The effect of milk supplementation on bone mineral density in postmenopausal Chinese women in Malaysia

Dietary studies often report low calcium intake amongst post-menopausal Malaysian women and calcium deficiency has been implicated as part of the etiology of age-related bone loss leading to osteoporosis. Therefore, the objective of this study was to examine the effectiveness of high calcium skimmed milk (Anlene Gold, New Zealand Milk, Wellington, New Zealand) to reduce bone loss in Chinese postmenopausal women. Two hundred subjects aged 55–65 years and who were more than 5 years postmenopausal were randomized to a milk group and control group. The milk group consumed 50 g of high calcium skimmed milk powder daily, which contained 1200 mg calcium (taken as two glasses of milk a day). The control group continued with their usual diet. Using repeated measures ANCOVA, the milk supplement was found to significantly reduce the percentage of bone loss at the total body compared to the control group at 24 months (control –1.04%, milk –0.13%; P<0.001). At the lumbar spine, the percentage of bone loss in the control group was significantly higher (–0.90%) when compared to the milk (–0.13%) supplemented group at 24 months (P<0.05). Similarly, milk supplementation reduced the percentage of bone loss at the femoral neck (control –1.21%, milk 0.51%) (P<0.01) and total hip (control –2.17%, milk –0.50%) (P<0.01). The supplemented group did not experience any significant weight gain over the 24 months. The serum 25-hydroxy vitamin D level improved significantly (P<0.01) from 69.1±16.1 nmol/l at baseline to 86.4±22.0 nmol/l at 24 months in the milk group. In conclusion, ingestion of high calcium skimmed milk was effective in reducing the rate of bone loss at clinically important lumbar spine and hip sites in postmenopausal Chinese women in Malaysia. Supplementing with milk had additional benefits of improving the serum 25-hydroxy vitamin D status of the subjects.     

Milk consumption and bone mineral content in Chinese adolescent girls

A cross-sectional study of a random sample of 649 girls, aged 12-14 years (mean +/- SD: 12.9 +/- 0.6 years), in the Beijing area examined the relationship between diet and bone mineral status. Food and nutrient intakes over the past year were estimated by means of a semiquantitative food frequency questionnaire. Bone mineral content (BMC) and bone width (BW) at the distal one-third and one-tenth radius and ulna were measured by single-photon absorptiometry. Results showed Beijing pubertal girls had a low mean milk consumption (fresh and powdered milk, vitamin D-fortified milk, and yogurt) at 50 g/day (95% confidence interval [CI] 44-55 g/day whereas one-third consumed no milk at all. Mean calcium intake was 356 +/- 97 mg/day of which only 21% was provided by milk and milk products. Milk intake varied by region (rural, suburban, and urban: 9, 36, and 83 g/day, respectively, p < 0.0005) as did the proportion of milk consumers in the three areas (30%, 64%, and 91%, p < 0.0005). Bone mineral density (BMD) at the distal one-third and one-tenth radius and one-tenth ulna was positively associated with milk consumption (p < 0.05). Multiple regression analysis of BMC on foods and nutrients as well as confounding factors, including weight, bone age, Tanner stage, and School Physical Activity Score (SPAS), showed that milk intake was the only dietary factor included in the models for BMC at the four bone sites measured. The model explained 54%-65% of the variation in BMC, and milk alone accounted for up to 3.2% of the variation. Milk was the only food group with significant partial correlation with BMC. SPAS, weight, bone age, and Tanner stage each accounted for a smaller variation in BMC (<1.8%). The results indicate that milk (presumably as an integrated source of nutrients) had a beneficial effect on bone mass of Beijing pubertal girls and was a better nutritional determinant of BMC than intake of any milk nutrient alone. Promotion of milk consumption should be considered for achieving optimal bone mass in this population group.     

A case of the milk-alkali syndrome with a small amount of milk and magnesium oxide ingestion--the contribution of sustained metabolic alkalosis induced by hypertonic dehydration

We described a patient with the milk-alkali syndrome induced by the ingestion of small amount of milk (200 ml/day) and ice cream (145 g/day) and the administration of small dose of absorbable alkali (magnesium oxide 2.0 g/day) for the treatment of chronic constipation. The present case shows not only triads, i.e., hypercalcemia (s-Ca 14.3 mg/dl), metabolic alkalosis (s-HCO3- 37.4 mEq/L), and renal insufficiency (s-Cre 2.3 mg/dl) but also hypernatremia (s-Na 161 mEq/L) and hypertonic dehydration after the frequent episodes of elevated body temperature. The milk-alkali syndrome has been defined as the hypercalcemia with a metabolic alkalosis from a high amount of calcium intake and long term administration of absorbable alkali in any form, usually as calcium carbonate for the treatment of peptic ulcer. As the present case could be distinguished from any other cases previously reported with regard to the amount of calcium (0.4 g/day) and alkali (36 mEq/day) intake and the clinical situations that induced the syndrome, we compared the present case with the previous reports, calculating the amount of calcium and alkali intake from milk and absorbable alkali. After the introduction of the H2 blockers for peptic ulceration, the most cases with milk-alkali syndrome had provoked by the smaller amount of calcium than previously reported, which were associated with the treatment of relatively large amount of alkali (50-150 mEq/day), suggesting the role of sustained metabolic alkalosis for the development. In the present case the metabolic alkalosis induced by hypertonic dehydration and enhanced by absorbable alkali intake also could cause an increase of renal tubular reabsorption of calcium and a decrease of ionized calcium which might produce increased secretion of parathyroid hormone followed by vitamin D3 activation and increased Ca absorption from the gut. The metabolic alkalosis might be essential to the development of the milk-alkali syndrome without a high calcium and absorbable alkali intake.     

Estimation of the oxalate content of foods and daily oxalate intake

BACKGROUND: The amount of oxalate ingested may be an important risk factor in the development of idiopathic calcium oxalate nephrolithiasis. Reliable food tables listing the oxalate content of foods are currently not available. The aim of this research was to develop an accurate and reliable method to measure the food content of oxalate. METHODS: Capillary electrophoresis (CE) and ion chromatography (IC) were compared as direct techniques for the estimation of the oxalate content of foods. Foods were thoroughly homogenized in acid, heat extracted, and clarified by centrifugation and filtration before dilution in water for analysis. Five individuals consuming self-selected diets maintained food records for three days to determine their mean daily oxalate intakes. RESULTS: Both techniques were capable of adequately measuring the oxalate in foods with a significant oxalate content. With foods of very low oxalate content (<1.8 mg/100 g), IC was more reliable than CE. The mean daily intake of oxalate by the five individuals tested was 152 +/- 83 mg, ranging from 44 to 352 mg/day. CONCLUSIONS: CE appears to be the method of choice over IC for estimating the oxalate content of foods with a medium (>10 mg/100 g) to high oxalate content due to a faster analysis time and lower running costs, whereas IC may be better suited for the analysis of foods with a low oxalate content. Accurate estimates of the oxalate content of foods should permit the role of dietary oxalate in urinary oxalate excretion and stone formation to be clarified. Other factors, apart from the amount of oxalate ingested, appear to exert a major influence over the amount of oxalate excreted in the urine.     

Nutritional risk factors in calcium stone disease in Japan

The purpose of this study is to examine the nutritional environment affecting calcium stone disease in Japan. The following results were obtained. Renal stone disease in the late 1970s increased by about three times than that of the 1940s . Fats and oils, animal protein and calcium intake increased remarkably after the second World War and milk plus milk products, meat and animal products were increased surprisingly compared with 1950. The most ingested nutrients of calcium stone formers were not much different from the results of the National Nutritive Survey in Japan. But the ingested amount of calcium was unexpectedly small and did not reach the level of the daily nutritional requirement in Japanese (15 mmol). The ingested amount of total protein correlated with urinary calcium excretion and had the highest coefficient of determination to the urinary calcium excretion by multiple regression analysis. We have finished our research of individual dietary habits and suggest that the following individual dietary guidance is the primary treatment for the prophylaxis of renal stone disease.     

A meta-analysis of milk intake and fracture risk: low utility for case finding

A low intake of calcium is widely considered to be a risk factor for future fracture. The aim of this study was to quantify this risk on an international basis and to explore the effect of age, gender and bone mineral density (BMD) on this risk. We studied 39,563 men and women (69% female) from six prospectively studied cohorts comprising EVOS/EPOS, CaMos, DOES, the Rotterdam study, the Sheffield study and a cohort from Gothenburg. Cohorts were followed for 152,000 person-years. The effect of calcium intake as judged by the intake of milk on the risk of any fracture, any osteoporotic fracture and hip fracture alone was examined using a Poisson model for each sex from each cohort. Covariates examined were age and BMD. The results of the different studies were merged by using the weighted -coefficients. A low intake of calcium (less than 1 glass of milk daily) was not associated with a significantly increased risk of any fracture, osteoporotic fracture or hip fracture. There was no difference in risk ratio between men and women. When both sexes were combined there was a small but non-significant increase in the risk of osteoporotic and of hip fracture. There was also a small increase in the risk of an osteoporotic fracture with age which was significant at the age of 80 years (RR=1.15; 95% CI=1.02–1.30) and above. The association was no longer significant after adjustment for BMD. No significant relationship was observed by age for low milk intake and hip fracture risk. We conclude that a self-reported low intake of milk is not associated with any marked increase in fracture risk and that the use of this risk indicator is of little or no value in case-finding strategies.     

Short-term effects on bone turnover of replacing milk with cola beverages: a 10-day interventional study in young men

In the Western world, increased consumption of carbonated soft drinks combined with a decreasing intake of milk may increase the risk of osteoporosis. This study was designed to reflect the trend of replacing milk with carbonated beverages in a group of young men on a low-calcium diet and studies the effects of this replacement on calcium homeostasis and bone turnover. This controlled crossover intervention study included 11 healthy men (22-29 years) who were given a low-calcium basic diet in two 10-day intervention periods with an intervening 10-day washout. During one period, they drank 2.5 l of Coca Cola per day and during the other period 2.5 l of semi-skimmed milk. Serum concentrations of calcium, phosphate, 25-hydroxycholecalciferol, 1,25-dihydroxycholecalciferol (1,25(OH)2D), osteocalcin, bone-specific alkaline phosphatase (B-ALP) and cross-linked C-telopeptides (CTX), plasma intact parathyroid hormone (PTH) and urinary cross-linked N-telopeptides (NTX) were determined at baseline and endpoint of each intervention period. An increase in serum phosphate (P<0.001), 1,25(OH)2D (P<0.001), PTH (P=0.046) and osteocalcin (P<0.001) was observed in the cola period compared to the milk period. Also, bone resorption was significantly increased following the cola period, seen as increased serum CTX (P<0.001) and urinary NTX (P<0.001) compared to the milk period. No changes were observed in serum concentrations of calcium or B-ALP. This study demonstrates that over a 10-day period high intake of cola with a low-calcium diet induces increased bone turnover compared to a high intake of milk with a low-calcium diet. Thus, the trend towards a replacement of milk with cola and other soft drinks, which results in a low calcium intake, may negatively affect bone health as indicated by this short-term study.     

Milk, rather than other foods, is associated with vertebral bone mass and circulating IGF-1 in female adolescents

Summary  Low calcium intake hampers bone mineral acquisition in adolescent girls. This study explores dietary calcium sources and nutrients possibly associated with vertebral mass. Milk intake is not influenced by genetic variants of the lactase gene and is positively associated with serum IGF-1 and with lumbar vertebrae mineral content and density. Introduction  Low calcium intake hampers bone mineral acquisition during adolescence. We identified calcium sources and nutrients possibly associated with lumbar bone mineralization and calcium metabolism in adolescent girls and evaluated the possible influence of a genetic polymorphic trait associated with adult-type hypolactasia. Methods  Lumbar bone mineral content (BMC), bone mineral density (BMD), and area, circulating IGF-1, markers of bone metabolism, and −13910 LCT (lactase gene) polymorphism; and intakes of milk, dairy products, calcium, phosphorus, magnesium, proteins, and energy were evaluated in 192 healthy adolescent girls. Results  After menarche, BMC, BMD, serum IGF-1, and serum PTH were tightly associated with milk consumption, but not with other calcium sources. All four parameters were also associated with phosphorus, magnesium, protein, and energy from milk, but not from other sources. Girls with milk intakes below 55 mL/day have significantly lower BMD, BMC, and IGF-1 and higher PTH compared to girls consuming over 260 mL/day. Neither BMC, BMD, calcium intakes, nor milk consumption were associated with −13910 LCT polymorphism. Conclusions  Milk consumption, preferably to other calcium sources, is associated with lumbar BMC and BMD in postmenarcheal girls. Aside from being a major source of calcium, milk provides phosphates, magnesium, proteins, and as yet unidentified nutrients likely to favor bone health.     

Dolomite supplementation improves bone metabolism through modulation of calcium-regulating hormone secretion in ovariectomized rats

Dolomite, a mineral composed of calcium magnesium carbonate (CaMg (CO₃)₂), is used as a food supplement that supplies calcium and magnesium. However, the effect of magnesium supplementation on bone metabolism in patients with osteoporosis is a matter of controversy. We examined the effects of daily supplementation with dolomite on calcium metabolism in ovariectomized (OVX) rats. Dolomite was administered daily to OVX rats for 9 weeks. The same amount of magnesium chloride as that supplied by the dolomite was given to OVX rats as a positive control. Histological examination revealed that ovariectomy decreased trabecular bone and increased adipose tissues in the femoral metaphysis. Dolomite or magnesium supplementation failed to improve these bone histological features. Calcium content in the femora was decreased in OVX rats. Neither calcium nor magnesium content in the femora in OVX rats was significantly increased by dolomite or magnesium administration. Urinary deoxypyridinoline excretion was significantly increased in OVX rats, and was not affected by the magnesium supplementation. Serum concentrations of magnesium were increased, and those of calcium were decreased, in OVX rats supplemented with dolomite or magnesium. However, there was a tendency toward decreased parathyroid hormone secretion and increased calcitonin secretion in OVX rats supplemented with dolomite or magnesium. Serum 1,25-dihydroxyvitamin D₃ and osteocalcin levels were significantly increased in the supplemented OVX rats. These results suggest that increased magnesium intake improves calcium metabolism in favor of increasing bone formation, through the modulation of calcium-regulating hormone secretion.     

Effect of dietary calcium on stone forming propensity

PURPOSE: Epidemiological studies have reported that high calcium diet protects against kidney stone formation in normal subjects. This metabolic study was designed to elucidate the physiological and physicochemical effects conferring this apparent protection. MATERIALS AND METHODS: A total of 21 normal volunteers underwent 2 phases of study in a crossover, randomized design, wherein they consumed constant metabolic diets that matched the estimated highest and lowest quintiles of calcium intake from published epidemiological studies. RESULTS: Urinary calcium was significantly greater on the high calcium diet (148 +/- 55 versus 118 +/- 43 mg. daily, p <0.01, p <0.01) but urinary oxalate did not differ between diets. There was no difference in relative saturation ratio of calcium oxalate between the 2 diets. The high calcium diet significantly increased saturation of brushite and decreased that of uric acid. Due to the other differences between the diets (more fluid, potassium, magnesium and phosphate in the high calcium diet), the high calcium diet also increased 24-hour urinary volume, potassium, phosphorus, pH and citrate. After adjustment of these confounding variables, the high calcium diet significantly increased relative saturation ratio of calcium oxalate by 24%. CONCLUSIONS: High calcium diet from published epidemiological studies does not alter the propensity for calcium oxalate crystallization in normal subjects despite increased urinary calcium and unaltered urinary oxalate because of the greater amounts of ingested fluid, potassium and phosphate. However, high calcium intake alone, without concomitant changes in the diet, poses a modest risk for calcium stone formation.     

Milk intake and risk of hip fracture in men and women: A meta‐analysis of prospective cohort studies

Milk contains calcium, phosphorus, and protein and is fortified with vitamin D in the United States. All these ingredients may improve bone health. However, the potential benefit of milk on hip fracture prevention is not well established. The objective of this study was to assess the association of milk intake with risk of hip fracture based on a meta‐analysis of cohort studies in middle‐aged or older men and women. Data sources for this study were English and non‐English publications via Medline (Ovid, PubMed) and EMBASE search up to June 2010, experts in the field, and reference lists. The idea was to compare prospective cohort studies on the same scale so that we could calculate the relative risk (RR) of hip fracture per glass of milk intake daily (approximately 300 mg calcium per glass of milk). Pooled analyses were based on random effects models. The data were extracted by two independent observers. The results show that in women (6 studies, 195,102 women, 3574 hip fractures), there was no overall association between total milk intake and hip fracture risk (pooled RR per glass of milk per day = 0.99; 95% confidence interval [CI] 0.96–1.02; Q‐test p = .37). In men (3 studies, 75,149 men, 195 hip fractures), the pooled RR per daily glass of milk was 0.91 (95% CI 0.81–1.01). Our conclusion is that in our meta‐analysis of cohort studies, there was no overall association between milk intake and hip fracture risk in women but that more data are needed in men. © 2011 American Society for Bone and Mineral Research.     

Reduction of exogenous oxalate in urine of rats by binding with aluminium-oxyhydrate (Andursil®) and an anion-exchanger (Colestid®) in the intestinal tract

Summary The influence of calcium carbonate, aluminium oxyhydrate (Andursil^®) and an anion exchanger (Colestid^®) on the absorption of oxalate from the intestine in rats was investigated. The animals were administered daily doses of 15mg oxalate as a ¹⁴C-sodium-oxalate solution by means of a throat probe, and the substances of interest were mixed with the food. The intake of food and the ¹⁴C-activity in the urine were measured during four urine-collecting periods of 3 days each. The quantity of the enterally administered oxalate excreted with urine has a negative correlation to the amount of the investigated test substances ingested with food.     

Bone mineral density and osteo sono assessment index in adolescents

The standard value for bone mineral density in the distal radius (R-BMD) and the osteo sono assessment index (OSI) in the os calcaneus for each sex and age in teenagers have not yet been fully reported. The R-BMD and OSI of junior and senior high school students were measured by dual energy X-ray absorptiometry (DEXA) or by a quantitative ultrasound technique. Subjects measured by DEXA included 635 junior and senior high school students (274 males and 361 females, aged 12–17 years). Ultrasound measurements were made for 2878 subjects (1733 males, 1145 females, aged 12–18 years). All subjects filled out questionnaires about their past history, family history, past and present eating habits, sports activities, and for females, the presence of menses, regularity of menses, and so on. The R-BMD in 15- to 17-year-old males was significantly higher than that in females. The R-BMD rate of increase in males was almost linear; the rate of increase in females was significantly highest from ages 12 to 13, after which R-BMD increased gradually. The OSI in 15- to 18-year-old males was significantly higher than that in females. The OSI rate of increase in males was almost linear from ages 12 to 17. The OSI in females, except in 14-year-olds, was roughly equal at each age. The OSI was significantly higher in those who regularly participated in sports, either currently or in the past. It was significantly higher in those who previously or currently consumed milk on a daily basis compared with those who had consumed little or no milk. To prevent osteoporosis, increasing peak bone mass is very important. Adequate calcium intake from dairy products which are rich in calcium and absorbed easily, and exercise in adolescence, are expected to result in increased bone formation and increased OSI. Received for publication on Feb. 17, 1999; accepted on Oct. 5, 1999     

Validity of a Dietary Calcium Questionnaire Modified to Include Supplement Use in Athletes

When conducting research in the area of bone health, accurate measurement of calcium intake is crucial. The rapid assessment method (RAM) is one technique that has frequently been used for its measurement of calcium intake. However, the RAM and other currently established questionnaires lack the assessment of dietary supplement use, which is common for athletes. Our objective was to evaluate the validity of a RAM questionnaire designed to assess daily calcium consumption which was further modified to meet the needs of athletes who frequently consume dietary supplements. Usefulness of the modified RAM for athletes and non-athletes was evaluated as well as utility among those who do and do not use supplements. The 47 volunteers (n = 31 women, 16 men) were between the ages of 18 and 25 including, 33 athletes and 14 controls. The population also contained 23 supplement users and 24 non-supplement users. Participants completed the modified RAM and were instructed to complete a three-day diet record (3DR), logging food intake for 2 weekdays and 1 weekend day. The data collected via the modified RAM was compared with the 3DR. Mean calcium intake was 935mg ± 420mg and 1085mg ± 573mg, for the modified RAM and 3DR respectively. A strong positive correlation (r) was found between calcium intake measured with the modified RAM and 3DRs (r(45) = 0.854, p < 0.01). Intraclass correlation coefficients (ICC) revealed that agreement between the two instruments was good (ICC = 0.76, df = 45, p < 0.01) and much improved when compared to agreements without consideration of supplements (ICC = 0.05, df = 21, p > 0.05). We have found the modified RAM to be a valid tool which can be used to estimate calcium intake in the athletes and controls we strive to study. The accuracy of this instrument improved by including assessment of dietary supplement sources of calcium.

Key points

• When conducting research on bone health, accurate measurement of calcium intake is crucial. The rapid assessment method (RAM) is one technique that has frequently been used for its measurement; however, currently established questionnaires lack assessment of dietary supplement use, which is common for athletes.
• We report that estimated calcium intake from the LMU RAM modified to evaluate supplement use has good agreement with three-day diet records (3DRs). There was a strong correlation between the two methods with about 69% (r = 0.83, r² = 0.69) of the variability in calcium intake quantified via the LMU RAM being accounted for by the 3DR.
• Calculated intraclass correlation coefficients between 0.63 and 0.77 reveal that the LMU RAM appears to be a valid tool of measuring daily calcium intake in athletes and non-athletes and among those who do and do not use supplements.
• When evaluating calcium intake without considering supplements, agreement (ICC) and correlation (r) values decreased considerably.
• We found the LMU RAM to be a valid measurement of calcium intake in athletes and controls. Without the addition of a section on supplement use, estimated calcium intake would have decreased an average of 32%.

Key words: Sports nutrition, rapid assessment, athletic, bone health, osteoporosis.     

Contribution of dietary oxalate to urinary oxalate excretion

BACKGROUND: The amount of oxalate excreted in urine has a significant impact on calcium oxalate supersaturation and stone formation. Dietary oxalate is believed to make only a minor (10 to 20%) contribution to the amount of oxalate excreted in urine, but the validity of the experimental observations that support this conclusion can be questioned. An understanding of the actual contribution of dietary oxalate to urinary oxalate excretion is important, as it is potentially modifiable. METHODS: We varied the amount of dietary oxalate consumed by a group of adult individuals using formula diets and controlled, solid-food diets with a known oxalate content, determined by a recently developed analytical procedure. Controlled solid-food diets were consumed containing 10, 50, and 250 mg of oxalate/2500 kcal, as well as formula diets containing 0 and 180 mg oxalate/2500 kcal. Changes in the content of oxalate and other ions were assessed in 24-hour urine collections. RESULTS: Urinary oxalate excretion increased as dietary oxalate intake increased. With oxalate-containing diets, the mean contribution of dietary oxalate to urinary oxalate excretion ranged from 24.4 +/- 15.5% on the 10 mg/2500 kcal/day diet to 41.5 +/- 9.1% on the 250 mg/2500 kcal/day diet, much higher than previously estimated. When the calcium content of a diet containing 250 mg of oxalate was reduced from 1002 mg to 391 mg, urinary oxalate excretion increased by a mean of 28.2 +/- 4.8%, and the mean dietary contribution increased to 52.6 +/- 8.6%. CONCLUSIONS: These results suggest that dietary oxalate makes a much greater contribution to urinary oxalate excretion than previously recognized, that dietary calcium influences the bioavailability of ingested oxalate, and that the absorption of dietary oxalate may be an important factor in calcium oxalate stone formation.     

Dietary habits of Japanese renal stone formers and clinical effects of prophylactic dietary treatment

The daily consumption of various nutrients and the daily habits of 241 male stone formers were investigated. The patients (especially uric acid stone formers and hypercalciuric (greater than or equal to 300 mg/day) calcium stone formers) ingested much more total protein and animal protein than healthy Japanese. However, the amount of ingested calcium by the patients (470 mg) was less than that of healthy subjects (553 mg) and did not reach the level of the daily nutritive requirement (600 mg). The amount of ingested nutrients during the evening meal by the patients was about 50% of the daily amount with over 60% of the daily animal protein being ingested at dinner. This tendency was high in subjects who were in their 20's to 40's. The interval from dinner until retiring in the patients was not different from that of healthy males, but it was under 4 hours in over 50% of those in their 30's and 40's in both groups. From these results, we thought that a rapid change in nutritional status and dietary style in the short period after World War II had strongly affected the incidence of renal stone disease in Japan. Therefore, we have established the following general guidelines: 1) increased fluid intake, especially after dinner, 2) correct and avoid unbalanced diet (the diet should include all kinds of food, with vegetables being eaten at every meal and avoidance of an excessive intake of meat), 3) eat three meals a day and avoid an excessive intake at dinner, and 4) extend the interval from dinner until retiring. By following these individual dietary guidelines, the 5-year stone recurrence rate and the stone episode rate decreased remarkably in the period of not only outpatient visits but also in the period when the outpatient visits were discontinued. From these results, we conclude that individual dietary management should be the primary measure for the prophylaxis of renal stone disease in Japan.     

A Prospective Study of the Intake of Vitamins C and B6, and the Risk of Kidney Stones in Men

Purpose

The association between the intake of vitamins C and B6, and kidney stone formation was examined.

Materials and Methods

We conducted a prospective study of the relatioship between the intake of vitamins C and B6 and the risk of symptomatic kidney stones in a cohort of 45,251 men 40 to 75 years old with no history of kidney calculi. Vitamin intake from foods and supplements was assessed using a semiquantitative food frequency questionnaire completed in 1986.

Results

During 6 years of followup 751 incident cases of kidney stones were documented. Neither vitamin C nor vitamin B6 intake was significantly associated with the risk of stone formation. For vitamin C the age-adjusted relative risk for men consuming 1,500 mg. daily or more compared to less than 250 mg. daily was 0.78 (95 percent confidence interval 0.54 to 1.11). For vitamin B6 the age-adjusted relative risk for men consuming 40 mg. daily or more compared to less than 3 mg. daily was 0.91 (95 percent confidence interval 0.64 to 1.31). After adjusting for other potential stone risk factors the relative risks did not change significantly.

Conclusions

These data do not support an association between a high daily intake of vitamin C or vitamin B6 and the risk of stone formation, even when consumed in large doses.     

Dietary risk factors for hyperoxaluria in calcium oxalate stone formers

BACKGROUND: Hyperoxaluria is a major predisposing factor in calcium oxalate urolithiasis. The aim of the present study was to clarify the role of dietary oxalate in urinary oxalate excretion and to assess dietary risk factors for hyperoxaluria in calcium oxalate stone patients. METHODS: Dietary intakes of 186 calcium oxalate stone formers, 93 with hyperoxaluria (>or=0.5 mmol/day) and 93 with normal oxalate excretion (<0.4 mmol/day), were assessed by a 24-hour weighed dietary record. Each subject collected 24-hour urine during the completion of the food record. Oxalate content of foods was measured by a recently developed analytical method. RESULTS: The mean daily intakes of energy, total protein, fat and carbohydrates were similar in both groups. The diets of the patients with hyperoxaluria were estimated to contain 130 mg/day oxalate and 812 mg/day calcium as compared to 101 mg/day oxalate and 845 mg/day calcium among patients without hyperoxaluria. These differences were not significant. The mean daily intakes of water (in food and beverages), magnesium, potassium, dietary fiber and ascorbic acid were greater in patients with hyperoxaluria than in stone formers with normal oxalate excretion. Multiple logistic regression analysis revealed that urinary oxalate excretion was significantly associated with dietary ascorbate and fluid intake, and inversely related to calcium intake. Differences of estimated diet composition of both groups corresponded to differences in urinary parameters. CONCLUSIONS: These findings suggest that hyperoxaluria predominantly results from increased endogenous production and from intestinal hyperabsorption of oxalate, partly caused by an insufficient supply or low availability of calcium for complexation with oxalate in the intestinal lumen.     

2型糖尿病住院患者膳食结构调查研究

目的 了解2型糖尿病住院患者的膳食摄入情况,分析影响患者膳食摄入的相关因素,为糖尿病膳食计划的制定提供依据.方法 采用信息表和糖尿病患者饮食摄入量表对282例2型糖尿病住院患者进行膳食结构调查,根据调查资料对患者饮食控制状况、膳食结构状况及影响因素进行分析.结果 282例2型糖尿病住院患者谷类、蔬菜类、水果类、畜禽肉类、鱼虾类、油脂类摄入偏高;蛋类摄入合适;豆类、乳类摄入偏低.10.64％日摄入总热量不足,53.19％摄入量合适,102例(36.17％)摄入过剩;不同体型之间日摄入总热量差异显著(P＜0.01);超重体型日摄入总热量过剩比例最高(50.00％);是否有领导职务、是否接受过营养指导和是否为新诊断患者是影响膳食结构的主要因素.结论 2型糖尿病住院患者膳食结构不合理,营养摄入过剩,需要有针对性加强饮食指导;新诊断患者、在职领导及超重患者是重点干预对象.     

Questionnaire about Calcium Intake: Can We Trust the Answers?

The aim of this study was to construct and evaluate reliable questions concerning calcium intake and to include them in a questionnaire to be used in a community-based intervention program for preventing osteoporosis. Estimating calcium intake is an important factor in evaluating risk profiles for community residents. A very large amount of calcium in the Swedish diet comes from dairy foods. Two questionnaires were designed. Questionnaire A contained eight questions concerning consumption of dairy foods. Questionnaire B contained 52 questions on consumption of calcium-rich food groups and dishes, and also included the eight questions mentioned above. Questionnaire A was sent to 467 randomized women aged 20–30 and 50–60 years. Women with a low calcium intake also answered questionnaire B. In order to validate the questionnaires a selected number of the women were interviewed using a dietary history. In total 363 women answered questionnaire A, 118 of whom had a calcium intake below the recommended amount. Ninety-six women completed questionnaire B. Twenty-two women were interviewed with the dietary history. Statistical analyses using t-tests of the differences between answers to the same questions in two questionnaires and the interview, gave the following results. Questionnaire A provides reliable information about those who do not reach the recommended level of calcium intake. Questionnaire B does not provide any more information than questionnaire A. It is not possible to rank calcium levels in the diet with the questionnaires. Using the estimated calcium intake from dairy foods obtained in questionnaire A, individuals at risk of consuming less than the recommended intake of calcium can be identified, as can those consuming the required amount. In conclusion, questionnaire A is useful in discriminating between subjects with low and high calcium intake. Received: 12 December 1997 / Accepted: 3 July 1998