Dietary intake and bioavailability of trace elements

Can magnesium sulfate prophylaxis reduce colistin nephrotoxicity?

The study aimed to investigate the role of magnesium sulfate prophylaxis in nephrotoxicity caused by colistin. Thirty Wistar Albino rats were divided into four groups: control, colistin, magnesium (Mg), and Mg+colistin. The drugs were administered to the groups for seven days. Urea-creatinine values were measured at the beginning (T0) and end (T1) of the study. Malondialdehyde (MDA) levels were measured in plasma and kidney tissue, glutathione (GSH) levels were analyzed in the erythrocyte and kidney tissues. At the end of the study, the semiquantitative score (SQS) was calculated by the histopathological examination of the kidneys. Urea values significantly decreased in Mg and Mg+colistin groups compared to the baseline (p=0.013 and p=0.001). At the time of T1, these groups had significantly lower urea values than the colistin and control groups. Creatinine value was significantly increased in the colistin group compared to baseline (p=0.005), the creatinine value in the colistin group was significantly higher than the Mg+colistin group (p=0.011). Plasma MDA levels were significantly higher in the colistin group compared to the other groups at the time of T1 (p<0.001). The Mg+colistin group had lower renal MDA levels than the colistin group. The colistin group had significantly higher renal tubular grade (p=0.035), renal affected area (p<0.001), and SQS (p=0.001) than the Mg+colistin group. The results of the study suggested that Mg sulfate may have a nephrotoxicity-reducing effect on colistin.

Can magnesium sulfate prophylaxis reduce colistin nephrotoxicity?

The study aimed to investigate the role of magnesium sulfate prophylaxis in nephrotoxicity caused by colistin. Thirty Wistar Albino rats were divided into four groups: control, colistin, magnesium (Mg), and Mg+colistin. The drugs were administered to the groups for seven days. Urea-creatinine values were measured at the beginning (T0) and end (T1) of the study. Malondialdehyde (MDA) levels were measured in plasma and kidney tissue, glutathione (GSH) levels were analyzed in the erythrocyte and kidney tissues. At the end of the study, the semiquantitative score (SQS) was calculated by the histopathological examination of the kidneys. Urea values significantly decreased in Mg and Mg+colistin groups compared to the baseline (p=0.013 and p=0.001). At the time of T1, these groups had significantly lower urea values than the colistin and control groups. Creatinine value was significantly increased in the colistin group compared to baseline (p=0.005), the creatinine value in the colistin group was significantly higher than the Mg+colistin group (p=0.011). Plasma MDA levels were significantly higher in the colistin group compared to the other groups at the time of T1 (p<0.001). The Mg+colistin group had lower renal MDA levels than the colistin group. The colistin group had significantly higher renal tubular grade (p=0.035), renal affected area (p<0.001), and SQS (p=0.001) than the Mg+colistin group. The results of the study suggested that Mg sulfate may have a nephrotoxicity-reducing effect on colistin.

Pharmacokinetic Profile of Oral Magnesium Hydroxide

Despite the presumption of a beneficial effect of magnesium (Mg) supplementation on various diseases, little is known concerning the pharmacokinetics of Mg hydroxide. This study was designed to provide a pharmacokinetic profile of Mg hydroxide after a single oral dose. Ten healthy male adults participated in this cross-over study with three 24-hr study days. Interventions were (i) none (baseline), (ii) oral intake of three (3 × 360 mg) tablets of Mg hydroxide (Mablet^® ) and (iii) IV bolus infusion of 2 g Mg sulphate (index drug). Blood samples were collected before the single dose, after (i.e. after treatment administration) 15, 30, 60, 90 and 120 min. and after 3, 4, 6, 8, 12 and 24 hr. Urine was collected in four 6-hr periods per study day. Blood (N = 10) and urine (N = 6) Mg were analysed by descriptive statistics. Bioavailability was 14.9% (CI: 8.3; 26.8), blood clearance was 5.1 L/hr (CI: 2.1; 17.0), apparent volume of distribution was 60.2 L (CI: 35.6; 102.0), elimination constant was 0.08 per hour (CI: 0.05; 0.14), half-life was 8.3 hr (CI: 4.8; 14.1), C_max was 0.11 mmol/L (CI: 0.07; 0.14), and AUC_[0-24] was 92.3 mmol/L × min. (CI: 45.5; 139.1). Urine Mg excretion augmented by 17.7% (CI: 8.9; 35.0) from baseline. No severe side effects were observed. The bioavailability of Mg hydroxide was 15%, and it constitutes a clinically relevant option for oral Mg supplementation. No severe side effects were seen.

Comparison of dietary fat and fatty acid intake estimated by the duplicate diet collection technique and estimated dietary records

INTRODUCTION

A high saturated fatty acid intake is a well recognized risk factor for coronary heart disease development. More recently a high intake of n-6 polyunsaturated fatty acids (PUFA) in combination with a low intake of the long chain n-3 PUFA, eicosapentaenoic acid and docosahexaenoic acid has also been implicated as an important risk factor.

AIM

To compare total dietary fat and fatty acid intake measured by chemical analysis of duplicate diets with nutritional database analysis of estimated dietary records, collected over the same 3-day study period.

METHODS

Total fat was analysed using soxhlet extraction and subsequently the individual fatty acid content of the diet was determined by gas chromatography. Estimated dietary records were analysed using a nutrient database which was supplemented with a selection of dishes commonly consumed by study participants.

RESULTS

Bland & Altman statistical analysis demonstrated a lack of agreement between the two dietary assessment techniques for determining dietary fat and fatty acid intake.

CONCLUSION

The lack of agreement observed between dietary evaluation techniques may be attributed to inadequacies in either or both assessment techniques. This study highlights the difficulties that may be encountered when attempting to accurately evaluate dietary fat intake among the population.

How to use the world's scarce selenium resources efficiently to increase the selenium concentration in food

The world's rare selenium resources need to be managed carefully. Selenium is extracted as a by-product of copper mining and there are no deposits that can be mined for selenium alone. Selenium has unique properties as a semi-conductor, making it of special value to industry, but it is also an essential nutrient for humans and animals and may promote plant growth and quality. Selenium deficiency is regarded as a major health problem for 0.5 to 1 billion people worldwide, while an even larger number may consume less selenium than required for optimal protection against cancer, cardiovascular diseases and severe infectious diseases including HIV disease. Efficient recycling of selenium is difficult. Selenium is added in some commercial fertilizers, but only a small proportion is taken up by plants and much of the remainder is lost for future utilization. Large biofortification programmes with selenium added to commercial fertilizers may therefore be a fortification method that is too wasteful to be applied to large areas of our planet. Direct addition of selenium compounds to food (process fortification) can be undertaken by the food industry. If selenomethionine is added directly to food, however, oxidation due to heat processing needs to be avoided. New ways to biofortify food products are needed, and it is generally observed that there is less wastage if selenium is added late in the production chain rather than early. On these bases we have proposed adding selenium-enriched, sprouted cereal grain during food processing as an efficient way to introduce this nutrient into deficient diets. Selenium is a non-renewable resource. There is now an enormous wastage of selenium associated with large-scale mining and industrial processing. We recommend that this must be changed and that much of the selenium that is extracted should be stockpiled for use as a nutrient by future generations.

Iron, zinc, manganese and copper intakes in Japanese children aged 3 to 5 years

This study aimed to measure and evaluate the intakes for the four trace elements of Fe, Zn, Mn, and Cu in 3- to 5-y-old Japanese preschool children. The study group consisted of a total of 90 3- to 5-y-old children living in Yokkaichi, Mie, Japan. Diet samples were collected by the duplicate-portion technique on 3 d at three different seasons between summer in 1999 and winter in 2000. The medians of annual mean daily intakes (25th-75th percentile) of Fe, Zn, Mn, and Cu in the 3- to 5-y-old children were 3.1 mg (2.4 to 3.6), 4.0 mg (3.4 to 4.7), 1.3 mg (1.1 to 1.6), and 0.45 mg (0.35 to 0.56), respectively. The annual mean value of the total daily diet intake had significant correlations with the Fe, Zn, Mn and Cu intakes (Spearman's r=0.55, 0.67, 0.58, and 0.55, respectively; p<0.001 for all). There were significant correlations between each mineral intake. The Zn and Mn intakes had differences among ages (p=0.003 and 0.005, respectively) and the Zn intake significantly differed between boys and girls (p=0.031). The proportion of subjects whose Mn intake was the AI or less was 82%, and the proportions of subjects whose Fe, Zn, and Cu intakes were the estimated average requirements (EARs) or less were 72, 83, and 13%, respectively. Many Japanese children are deficient in Fe and Zn compared with the dietary reference intakes (DRIs). However, data in a balance study examining intakes and excretion of trace minerals are insufficient in children and DRIs for trace elements may change in future.

Effect of sub-deficient zinc status on insulin sensitivity after burn injury in rats

Although zinc status is an important parameter in insulin sensitivity, data concerning its implication in noxious burn-induced insulin resistance are scarce. The present study was designed to evaluate the impact of zinc status before burn on the recovery of injury with focus on plasma insulin and glucose levels. The experiment was performed in male adult Wistar rats fed from weaning with a zinc normal diet (80 ppm) or a depleted zinc diet (10 ppm) for 8 weeks and burned to third degree on 20% of their total body surface area. Blood and tissue samples were collected 3, 6, and 24 h after injury in order to study biochemical parameters and the glucose/insulin response in relation with the zinc status. After burn, zinc-depleted rats presented an exacerbated decrease in plasma zinc level. In addition, the burn-induced insulin resistance, leading to protein catabolism, was emphasized, with higher plasma insulin, glucose, and leptin levels in zinc-deficient animals versus normal-fed rats. Our experimental results underlined the interest to early control the zinc status in order to limit the deleterious effects of oxidative stress and insulin resistance in burned patients.

Dietary intake of nickel and zinc by young children--results from food duplicate portion measurements in comparison to data calculated from dietary records and available data on levels in food groups

The daily dietary intake of nickel (Ni) and zinc (Zn) by 42 young children, 21 boys and 21 girls, from 4 to 7 years of age, living in urban and rural areas of Germany and having different food consumption behaviour, was determined by the duplicate method with a 7-day sampling period. Dietary records were also kept by the children's parents for the 7-day sampling period. Individual reported food items were identified, assigned to food groups and, together with known Ni and Zn concentrations of foodstuffs, daily intake rates were calculated. The same method was used for calculations of the energy, fat, protein and carbohydrate intake rates. The levels in the food duplicates, determined by atomic absorption spectrometry, were in the range of 69-2000 microg Ni/kg(dry weight) (geometric mean (GM): 348) and 7.1-43 mg Zn/kg(dry weight) (GM: 17.5). Daily intake rates based on the 294 individual food duplicate analyses were 12-560 microgNi/d (GM: 92.3) and 1.5-11 mgZn/d (GM: 4.63). The results from the dietary records were 35-1050 microg Ni/d (GM: 123) and 1.7-15 mg Zn/d (GM: 5.35). The results of the daily intake rates from both methods showed a correlation with regard to Zn (r=0.56), but no correlation was found between either the Ni intake rates determined with both methods or between the Ni intake rates measured by the duplicate method and calculated intake rates from the dietary records of energy, fat, protein, carbohydrates or drinking water. In the case of nickel, the discrepancies between the methods lead one to suppose that the main factors influencing Ni intake by food are not directly caused by easily assessable food ingredients themselves. It is possible that other factors, such as contaminated drinking water or the transition of Ni from kettles or other household utensils made from stainless steel into the food, may be more relevant. In addition there are some foodstuffs with great variations in concentrations, often influenced by the growing area and environmental factors. Further, some food groups naturally high in Nickel like nuts, cocoa or teas might not have been kept sufficient within the records. In summary, the dietary record method gave sufficient results for Zn, but is insufficient for Ni. Based on the food duplicate analysis, children living in urban areas with consumption of food products from a family-owned garden or the surrounding area and/or products from domestic animals of the surrounding area had about one-third higher Ni levels in their food than children either living in an urban area or children consuming products exclusively from the supermarket. Only slight differences were found with regard to Zn. Compared to the recommendations of the German Society of Nutrition (DGE) (25-30 microgNi/d and 5.0 mgZn/d), the participants of the study had a clearly increased Ni and, in view of the geometric mean value, a nearly adequate Zn intake. Health risks are especially given with regard to the influence of nickel intake by food on dermatitis for nickel-sensitive individuals.

Dietary exposure to copper in the European Union and its assessment for EU regulatory risk assessment

EU legislation requires a multimedia exposure assessment for substances supplied within the EU. Dietary intake is the main source of exposure for the majority of the population hence an essential component of the human risk assessment. This paper describes the available data for dietary copper and its use in estimating daily intake including variability and determinants of exposure. Typical and reasonable worst-case estimates are derived for the general population from the available peer reviewed literature. Intakes from drinking water are found to exhibit more variability than those from food. Therefore, different exposure scenarios are derived to reflect the range of acute and chronic exposures that may occur. Estimates of typical copper intakes for the EU population are in the range 0.8-1.8 mg/day. Typical copper intakes of men are higher than those of women while the intake among the general adult population is higher than that of the elderly. Intakes of both men and women are generally close to the WHO normative requirements but may be somewhat lower in specific locations where background levels of copper are unusually low. Alcoholic beverages represent minor contribution daily copper intakes. Intakes for children are rather variable ranging broadly from 0.7 to 1.5 mg/day and are somewhat age and sex dependent. Greater uncertainty applies to the assessment of local exposure incorporating food produced on land directly impacted by contemporary copper industry emissions. Specifically, the extent to which soil is enriched in copper in these conditions is unclear. However, effective homeostatic control mechanisms in plants limit uptake and transfer to the human food chain. A best estimate of 0.25 mg/day in addition to regional exposure was derived. Drinking water is estimated to contribute only marginally to total copper intake in most cases. Higher intakes may occur in areas of poor water quality and/or corroded distribution systems. Such elevated exposures appear unusual but their frequency is unknown.

Impact of micronutrient dietary intake and status on intestinal zinc absorption in late middle-aged men: the ZENITH study

BACKGROUND

Adjustments in intestinal absorption and losses of zinc (Zn) are thought to maintain Zn homeostasis when dietary intake levels are altered. Zn status may also influence efficiency of intestinal Zn absorption.

OBJECTIVES

To determine the impact of dietary intake and status of some micronutrients on Zn absorption in late middle-aged men.

DESIGN AND PARTICIPANTS

Dietary intake and status of Zn, Cu, Fe, vitamin A, C and fibre, and absorption of Zn were measured in 48 men, aged 58-68 y, confined to a metabolic unit and consuming a typical French diet. Dietary intake was estimated using 4-day food-intake records (including the weekend) and the GENI program. To assess Zn status, serum, erythrocyte, urine Zn levels and serum alkaline phosphatase activity were determined. Zn absorption was determined using the isotope double-labelling method. Zn stable isotopic ratios were measured in plasma samples collected before and 48 h after isotope administration using ICP/MS.

RESULTS

Zn intake within the group of men varied from 5.7 to 20.5 mg/day and averaged 12.9 mg/day. Serum Zn level varied from 10 to 18 micromol/l and averaged 12.9 micromol/l. Zn absorption varied from 12 to 46% and averaged 29.7%. Zn absorption was not significantly (P > 0.05) correlated with Zn intake or with any of the Zn status parameters. Zn absorption was only slightly negatively correlated with serum and erythrocyte Zn levels and with serum Fe and ferritin levels in this study.

CONCLUSION

Zn dietary intake and Zn absorption were satisfactory and led to an adequate Zn status in this population.

Protective role of magnesium in cardiovascular diseases: a review

A considerable number of experimental, epidemiological and clinical studies are now available which point to an important role of Mg2+ in the etiology of cardiovascular pathology. In human subjects, hypomagnesemia is often associated with an imbalance of electrolytes such as Na+, K+ and Ca2+. Abnormal dietary deficiency of Mg2+ as well as abnormalities in Mg2+ metabolism play important roles in different types of heart diseases such as ischemic heart disease, congestive heart failure, sudden cardiac death, atheroscelerosis, a number of cardiac arrhythmias and ventricular complications in diabetes mellitus. Mg2+ deficiency results in progressive vasoconstriction of the coronary vessels leading to a marked reduction in oxygen and nutrient delivery to the cardiac myocytes. Numerous experimental and clinical data have suggested that Mg2+ deficiency can induce elevation of intracellular Ca2+ concentrations, formation of oxygen radicals, proinflammatory agents and growth factors and changes in membrane perrmeability and transport processes in cardiac cells. The opposing effects of Mg2+ and Ca2+ on myocardial contractility may be due to the competition between Mg2+ and Ca2+ for the same binding sites on key myocardial contractile proteins such as troponin C, myosin and actin. Stimulants, for example, catecholamines can evoke marked Mg2+ efflux which appears to be associated with a concomitant increase in the force of contraction of the heart. It has been suggested that Mg2+ efflux may be linked to the Ca2+ signalling pathway. Depletion of Mg2+ by alcohol in cardiac cells causes an increase in intracellular Ca2+, leading to coronary artery vasospasm, arrhythmias, ischemic damage and cardiac failure. Hypomagnesemia is commonly associated with hypokalemia and occurs in patients with hypertension or myocardial infarction as well as in chronic alcoholism. The inability of the senescent myocardium to respond to ischemic stress could be due to several reasons. Mg2+ supplemented K+ cardioplegia modulates Ca2+ accumulation and is directly involved in the mechanisms leading to enhanced post ischemic functional recovery in the aged myocardium following ischemia. While many of these mechanisms remain controversial and in some cases speculative, the beneficial effects related to consequences of Mg2+ supplementation are apparent. Further research are needed for the incorporation of these findings toward the development of novel myocardial protective role of Mg2+ to reduce morbidity and mortality of patients suffering from a variety of cardiac diseases.

Assessment of iodine intake in vegans: weighed dietary record vs duplicate portion technique

OBJECTIVE

To compare iodine intakes estimated from weighed dietary records with iodine intakes obtained by direct analysis of duplicate diets in a group of vegans.

DESIGN

Cross-sectional study.

SETTING

London and the south-east of England.

SUBJECTS

Thirty-three vegans consuming their habitual diet were recruited through the UK Vegan Society; 26 subjects (11 males, 15 females), age 21-84 y, completed the study.

INTERVENTIONS

Iodine intakes were estimated from 4 day weighed dietary records and compared with iodine intakes obtained by direct analysis of concurrent 4 day duplicate diets.

RESULTS

There was wide variation in iodine intakes. Mean daily iodine intake in males was significantly lower (P<0.05) when estimated from dietary records (42 microg) compared with that analysed from duplicate diets (137 microg). Conversely, in females the mean daily iodine intake from dietary records (1448 microg) was higher (P=0.43) than from duplicate diets (216 microg). Variation in iodine intakes determined by the two different methods may be attributed to the absence of iodine content of some foods, in particular foods suitable for vegan consumption, in food composition tables and the variability in iodine content of seaweed.

CONCLUSIONS

The use of current food tables to estimate iodine intake in vegans is limited. It is not always practical to determine iodine intake using the duplicate portion technique, therefore more reliable information on iodine content of foods, incorporating the variation within foods, is needed.

Daily dietary intake of chromium in southern Spain measured with duplicate diet sampling

We measured daily dietary Cr intake in southern Spain by sampling duplicate diets for seven consecutive days in different population groups. Cr was determined by electrothermal atomization-atomic absorption spectrometry. The samples were mineralized in a digestion block with HNO(3), HClO(4) and V(2)O(5). A total of 161 duplicate diets from twenty-three subjects were analysed, and mean levels of Cr intake ranged from 9.39 to 205.16 microg/d. Mean Cr intake (100 microg/d) was similar to levels found for most other countries, and was within the range recommended by the National Research Council for a safe and adequate daily intake (50-200 microg/d). Chromium intake correlated significantly with energy, protein and carbohydrate intake, and with the daily intake of Zn, Fe, Mg, K, Na, Ca and nicotinic acid in the diets analysed.

Essentiality of selenium in the human body: relationship with different diseases

In the present review different aspects related to the essential element selenium in the human organism are considered. A large number of human studies have been performed in order to improve knowledge on the influence of this element in the origin and development of several degenerative diseases. Selenium deficiencies among human beings as well as animals are being recognized worldwide to be related to a number of pathologies. This element has also the special characteristic that the range between its essential and toxic character is very close, and consequently daily dietary intake should be appropriately monitored in individuals. Nevertheless, nowadays there is still a lot of controversy about the optimum dietary level of this element in order to cure or to prevent the appearance of diseases such as cirrhosis, cancer, diabetes, or cardiovascular pathologies. Results obtained in several animal and epidemiological studies have indicated that Se could constitute a dietary factor with protective action against several degenerative diseases.

Iodine intake and iodine deficiency in vegans as assessed by the duplicate-portion technique and urinary iodine excretion

I intake and I deficiency were investigated in thirty vegans (eleven males and nineteen females) consuming their habitual diet. I intake was estimated using the chemical analysis of 4 d weighed duplicate diet collections. The probability of I-deficiency disorders (IDD) was judged from the measurement of urinary I excretion in 24 h urine specimens during the 4 d. There was wide variation in I intake. Mean I intake in males was lower than the reference nutrient intake (RNI; Department of Health, 1991) and mean intake in females was above the RNI, although 36% males and 63% females had I intakes below the lower RNI. Mean I intake in subjects who consumed seaweed (n 3) was in excess of the RNI, and approached the provisional maximum tolerable daily intake (World Health Organization/Food and Agriculture Organization Joint Expert Committee on Food Additives, 1989). The probability of IDD in the group investigated was moderate to severe: three of five subgroups were classified as moderate and two subgroups were classified as severe IDD possibility. The findings highlight that vegans are an 'at risk' group for I deficiency. The I status of vegans and the subclinical effects of low I intakes and infrequent high I intakes on thyroid function in this group should be further studied. Our work has also raised the question of adequate I intakes in groups where cow's milk is not consumed, and has exposed a need for more research in this area.

Determination of the daily selenium intake in Slovakia

Three models were used to determine the daily dietary Selenium intake in Slovakia. The Selenium content of food produced and consumed in the Slovak Republic was used to estimate and calculate the daily Selenium intake based on food consumption data per capita and seven days, (24 h) eating protocol models. In a duplicate portion model, Selenium was analyzed in a whole day hospital diet during an eight-day period. According to these models the daily dietary Selenium intake was 38.2 microg; 43.3 +/- 6.5 microg for men and 32.6 /- 6.6 microg for women; 27.1 +/- 7.8 microg for normal and 32.3 +/- 4.8 microg for nourishing hospital diets. The main contributors of Selenium to daily intake were the following: eggs, pork, and poultry. The obtained results indicate that the daily dietary intake of Selenium of the Slovak people is below the recommended values.

Blood levels of copper, iron, zinc, and lead in adults in India and Pakistan and the effect of oral zinc supplementation for six weeks

Deficiency in the intake of trace elements, such as copper (Cu), iron (Fe), selenium (Se), and zinc (Zn), is very common in the general population of most developing countries. A preliminary study in India and Pakistan showing the plasma levels of Zn and Fe indicates that approx 50% of the subjects who participated have low levels of both Fe and Zn, suggesting a marginal deficiency. The low plasma levels of these elements are more pronounced in females. The mean levels of Ze, Cu, and Fe in the plasma of 83 subjects were 0.71 +/- 0.11, 0.96 +/- 0.10, and 0.80 +/- 0.12 mg/L, respectively. The Cu:Zn ratio in the plasma was 1.43 +/- 0.16. Three groups of 15 subjects each were given three different levels of oral supplements of Zn (15, 30, and 45 mg of Zn as Zn gluconate) for 6 wk, and blood samples were analyzed during various intervals. Plasma concentration of Zn increased significantly (p < 0.001) in all the groups after 4 wk of supplementation and reached almost normal levels after 6 wk. Along with the increase in Zn, there was a significant decrease (p < 0.001) in plasma Cu levels. There were no changes in the concentration of Fe during the supplementation period. The supplementation was well tolerated by most subjects. The results of this pilot study indicate that Zn supplementation is a practical possibility comparable to that of Fe supplementation in order to prevent marginal Zn deficiency in vulnerable groups in the general population of developing countries.

Dietary intake of heavy metals in Bombay city, India

Concentrations of heavy metals such as Pb, Cd, Cu and Zn have been estimated in air particulates, water and food samples collected from different suburbs in Bombay during 1991-1994. The concentrations of these metals are translated into intake rates through inhalation and ingestion pathways. Results indicate the highest concentration of Pb and Cu are in pulses (green gram), Cd in leafy vegetables (amaranth) and Zn in meat. Root vegetables and fruits contained a lower concentration of these metals. Total intakes of Zn, Cu, Pb and Cd through air, water and food were 10,500 micrograms/day, 1500 micrograms/day, 30 micrograms/day and 4.3 micrograms/day, respectively. Although the major contribution for the daily intake is the ingestion route, eventual uptake in the body stream is contributed through inhalation for Pb (41%) and Cd (16%) and ingestion for Cu (98.8%) and Zn (99.6%). The total intake of these elements through the duplicate diet study is 9500 micrograms/day for Zn, 1770 micrograms/day for Cu, 27 micrograms/day for Pb and 2.5 micrograms/day for Cd, respectively. The daily intake of these metals by the population of Bombay is well below the recommended dietary values.

Selenium content of convenience and fast foods in Ayrshire, Scotland

Selenium concentrations were determined via hydride generation atomic absorption spectrometry in more than 100 convenience and fast foods including 34 vegetarian dishes. The foods were purchased mainly in Ayrshire, Scotland but some came from other parts of the UK. The results indicate a considerable amount of selenium in certain mushrooms, spinach, fish, offals and chicken-based products. The selenium content of beef- and pork-based products was generally somewhat lower. Vegetarians having a sufficient intake of mushrooms (in particular button and closed cap mushrooms) and spinach do not seem to be at risk of selenium deficiency provided of course that the selenium in mushrooms, in particular, is bioavailable.

The relationship of nutritional copper to the development of postmenopausal osteoporosis in rats

Factors that influence tissue copper concentration include age, diet, hormones, and pregnancy. In this study we altered diet independently, hormone (estrogen) independently, and various combinations of diet and hormone in animals of the same age to study the effects of ovariectomy complicated with dietary copper deficiency; a deficiency that has been demonstrated to cause bone defects. Sprague-Dawley rats were placed on various combinations of copper deficient or enriched diets before and/or after ovariectomy to determine if copper deficiency aggravated osteoporosis and if return to a copper-adequate diet alleviated it. In this study, ovariectomy did induce an osteopenia that was characterized by decreased trabecular bone. This osteopenia was slightly more severe with copper deficiency, but was not necessarily alleviated by the return of normal copper levels to the diet.

Daily dietary intake of copper, zinc and selenium by different population groups in Burundi, Africa

Daily dietary intake of copper, zinc and selenium for different population groups in Burundi, Africa, has been determined, using different sampling strategies, by atomic absorption spectrometry. Recommended daily intakes (RDA, National Academy, USA) are met for copper and zinc. For selenium, especially the rural population risk a deficiency as observed with a daily intake of 17 micrograms. The importance of different types of food in daily intake is discussed. Legumes proved to be an important source of copper, while for selenium fish contributes in a large part in dietary intake. Calculated total daily intakes are compared with intakes recently published for other countries.