Mineral contents in model diet samples for different age groups

Dietary and other sources of aluminium intake

Aluminium in the food supply comes from natural sources including water, food additives, and contamination by aluminium utensils and containers. Most unprocessed foods, except for certain herbs and tea leaves, contain low (< 5 micrograms Al/g) levels of aluminium. Thus most adults consume 1-10 mg aluminium daily from natural sources. Cooking in aluminium containers often results in statistically significant, but not practically important, increases in the aluminium content of foods. Intake of aluminium from food additives varies greatly (0 to 95 mg Al daily) among residents in North America, with the median intake for adults being about 24 mg daily. Generally, the intake of aluminium from foods is less than 1% of that consumed by individuals using aluminium-containing pharmaceuticals. Currently the real scientific question is not the amount of aluminium in foods but the availability of the aluminium in foods and the sensitivity of some population groups to aluminium. Several dietary factors, including citrate, may affect the absorption of aluminium. Aluminium contamination of soy-based formulae when fed to premature infants with impaired kidney function and aluminium contamination of components of parenteral solutions (i.e. albumin, calcium and phosphorus salts) are of concern.

Assessment of daily intake of trace elements due to consumption of foodstuffs by adult inhabitants of Rio de Janeiro city

Concentrations of Al, Cd, Cr, Cu, Mn, Ni, Pb, U and Zn were determined in vegetables (leafy vegetables, fruit, root, grain and cereal), derived products (sugar, coffee, manioc flour, wheat flour, corn flour, and pasta) and animal products (meat, fish, milk) most frequently consumed by adult inhabitants of Rio de Janeiro city. A total of 90 samples were analyzed using inductively coupled plasma mass spectrometry (ICPMS) as the principal method following sample dissolution by dry and wet ashing. Generally, highest contributions for the intake of micronutrients (Cu, Mn, Ni and Zn) arise from bean, rice and wheat flour consumption. Meat, cow milk and the flours, wheat and manioc, are major sources of Al, Cd, Pb and U intake. The daily intake of nine elements via foodstuffs was estimated as: 3.4x10(-4) mg of U, 1.8x10(-3) mg of Cd, 2.8x10(-2) mg of Pb, 2.3x10(-2) mg of Cr, 8.9x10(-2) mg of Ni, 1.12 mg of Cu, 2.5 mg of Mn, 3.5 mg of Al and 4.8 mg of Zn. The intake of toxic elements ranged between 2.7% (Cd) and 30% (U) of the provisional tolerable daily intake and reference dose values indicating that food consumption is, at present, no critical factor for the uptake of these toxic metals, in the population studied here. Concerning micronutrients, the recommended values of daily intake of Cu and Mn are conveniently supplied by the diet; however, for Cr and Zn they are lower than the recommend daily allowance. Due to high metal concentrations and consumption rates, black bean is the foodstuff that provided the highest ingestion rates of Cu, Mn, Ni and Zn (36-60% of the reference dose), being therefore a very important source of micronutrient supply.

Ionized magnesium level in whole blood of healthy Japanese children

Magnesium (Mg) catalyzes or activates more than 300 enzymes in the body, and it plays a pivotal role in the metabolism of carbohydrates, fats and proteins. Until recently Mg has only been measured as a total substance concentration; however, it is the free ionized form of magnesium (iMg2+) that is physiologically active. In 1992, a novel ion selective electrode (ISE) utilizing a neutral carrier-based membrane for assessment of iMg2+ in whole blood, plasma or serum was designed and it was used to measure the iMg2+ level in whole blood of 160 healthy Japanese children. There was a significant positive correlation between serum total magnesium (SMg) and iMg2+. Percent ionized magnesium (iMg2+/SMg) was 58.3 +/- 4.1% and increased with growth (age and bodyweight). The level of iMg2+ was 1.29 +/- 0.08 mg/dL (range, 1.09-1.51) ¿0.535 +/- 0.033 mmol/L (range, 0.452-0.627)¿ and was constant irrespective of growth. On the other hand, SMg, serum total calcium (SCa) and ionized calcium (iCa2+) decreased with growth. Thus only iMg2+ level was constant irrespective of growth. It is suspected that the buffer action of protein binding Mg may keep the iMg2+ level constant, because iMg2+ plays an important part in the activation of many enzymes.

Measurement of the daily dietary calcium and magnesium intake in Belgium, using duplicate portion sampling

The daily dietary calcium and magnesium intakes in Belgium were evaluated by sampling duplicate portions of food, destruction in a microwave oven and their calcium and magnesium contents determined by atomic absorption spectroscopy. The mean intake value for calcium (618 +/- 125 mg/day) was found to be less than those values measured in most other countries and was below the recommended daily allowance (RDA). The mean intake value for magnesium (271 +/- 44 mg/day) was similar to levels found in most other countries, but was below the RDA value for healthy adult men (350 mg/day) whilst being adequate for healthy women (280 mg/day).

Daily dietary copper intake in Belgium, using duplicate portion sampling

Daily dietary copper intake in Belgium has been evaluated by duplicate portion sampling, heating in a microwave oven and atomic absorption spectrometric determination of this element. The mean intake value (1.5 +/- 0.4 mg/day) is similar to levels found for most other countries, but is situated at the lower end of the recommended range for a safe and adequate daily dietary intake.

Daily dietary intake of manganese by several population groups in Belgium: preliminary reports

Atomic absorption spectrometry is used to determine manganese content of several duplicate meals consumed by different population groups in the Antwerp region (Belgium). Daily elemental intake, beverages not included, is calculated and proven to be within the recommended daily allowances (National Academy of Sciences, USA) except for a higher intake by macrobiotics (6.7 +/- 3.8 mg per day). Intake level of vegetarians is similar to that of omnivorous adults, 2.9 +/- 2.0 and 2.5 +/- 0.3 mg per day, respectively. Values obtained in this study are compared with scarce data on intake by similar groups in other countries.

Daily dietary manganese intake in Belgium, using duplicate portion sampling

Daily dietary manganese intake in Belgium was evaluated by duplicate portion sampling, destruction by cooking in a microwave oven and subsequent analysis for this element by atomic absorption spectrometry. The mean intake value (3.1 +/- 1.1 mg/day) is similar to levels found for most other countries and is within WHO/RDA and National Research Council, USA recommended intake ranges.

Influence of dietary aluminum on cytokine production by mitogen-stimulated spleen cells from Swiss Webster mice

Swiss Webster mice were exposed to excess dietary aluminum (Al) (1000 micrograms Al/g diet, Al as Al lactate) from conception to 6 months of age. Splenic lymphocytes (10(6) per culture) were incubated for 24 hrs with concanavalin A (5 micrograms/ml). Concentrations of interleukin-2, interferon-gamma and tumor necrosis factor-alpha, as measured in supernatants via ELISA with monoclonal antibodies, were depressed in spleen cells from aluminum treated mice relative to controls. Experiments using the fluorescence activated cell sorter demonstrated a shift in T-cell populations from treated mice with a deficiency of CD4+ cells. These findings suggest a deficit in immune effector cell function after long term in vivo aluminum exposure.