Body Potassium Research Articles

Monitoring of patients on long-term glucocorticoid therapy: a population-based cohort study.

About 1% of the general population receives long-term systemic glucocorticoids. The monitoring provided to these patients is unknown. We conducted a population-based cohort study using The Health Improvement Network database. A total of 100,944 adult patients prescribed systemic glucocorticoids for >3 months between January 2000 and December 2012 were studied. The monitoring done before prescribing glucocorticoid therapy and during exposure to the drug was examined. This included measurement of body weight, blood pressure, lipids, glucose and potassium levels, referrals for dual-energy X-ray absorptiometry (DEXA-scan) or to an ophthalmologist/optician, and vaccinations. We assessed factors associated with the odds of being monitored before and during exposure. Before glucocorticoid initiation, weight and blood pressure were monitored in < 20% and < 50% of patients, respectively. Glucose and lipid levels were monitored in less than one-third of the patients, while DEXA-scan and eye monitoring were offered to <15% of them. Vaccination against flu and pneumococcus was given to 57% and 46% of the patients, respectively. During exposure to the drug, <60% of patients who were prescribed the drug for more than a year had their weight, glucose, or lipid levels recorded at least once and <25% of patients were referred at least once for DEXA-scan or screening for eye diseases. Overall, the odds of being monitored were higher in older patients and in those with comorbidities. There were variations in the level of monitoring provided across the UK, but the monitoring has improved over the last 12 years. Although the extent of monitoring of people on long-term glucocorticoids has improved over time, the overall monitoring provided is not satisfactory, particularly in young patients and those without comorbidities.

Risk factors for the development of hypokalemia in neonatal diarrheic calves.

BackgroundNeonatal diarrheic calves have a clear negative potassium balance because of intestinal losses and decreased milk intake but in the presence of acidemia, they usually show normokalemic or hyperkalemic plasma concentrations.ObjectivesTo assess whether marked hypokalemia occurs in response to the correction of acidemia and dehydration and to identify factors that are associated with this condition.AnimalsEighty‐three calves with a clinical diagnosis of neonatal diarrhea.MethodsProspective cohort study. Calves were treated according to a clinical protocol using an oral electrolyte solution and commercially available packages of 8.4% sodium bicarbonate, 0.9% saline and 40% dextrose infusion solutions.ResultsThe proportion of hypokalemic calves after 24 hours of treatment (19.3%) was twice as great as it was on admission to the hospital. Plasma K+ after 24 hours of treatment was not significantly correlated to venous blood pH values at the same time but positively correlated to venous blood pH values on admission (r = 0.51, P < .001). Base excess on admission (Odds ratio [OR] = 0.81, 95% confidence interval [CI] = 0.70–0.94), duration of diarrhea (OR = 1.37, 95% CI = 1.05–1.80), milk intake during hospitalization (OR = 0.54, 95% CI = 0.37–0.79) and plasma sodium concentrations after 24 hours (OR = 1.12, 95% CI = 1.01–1.25) were identified to be independently associated (P < .05) with a hypokalemic state after 24 hours of treatment.Conclusions and Clinical ImportanceFindings of this study suggest that marked depletion of body potassium stores is evident in diarrheic calves that suffered from marked metabolic acidosis, have a low milk intake and a long history of diarrhea.

Quantifying the dietary potassium requirement of subadult grass carp (Ctenopharyngodon idellus)

A growth trial lasting for 12 weeks was conducted in a semi flow-through system to determine the dietary potassium requirement of juvenile grass carp (Ctenopharyngodon idellus) with an initial body weight of 4.8 g. Seven isonitrogenous and isoenergetic semi-purified diets were compounded with different dietary potassium levels: 1.50, 2.32, 3.28, 5.30, 7.12, 9.45 and 10.44 g kg(-1) diet. The results showed that specific growth rate and feed efficiency of grass carp were significantly (P 0.05). The Na+-K+ ATPase activity value in the gills varied significantly (P 0.05). Body potassium and moisture contents increased and lipid content decreased with dietary potassium content, while ash content in fish body increased first and then decreased as potassium content increased (P < 0.05). Body protein in the 10.44 g kg(-1) group was significantly lowered (P < 0.05). However, calcium, magnesium, phosphorus and sodium contents in dry matter were not affected by dietary potassium level. When the potassium content of water was 1.86-3.10 mg L-1, judging from the polynomial regression analysis for the specific growth rate of fish and the Na+-K+ ATPase activity in the gill, and the broken-line analysis for body potassium content, the optimal dietary potassium content for juvenile grass carp was 4.65, 7.27 and 5.98 g kg(-1) diet respectively. (C) 2014 Elsevier B.V. All rights reserved.

Bioimpedance phase angle indicates catabolism in Type 2 diabetes.

Body cell mass is directly proportional to the bioimpedance phase-angle which is an indicator of the amount of electrical charge that cell membranes can hold and is an index of cellular health and function. To evaluate whether the bioimpedance phase angle is relevant for indicating catabolism in people with diabetes and whether it discriminates between people with diabetes receiving different types of therapy. A cross-sectional study was performed in 182 people with Type 2 diabetes and 107 age- and BMI-matched control subjects. The phase angle was measured at 5, 50 and 100 kHz using multifrequency bioimpedance analysis. The phase angles were compared among different diabetes therapy groups (untreated patients with diabetes, patients receiving oral antidiabetic drugs and patients receiving insulin therapy). The phase angle at 100 kHz strongly correlated with total body potassium (r=0.70, P=0.001), and was therefore a good indicator of body cell mass. The phase angle at 100 kHz discriminated more strongly between patients with Type 2 diabetes and control subjects than did the phase angle at 50 kHz. Compared with control subjects, patients with Type 2 diabetes had a smaller phase angle at 100 kHz (men: 5.2° vs. 4.5°, P<0.0001; women: 4.8° vs. 4.2°, P<0.0001) and a smaller phase angle at 50 kHz (men: 5.9° vs. 5.3°, P<0.0001; women: 5.4° vs. 4.8°, P=0.0001), but a larger phase angle at 5 kHz (men: 2.0° vs. 2.6°, P=0.0001; women: 2.3° vs. 3.0°, P=0.00001). Phase angle ratios better discriminated between patients and control subjects than phase angles alone (phase angle at 5kHz/ phase angle at 50 kHz ratio, P=1.51×10(-16) ; phase angle at 5kHz/phase angle at 100kHz ratio, P=2.13×10(-15) ). No differences were found among phase angles in the different therapy groups. In patients with diabetes, the phase angle at 50 kHz and the phase angle at 100 kHz correlated inversely with duration of disease (men: P=0.026, P=0.016; women: only phase angle at 100 kHz, P=0.003) and with HbA1c concentration (men: P=0.010, P=0.001; women: P=0.007, P=0.043). The phase angle at 100 kHz is a promising measurement for assessing catabolic state in people with diabetes.

The GH receptor exon 3 deleted/full-length polymorphism is associated with central adiposity in the general population.

To test the hypothesis that the GH receptor (GHR) exon 3 deleted (d3)/full-length (fl) polymorphism influences anthropometry and body composition in the general population. The Swedish Obese Subjects (SOS) reference study is a cross-sectional population-based study, randomly selected from a population registry. A subgroup of the population-based Malmö Diet and Cancer study (MDC-CC) was used as a replication cohort. The SOS reference study comprises 1135 subjects (46.2% men), with an average age of 49.5 years. The MDC-CC includes 5451 successfully genotyped subjects (41.5% men), with an average age of 57.5 years. GHR d3/fl genotypes were determined using TagSNP rs6873545. Linear regression analyses were used to test for genotype-phenotype associations. In the SOS reference study, subjects homozygous for the d3-GHR weighed ∼4 kg more (P=0.011), and had larger waist-to-hip ratio (WHR, P=0.036), larger waist circumference (P=0.016), and more fat-free mass estimated from total body potassium (P=0.026) than grouped fl/d3 and fl/fl subjects (d3-recessive genetic model). The association with WHR was replicated in the MDC-CC (P=0.002), but not those with other anthropometric traits. In this population-based study, the GHR d3/fl polymorphism was found to be of functional relevance and associated with central adiposity, such that subjects homozygous for the d3-GHR showed an increased abdominal obesity.

The effect of intensive nutrition interventions on weight gain after kidney transplantation: protocol of a randomised controlled trial.

BackgroundWeight gain and obesity are common after kidney transplantation, particularly during the first year. Obesity is a risk factor for the development of new-onset diabetes after transplantation, and is associated with reduced graft survival. There is a lack of evidence for effective interventions to prevent weight gain after kidney transplantation.Methods/DesignThe effect of INTEnsive Nutrition interventions on weight gain after kidney Transplantation (INTENT) trial is a single-blind (outcomes assessor), randomised controlled trial to assess the effect of intensive nutrition interventions, including exercise advice, on weight gain and metabolic parameters in the first year after transplantation. Participants will be randomised during the first post-transplant month to either standard care (four visits with a renal dietitian over twelve months) or intensive nutrition intervention (eight visits with a renal dietitian over the first six months, four visits over the second six months, and three visits over the first six months with an exercise physiologist). In the intensive intervention group, nutrition counselling will be provided using motivational interviewing techniques to encourage quality engagement. Collaborative goal setting will be used to develop personalised nutrition care plans. Individualised advice regarding physical activity will be provided by an exercise physiologist. The primary outcome of the study is weight at six months after transplant, adjusted for baseline (one month post-transplant) weight, obesity and gender. Secondary outcomes will include changes in weight and other anthropometric measures over 12 months, body composition (in vivo neutron activation analysis, total body potassium, dual-energy X-ray absorptiometry, and bioelectrical impedance), biochemistry (fasting glucose, lipids, haemoglobin A1c and insulin), dietary intake and nutritional status, quality of life, and physical function.DiscussionThere are currently few randomised clinical trials of nutrition interventions after kidney transplantation. The INTENT trial will thus provide important data on the effect of intensive nutrition interventions on weight gain after transplant and the associated metabolic consequences. Additionally, by assessing changes in glucose metabolism, the study will also provide data on the feasibility of undertaking larger multi-centre trials of nutrition interventions to reduce the incidence or severity of diabetes after transplantation.Trial registrationAustralian New Zealand Clinical Trials Registry Number: ACTRN12614000155695

DESIGN ,AND PERFORMANCE OF INMAS WHOLE-BODY COUNTER

A whole-body counter has been commissioned at INMAS for radiation protection and clinical applications including body potassium estimations. It has 4-crystal bed geometry inside a shielded enclosure. The background index of the system (counts) per minute per cc detector volume in the energy band 0.1-2 me V is about 0.6 comparing favorably with other whole-body monitors in the world. The sensitivity is 0.5 cpm per gram of K. Body potassium can be estimated can be estimated correct to 10 g for one hour counting. The variation in detector response to a point source on the mid-line of the bed is + - 10% of the mean over a length of 170 cm. The usefulness of the large dimensions of the enclosure chosen is discussed.

Long-term effect of childhood liver transplantation on body cell mass.

Malnutrition is common in end-stage liver disease, but a correction after transplantation is expected. Body cell mass (BCM) assessment using total body potassium (TBK) measurements is considered the gold standard for assessing nutritional status. The aim of this study was to examine the BCM and, therefore, nutritional status of long-term survivors after childhood liver transplantation. This was a longitudinal nested cohort study of patients undergoing transplantation at <18 years of age and surviving >3 years with ongoing review at our center. TBK measurements were obtained before transplantation and during long-term follow-up. BCM was calculated from TBK and was adjusted for the height raised to power p, which depended on sex (BCM/height(p)). The effects of the age at transplant, linear growth impairment, a diagnosis of biliary atresia, and steroid use were assessed. Thirty-two patients (20 males) participated; 59% had biliary atresia. The median age at transplant was 2.11 years (range = 0.38-10.92 years). Posttransplant testing was performed at a median of 7.23 years (range = 3.28-14.99 years) when they were 10.12 years old (range = 4.56-20.77 years). This cohort attained mean z scores for height, weight, and body mass index of -0.41 ± 1.36, -0.26 ± 1.14, and 0.04 ± 0.99, respectively. BCM/height(p) was reduced before transplantation but was further reduced after transplantation (P < 0.001) despite the normalization of height and weight. Weight recovery, therefore, likely came from increased fat mass and not BCM. Linear growth impairment was associated with a greater reduction in posttransplant BCM/height(p) (P = 0.02). In multivariate analyses, only an older age at transplant predicted reduced posttransplant BCM/height(p) (P = 0.02). The age at transplant, sex, steroid use, and underlying diagnosis did not predict changes in BCM/height(p) after transplantation. In conclusion, weight recovery in long-term survivors of childhood liver transplantation is likely due to increased fat mass because BCM remains reduced. Nutritional compromise persists in long-term survivors of childhood liver transplantation.

Quantifying the dietary potassium requirement of juvenile grass carp (Ctenopharyngodon idellus)

A growth trial lasting for 12 weeks was conducted in a semi flow-through system to determine the dietary potassium requirement of juvenile grass carp (Ctenopharyngodon idellus) with an initial body weight of 4.8 g. Seven isonitrogenous and isoenergetic semi-purified diets were compounded with different dietary potassium levels: 1.50, 2.32, 3.28, 5.30, 7.12, 9.45 and 10.44 g kg(-1) diet. The results showed that specific growth rate and feed efficiency of grass carp were significantly (P 0.05). The Na+-K+ ATPase activity value in the gills varied significantly (P 0.05). Body potassium and moisture contents increased and lipid content decreased with dietary potassium content, while ash content in fish body increased first and then decreased as potassium content increased (P < 0.05). Body protein in the 10.44 g kg(-1) group was significantly lowered (P < 0.05). However, calcium, magnesium, phosphorus and sodium contents in dry matter were not affected by dietary potassium level. When the potassium content of water was 1.86-3.10 mg L-1, judging from the polynomial regression analysis for the specific growth rate of fish and the Na+-K+ ATPase activity in the gill, and the broken-line analysis for body potassium content, the optimal dietary potassium content for juvenile grass carp was 4.65, 7.27 and 5.98 g kg(-1) diet respectively. (C) 2014 Elsevier B.V. All rights reserved.

Distinct gender differences in the anthropometric profile of South African HIV‐positive individuals on highly active anti‐retroviral treatment (641.16)

Highly active antiretroviral therapy (HAART) has extended life expectancy and enhanced the well‐being of HIV+ individuals. Since there are concerns regarding HAART‐mediated onset of cardio‐metabolic diseases in the long‐term, we evaluated the anthropometric profile of HIV‐infected individuals in the Drakenstein District (Western Cape, South Africa). HIV+ patients (n=44 males, n=102 females; 20‐40 yrs) were recruited for 3 groups: 1) control (HIV+, HAART not initiated yet), 2) HIV+ (HAART 蠄 3 years), and 3) HIV+ (HAART 蠅 3 years). Participants underwent a) anthropometric (triceps skin fold [TSF], and b) bioelectrical impedance measurements (body cell mass [BCM], fat free mass [FFM], protein, mineral, total body potassium and calcium, glycogen, and fat mass [FM]). Our data reveal that HIV+ males on HAART 蠄 3 years displayed a trend for lower BCM, FFM, FM, TSF and protein content (vs. control group). Females exhibited reduced BCM (p=0.001) and lower protein (p=0.003), muscle (p=0.001), glycogen (p=0.001), FM (p=0.0005) and FFM (p=0.002) content. However, with longer‐term treatment (HAART 蠅 3 years), females displayed higher BCM (p=0.0001), protein (p=0.01), muscle (p=0.0003), glycogen (p=0.0001), FM (p=0.00003) and FFM (p=0.0002) vs. the short‐term treatment group (HAART 蠄 3 years). Their waist‐to‐hip ratio also increased vs. the control female group (p=0.02). By contrast, males on HAART 蠅 3 years did not show any significant increases compared to the HAART 蠄 3 years group. This study found striking gender‐based anthropometric differences in South African HIV+ individuals on HAART. While both genders initially exhibit muscle wasting, HIV+ females show a strong improvement with longer‐term treatment compared to males. However, higher abdominal fat accumulation in females with longer‐term treatment potentially increases their risk for the future onset of cardio‐metabolic complications.Grant Funding Source: Harry Crossley Foundation, Stellenbosch University

Diet, weight, cytokines and bone health in postmenopausal women.

To investigate diet and nutrition-related factors associated with bone loss in a group of postmenopausal (PM) women. Nutritional intake, inflammatory markers and body composition (weight, body mass index, fat/lean mass) were analysed for associations with bone mineral density (BMD). A cross sectional study examining correlations between BMD (Duel-energy X ray absorptiometry; (DXA) and dietary intake (3-day diaries), body composition and plasma bone and inflammatory markers: C-terminal telopeptide of type I collagen (CTX) and procollagen type I N propeptide (P1NP), C- reactive protein (CRP), interleukin 6 and 10 (IL-6, IL-10), tumour necrosis factor (TNF) and osteoprotegerin (OPG). Community dwelling women from the Auckland, Hawke's Bay and Manawatu regions in New Zealand. 142 healthy, PM women aged 50-70 years. OPG (per kilogram fat mass) was increased in women with osteoporosis (p<0.001) compared to groups classified with normal BMD and osteopenia. Protein, vitamin B12, zinc, potassium and dairy intake were all positively correlated with higher BMD while dairy and potassium intakes also inversely correlated with CTX. Body composition (weight, BMI and fat/lean mass) had strong positive associations with BMD. Multiple regression analysis showed body weight, potassium and dairy intake were predictors of increased BMD in PM women and explained 39% (r2=0.39, p< 0.003) of variance. BMD was negatively correlated with OPG and positively with weight, dairy and potassium intake. This study highlights the importance of maintaining adequate body weight and emphasising dairy and potassium predominantly sourced from fruit/vegetables to reduce bone loss at midlife.

Body Composition Changes in the First 6 Months of Life According to Method of Feeding

Early feeding choices may affect long-term health outcomes. Therefore, understanding body composition changes in healthy breastfed infants has become an important research focus. The aims of this review were to investigate the body composition changes that occur during weight loss in breastfed term newborns and to examine body composition differences between exclusively/predominantly breastfed and exclusively formula-fed infants in the first 6 months of life. We performed a review of the existing literature using PubMed. We searched for studies published in English since January 1, 2000, that involved human infants ranging in age from birth to 6 months. We used the following MEDLINE Medical Subject Headings: ((breastfeeding) OR (infant formula)) AND ((body composition) OR (bioelectrical impedance) OR (absorptiometry, photon) OR (total body potassium) OR (isotope dilution) OR (air-displacement plethysmography)). Our search yielded 6 studies. Two studies reported that newborn weight loss was due to a reduction in the quantity of both fat mass and fat-free mass. Three out of 4 articles that evaluated body composition changes according to method of feeding reported no differences in body composition between exclusively/predominantly breastfed and exclusively formula-fed infants in the first 4.5 months of life. One study reported that exclusively breastfed infants at 3 months of age and exclusively breastfed boys at 6 months of age had higher fat mass contents compared to exclusively formula-fed infants. Because of the limited number of studies available, larger studies are needed to clarify the differences in body composition between exclusively/predominantly breastfed and exclusively formula-fed infants.

Total body potassium revisited

There are a multitude of methods available today that can be used to assess body composition in humans, from pre-term infants to the oldest adults. A body composition method is usually focused at a specific component of body composition, such as fat mass, total body water (TBW) or body cell mass (BCM). Many methods have been developed over the past century, with one of the earliest measures of body composition being total body potassium counting (TBK), which was first recognized in 1950s. There were a large number of whole body counters (WBC) available in 1970s,1 but over time the use of TBK facilities has decreased and old counters have been decommissioned. With other more accessible body composition technologies becoming more commonplace, today TBK is a rarely utilized method. However, as no alternative technology provides a direct and precise measure of BCM,2 the need for accurate body composition techniques for clinical and public health demands that TBK counting as a method should be revisited.

Prediction of background in low-energy spectrum of Phoswich detector

In vivo monitoring of actinides in occupational workers is done using Phoswich detector by measuring the low-energy X ray and gamma rays. Quantification of actinides like plutonium and americium in the lungs is extremely difficult due to higher background in the low-energy regions, which is from ambient background as well as from the subject. In the latter case, it is mainly due to the Compton scattering of body potassium, which varies person-to-person. Hence, an accurate prediction of subject-specific background counts in the lower-energy regions is an essential element in the in vivo measurement of plutonium and americium. Empirical equations are established for the prediction of background count rate in (239)Pu and (241)Am lower-energy regions, called 'target regions', as a function of count rate in the monitoring region (97-130 keV)/(40)K region in the high-energy spectrum, weight-to-height ratio of the subject (scattering parameter) and the gender.

Thyrotoxic Periodic Paralysis: Correct Hypokalemia with Caution

BackgroundThyrotoxic periodic paralysis is rare in Caucasian populations, but affects approximately 2% of East Asians with thyrotoxicosis (13% of males, 0.17% of females). The presentation is characterized by abrupt-onset hypokalemia and profound proximal muscular weakness, and commonly occurs after carbohydrate loading or exercise. ObjectivesTo raise awareness of this condition through the description of a typical case of thyrotoxic periodic paralysis; to remind readers that, despite intravascular hypokalemia, total body potassium is normal and that correction must be done with caution; to highlight the differences in treatment compared to familial hypokalemic periodic paralysis. Case ReportWe describe the presentation of a 36-year-old Filipino man with a background history of Graves disease. Over-administration of intravenous potassium was narrowly averted in this case. ConclusionIt may be important to check thyroid function in patients presenting with acute paralysis, especially those of Asian origin. In patients with thyrotoxic periodic paralysis, administration of potassium, with cardiac monitoring and a total dose of <50 mmol, limits the dysrhythmia risk. Patients are likely to benefit from the prescription of non-selective beta-blockers until they become euthyroid. In contrast to familial periodic paralysis, regular oral potassium supplementation is ineffective in thyrotoxic periodic paralysis, and acetazolamide precipitates, rather than prevents, attacks.

Life-threatening hypokalemia following rapid correction of respiratory acidosis

A 56-year-old woman with a history of paraplegia and chronic pain due to neuromyelitis optica (Devic's syndrome) was admitted to a spinal cord injury unit for management of a sacral decubitus ulcer. During the hospitalization, she required emergency transfer to the intensive care unit (ICU) because of progressive deterioration of respiratory muscle function, severe respiratory acidosis, obtundation and hypotension. Upon transfer to the ICU, arterial blood gas revealed severe acute-on-chronic respiratory acidosis (pH 7.00, PCO2 120 mm Hg, PO2 211 mm Hg). The patient was immediately intubated and mechanically ventilated. Intravenous fluid boluses of normal saline (10.5 L in about 24 h) and vasopressors were started with rapid correction of hypotension. In addition, she was given hydrocortisone. Within 40 min of initiation of mechanical ventilation, there was improvement in acute respiratory acidosis. Sixteen hours later, however, the patient developed life-threatening hypokalemia (K+ of 2.1 mEq/L) and hypomagnesemia (Mg of 1.4 mg/dL). Despite aggressive potassium supplementation, hypokalemia continued to worsen over the next several hours (K+ of 1.7 mEq/L). Urine studies revealed renal potassium wasting. We reason that the recalcitrant life-threatening hypokalemia was caused by several mechanisms including total body potassium depletion (chronic respiratory acidosis), a shift of potassium from the extracellular to intracellular space (rapid correction of respiratory acidosis with mechanical ventilation), increased sodium delivery to the distal nephron (normal saline resuscitation), hyperaldosteronism (secondary to hypotension plus administration of hydrocortisone) and hypomagnesemia. We conclude that rapid correction of respiratory acidosis, especially in the setting of hypotension, can lead to life-threatening hypokalemia. Serum potassium levels must be monitored closely in these patients, as failure to do so can lead to potentially lethal consequences.

Changes in serum aldosterone are associated with changes in obesity-related factors in normotensive overweight and obese young adults.

Recent data suggest excess circulating aldosterone promotes cardiometabolic decline. Weight loss may lower aldosterone levels, but little longitudinal data is available in normotensive adults. We aimed to determine whether, independent of changes in sodium excretion, reductions in serum aldosterone are associated with favorable changes in obesity-related factors in normotensive overweight/obese young adults. We studied 285 overweight/obese young adult participants (body mass index ≥ 25 and<40 kg m⁻², age 20-45 years) in a clinical trial examining the effects of a 1-year diet and physical activity intervention with or without sodium restriction on vascular health. Body weight, serum aldosterone, 24-h sodium and potassium excretion and obesity-related factors were measured at baseline, 6, 12 and 24 months. Weight loss was significant at 6 (7%), 12 (6%) and 24 months (4%; all P<0.0001). Decreases in aldosterone were associated with decreases in C-reactive protein, leptin, insulin, homeostasis assessment of insulin resistance, heart rate, tonic cardiac sympathovagal balance and increases in adiponectin (all P<0.05) in models adjusting for baseline age, sex, race, intervention arm, time since baseline, and sodium and potassium excretion. Weight loss and reductions in thigh intermuscular fat (intermuscular adipose tissue area; IMAT) were associated with decreases in aldosterone in the subgroup (n=98) with metabolic syndrome (MetS) at baseline (MetS × weight loss, P=0.04; MetS × change in IMAT, P=0.04). Favorable changes in obesity-related factors are associated with reductions in aldosterone in young adults with no risk factors besides excess weight, an important finding, given aldosterone's emergence as an important cardiometabolic risk factor.

Extracellular Potassium Homeostasis: Insights from Hypokalemic Periodic Paralysis

Extracellular potassium makes up only about 2% of the total body's potassium store. The majority of the body potassium is distributed in the intracellular space, of which about 80% is in skeletal muscle. Movement of potassium in and out of skeletal muscle thus plays a pivotal role in extracellular potassium homeostasis. The exchange of potassium between the extracellular space and skeletal muscle is mediated by specific membrane transporters. These include potassium uptake by Na(+), K(+)-adenosine triphosphatase and release by inward-rectifier K(+) channels. These processes are regulated by circulating hormones, peptides, ions, and by physical activity of muscle as well as dietary potassium intake. Pharmaceutical agents, poisons, and disease conditions also affect the exchange and alter extracellular potassium concentration. Here, we review extracellular potassium homeostasis, focusing on factors and conditions that influence the balance of potassium movement in skeletal muscle. Recent findings that mutations of a skeletal muscle-specific inward-rectifier K(+) channel cause hypokalemic periodic paralysis provide interesting insights into the role of skeletal muscle in extracellular potassium homeostasis. These recent findings are reviewed.

Magnesium Glycinate Supplementation in Bariatric Surgery Patients and Physically Fit Young Adults

Moderate deficiencies of magnesium could occur in diverse groups of people. Three questions that need to be answered are: One, what forms of magnesium supplements can correct the problem? Two, what types of people are prone to this problem? Three, what benefits are derived from correcting this problem? Some recent pilot data from our laboratory has been directed toward these questions. In one study, 6 week supplementation with 400 mg of magnesium as magnesium glycinate was effective at raising plasma magnesium readings in people who have had bariatric surgery (comparison made pre‐surgery to 6 weeks post‐surgery). Magnesium oxide did not produce this effect in these same type people, albeit at a slightly lower dose. In physically fit young adults, supplementation for 4 weeks with 400 mg of magnesium as magnesium glycinate, but not placebo, raised erythrocyte potassium content (a reflection of magnesium's role in body potassium retention and distribution). Magnesium supplementation also improved two measures of exercise performance (pre‐supplementation vs post‐supplementation). Interestingly, plasma magnesium was not increased significantly, though this does not provide the most sensitive indicator of altered magnesium status. In conclusion, the positive results obtained in this pilot work suggests that young fit adults, as well as people who have had bariatric surgery, tend to have less than optimal magnesium intake. The glycinate form of magnesium can improve magnesium status. In addition, in the pilot work, no reports were given of diarrhea, which can be a problem with some types of magnesium supplements.

Abstract P096: Excess Sodium and Inadequate Potassium Dietary Intake by Italian Children and Adolescents: Results of the MINISAL Survey

Introduction: The MINISAL survey aimed to assess the age-, gender- and region-specific habitul sodium and potassium intake and its association with relevant anthropometric characteristics in a national sample of Italian healthy children and adolescents referred to centers recognised by the Italian Society of Gastroenterology and Pediatric Nutrition. Methods: The study population included 1422 6 to 18 yrs. old subjects from ten regions. Main anthropometric indexes, blood pressure (BP) and 24h urinary sodium and potassium excretion (as proxy for habitual sodium and potassium intake) were measured using carefully standardised procedures. Potentially incomplete 24h collections were identified and excluded from the analysis based on values of urinary creatinine/Kg body weight and/or a urinary volume below the 5 th percentile of the overall distribution. The analysis was carried out upon stratification by gender (M=788, F=644), puberal age category: &lt;9 yrs, 9-11 yrs. and 5 months, &gt;11 yrs. and 5 mo. (male); &lt; 8 yrs., 8-10 yrs. and 2 mo., &gt; 10 yrs. and 2 mo. (female), and scholar age category: 6-10 yrs., 11-13 yrs. and 14-18 yrs (both male and female participants). The relationships among body weight, sodium, potassium and creatinine excretion were analysed using Z-scores as an index of body mass. Results: The 24h sodium and potassium excretion were higher in male than in female participants (respectively, 130±63 vs 119±56 mmol; p=0.001 and 39±18 vs 37±16 mmol; p=0.003). Upon stratification by puberal age and gender, 24h urinary sodium and potassium excretion were respectively 109±54 and 36±19 mol in category 1, 134±60 and 40±16 in category 2 and 152±69 and 43±17 in category 3 for male subjects (p&lt;0.01); 98±39 and 33±13 in category 1, 105±45 and 34±13 in category 2 and 137±63 and 40±18 mmol in category 3 for female individuals (p&lt;0.05). The expected gender difference in 24h urinary creatinine was observed in all age categories (p&lt;0.05). Male individuals had consistently greater sodium, potassium and creatinine excretion than female individuals (p between &lt;0.001 and &lt;0.05). Upon stratification of the study population in four body weight categories (BMI Z-score &lt;0, 0 to &lt;0,9, 1 to &lt;1,9 and ≥2), 24h sodium excretion was significantly greater in obese compared to normal weight children. 24h potassium excretion was also greater in obese children and adolescents compared with their normal weight counterparts (p=0.002). No significant difference was observed in either sodium or potassium excretion by geographical area. Conclusions: The MINISAL survey indicates a substantial age-, gender- and body mass-related variation with average values of sodium intake definitely high when related to true physiological needs or to the “adequate intakes” defined by the health institutions. By contrast, the habitual potassium intake was relatively low and such to indicate an inadequate fruit and vegetable consumption.