Blood pressure and urinary sodium and potassium excretion in cadmium-treated male rats

Subcutaneous injection of cadmium chloride (as CdCl2) in the backs of male Wistar rats at the four doses of 0.01, 0.1, 0.5, and 1.0 mg/kg body wt was performed twice a day for 7 consecutive days and the animals were maintained without any treatment for an additional period up to 60 days. Treatment with 0.1, 0.5, and 1.0 mg Cd markedly decreased the urinary Na and K excretion from Day 1 to Day 3. The significant increase in blood pressure of rats treated with 0.1 mg Cd was not present from Day 8 to Day 32 during which the water retention significantly increased. The blood pressure of rats treated with 1.0 mg Cd significantly increased although the increase in water and Na retention was not observed on Day 32. These observations suggest that the decrease in the urinary excretion of Na and the increase in water retention may be not associated with the main factor for the elevation of the blood pressure induced by Cd. Cd concentrations in the heart, abdominal aorta, and lung of rats treated with 1.0 mg Cd were markedly lower than those in the liver and kidney. Changes in the level of Ca and Mg were only observed in the lung and not in the heart and aorta.     

Associations between dietary intake and urinary excretion of sodium, potassium, phosphorus, magnesium, and calcium

OBJECTIVES AND METHODS: The associations between dietary intake and urinary excretion of sodium (Na), potassium (K), calcium (Ca), magnesium (Mg), and phosphorus (P), and the major dietary sources derived from the urinary minerals were studied in a nutritional survey of 219 Japanese females aged 27-84 years, who completed anthropometric measurements, a one-day dietary record, and a 24 hr urine collection. RESULTS: The minerals excreted in the urine were significantly and positively correlated with each other, in which Na excretion was correlated with K and Ca excretion (r = 0.490 and r = 0.482, respectively, p < 0.01) and Ca excretion was correlated with Mg excretion (r = 0.526, p < 0.01). The ratios of urinary exertion to dietary intake of Na, K, Ca, Mg, and P were 81.5%, 62.7%, 24.5%, 21.7%, and 56.1%, respectively. The dietary intake and the urinary excretion of the minerals expressed per body weight (kg) were significantly and positively correlated (Na, r = 0.267; K, r = 0.460; Ca, r = 0.181; Mg, r = 0.245; P, r = 0.351, p < 0.01). Further examinations using chief component analysis for food intake showed several significant positive correlations, including between Na intake and the intake of vegetables, noodles, and seasonings (r = 0.332-0.381, p < 0.01); between K, Mg and P intake and the intake of vegetables, fruits, and potatoes (r = 0.332-0.533, p < 0.01); and between Ca intake and the intake of bread and dairy foods (r = 0.428, p < 0.01). In addition, significant positive associations were found between Na excretion and the intake of confectionaries, nuts, and seeds (r = 0.223, p < 0.01). Weak correlations were also found between K excretion and the intake of vegetables (r = 0.296, p < 0.01); between Ca and P excretion and the intake of meat, oil, and fats (r = 0.135, P < 0.05; r = 0.193, P < 0.01, respectively), and between Mg excretion and the intake of bread and dairy foods (r = 0.137, P < 0.05). CONCLUSIONS: Findings from this study indicate that, while urinary excretion of Ca and Mg is unlikely to be a reliable biochemical marker of dietary intake, the levels of urinary excretion of Na, K, and P can be reflective of the intake of salt, vegetables, and meats, respectively. The urinary excretion of the minerals, particularly Na, K, and Ca, may be highly linked to salt intake in Japanese females.     

The effect of dietary caffeine on urinary excretion of calcium,magnesium, sodium and potassium in healthy young females

Twelve female college students drank decaffeinated coffee or tea to which 0, 150 or 300 mg caffeine had been added. Each subject had fasted at least ten hours before drinking each of the three test beverages. Urine samples were collected at one, two and three hours after caffeine consumption. Total urinary three hour excretion of calcium, magnesium and sodium, but not potassium, increased significantly after caffeine intake. The increased output of calcium and sodium was mainly due to significantly increased urinary calcium and sodium concentrations, while the increased output of magnesium appeared to be due to the combination of both a slightly increased urinary magnesium concentration and volume. Total urine volume correlated significantly with dose of caffeine per body weight when 300 mg of caffeine was consumed. The effects of caffeine on mineral excretion were primarily due to changes in mineral concentration and increased urinary volume at one and two hours.     

Dietary sodium, calcium, and potassium, and blood pressure

The cross-sectional association of systolic blood pressure with dietary sodium, calcium, and potassium, as estimated from dietary histories, was investigated by multiple regression analysis of data gathered in the Netherlands in the early 1950s in a general health examination of 2,291 middle-aged civil servants and spouses of civil servants. A statistically significant negative trend with systolic blood pressure was seen for calcium intake in both males and females, even after adjustments for covariates. For sodium and potassium intake, the observed negative trends were not significant after multivariate analyses. In addition, no consistent associations were found between diastolic blood pressure and the micronutrients after multivariate analyses, except for a significant negative association with calcium intake in females. In this study population, blood pressure was a strong independent risk factor of total mortality: 15- and 25-year mortality was about twice as high for hypertensives (greater than or equal to 160 mmHg) as for normotensives (less than 160 mmHg). These findings support the conclusion in recent epidemiologic studies that higher intakes of calcium are associated with lower systolic blood pressure, and they extend the evidence to an earlier time period.     

Association of dietary calcium,magnesium, sodium,and potassium intake and hypertension: a study on an 8-year dietary intake data from the National Health and Nutrition Examination Survey

BACKGROUND/OBJECTIVESThere has been an increased interest in determining calcium magnesium, sodium, and potassium''s distinct effects on hypertension over the past decade, yet they simultaneously regulate blood pressure. We aimed at examining the association of dietary calcium, magnesium, sodium, and potassium independently and jointly with hypertension using National Health and Nutrition Examination Survey data from 2007 to 2014.MATERIALS/METHODSThe associations were examined on a large cross-sectional study involving 16684 US adults aged>20 years, using multivariate analyses with logistical models.RESULTSSodium and calcium quartiles assessed alone were not associated with hypertension. Potassium was negatively associated with hypertension in the highest quartile, 0.64 (95% confidence interval [CI], 0.48–0.87). When jointly assessed using the high and low cut-off points, low sodium and corresponding high calcium, magnesium, and potassium intake somewhat reduced the odds of hypertension 0.39 (95% CI, 0.20–0.76). The sodium-to-potassium ratio was positively associated with hypertension in the highest quartile1.50 (95% CI, 1.11–2.02). When potassium was adjusted for sodium intake and sodium-to-potassium ratio assessed among women, increased odds of hypertension were reported in the highest quartile as 2.02 (95% CI, 1.18–3.34) and 1.69 (95% CI, 1.12–2.57), respectively. The association of combined minerals on hypertension using dietary goals established that men meeting the reference intakes for calcium and exceeding for magnesium had reduced odds of hypertension 0.51 (95% CI, 0.30–0.89). Women exceeding the recommendations for both calcium and magnesium had the lower reduced odds of 0.30 (95% CI, 0.10–0.69).CONCLUSIONSOur results suggest that the studied minerals'' association on hypertension is stronger when jointly assessed, mostly after gender stratification. As compared to men, women increased their risk of hypertension even with a low sodium intake. Women would also reasonably reduce their risk of developing hypertension by increasing calcium and magnesium intake. In comparison, men would somewhat be protected from developing hypertension with calcium intake meeting the dietary goals and magnesium exceeding the nutritional goals.     

The effect of dietary caffeine on urinary excretion of calcium,magnesium, phosphorus,sodium, potassium,chloride and zinc in healthy males

Fifteen males drank decaffeinated coffee to which 0, 150 or 300 mg caffeine had been added. Each subject had fasted at least ten hours before drinking each of the three test beverages. Urine samples were collected at one, two and three hours after caffeine consumption. Total urinary three hour excretion of calcium, magnesium, sodium and chloride increased significantly after caffeine intake, while zinc, phosphorus, potassium, creatinine and volume were unchanged. The increased outputs were due to increased urinary mineral concentrations.     

Diet and blood pressure in South Africa: Intake of foods containing sodium, potassium, calcium, and magnesium in three ethnic groups

OBJECTIVES: We investigated whether habitual intakes of sodium (Na), potassium, magnesium, and calcium differ across South African ethnic groups, assessed the proportion of Na intake, which is discretionary, and identified which food sources were the major contributors to Na intake. METHODS: This was a cross-sectional study of 325 black, white, and mixed ancestry hypertensive and normotensive subjects. Three repeated 24-h urine samples were collected for assessment of urinary Na, and three corresponding 24-h dietary recalls were administered by trained fieldworkers. Blood pressure and weight were measured at each visit. Secondary analyses were performed on existing dietary databases obtained from four regional surveys undertaken in South African adults. RESULTS: Mean urinary Na excretion values equated to daily salt (NaCl) intakes of 7.8, 8.5, and 9.5 g in black, mixed ancestry, and white subjects, respectively (P < 0.05). Between 33% and 46% of total Na intake was discretionary, and, of the non-discretionary sources, bread was the single greatest contributor to Na intake in all groups. Ethnic differences in calcium intake were evident, with black subjects having particularly low intakes. Urban versus rural differences existed with respect to sources of dietary Na, with greater than 70% of total non-discretionary Na being provided by bread and cereals in rural black South Africans compared with 49% to 54% in urban dwellers. CONCLUSION: White South Africans have higher habitual intakes of Na, but also higher calcium intakes, than their black and mixed ancestry counterparts. All ethnic groups had Na intakes in excess of 6 g/d of salt, whereas potassium intakes in all groups were below the recommended level of 90 mM/d. Dietary differences may contribute to ethnically related differences in blood pressure.     

The effect of dietary sodium on urinary calcium and potassium excretion in normotensive men with different calcium intakes

On the basis of their usual calcium intake, 12 healthy normotensive male students were divided into a low and a high calcium group. Both groups were provided with complete diets containing the same calculated quantities, expressed per MJ, of protein, fat, carbohydrate, sodium, potassium, phosphorus, and calcium. After an initial period of two weeks during which all participants received an additional 100 mmol sodium daily, 6 participants received an additional 22 mmol sodium/day (low sodium), the other 6 participants 178 mmol sodium/day (high sodium). After two weeks the sodium regimes were crossed over for a subsequent two-week period. When the second week of the low sodium period is compared with the second week of the high sodium period, the increase in the calcium/creatinine ratio, expressed on molar basis, was 0.059 for the low and 0.053 for the high calcium group (p less than 0.05). The increase in the molar potassium/creatinine ratio was 0.65 for the low and 0.03 for the high calcium group (p less than 0.025). However, after correcting for the calcium intake the effect in the low calcium group was found to be greater (p less than 0.05). Sodium supplementation was found to have no effect on blood pressure, but mean systolic (p less than 0.10) and diastolic in the high calcium group were lower. This suggests that calcium may well play a role in the regulation of blood pressure.     

Relationship of urinary sodium/potassium excretion and calcium intake to blood pressure and prevalence of hypertension among older Chinese vegetarians

OBJECTIVE: To examine the associations of dietary sodium and potassium, as reflected by the urinary sodium/potassium excretion, and calcium intake with blood pressure and the prevalence of hypertension among older Chinese vegetarians in Hong Kong. DESIGN: Cross-sectional study. SETTING: Research clinic in a teaching hospital in Hong Kong. SUBJECTS: A total of 111 ambulatory vegetarians over the age of 55 were recruited from members of religious organizations or old age hostels. MAIN OUTCOME MEASURES: Hypertension was defined as supine blood pressure >140/90 mmHg or a history of hypertension. Dietary sodium, potassium and calcium intakes were assessed by 24 h recall method or fasting urinary sodium or potassium/creatinine ratios. RESULTS: Seventy-one subjects (64%) were found to have hypertension. Compared with normotensive subjects, hypertensive subjects had lower calcium intake (411+/-s.d. 324 vs 589+/-428 mg, P=0.04), but higher urinary sodium/creatinine ratio (32.6+/-19.3 vs 21.0+/-12.4, P=0.00) and sodium/potassium ratio (4.7+/-2.8 vs 3.4+/-2.3, P=0.02). Among 88 subjects not taking diuretics or antihypertensive drugs, systolic blood pressure was related to calcium intake (r=-0.40), urinary sodium/creatinine ratio (r=0.39), urinary sodium/potassium ratio (r=0.30) and age (r=0.23). Diastolic blood pressure was related to urinary sodium/creatinine (r=0.29). Twenty-three subjects with high urinary sodium/potassium and low calcium intake and 16 subjects with low urinary sodium/potassium ratio and high calcium intake differed markedly with respect to systolic blood pressure (159+/-26 vs 130+/-15 mmHg) and prevalence of hypertension (78% vs 25%). CONCLUSIONS: Older Chinese vegetarians are predisposed to hypertension because of their sodium-rich but calcium-deficient diets.     

Personal, social and environmental correlates of vegetable intake in normal weight and overweight 9 to 13-year old boys

Background  

The first aim of the present study was to investigate differences in correlates of vegetable intake between the normal weight and the overweight boys in the Pro Children Cross Sectional Study. The second aim was to explore whether the association between vegetable intake and potential correlates is different in overweight boys compared with normal weight boys.     

Influence of calcium, magnesium, sodium, potassium and pH on copper toxicity to barley (Hordeum vulgare)

The extent to which Ca(2+), Mg(2+), Na(+), K(+) ions and pH independently influence copper toxicity to barley (Hordeum vulgare) was assessed by measuring root growth in nutrient solutions. Increased Ca(2+) activity resulted in a sixfold decrease in [EC50(cu2+)] values, while a positive relationship between the cation activity and the EC50 was expected. Increased Mg(2+) activity resulted in a twofold increase in [EC50(cu2+)] values. Na(+), K(+) and H(+) activities did not significantly affect Cu(2+) toxicity. The obtained results indicated that competition for binding sites between Cu(2+) and cations such as Ca(2+), Mg(2+), Na(+), K(+) and H(+) is not an important factor in determining Cu(2+) toxicity to H. vulgare. However, the EC50s could, with one exception, be predicted within a factor three based on the free Cu(2+) activity, indicating that the free Cu(2+) activity cannot only be used to predict metal toxicity to aquatic, but also to terrestrial organisms.     

Calcium,magnesium, sodium and potassium levels in foodstuffs from the second French Total Diet Study

Calcium (Ca), magnesium (Mg), sodium (Na) and potassium (K) contents in 1319 foodstuffs habitually consumed by the French population were determined for the second French Total Diet Study (TDS), using micro-sampling flame atomic absorption spectrometry after microwave-assisted digestion. Concentration and distribution of these minerals in food samples were reported and compared with results from the previous French TDS. For Ca, the results indicate that the food presenting the highest levels are dairy products (1597 mg kg^?1), tofu (802 mg kg^?1) and some fish and cereal products; for Mg, tofu (1340 mg kg^?1), “Sweeteners, honey and confectionery” (672 mg kg^?1) especially dark chocolate (2225 mg kg^?1) and certain grains such as nuts and oilseeds (1069 mg kg^?1) and some cereal products; for Na, processed meats such as delicatessen (12,422 mg kg^?1), “Salts, spices, soup and sauces” (21,028 mg kg^?1), some cheeses and cereal products; and for K, “Cereal and cereal products” (4378 mg kg^?1), “Meats and offal” (3993 mg kg^?1), “Nuts and oilseeds” (7355 mg kg^?1) and “Sweeteners, honey and confectionery” (3445 mg kg^?1) (especially chocolate).     

Serum zinc and copper in relation to diet in 3- to 18-year old Finnish girls and boys

Serum zinc (S-Zn) and copper (S-Cu) concentrations were measured and compared with data on dietary intakes of energy, protein, fat, carbohydrate, zinc, copper, phosphorus, calcium, iron, sucrose, vitamin C and dietary fibre, collected by means of the 48-h recall method in 1634 3-, 6-, 9-, 12-, 15- and 18-year old girls and boys. The intake of fibre was inversely related to S-Cu but not to S-Zn. None of the dietary components measured seemed to have a distinct negative effect on S-Zn, indicating that such factors were present at levels too low to affect S-Zn, or associated with factors favouring Zn bioavailability. Factors decreasing the bioavailability of Zn or Cu may especially affect adolescent girls whose average intakes of both Zn and Cu were low.     

The effects of potassium, magnesium, calcium, and fiber on risk of stroke

Stroke mortality represents the third leading cause of death worldwide, after coronary artery disease and cancer. High blood pressure is a major risk factor for stroke. A recent study has identified potassium, magnesium, and fiber as significant modulators of stroke risk in men. The protective effects were particularly pronounced in hypertensive subjects. The observed protection may be due to direct and indirect effects of these nutrients on blood pressure and regulatory functions, such as endothelial function. A high intake of these nutrients, singularly or in combination, is associated with a more healthful overall lifestyle. The best strategy to achieve a high intake of these nutrients is a diet rich in fruits and vegetables.     

Relation of urinary calcium and magnesium excretion to blood pressure: The International Study Of Macro- And Micro-nutrients And Blood Pressure and The International Cooperative Study On Salt, Other Factors, And Blood Pressure

Data indicate an inverse association between dietary calcium and magnesium intakes and blood pressure (BP); however, much less is known about associations between urinary calcium and magnesium excretion and BP in general populations. The authors assessed the relation of BP to 24-hour excretion of calcium and magnesium in 2 cross-sectional studies. The International Study of Macro- and Micro-Nutrients and Blood Pressure (INTERMAP) comprised 4,679 persons aged 40-59 years from 17 population samples in China, Japan, the United Kingdom, and the United States, and the International Cooperative Study on Salt, Other Factors, and Blood Pressure (INTERSALT) comprised 10,067 persons aged 20-59 years from 52 samples around the world. Timed 24-hour urine collections, BP measurements, and nutrient data from four 24-hour dietary recalls (INTERMAP) were collected. In multiple linear regression analyses, urinary calcium excretion was directly associated with BP. After adjustment for multiple confounders (including weight, height, alcohol intake, calcium intake, urinary sodium level, and urinary potassium intake), systolic BP was 1.9 mm Hg higher per each 4.1 mmol per 24 hours (2 standard deviations) of higher urinary calcium excretion (associations were smaller for diastolic BP) in INTERMAP. Qualitatively similar associations were observed in INTERSALT analyses. Associations between magnesium excretion and BP were small and nonsignificant for most of the models examined. The present data suggest that altered calcium homoeostasis, as exhibited by increased calcium excretion, is associated with higher BP levels.