Nutrition and blood pressure among elderly men and women (Dutch Nutrition Surveillance System)

Associations between blood pressure and nutrition-related variables (body mass index, dietary intake, and 24-hr excretion of sodium, potassium, magnesium, and calcium in the urine) were investigated in men (n = 138) and women (n = 117) 65-79 years old not using drugs known to affect blood pressure and not on a diet. Among men, body mass index was positively and creatinine clearance was inversely associated with systolic blood pressure, whereas body mass index and urinary sodium:potassium ratio were positively associated with diastolic blood pressure. Among women, both age and urinary calcium:creatinine ratio were positively associated with systolic as well as diastolic blood pressure. Coffee consumption was positively correlated with blood pressure and urinary calcium:creatinine ratio among the women. From the results it appears that, besides "normal" weight, increased potassium intake and urinary excretion may exert a protective effect among elderly men against hypertension when sodium exposure is relatively high. The positive association between urinary calcium:creatinine ratio and blood pressure among the women may be partly due to coffee consumption.     

Urinary sodium and blood pressure in vegetarians

Urinary sodium, potassium urea, creatinine, uric acid, plasma urea, creatinine, cholesterol, blood pressures, height, weight, and skinfold thickness were measured in some or all of 106 matched pairs of vegetarians (mainly Seventh-Day Adventists) and nonvegetarians. Mean blood pressures were lower in vegetarians (141.9/88.9 mm) than nonvegeterians (148.0/90.9 mm) but the urinary excretion of sodium was higher, although not significantly, in the vegetarians (mean of 169.7 compared with 161.2 mmole/day). The vegetarians also had a higher urinary potassium excretion (62.9 mmole/day) than the nonvegetarians (54.8 mmole/day) thus giving them a lower mean sodium to potassium ratio (3.0 compared with 3.3). Both systolic and diastolic blood pressures correlated positively with plasma cholesterol levels which were less in vegetarians (6.0 mmole/liter) than nonvegetarians (6.6 mmole/liter). They also correlated positively with the urinary sodium to potassium ratio, but only in nonvegetarians. It was concluded that dietary sodium does not explain the blood pressure differences between vegetarians and nonvegetarians.     

Does dietary recall adequately assess sodium, potassium, and calcium intake in hypertensive patients?

OBJECTIVE: A diet low in sodium, high in potassium, and high in calcium is recommended to lower blood pressure. However, compliance with this diet is poor, probably because of dietary intake underestimation. Therefore, we compared electrolyte intake as estimated from dietary recall with a 24-h urinary excretion. METHODS: Thirty-six patients (26 men and 10 women) with a mean age of 46 +/- 8 y participated in the study. All participants had essential hypertension and were on no drug therapy (n = 20) or non-diuretic monotherapy (n = 16). Patients were instructed to consume a low-sodium (50 mmol/d), high-potassium (supplementation with 30 to 60 mmol/d), and high-calcium (1000 mg/d) diet. Compliance with the diet was assessed at baseline and then 1, 2, and 3 mo after starting the diet. Sodium, potassium, and calcium intakes were carefully estimated from patients' dietary recall and 24-h urinary collection. RESULTS: Estimated sodium intake significantly correlated with 24-h urinary excretion (R = 0.43 P < 0.001). However, estimated sodium intake was lower than urinary sodium excretion by 34% at baseline and by 47% after 3 mo of dieting (P < 0.05). Estimated potassium intake correlated with 24-h urinary excretion. Estimated calcium intake significantly increased from 933 +/- 83 mg/d to 1029 +/- 171 mg/d (P < 0.05). Calcium intake derived from patients' recall far exceeded and only slightly correlated with 24-h urinary excretion (R = 0.23, P < 0.01). CONCLUSIONS: Patients tend to underestimate their sodium intake by 30% to 50%; therefore, urinary sodium excretion is more accurate to assess sodium intake. Thus, 24-h urinary sodium excretion should be used in clinical practice and in clinical trials, especially when dietary non-compliance is suspected.     

补充钾和钙对血压偏高青年动脉血压及钠代谢影响的长期观察

目的　观察在食盐中添加钾和钙降低血压偏高青年动脉血压的作用及其对钠代谢的影响。方法　选取年龄 18～ 2 2岁的 2 2 0名血压偏高青年 ,采用随机、单盲、对照的方法分为补充钾钙组110名 (男 5 8名 ,女 5 2名 ) ,对照组 110名 (男 5 6名 ,女 5 4名 ) ,进行为期 2年的补钾补钙干预对照试验。干预组及其共同生活的家庭成员每人每天补充钾和钙各 10mmol,与食盐混合在一起。结果　经2年期试验 ,补钾补钙组夜 12h尿中K+含量为 ( 4 8± 2 3 )mmol,尿Na+含量为 ( 6 2 4± 2 8 2 )mmol;对照组尿K+含量为 ( 7 8± 3 6 )mmol,尿Na+含量为 ( 71 8± 2 7 5 )mmol,两者比较 ,差异有显著意义。补钾补钙组血压较基线平均下降了 5 3/ 1 8mmHg ,对照组血压较基线上升了 1 3 / 1 7mmHg,二者比较收缩压相差 6 6mmHg ,舒张压相差 3 5mmHg。结论　在家庭日常食盐中适量添加钾和钙 ,可促进钠盐的排泄 ,降低血压偏高青年的动脉血压 ,是有效预防青年高血压的重要途径。     

Blood pressure and urinary sodium in men and women: the Norfolk Cohort of the European Prospective Investigation into Cancer (EPIC-Norfolk)

BACKGROUND: Abundant evidence indicates that a high sodium intake is causally related to high blood pressure, but debate over recommendations to reduce dietary sodium in the general population continues. A key issue is whether differences in usual sodium intake within the range feasible in free-living populations have clinical or public health relevance. OBJECTIVE: We examined the relation between blood pressure and urinary sodium as a marker of dietary intake. DESIGN: This was a study of 23104 community-living adults aged 45-79 y. RESULTS: Mean systolic and diastolic blood pressure increased as the ratio of urinary sodium to creatinine increased (as estimated from a casual urine sample), with differences of 7.2 mm Hg for systolic blood pressure and 3.0 mm Hg for diastolic blood pressure (P < 0.0001) between the top and bottom quintiles. This trend was independent of age, body mass index, urinary potassium:creatinine, and smoking and was consistent by sex and history of hypertension. The prevalence of those with systolic blood pressure >/= 160 mm Hg halved from 12% in the top quintile to 6% in the bottom quintile; the odds ratio for having systolic blood pressure >/= 160 mm Hg was 2.48 (95% CI: 1.90, 3.22) for men and 2.67 (95% CI: 2.08, 3.43) for women in the top compared with the bottom quintile of urinary sodium. Estimated mean sodium intakes in the lowest and highest quintiles were approximately 80 and 220 mmol/d, respectively. CONCLUSIONS: Within the usual range found in a free-living population, differences in urinary sodium, an indicator of dietary sodium intake, are associated with blood pressure differences of clinical and public health relevance. Our findings reinforce recommendations to lower average sodium intakes in the general population.     

24小时尿钠、钾、钙、镁、肌酐与血压之间的初步探讨

对我国北京、福州两地区共2008名正常人进行了血压普查并测定了24小时尿钠、钾、钙、镁和肌酐排泄量,探讨了上述阳离子与血压的关系。北京地区血压及尿钠排泄量高于福州地区。除少数例外,结果显示血压与尿钠、镁排泄量呈正相关而与尿钾、钙排泄量呈负相关;与钠/钾比值呈正相关而与钙/镁比值呈负相关。进一步证实我国人群血压随钠摄入量上升而增高。     

Relationship between diet and blood pressure in a representative Mediterranean population

Summary. Background: Hypertension is strongly associated with cardiovascular and renal disease. However, despite the efforts made to control hypertension via drug treatment, prevalence of controlled hypertension could be considered low. Aim of the study: We performed the present study to investigate dietary habits among groups with different blood pressure status (normotensive, non-medicated hypertensive, medicated hypertensive) and to analyze the association between blood pressure and intakes of selected nutrients in normotensive and non-medicated hypertensive subjects (n = 1357), and furthermore in those undergoing hypertension drug treatment (n = 210; controlled and non-controlled). Methods: The present cross-sectional, population-based survey (Gerona, Spain) included cardiovascular risk measurements and analysis of dietary intake with corresponding questionnaires. Results: Nutrient intake was similar among groups of different blood pressure status after adjusting for sex, age and energy consumption. Multiple linear regression analysis, after adjustment for several confounders, showed that dietary intake of sodium was directly related to blood pressure. The same was seen for the sodium to potassium ratio and both were independent of hypertension drug treatment. In contrast, an inverse association was observed between blood pressure and dietary calcium intake. Moderate sodium (< 2400 mg Na/d) intake reduced the risk of hypertension by 30 % and 52 % (Odds ratio 0.70; 95 % CI 0.52–0.94, respectively) in normotensive and non-medicated hypertensive subjects. Furthermore, moderate sodium in combination with a calcium intake of more than 800 mg/d reduced the risk of inadequate blood pressure control, by 52 % (Odds ratio 0.48; 95 % CI 0.24–0.95) in subjects undergoing hypertension drug treatment. Controlled hypertension subjects have a significantly higher calcium intake than non-controlled. Conclusion: These results emphasize the importance of diet and overall of sodium intake as non-pharmacological approach in the prevention and treatment of hypertension. Received: 19 November 2001, Accepted: 20 June 2002     

Renal and gastrointestinal potassium excretion in humans: new insight based on new data and review and analysis of published studies

OBJECTIVES: Little is known about the relationship between the renal and gastrointestinal excretion of potassium in humans. This information is important in light of strong associations of potassium intake with hypertension and occlusive stroke. METHODS: We determined the relationship between fecal and urinary excretion of potassium under both fixed and variable potassium intakes using our unpublished archival data and published data of others. Twenty-five subjects were evaluated. RESULTS: On a fixed, low oral potassium intake (61.2 +/- 4.7 mmol/day; mean +/- SD), there was an inverse relationship between fecal and urinary potassium excretion (r = -0.66, p = 0.040). In studies in which potassium intake varied between 61-135 mmol/day, fecal and urinary potassium excretions were positively correlated (r = 0.58, p = 0.024). Considerable within-and-between-subject variation was observed in the relationship between fecal and urinary potassium excretion. CONCLUSIONS: Inter-individual variation in fecal potassium excretion may arise from both variation in dietary potassium intake and intrinsic individual differences in the renal versus gastrointestinal handling of potassium.     

Sodium and potassium intake and risk of cardiovascular events and all-cause mortality: the Rotterdam Study

Background Dietary electrolytes influence blood pressure, but their effect on clinical outcomes remains to be established. We examined sodium and potassium intake in relation to cardiovascular disease (CVD) and mortality in an unselected older population. Methods A case–cohort analysis was performed in the Rotterdam Study among subjects aged 55 years and over, who were followed for 5 years. Baseline urinary samples were analyzed for sodium and potassium in 795 subjects who died, 206 with an incident myocardial infarction and 181 subjects with an incident stroke, and in 1,448 randomly selected subjects. For potassium, dietary data were additionally obtained by food-frequency questionnaire for 78% of the cohort. Results There was no consistent association of urinary sodium, potassium, or sodium/potassium ratio with CVD and all-cause mortality over the range of intakes observed in this population. Dietary potassium estimated by food frequency questionnaire, however, was associated with a lower risk of all-cause mortality in subjects initially free of CVD and hypertension (RR = 0.71 per standard deviation increase; 95% confidence interval: 0.51–1.00). We observed a significant positive association between urinary sodium/potassium ratio and all-cause mortality, but only in overweight subjects who were initially free of CVD and hypertension (RR = 1.19 (1.02–1.39) per unit). Conclusion The effect of sodium and potassium intake on CVD morbidity and mortality in Western societies remains to be established.     

Effects of volume expansion and contraction on potassium homeostasis in normal and hypertensive humans

To investigate the role of potassium on blood pressure we measured serum potassium, urinary excretion of potassium and sodium, fractional excretion of potassium, urinary sodium:potassium ratio, plasma renin activity, aldosterone, and norepinephrine during dynamic maneuvers in normotensive and hypertensive subjects. After baseline measurements, we expanded intravascular volume with infusion of intravenous saline and then induced sodium and volume depletion by diuretic administration during a low sodium salt diet. These studies were performed in 431 normotensive and 478 hypertensive subjects enabling evaluation of the effects of age, race, and sex, as well as blood pressure, on the results. Among normotensives, we found that white subjects had significantly P less than 0.05) higher levels of serum and urine potassium, fractional potassium excretion and lower urinary sodium:potassium ratios than black subjects and that males had the same patterns of differences compared to females. Similar, but less consistent racial differences were seen among the hypertensive subjects. We also observed significant (P less than .05) correlations between urinary potassium excretion and body weight in both normal and hypertensive groups. In normal subjects, a significant correlation was observed between the urinary sodium:potassium ratio and blood pressure that was not seen in the hypertensives. The latter, however, displayed a significant (P less than .05) inverse relationship between serum potassium and blood pressure. Multiple regression analysis revealed that urinary potassium excretion was influenced by age, race, sex, body weight, blood pressure, creatinine clearance, renin, and aldosterone. These observations reveal important relationships between potassium homeostasis and blood pressure control that deserve further study.     

Water sodium, urinary electrolytes, and blood pressure of adolescents.

Blood pressure measurements were made on children in their fourth year at secondary schools in parts of Scunthorpe Health District supplied with drinking water of varying sodium content. Of the 3131 children, 2740 were examined (1394 boys and 1346 girls). Boys had slightly higher systolic pressures and slightly lower diastolic pressures than the girls. There was no difference between the blood pressure distributions of children in areas supplied with water containing 105 mg/l sodium, 50 mg/l sodium, or less than 15 mg/l sodium. Small differences were found in the weights of children in these areas, and slightly more of the children in the area supplied with water containing more than 105 mg/l sodium had relatives who had been treated for hypertension. Standardisation for these factors did not show any relation between water salinity and either systolic or diastolic blood pressure. Studies of the urinary sodium, potassium, and the ratios of these to creatinine on a sample of 769 boys showed no correlation with assessments of usual sodium intake, but urinary sodium correlated well with salt and fluid intake at the meal immediately preceding examination. The relation between median blood pressure and urinary sodium concentration and lack of a clear relation with sodium creatinine ratio supports the hypothesis that it may be the ratio of salt to fluid intake rather than total dietary sodium that is relevant to the regulation of blood pressure.     

Decreasing dietary sodium while following a self-selected potassium-rich diet reduces blood pressure

Reducing dietary sodium reduces blood pressure (BP), a major risk factor for cardiovascular disease, but few studies have specifically examined the effect on BP of altering dietary sodium in the context of a high potassium diet. This randomized, crossover study compared BP values in volunteer subjects self-selecting food intake and consuming low levels of sodium (Na+; 50 mmol/d) with those consuming high levels of sodium (> or =120 mmol/d), in the context of a diet rich in potassium (K+). Sodium supplementation (NaSp) produced the difference in Na+ intake. Subjects (n = 108; 64 women, 44 men; 16 on antihypertensive therapy) had a mean age of 47.0 +/- 10.1 y. Subjects were given dietary advice to achieve a low sodium (LS) diet with high potassium intake (50 mmol Na+/d, >80 mmol K+/d) and were allocated to NaSp (120 mmol Na+/d) or placebo treatment for 4 wk before crossover. The LS diet decreased urinary Na+ from baseline, 138.7 +/- 5.3 mmol/d to 57.8 +/- 3.8 mmol/d (P < 0.001). The NaSp treatment returned urinary Na+ to baseline levels 142.4 +/- 3.7 mmol/d. Urinary K+ increased from baseline, 78.6 +/- 2.3 to 86.6 +/- 2.1 mmol/d with the LS diet and to 87.1 +/- 2.1 mmol/d with NaSp treatment (P < 0.001). The LS diet reduced home systolic blood pressure (SBP) by 2.5 +/- 0.8 mm Hg (P = 0.004), compared with the NaSp treatment. Hence, reducing Na+ intake from 140 to 60 mmol/d significantly decreased home SBP in subjects dwelling in a community setting who consumed a self-selected K+-rich diet, and this dietary modification could assist in lowering blood pressure in the general population.     

Salt and blood pressure in Belgium.

Blood pressure, pulse rate, body weight, and height were measured on two occasions in the inhabitants of a random 10% sample of households in a Belgian village. Twenty-four-hour urinary excretion of creatinine, sodium, and potassium was also determined. In subjects over the age of 19 there was a significant correlation for both systolic and diastolic pressure with age and body weight and, in women, also with pulse rate. After adjusting for these three variables, the systolic blood pressure in men was negatively correlated with the daily urinary potassium excretion, and the diastolic blood pressure in women negatively with the urinary sodium: creatinine ratio. The present data, obtained within one society, do not support a role for dietary sodium in the distribution of blood pressure within this population. Comparison of the present results with data from other countries does not refute the salt-genetic hypothesis but suggests also that a high potassium intake may lower blood pressure.     

Effect of increased dietary calcium on the development of reduced renal mass saline hypertension in rats

A diet fortified with calcium carbonate has been reported to reduce blood pressure in low-renin and salt-sensitive hypertensive patients. We have therefore examined the effect of increased dietary calcium on the development of reduced renal mass-saline hypertension in rats, a classical, low-renin, volume, and sodium-dependent model of hypertension. Rats with 70-75% reduction in renal mass were divided into experimental and control groups. The experimental rats were fed a sodium-free diet supplemented with calcium carbonate (2.0% calcium) and drank 1% saline for 5 weeks. Control rats consumed the salt-free diet and drank 1% saline for the same period. In control rats, as previously observed, blood pressure progressive increased from a control value of 120.0 +/- 1.2 to 174.2 +/- 1.2 mm Hg by the fifth week. In contrast, in the calcium-supplemented rats the development of hypertension was significantly attenuated; the blood pressure only increased from 117.0 +/- 1.2 to 134.0 +/- 3.8 mm Hg by the fifth week. This was associated with a 30% decrease in saline intake by the fifth week, with proportionate decreases in urine volume and sodium excretion but not potassium excretion. Urinary magnesium excretion increased. No such changes were seen in control rats. At the end of the treatment period, plasma levels of sodium, potassium, calcium, creatinine, BUN, and protein were not different, but plasma chloride and magnesium were lower in experimental rats; vascular smooth muscle cell membrane potentials were also not different. These data show that dietary calcium carbonate can attenuate the development of reduced renal mass-saline hypertension in the rat, possibly in part by altering sodium and water intake.     

Changes in 24-hour urinary excretion of sodium and potassium in a community-based heath education program on salt reduction

PURPOSE: To examine changes in urinary excretion of sodium, potassium and sodium/potassium ratio in a community-based health education program on salt reduction. SUBJECTS AND METHODS: The surveyed community was Kyowa town (census population in 1985 = 16,792) where we have conducted a community-based blood pressure control program since 1981 and health education on reduction of salt intake since 1983 for primary prevention of hypertension. A 24-hour urine collection was conducted for systematically selected samples of the participants aged 40-69 in cardiovascular risk surveys in 1982-86 (early period) and in 1990-94 (later period) to estimate changes in urine excretion of sodium, potassium, and sodium/potassium ratio. RESULTS: A 24-hour urine collection was available for 565 persons (410 men and 155 women) in 1982-86 and 1,461 persons (571 men and 890 women) in 1990-94. A decline in mean sodium excretion was larger in ages 40-49 than in other age groups, and for ages 40-69 combined, the decline was 0.9-1.1 g per day for men and women. Mean sodium excretion declined to 10 g or less per day for men and women aged 60-69. Mean potassium excretion did not change except for men aged 60-69 with an increase in potassium. Sodium/potassium ratio tended to decline for women aged 40-49, and declined significantly for other sex-age groups. A larger reduction in sodium excretion was seen among persons with a history of hypertension compared to those without it. CONCLUSIONS: A significant reduction in urinary excretion of sodium and sodium/potassium ratio was observed in a community-based health education program. Men and women aged 60-69 reached a recommended level of 10 g or less in sodium intake.     

A 7-week reduction in salt intake does not contribute to markers of bone metabolism in young healthy subjects

BACKGROUND: Sodium intake increases urinary calcium excretion and may thus lead to negative calcium balance and bone loss. OBJECTIVE: We hypothesised that reducing sodium intake would reduce urinary calcium excretion and have a beneficial influence in bone metabolism. DESIGN: A total of 29 subjects, 14 males and 15 females, were divided into two study groups. One group (low-sodium group (LS)) reduced sodium intake for 7 weeks by substituting low-salt alternatives for the most important dietary sources of sodium. The other group, serving as a control group (C), was given the same food items in the form of normally salted alternatives. Fasting serum samples as well as 24-h urine samples were obtained in the beginning and at the end of the study. Urinary sodium, urinary calcium, urinary creatinine, serum calcium, serum phosphate, serum creatinine, serum parathyroid hormone (s-PTH), serum C-terminal telopeptides of Type-I collagen and serum bone alkaline phosphatase (s-B-ALP) were analysed. RESULTS: The LS group showed a significant decline (P = 0.001) in urinary sodium/creatinine ratio without a significant effect on urinary calcium/creatinine ratio. In the LS group, s-PTH increased (P = 0.03). The C group showed an increase in s-PTH (P = 0.05) and in s-B-ALP, but no differences were observed between the study groups in the changes of serum markers of calcium and bone metabolism. CONCLUSIONS: We have shown that reducing the sodium intake of young, healthy people with adequate calcium intake over a 7-week period does not affect the markers of bone metabolism.     

南京市18岁及以上人群膳食钠与钾摄入状况及其与血压的相关性分析

目的 分析南京市城乡居民膳食钠和钾摄入状况及其与血压的相关性。 方法 以多阶段整群随机抽样的方法抽取6个城区1 062户(城市762户,农村300户)18岁及以上居民2 272人,使用连续3 d 24 h膳食回顾法和调味品称重法相结合的方法获得个人膳食钠和钾的摄入量同时进行医学体检获得血压,使用spearman等级相关和多因素logistic回归分析两者的关系。 结果 南京居民每标准人日钠和钾摄入中位数(第25百分位数~75百分位数)分别为4 543.6(3 226.7~6 362.7)mg和1 585.4(1 276.3~2 025.8)mg。实际每日摄入钠3 945.6(2 833.9~5 614.1)mg,钾1 366.6(1 119.2~1 729.1)mg;95.4%的居民膳食钠摄入量超过适宜摄入量(adequate intake,AI),85.3%的居民膳食钾摄入量低于AI值。钠的主要来源是调味品,烹调盐占69.9%,酱油占9.5%;钾主要来源为谷类(21.7%)、蔬菜(32.1%)及肉类(14.3%)。钠钾比值中位数为2.9,其与收缩压和舒张压呈正的等级相关(r_s=0.049,P=0.028;r_s=0.045,P=0.043)。调整人群基本信息、总能量及体质指数,钠钾比第三等份(3.0~4.3)是高血压的危险因素(OR=1.409,95%CI:1.058~1.875,P=0.019)。 结论 南京市居民膳食钠钾严重失衡,属于高钠低钾饮食。膳食中高的钠钾比值是高血压的危险因素。应加强健康教育,提倡低钠高钾膳食。     

Low dietary potassium intakes and high dietary estimates of net endogenous acid production are associated with low bone mineral density in premenopausal women and increased markers of bone resorption in postmenopausal women

BACKGROUND: The Western diet may be a risk factor for osteoporosis. Excess acid generated from high protein intakes increases calcium excretion and bone resorption. Fruit and vegetable intake could balance this excess acidity by providing alkaline salts of potassium. Algorithms based on dietary intakes of key nutrients can be used to approximate net endogenous acid production (NEAP) and to explore the association between dietary acidity and bone health. OBJECTIVE: We investigated the relation between dietary potassium and protein, NEAP (with an algorithm including the ratio of protein to potassium intake), and potential renal acid load (with an algorithm including dietary protein, phosphorous, potassium, magnesium, and calcium) and markers of bone health. DESIGN: Measurements of bone mineral density (BMD) (n = 3226) and urinary bone resorption markers (n = 2929) at the lumbar spine and femoral neck were performed in perimenopausal and early postmenopausal women aged 54.9 +/- 2.2 y (x +/- SD) in 1997-1999. BMD (g/cm(2)), free pyridinoline (fPYD), and free deoxypyridinoline (fDPD) were expressed relative to creatinine. Dietary intake was assessed with a food-frequency questionnaire. RESULTS: Comparison of the highest with the lowest quartile of potassium intake or the lowest with the highest NEAP showed a 6-8% increase in fPYD/creatinine and fDPD/creatinine. A difference of 8% in BMD was observed between the highest and lowest quartiles of potassium intake in the premenopausal group (n = 337). CONCLUSIONS: Dietary potassium, an indicator of NEAP and fruit and vegetable intake, may exert a modest influence on markers of bone health, which over a lifetime may contribute to a decreased risk of osteoporosis.     

Effects of dietary calcium from dairy products on ambulatory blood pressure in hypertensive men.

The effect of consumption of 400 mg vs 1,500 mg of dietary calcium per day was examined in 13 male volunteers who had been diagnosed as hypertensive. Dietary calcium consumption was varied by manipulation of the intake of dairy products over 4-week periods. Caffeine intake (mean = 500 mg/day) was monitored. Neither laboratory blood pressure measured by standard sphygmomanometry nor ambulatory blood pressure monitored by automated sphygmomanometry varied significantly among men consuming baseline, low-calcium, or high-calcium diets (laboratory blood pressure = 136/83, 133/83, and 137/84 mm Hg, respectively; ambulatory blood pressure = 136/86, 138/87, and 138/87 mm Hg, respectively). Serum ionized calcium values did not vary with the three diets (1.25, 1.26, and 1.25 mmol/L, respectively). The parathyroid hormone level decreased (39 mmol/L vs 37 mmol/L) and the urinary calcium:creatinine ratio was elevated (0.41 vs 0.50) in the high-calcium diet. Consumption of a diet containing 1,500 mg calcium per day over 4 weeks did not produce a significant decrease in blood pressure or alterations in calcium metabolic indexes.     

Dietary intake and practices in the Hong Kong Chinese population

OBJECTIVES: To examine dietary intake and practices of the adult Hong Kong Chinese population to provide a basis for future public health recommendations with regard to prevention of certain chronic diseases such as cardiovascular disease, hypertension, and osteoporosis. PARTICIPANTS: Age and sex stratified random sample of the Hong Kong Chinese population aged 25 to 74 years (500 men, 510 women). METHOD: A food frequency method over a one week period was used for nutrient quantification, and a separate questionnaire was used for assessment of dietary habits. Information was obtained by interview. RESULTS: Men had higher intakes of energy and higher nutrient density of vitamin D, monounsaturated fatty acids and cholesterol, but lower nutrient density of protein, many vitamins, calcium, iron, copper, and polyunsaturated fatty acids. There was an age related decrease in energy intake and other nutrients except for vitamin C, sodium, potassium, and percentage of total calorie from carbohydrate, which all increased with age. Approximately 50% of the population had a cholesterol intake of < or = 300 mg; 60% had a fat intake < or = 30% of total energy; and 85% had a percentage of energy from saturated fats < or = 10%; criteria considered desirable for cardiovascular health. Seventy eight per cent of the population had sodium intake values in the range shown to be associated with the age related rise in blood pressure with age. Mean calcium intake was lower than the FAO/WHO recommendations. The awareness of the value of wholemeal bread and polyunsaturated fat spreads was lower in this population compared with that in Australia. There was a marked difference in types of cooking oil compared with Singaporeans, the latter using more coconut/palm/mixed vegetable oils. CONCLUSION: Although the current intake pattern for cardiovascular health for fat, saturated fatty acid, and cholesterol fall within the recommended range for over 50% of the population, follow up surveys to monitor the pattern would be needed. Decreasing salt consumption, increasing calcium intake, and increasing the awareness of the health value of fibre may all be beneficial in the context of chronic disease prevention.