Oligofructose stimulates calcium absorption in adolescents

BACKGROUND

In rats, nondigestible oligosaccharides stimulate calcium absorption. Recently, this effect was also found in human subjects.

OBJECTIVE

The objective of the study was to investigate whether consumption of 15 g oligofructose/d stimulates calcium absorption in male adolescents.

DESIGN

Twelve healthy, male adolescents aged 14-16 y received, for 9 d, 15 g oligofructose or sucrose (control treatment) daily over 3 main meals. The treatments were given according to a randomized, double-blind, crossover design, separated by a 19-d washout period. On the 8th day of each treatment period, 44Ca was given orally with a standard breakfast containing approximately 200 mg Ca. Within half an hour after administration of 44Ca, 48Ca was administered intravenously. Fractional calcium absorption was computed from the enrichment of 44Ca:43Ca and 48Ca:43Ca in 36-h urine samples, which was measured by inductively coupled plasma mass spectrometry.

RESULTS

An increase in true fractional calcium absorption (%) was found after consumption of oligofructose (mean difference +/- SE of difference: 10.8+/-5.6; P < 0.05, one sided). The results are discussed in relation to the methods used.

CONCLUSION

Fifteen grams of oligofructose per day stimulates fractional calcium absorption in male adolescents.

Nondigestible oligosaccharides do not interfere with calcium and nonheme-iron absorption in young, healthy men

The effect of inulin, fructooligosaccharides, and galactooligosaccharides on true intestinal absorption of iron and calcium was measured in men by using double stable-isotope techniques (oral 57Fe and 44Ca and intravenous 58Fe and 48Ca). The incorporation of iron isotopes into erythrocytes and the urinary excretion of calcium isotopes was measured with an inductively coupled plasma mass spectrometer. Twelve healthy, nonanemic, male subjects aged 20-30 y received four treatments consisting of a constant basal diet supplemented with 15 g/d inulin, fructooligosaccharide, or galactooligosaccharide, or not supplemented (control treatment). These four treatments were given for 21 d each according to a randomized, crossover design. Iron absorption was measured over the last 7 d of treatment (days 15-21) and calcium absorption was measured on day 21 of each treatment period. Mean (+/- SEM) iron absorption was 5.5 +/- 1.6%, 6.1 +/- 1.9%, 5.3 +/- 1.9%, and 5.1 +/- 1.5%, respectively, during treatment with inulin, fructooligosaccharide, galactooligosaccharide, or the control; mean ( SEM) calcium absorption was 25.8 +/- 2.3%, 26.3 +/- 1.9%, 26.3 +/- 2.6%, and 28.1 +/- 4.3%, respectively. None of the differences between treatments was significant. It is concluded that 15 g/d inulin, fructooligosaccharide, or galactooligosaccharide did not have a negative effect on iron and calcium absorption in young healthy men.

A new method to measure iron absorption from the enrichment of 57Fe and 58Fe in young erythroid cells

Iron absorption can be measured by the incorporation of stable iron isotopes into erythrocytes, 14 days after isotope administration. The disadvantage of this method is the high dose of isotopes needed to obtain a sufficient enrichment. Therefore, in this study cell fractions rich in young erythroid cells were prepared by using a density separation method. From 10 women blood was taken 4, 5, and 7 days after oral and intravenous administration of 57Fe and 58Fe. In these cell fractions and in whole blood taken 14 days after isotope administration, isotope enrichment was measured and absorption calculated. Absorption calculated from the isotope enrichment in the reticulocyte-rich cell fractions (12.2 +/- SEM 3.7%) was not significantly different from absorption based on whole-blood values (13.0 +/- 3.3%). Because a threefold higher isotope enrichment was found in the cell fractions, the required dose of stable isotopes can be reduced to one-third of the dose used in the traditional method without loss of sensitivity.

Interaction of dietary Ca, P, Mg, Mn, Cu, Fe, Zn and Se with the accumulation and oral toxicity of cadmium in rats

The toxicity of Cd was examined in rats fed diets containing 30 mg Cd/kg as CdCl2 for 8 wk. The Cd-containing diets were supplemented with various combinations of the minerals Ca, P, Mg, Mn, Cu, Fe, Zn and Se in order to investigate the protective effect of these mineral combinations on Cd accumulation and toxicity. The mineral combinations were chosen such that the effect of the individual components could be analysed. At the end of the 8-wk feeding period, the Cd concentrations in the liver and renal cortex were 13.9 and 19.5 mg/kg body weight, respectively. The feeding of 30 mg Cd/kg diet alone resulted in well known Cd effects, such as growth retardation, slight anaemia, increased plasma transaminase activities and alteration of Fe accumulation. Only supplements that contained extra Fe resulted in a significant protection against Cd accumulation and toxicity. The most pronounced effect was obtained using a supplement of Ca/P, Fe and Zn, which resulted in a 70-80% reduction in Cd accumulation in the liver and kidneys, as well as a reduction in Cd toxicity. The protective effect of the mineral combinations was mainly due to the presence of Fe2+, but in combinations with Ca/P and Zn the effect of Fe was most pronounced. Compared with Fe2+ the protective effect of Fe3+ was significantly lower. Addition of ascorbic acid to Fe in both forms improved the Fe uptake, but consequently did not decrease Cd accumulation. Thus, the mineral status of the diet may have a considerable impact on the accumulation and toxicity of Cd, fed as CdCl2 in laboratory animals. For the risk assessment of Cd intake, special consideration should be given to an adequate intake of Fe.

Minerals and trace elements in total diets in The Netherlands

1. During a period of 2.5 years, every 3 months 221 different food items forming a 'market basket' were purchased, prepared and divided into twenty-three food-commodity groups. The 'market basket' was based on a study of the dietary intake of 18-year-old male, Dutch adolescents. In the (homogenized) food groups various minerals and trace elements were determined. 2. The mean daily amounts of cadmium (21 micrograms), mercury (0.7 micrograms), lead (32 micrograms), tin (0.65 mg), arsenic (38 micrograms) and bromine (8 mg) in the diet of adolescents, as calculated from the concentrations analysed in the food groups, were all (well) below the Food and Agriculture Organization/World Health Organization acceptable daily intake (ADI) value (Codex Alimentarius Commission, 1984). 3. The mean daily amounts of zinc (14 mg) and selenium (72 micrograms) seemed to be adequate compared with the Dutch recommendations, (Voedingsraad (Dutch Nutrition Council) 1986). The amounts of copper (mean value 1.5 mg/d) and iron (mean value 14 mg/d) in the total diet were marginal. Contents of calcium (1340 mg/d), magnesium (433 mg/d) and iodine (402 micrograms/d) were all well above the Dutch recommendations for male adolescents. Sodium intake, corresponding to 11 g sodium chloride/d, was higher than advised. 4. It is concluded that the amounts of As, Br and toxic heavy metals in Dutch total-diet samples of male adolescents are of little concern as regards health aspects. Among the essential trace elements, Fe and Cu contents seem to be marginal. Some concern regarding the salt content is indicated.

Pesticides and other chemical residues in Dutch total diet samples (June 1976-July 1978)

Over a period of 2 yr 126 different food items of a market basket of 16-18-yr old males were purchased every 2 months. The foodstuffs were prepared as for eating, and were combined in 12 commodity groups. Twelves samples of each food group were homogenized and analysed for 78 different chemicals, including pesticides, PCBs, bromine, heavy metals, arsenic and selenium. Thirty-four of these chemicals were detected in the various samples and the means and ranges of residue concentrations found in each food group are reported. Most chemicals were found in concentrations below the Dutch residue tolerance limits, the two exceptions were omethoate and carbendazim. Using the concentrations found in the total diet samples the daily intakes of the various chemicals were calculated. The daily intake figures were evaluated with the aid of the Acceptable Daily Intakes (ADI) recommended by FAO/WHO. For practically all chemicals examined the mean and the maximum intakes were well below the ADI.