Non-native capillary isoelectric focusing for the analysis of the microheterogeneity of glycoproteins

The purpose of the present study was to compare two measures of Fe absorption, one from single meals and the other from daily diets. Ten ileostomy subjects were given the same low-fibre composite diet for all three meals each day for five consecutive days. After 3 weeks the experiment was repeated with a high-fibre diet. The morning meal constituted one-seventh of the total daily diet intake, the mid-day meal two-sevenths and the evening meal four-sevenths of the total daily diet intake. On days 4 and 5 of each diet period the morning meal was labelled with 55Fe and all three meals were labelled with 59Fe. The activities retained in the subjects 19 d later showed the Fe absorption from the low-fibre diet measured from the morning meals to be almost 80% greater than the average Fe absorption measured from all meals during the same 2 d. With the high-fibre diet the absorption from the morning meals was less than 50% greater than the average for all meals but the difference was not significant. We suggest that all meals of the day should be labelled with radioFe in order to avoid inflating the measures of Fe absorption.     

Primary hemochromatosis and dietary iron

Primary haemochromatosis is characterized by an unusually high degree of iron absorption resulting in the accumulation of excessive amounts of tissue iron. Excess stores of iron are removed by repeated phlebotomy. Health personnel and a number of patients with primary haemochromatosis have expressed their desire for advice on special diets to try and reduce the number of phlebotomies per year. This article gives advice on how patients with primary haemochromatosis can decrease their dietary iron intake and how they can put together meals to obtain low bioavailability, and therefore a lower iron absorption. The diet should be varied and be rich in bread and cereals, and fruit and vegetables. The amount of meat, Norwegian brown whey cheese (iron supplemented) and alcohol should be limited. Tea or coffee with meals will reduce iron absorption. Food rich in ascorbic acid (fruit and fruit juice) should be avoided with meals. Ascorbic acid supplements are not recommended.     

Zinc balance in adolescent females consuming a low- or high-calcium diet

There is increasing evidence that calcium intake up to the threshold amount (1480 mg/d) increases bone mass during growth. However, there is concern that such a high calcium intake may interfere with the utilization of other nutrients such as zinc, which is also important for skeletal development. The purpose of our study was to investigate the effect of long-term calcium supplementation on zinc utilization in 26 adolescent females (mean +/- SD age 11.3 +/- 0.5 y) during a 14-d period. Each day subjects consumed a metabolic diet containing 722 mg Ca and 6.3 mg Zn. Participants were randomly assigned to receive either a placebo or a calcium supplement containing 1000 mg supplemental Ca/d as calcium citrate malate. Supplementation began 15 wk before the balance period to allow for adaptation to the greater calcium intake. Mean (+/-SD) zinc balance (0.8 +/- 0.8 compared with 0.3 +/- 1.1 mg/d, P = 0.23), fecal zinc (4.3 +/- 0.6 compared with 4.7 +/- 1.4 mg/d, P = 0.27), urinary zinc (0.4 +/- 0.2 compared with 0.5 +/- 0.1 mg/d, P = 0.55), and net zinc absorption (21% compared with 15%, P = 0.33) were not significantly different between the high- and low-calcium groups. Our results suggest that increasing the recommended dietary allowance of calcium to 1500 mg/d as recommended by the National Institutes of Health consensus panel will not have adverse effects on zinc utilization in adolescent females.     

The (-)-enantiomer of gossypol inhibits proliferation of stromal cells derived from human breast adipose tissues by enhancing transforming growth factor beta1 production

BACKGROUND: Age-related osteoporosis may be associated with inefficient intestinal calcium absorption and bone remodeling. OBJECTIVE: We investigated the pathogenesis of age-related osteoporosis in Chinese women with habitual low calcium intakes. DESIGN: We studied the response of intestinal calcium absorption, calcitropic hormones, and biochemical bone markers to graded dietary calcium deprivation. RESULTS: The osteoporotic subjects (n = 25) had higher urinary calcium excretion (P < 0.05) and lower plasma 1,25-dihydroxyvitamin D concentrations (P < 0.02) than did age-matched control women (n = 25). Parathyroid hormone was not significantly different from that in age-matched control women but was significantly higher than in young women (n = 15, P < 0.05). Fractional 45Ca absorption was approximately 61% in all 3 groups when the diet was unmodified and increased to 71%, 69%, and 68% in the osteoporotic subjects, age-matched control women, and young women, respectively, when dietary calcium was reduced to 300 mg/d. When the osteoporotic women were calcium deprived, serum 1,25-dihydroxyvitamin D failed to increase but urinary calcium excretion persisted. In contrast, supplementation with 1200 mg Ca resulted in a lowering of parathyroid hormone (P < 0.005 compared with the unmodified diet) and 1,25-dihydroxyvitamin D (P < 0.01) and decreased fractional 45Ca absorption (P < 0.01), suggesting that the increased calcium intake was associated with a potent compensatory ability of the intestine and calcitropic hormones to adapt. Calcium supplementation lowered osteocalcin (P < 0.05) but not alkaline phosphatase, which remained elevated in the osteoporotic subjects at all stages. CONCLUSIONS: Elderly osteoporotic women had reduced 1,25-dihydroxyvitamin D production, excessive urinary calcium loss, and high bone turnover. The Chinese women had exceptionally potent intestinal calcium absorption.     

U-shape relationship between change in dietary cholesterol absorption and plasma lipoprotein responsiveness and evidence for extreme interindividual variation in dietary cholesterol absorption in humans

A possible relationship between change in dietary cholesterol absorption and plasma lipoprotein responsiveness was examined in 18 normal subjects fed low fat low cholesterol, high fat low cholesterol, and high fat high cholesterol diets. For the group, neither dietary cholesterol nor dietary fat affected the percentage dietary cholesterol absorption, whereas dietary cholesterol intake raised total and LDL-C and dietary fat raised total, LDL, and HDL-C. On a fixed diet there was approximately a 2-fold variation among subjects in percentage dietary cholesterol absorption. Subjects also varied in response to dietary cholesterol and fat with regard to dietary cholesterol absorption and plasma lipoprotein responsiveness. There was a U-shaped parabolic relationship between dietary cholesterol-induced percent change in LDL-C and the change in percentage dietary cholesterol absorption (R2 = 0.62, P = 0.005). A similar but weaker relationship characterized the responsiveness of HDL-C (R2 = 0.38, P = 0.05). For the group, increased cholesterol intake raised dietary cholesterol mass absorption from 1.6 to 4.6 mg/kg per day, but the range of increase was from 1 to 4.7 mg/kg per day. Increased fat intake also affected dietary cholesterol mass absorption with most subjects displaying a strong inverse relationship between fat intake and mass absorption (r = -0.77, P < 0.003). In summary: i) the percentage change in dietary cholesterol absorption in response to dietary cholesterol does appear to regulate diet responsiveness of LDL and HDL-C, and ii) the large variability in percent absorption and changes in percentage and mass absorption in response to dietary cholesterol suggest the presence of genetically determined differences among individuals in the regulation of dietary cholesterol absorption.     

The Chinese total diet study in 1990. Part II. Nutrients

This paper reports the intakes of 72 nutrients and their dietary sources obtained from the Chinese total diet study in 1990. Most of the nutrient intakes are close or equal to their corresponding recommended daily allowances (RDAs). Both the total energy intake (2203 kcal) and the proportions contributed by protein, fat, and carbohydrate meet the current Chinese RDAs and the World Health Organization (WHO) nutrient goals. The average protein intake was 64 g/day. The intake of essential amino acids all exceeded the Chinese RDA, and their proportions were generally consistent with the WHO recommended pattern. The average fat intake was 51.2 g/day (21.2% of the total energy intake). However, the dietary fat intake has been increasing significantly in the Chinese diet and the proportion of animal fat has reached 53% of the total fat intake. The total saturated:total monounsaturated: total polyunsaturated fatty acid ratio was 1.0:1.5:1.0. Although the average cholesterol intake was only 179 mg/day, it was 248 mg/day in the South 1 region. The intakes of thiamine and riboflavin were below the RDA. Retinol intakes in all the 4 regions were low. Most (80%) of the retinol (equivalent) intakes were from carotenoids. The average intake of total tocopherol was 89% of the RDA, and among the 4 regions, only the South 2 region has relatively low intake. The intakes of iron, copper, manganese, sodium, and phosphorus were adequate. The intakes of calcium, zinc, and potassium were insufficient, and intakes of selenium and magnesium were a little low. High sodium and low potassium intake is a traditional problem in the Chinese diet.     

Iron metabolism in rats consuming oil from fresh or fried sardines

The influence of the consumption of diets containing oil from either fresh sardines or fried sardines, under domestic conditions, on the dietary iron metabolism of rats has been investigated. Three groups of rats were fed, over 28 d, semipurified diets containing 8% of: olive oil (OO), fresh sardine (Clupea pilchardus) oil (SO) and oil from sardines previously fried in olive oil (FSO). Body mass and food intake were monitored and, during the periods 5-12 d and 21-28 d, faeces and urine were collected. At the end of the experiment, the animals were killed and blood, liver, spleen and a segment of skin were stored. Food intake and body mass decreased markedly in the SO rats. These parameters were slightly increased in the FSO group compared with OO. Iron absorption and retention were lower in SO than in OO or FSO. This was primarily caused by the poor food intake but also by the lower efficiency of absorption and high urinary Fe losses. Liver and spleen iron contents were reduced by half in SO compared with the other groups, partly owing to the smaller size of the organs, and liver Fe concentration also decreased. These results, together with the high total iron binding capacity, the decreased level of hemoglobin and total erythrocytic iron found in the SO animals, indicate that the consumption of fresh sardine oil as the only dietary fat resulted in iron depletion. The SO animals showed a higher Fe accumulation in skin than OO or FSO. It was concluded that a diet high in sardine fatty acid administered as a unique source of fat, can cause metabolic alterations including iron depletion, but these negative effects of sardine oil disappear with frying, probably owing to the exchange that takes place between fatty acids in the olive oil used in frying and those in the sardine oil.     

Proteins in renal stones and urine of stone formers

The iron status of a national sample of adults living in France and participating in the SU.VI.MAX cohort, was assessed using serum ferritin and hemoglobin concentrations. Complete data were obtained for 6648 women 35-60 y old and for 3283 men 45-60 y old. Assessment of iron dietary intakes was realized on a subsample of 3111 women and 2337 men who reported six 24 h dietary records during a one-year period; 22.7% of menstruating women and 5.3% of post-menopausal women presented a total depletion of iron stores (serum ferritin < 15 microg/l). Iron-deficient anemias were found in, respectively, 4.4% and less than 1% of these women. Three-quarters of the anemias were related to iron deficiency in menstruating women. In men, iron depletion and iron deficiency anemia were very rare. Post-menopausal women had much higher serum ferritin levels than menstruating women. In menstruating women, those using intrauterine devices had significantly lower serum ferritin levels than those without contraception, and much lower than those using oral contraception. The frequency of iron depletion reached 28.1% in women using intrauterine devices, but only 13.6% in those using oral contraceptives. The mean iron intake was 16.7 +/- 5.7 mg/d in men and 12.3 +/- 3.4 mg/d in women. Heme iron represented respectively, 11.1 and 10.4% of iron intake. Ninety-three percent of menstruating women had dietary iron intakes lower than recommended dietary allowances (RDA); 52.6% consumed less than two thirds of these RDA. In post-menopausal women and men, respectively 27.7% and 3.6% had dietary intakes lower than RDA. Serum ferritin was positively correlated with meat, fish and total iron intake, and negatively correlated with dietary products consumption, calcium and fiber intake.     

Analysis of mRNA for class I HLA on human gametogenic cells

The iron fortificant NaFeEDTA could have a potential negative effect on the metabolism of other minerals. We have used stable isotopes to monitor zinc and calcium metabolism in 10 women consuming a single meal of high-extraction wheat rolls (100 g flour) fortified with 5 mg Fe as either FeSO4 or NaFeEDTA. Six-day chemical balances were made simultaneously to study apparent zinc and calcium retention from the complete diet containing the differently iron-fortified breads (200 g flour; 10 mg added Fe/d). Mean 70Zn absorption from the bread meal increased from 20.9% with FeSO4 to 33.5% with NaFeEDTA (P < 0.05) whereas mean 44Ca absorption was 53.3% from both breads. When NaFeEDTA-fortified bread was consumed, there was a small but significant increase in urinary excretion of 70Zn and 44Ca. There was a similar small increase in urinary zinc excretion during the 6-d balance, although the apparent retention of zinc and calcium was not different. Thus, we found no negative overall effect of NaFeEDTA consumption on the metabolism of zinc and calcium. In contrast, the results suggest that NaFeEDTA added to low-bioavailability diets might increase zinc absorption as well as provide iron with high bioavailability.     

Early prostate cancer detection and potential for surgical cure in men with poorly differentiated tumors

Postgastrectomy osteopenia is observed generally in humans. Fructooligosaccharides increase the absorption of calcium from the large intestine of healthy rats. Thus, we have examined whether they stimulate calcium absorption and prevent osteopenia in rats following total gastrectomy. Rats were subjected to either a sham surgical operation or Billoth II gastrectomy. Seven rats from each surgical treatment group were fed a control diet, and another seven rats of each treatment group were fed a diet containing fructooligosaccharides (75 g/kg diet) for 4 wk. For 5 d each week, feces were collected, and the calcium and phosphorus contents were measured for calculation of the absorption of these minerals. At the end of the experiment, the rats were killed and bones were collected. The net calcium absorption, calcium content and bone mineral density of the femur and tibia in gastrectomized rats fed the control diet were significantly less than those in sham-operated rats fed control diet. The net calcium absorption in rats fed the fructooligosaccharides diet was greater than that in rats fed control diet. Moreover, dietary fructooligosaccharides prevented the decrease in the calcium content and bone mineral density in gastrectomized rats. Dietary fructooligosaccharides enhanced calcium absorption and prevented the changes indicative of postgastrectomy osteopenia such as decreases in bone calcium content and bone mineral density in gastrectomized rats.     

Dietary calcium intake and its relation to bone mineral density in patients with inflammatory bowel disease

OBJECTIVES: To investigate calcium intake and its association with bone mineral density (BMD) and the type and extent of the disease in patients with inflammatory bowel disease (IBD). SETTING: University hospital clinic. SUBJECTS: A total of 152 unselected IBD patients and 73 healthy controls. MEASUREMENTS: Dietary calcium intake was assessed with a food frequency questionnaire and BMD of the lumbar spina and proximal femur was measured. RESULTS: The IBD patients had lower dietary calcium intake (1034 [SD 493] mg) than the controls (1334 [514] mg, P < 0.001). The difference was significant in the males (1047 [552] mg and 1575 [586] mg, respectively, P < 0.001), but not in the females (1020 [422] mg and 1112 [303] mg). The dietary daily calcium intake was below 1000 mg in 53% of the patients and 27% of the controls (P = 0.0004) and below 400 mg in 9.2% of the patients and none of the controls (P = 0.007). The calcium intake was not associated with the severity or the type of IBD. Seventy-one (47%) patients and eight (11%) controls avoided lactose in their diet (P < 0.001). In the IBD patients, no association between the calcium intake and BMD was detected, whereas in the controls a positive correlation between the calcium intake and the BMD of the proximal femur was found. CONCLUSIONS: Calcium intakes below the recommendations are seen more often in the IBD patients than in the healthy controls, but in the IBD patients the calcium intake is not associated with BMD in a cross-sectional study. A low-lactose diet is common among IBD patients. To reduce the risk of inadequate calcium intake, unnecessary dietary restrictions concerning, e.g. milk products, should be avoided for these patients.     

Biochemical effects of calcium supplementation in postmenopausal women: influence of dietary calcium intake

We studied the biochemical effects of calcium supplementation during a 2-mo course in postmenopausal women (x +/- SD: 64 +/- 5 y of age and 14.5 +/- 6.7 y since menopause). The effects on calcium homeostasis and bone remodeling were assessed after 1 and 2 mo of daily administration of either calcium carbonate (1200 mg elemental Ca/d, n = 60) or a placebo (n = 56). The daily dietary calcium intake assessed before the beginning of calcium supplementation was 786 mg/d. We found a significant inverse relation between baseline intact parathyroid hormone (iPTH) and dietary calcium intake before supplementation (r = -0.48, P = 0.0002). A significant increase in urinary excretion of pyridinoline was observed when the dietary calcium intake was lower than the median value. Calcium supplementation resulted in a significant increase in 24-h urinary calcium (39%, P < 0.02) and a significant reduction of bone alkaline phosphatase at 2 mo and of all bone-resorption markers (hydroxyproline, pyridinoline, and deoxypyridinoline) at I and 2 mo without significant changes in 44-68 PTH fragments or iPTH concentrations. When the dietary calcium intake was low (mean +/- SD: 576 +/- 142 mg/d), calcium supplementation was responsible for a greater increase in urinary calcium excretion and a greater decrease in markers of bone turnover. The greatest variations were observed for deoxypyridinoline at 1 and 2 mo (-18.5%, P < 0.05) and for pyridinoline at 1 mo (-16.3%, P < 0.01). Two months of calcium supplementation in postmenopausal women was efficient in reducing markers of bone turnover, with a greater effect in women with a low dietary calcium intake.     

A highly polymorphic microsatellite within intron 5 of the porcine 54/56 kDa vacuolar H(+)-ATPase subunit gene (V-ATPase)

OBJECTIVE: To assess the validity of a short calcium food frequency questionnaire (FFQ) for use in young children. DESIGN: Calcium intake from an estimated 4 d diet record (4DDR) was compared with the calcium intake from a 35 item FFQ specifically designed to assess habitual calcium intake and previously validated for adult women. SUBJECTS: Forty-one girls and 26 boys aged 3-6 y recruited by advertisement for studies of nutrition and bone health. RESULTS: Mean (s.d.) calcium intakes were 798 mg (271) and 942 mg (419) for the 4DDR and FFQ respectively, (r = 0.52). Mean difference (s.d. of difference) in calcium intake between the two methods was 144 mg (355), showing that the FFQ may estimate calcium intakes 565 mg below to 854 mg above diet record values. 84% of subjects when classified by the 4DDR fell into the same or adjacent quartiles when classified by the FFQ. Only two subjects were classified in extreme quartiles for the two methods. The FFQ correctly identified 68% of children with recorded intakes less than 800 mg. CONCLUSIONS: The short calcium FFQ tended to overestimate actual calcium intakes in young children, and would not be appropriate for determining calcium intake of individuals. However, the FFQ demonstrated good ability to classify subjects into extremes of calcium intake. Moreover, the predictive value of the FFQ in identifying children with intakes below the current recommended intake of 800 mg was reasonably high (79%).     

Iron stores in man in relation to diet and iron requirements

OBJECTIVE: To calculate iron stores in man and their rates of changes in relation to iron requirements and dietary iron intake and bioavailability. METHOD: Newly established relationships between iron absorption from whole diets and serum ferritin (SF) and between SF and iron stores allow calculations of amounts of stored iron under different conditions (diets, losses) at stationary states when absorption equals losses. Rate of growth of stores can also be calculated. All calculations are based on observations and require no model assumptions. RESULTS: Present calculations of iron stores agree with previously observed phlebotomy values. Differences in intake and bioavailability of dietary iron and in iron requirements had marked effects on amounts of stored iron. A wide range of diets was studied, from a hypothetical high-meat diet typical for early man to diets in developing countries. A new equation is given for the translation of SF into iron stores. Analyses of growth rate of stores under different conditions showed a fast growth from zero iron stores during the first year (reaching about 80% of final amounts) followed by a much slower rate for 2-3 y. A marked inertia was seen in rate of changes in iron stores that was more marked the closer stores were to their stationary states making it difficult to use SF to estimate short term changes in iron absorption in iron replete subjects. CONCLUSIONS: Realistic Western-type diets with good bioavailability can cover iron requirements in most women and can restitute iron stores during lactation. The high prevalence of iron deficiency in menstruating Western women is thus mainly related to a further low bioavailability of iron in present diets. Present analyses also demonstrated an effective control of iron absorption preventing development of iron overload in otherwise healthy subjects even if the diet is fortified with iron and even if meat intake is high.     

Increased dietary oxalate does not increase urinary calcium oxalate saturation in hypercalciuric rats

BACKGROUND: Human calcium oxalate (CaOx) nephrolithiasis may occur if urine is supersaturated with respect to the solid-phase CaOx. In these patients, dietary oxalate is often restricted to reduce its absorption and subsequent excretion in an effort to lower supersaturation and to decrease stone formation. However, dietary oxalate also binds intestinal calcium which lowers calcium absorption and excretion. The effect of increasing dietary oxalate on urinary CaOx supersaturation is difficult to predict. METHODS: To determine the effect of dietary oxalate intake on urinary supersaturation with respect to CaOx and brushite (CaHPO4), we fed 36th and 37th generation genetic hypercalciuric rats a normal Ca diet (1.2% Ca) alone or with sodium oxalate added at 0.5%, 1.0%, or 2.0% for a total of 18 weeks. We measured urinary ion excretion and calculated supersaturation with respect to the CaOx and CaHPO4 solid phases and determined the type of stones formed. RESULTS: Increasing dietary oxalate from 0% to 2.0% significantly increased urinary oxalate and decreased urinary calcium excretion, the latter presumably due to increased dietary oxalate-binding intestinal calcium. Increasing dietary oxalate from 0% to 2.0% decreased CaOx supersaturation due to the decrease in urinary calcium offsetting the increase in urinary oxalate and the decreased CaHPO4 supersaturation. Each rat in each group formed stones. Scanning electron microscopy revealed discrete stones and not nephrocalcinosis. X-ray and electron diffraction and x-ray microanalysis revealed that the stones were composed of calcium and phosphate; there were no CaOx stones. CONCLUSION: Thus, increasing dietary oxalate led to a decrease in CaOx and CaHPO4 supersaturation and did not alter the universal stone formation found in these rats, nor the type of stones formed. These results suggest the necessity for human studies aimed at determining the role, if any, of limiting oxalate intake to prevent recurrence of CaOx nephrolithiasis.     

Health care coverage and access for children in an urban state: the New York perspective

To clarify the role of the intestine, kidney, and bone in maintaining calcium homeostasis during pregnancy and lactation and after the resumption of menses, a longitudinal comparison was undertaken of 14 well-nourished women consuming approximately 1200 mg Ca/d. Measurements were made before conception (prepregnancy), once during each trimester of pregnancy (T1, T2, and T3), early in lactation at 2 mo postpartum (EL), and 5 mo after resumption of menses. Intestinal calcium absorption was determined from the enrichment of the first 24-h urine sample collected after administration of stable calcium isotopes. Bone mineral of the total body and lumbar spine was measured by dual-energy X-ray absorptiometry and quantitative computerized tomography, respectively. Twenty-four-hour urine and fasting serum samples were analyzed for calcium, calcitropic hormones, and biochemical markers of bone turnover. Despite an increase in calcium intake during pregnancy, true percentage absorption of calcium increased from 32.9+/-9.1% at prepregnancy to 49.9+/-10.2% at T2 and 53.8+/-11.3% at T3 (P < 0.001). Urinary calcium increased from 4.32+/-2.20 mmol/d at prepregnancy to 6.21+/-3.72 mmol/d at T3 (P < 0.001), but only minor changes in maternal bone mineral were detected. At EL, dietary calcium and calcium absorption were not significantly different from that at prepregnancy, but urinary calcium decreased to 1.87+/-1.22 mmol/d (P < 0.001) and trabecular bone mineral density of the spine decreased to 147.7+/-21.2 mg/cm3 from 162.9+/-25.0 mg/cm3 at prepregnancy (P < 0.001). Calcium absorption postmenses increased nonsignificantly to 36.0+/-8.1% whereas urinary calcium decreased to 2.72+/-1.52 mmol/d (P < 0.001). We concluded that fetal calcium demand was met by increased maternal intestinal absorption; early breast-milk calcium was provided by maternal renal calcium conservation and loss of spinal trabecular bone, a loss that was recovered postmenses.     

Evaluation of diet in a sample of Czech mothers six months after delivery

BACKGROUND: Health care of nursing mothers and their infants is an important priority of primary preventive care. The mother's diet plays an important role in this respect. The objective of the presented investigation was to assess the adequacy of the dietary intake of lactating mothers during the sixth month after delivery. METHODS AND RESULTS: Data on the education, body weight, height of the mother, dietary intake, evaluated from a three-day dietary record, were collected from 131 nursing mothers and compared with the Czech recommended dietary allowances for nursing mothers as well as with data from 265 controls, i.e. women who did no longer breastfeed their babies. From the results ensues a significantly higher calcium intake (937 mg; SD = 415, p < 0.001), vitamin B1 (1.1 mg, SD = 0.5, p < 0.001), total energy (8.7 MJ, SD = 2.6, p < 0.01), protein 75.4 g, SD = 18, p < 0.01), carbohydrates (281 g, SD = 112, p < 0.01) and riboflavin (1.3 mg, SD = 0.5, p < 0.01) in nursing women as compared with those not nursing. The nursing mothers, however, do not meet the Czech recommended dietary allowances as regards total energy, calcium, vitamin C, linoleic acid, vegetable proteins and iron. Other problematic nutrients-magnesium, zinc, folates, pyridoxine, selenium and iodine could not be assessed as they are not listed in the Czech food composition tables. In women with university education the energy and nutrient intake was in the majority more favourable than in women with elementary education. On the other hand no statistical differences were found in weight increments during the period from the beginning of gestation to the sixth month after delivery between nursing and not nursing mothers. CONCLUSIONS: The results of analysis of the dietary intake of nursing mothers indicate that the Czech recommended allowances are not met as regards energy, calcium, linoleic acid, protein and iron. Whether the intake is really inadequate or whether the recommended allowances are excessive remains an open question.     

Low calcium diet in hypercalciuric calcium nephrolithiasis: first do no harm

Many studies indicate that up-regulated production of 1,25(OH)2-vitamin D3 (calcitriol) with increased intestinal absorption of calcium is the primary event causing idiopathic hypercalciuria. Thus, a low calcium diet appears to be a straightforward strategy in calcium stone formers with hypercalciuria (HCSF). However, the efficacy of such a regimen has never been established, and lowering calcium intake from 1000 to 400 mg/day further enhances calcitriol production. On a diet chronically restricted in calcium, many stone formers increase their intake of animal flesh protein. The latter is known to increase renal mass, and calcitriol levels indeed are positively correlated with renal mass in animals as well as in HCSF. Thus, low calcium and high animal flesh protein consumption are independent stimuli for further up-regulation of calcitriol production. The rise in calcitriol suppresses parathyroid hormone synthesis thereby diminishing renal tubular calcium reabsorption, and increasing urinary calcium losses. Since calcitriol up-regulation also increases bone resorption, the combination of low calcium and high protein intake is particularly likely to induce negative calcium balance and thus osteopenia. Finally, low calcium intake carries the risk of insufficient intestinal binding of oxalate with subsequent increases in intestinal absorption and urinary excretion of oxalate. Indeed, most recent studies suggest that high amounts of calcium, when ingested simultaneously with oxalate-containing meals, are able to prevent hyperoxaluria during severe oral oxalate loading.     

Lactose maldigestion is not an impediment to the intake of 1500 mg calcium daily as dairy products

BACKGROUND: A National Institutes of Health consensus conference concluded that a daily calcium intake of 1500 mg reduces the severity of osteoporosis. Because dairy products are the main natural source of dietary calcium, a diet providing 1500 mg Ca must contain large quantities of dairy products. However, it is widely believed that the lactose content of these products will not be tolerated by persons with lactose maldigestion (approximately 30% of the adult US population). OBJECTIVE: We evaluated the symptoms of lactose maldigestion and digestion when the diet was supplemented with dairy products providing 1300 mg Ca/d. DESIGN: Sixty-two women (31 with lactose maldigestion and 31 without) were studied in a double-blind, randomized protocol. Symptoms were compared during 1-wk periods when the diet was supplemented with 480 mL (2 cups) milk, 56 g cheese, and 240 mL yogurt provided as conventional products (34 g lactose/d) or as lactose-hydrolyzed products (2 g lactose/d). RESULTS: Women who digested lactose reported no significant difference in symptoms between the 2 treatment periods. Women with lactose maldigestion reported significantly increased flatus frequency and subjective impression of rectal gas during the period of high lactose intake; however, bloating, abdominal pain, diarrhea, and the global perception of overall symptom severity were not significantly different between the 2 treatment periods. CONCLUSION: The symptoms resulting from lactose maldigestion are not a major impediment to the ingestion of a dairy-rich diet supplying approximately 1500 mg Ca/d.     

Dietary calcium intake in 18-year-old women: comparison with recommended daily intake and dietary energy intake

Average dietary calcium intake and energy intake of 113 18-year-old university students in Western Australia was examined. Four-day, weighted diet records, including 1 weekend day, were completed by the subjects. A large proportion of the students (68%) had an average daily calcium consumption below the 800 mg recommended by the National Health and Medical Research Council of Australia. A strong positive association was also found between dietary calcium and dietary energy intakes. Many young women on self-imposed energy reduction diets are at risk of a dietary calcium intake deficit at a time when it should be enhanced. These findings are significant for nursing practice as they indicate the need for further health education concerning the importance of dietary calcium in young women.