healthier food design.

Molecular mechanisms for the regulation of blood pressure by potassium

It has been well documented that the amount of potassium in the diet is associated with blood pressure levels in the population: the higher the potassium consumption, the lower the blood pressure and the cardiovascular mortality. In the last few years certain mechanisms for potassium regulation of salt reabsorption in the kidney have been elucidated at the molecular level. In this work we discuss the evidence demonstrating the relationship between potassium intake and blood pressure levels in human populations and in animal models, as well as the experimental data that reveal the effects of potassium on transepithelial Na⁺ reabsorption in different nephron segments. We also discuss the physiological relevance of K⁺-induced natriuresis, and finally, we focus on the molecular mechanisms by which extracellular potassium modulates the activity of the renal NaCl cotransporter, which is the mechanism that has been best dissected so far.

Association of Dietary Potassium Intake with the Development of Chronic Kidney Disease and Renal Function in Patients with Mildly Decreased Kidney Function: The Korean Multi-Rural Communities Cohort Study

Background

Dietary potassium has negative outcomes in patients with mildly impaired kidney function, while having positive outcomes in patients with hypertension. The association of dietary potassium intake with chronic kidney disease (CKD) development, with presence of hypertension, was studied in the Korean rural population with mildly impaired kidney function.

Material/Methods

From 3 rural areas of Korea, 5064 participants age ≥40 with CKD stage 2 at baseline were recruited. Patients were classified according to the quartile of dietary potassium intake. Newly developed CKD, defined as estimated glomerular filtration rate (eGFR) of <60 mL/min/1.73 m² at the time of follow-up, and eGFR decline, defined as eGFR decrease >15% at follow-up, were studied. The effect of dietary potassium on CKD development and eGFR decline were studied by Cox proportional hazard models. The association of potassium with blood pressures and C-reactive protein was also studied to examine the underlying mechanisms.

Results

Compared to 8.6% in normotensives, 15.7% of hypertensives developed CKD. The hazard ratio (HR) (95% confidence interval) of CKD was lower in high potassium diet only in hypertensives, with 0.60 (0.37–0.99) in the highest quartile. The eGFR decline was also lower in patients with higher potassium diet, with 0.70 (0.50–0.98) in Q3 and 0.54 (0.34–0.85) in Q4. Potassium intake has also been shown to decrease high diastolic blood pressure development (>90 mmHg) in hypertensives at 0.45 (0.25–0.83).

Conclusions

Dietary potassium was associated with lower risk of CKD development and eGFR decline, and this association was observed only in hypertensives.

Assessment of Efficacy of Oral Rehydration Salts in Children With Neurally Mediated Syncope of Different Hemodynamic Patterns

OBJECTIVE

To assess the efficacy of oral rehydration salts in children with neurally mediated syncope of different hemodynamic types.

METHODS

Children with unexplained syncope or pre-syncope who visited or were hospitalized between March 2012 and February 2015 were enrolled in the study. Checked by the head-up tilt test, 105 children (aged 4-18 years, with a mean age of 11.96 ± 2.86 years) were diagnosed with neurally mediated syncope. Of them, 73 had vasovagal syncope (vasodepressor type in 46, mixed/cardioinhibitory types in 27), and 32 had postural orthostatic tachycardia syndrome. They were randomized into the oral rehydration salts plus health education group (n = 55) and the health education alone group (n = 50). All treated children were followed up. The follow-up time ranged from 6 to 25 (14.82 ± 6.13) months. Short-term effects were assessed according to the recurrence of clinical symptoms and reviews of head-up tilt test results 6 months after drug withdrawal. Long-term effects were compared between both groups of children with neurally mediated syncope.

RESULTS

Short-term effect: No significant differences were found in subjective response rate and head-up tilt test negative results rate among different hemodynamic types ( P > .05). Long-term effect: Compared with the health education alone group, the cumulative response rate increased after treatment with oral rehydration salts ( P < .05). Among oral rehydration salts-treated children, the cumulative response rate was higher in those with vasodepressor vasovagal syncope than with mixed/cardioinhibitory vasovagal syncope ( P < .05).

CONCLUSION

Compared with children with mixed/cardioinhibitory vasovagal syncope, oral rehydration salt is more suitable for those with vasodepressor vasovagal syncope.

Rationale and Design of a Randomized Placebo-Controlled Clinical Trial Assessing the Renoprotective Effects of Potassium Supplementation in Chronic Kidney Disease

BACKGROUND/AIMS

Dietary potassium (K+) has beneficial effects on blood pressure and cardiovascular (CV) outcomes. Recently, several epidemiological studies have revealed an association between urinary K+ excretion (as proxy for dietary intake) and better renal outcomes in subjects with chronic kidney disease (CKD). To address causality, we designed the "K+ in CKD" study.

METHODS

The K+ in CKD study is a multicenter, randomized, double blind, placebo-controlled clinical trial aiming to include 399 patients with hypertension, CKD stage 3b or 4 (estimated glomerular filtration rate [eGFR] 15-44 mL/min/1.73 m2), and an average eGFR decline > 2 mL/min/1.73 m2/year. As safety measure, all included subjects will start with a 2-week open-label phase of 40 mmol potassium chloride daily. Patients who do not subsequently develop hyperkalemia (defined as serum K+ >5.5 mmol/L) will be randomized to receive potassium chloride, potassium citrate (both K+ 40 mmol/day), or placebo for 2 years. The primary end point is the difference in eGFR after 2 years of treatment. Secondary end points include other renal outcomes (> 30% decrease in eGFR, doubling of serum creatinine, end-stage renal disease, albuminuria), ambulatory blood pressure, CV events, all-cause mortality, and incidence of hyperkalemia. Several measurements will be performed to analyze the effects of potassium supplementation, including body composition monitoring, pulse wave velocity, plasma renin and aldosterone concentrations, urinary ammonium, and intracellular K+ concentrations.

CONCLUSION

The K+ in CKD study will demonstrate if K+ sup-plementation has a renoprotective effect in progressive CKD, and whether alkali therapy has additional beneficial effects.

Updates in the Metabolic Management of Calcium Stones

PURPOSE OF REVIEW

Urinary risk factors, such as hypercalciuria, hypocitraturia, and hyperoxaluria, either in combination or alone, are associated with calcium stones. Dietary habits as well as underlying medical conditions can influence urinary risk factors. Evaluation of the conglomerate of patients' stone risks provides evidence for individualized medical management, an effective and patient-supported approach to prevention.

RECENT FINDINGS

Many patients with stones desire prevention to avoid repeated surgical interventions. Yet, recent practice pattern assessments and health care utilization data show that many patients are rarely referred for metabolic evaluation or management. Innovations in metabolic management over the past decade have improved its effectiveness in reducing risk and preventing calcium stones. Although no new pharmacologic agents for calcium stone prevention have recently become available, there is relatively new thinking about some diet-based approaches. This review will synthesize current evidence to support individualized metabolic management of calcium stones.