Biomedical subjects

R Van Cauwenbergh

Publications and source records attributed to R Van Cauwenbergh.

16 recordsLinked to original sources

PubMed2002

Calcium, iron and zinc availability from weaning meals.

UNLABELLED: During the weaning period, solid foods are introduced in the diet to complement human milk or infant formula. Consequently, marginal deficiencies may easily develop because of inappropriate feeding and low bioavailability of nutrients. The objective of this study was to determine calcium, iron and zinc availability from weaning foods that contained a variety of ingredients but almost the same dietary fibre content, and to describe dietary factors that influence availability in a linear matter. Availability measurements from eight meals were made in vitro by a continuous-flow dialysis system with preliminary intraluminal digestion. Calcium, iron and zinc were analysed by flame atomic absorption spectrometry; ascorbic acid content was taken from food-composition tables; and macronutrient and mineral contents were obtained from the manufacturer. Calcium availability was higher in fruits (mean +/- SD, 39.2 +/- 4.1%) than vegetables (31.7 +/- 5.8%) (p < or = 0.001). Iron availability was marginally significant higher in vegetables (13.0 +/- 4.7%) than fruits (10.2 +/- 1.6%) (p = 0.027). Zinc availability showed higher availability in fruits (52.3 +/- 22.3%) than vegetables (22.1 +/- 5.6%) (p < or = 0.001). CONCLUSION: A major portion (47.8%) of the variance in calcium availability, as determined by multiple regression, could be explained by protein (p = 0.058, beta = -0.691). Major predictors of iron availability among the nutrients were iron content of the meal (p = 0.014, beta = -0.838), carbohydrates (p = 0.044, beta = -0.610) and dietary fibre (p = 0.235, beta = -0.285). Zinc availability was merely influenced by the protein (p = 0.010, beta = -0.876) and fat content of the meals (p = 0.295, beta = 0.255) in relation to other nutrients.

Calcium↗

PubMed2001

A method for in vitro determination of calcium, iron and zinc availability from first-age infant formula and human milk.

A method for in vitro determination of available calcium, iron and zinc content from infant food after digestion was evaluated. This method introduced an intraluminal digestive phase, adapted to the gastrointestinal conditions of infants younger than 6 months of age, prior to continuous flow dialysis of the resultant gastric digest. Precautions handling the method were discussed and enzymatic parameters were defined. Ruggedness of the method was determined from the availability of calcium, iron and zinc at different gastrointestinal conditions. Availability of all three elements was higher at gastric pH of 2 (20.0 +/- 1.1% for calcium, 4.06 +/- 0.66% for iron and 17.5 +/- 1.3% for zinc), than from the normal procedure (pH 4) (15.6 +/- 1.2% for calcium, 1.18 +/- 0.26% for iron and 8.2 +/- 0.9% for zinc). At pH 5, however, calcium availability appeared to be lower (11.7 +/- 1.0%) (P < 0.05). The intestinal pH also had a major influence on the availability. At low intestinal pH (5.5), availability was 40.5 +/- 2.3% for calcium, 3.01 +/- 0.58% for iron and 26.8 +/- 1.8% for zinc, which was higher compared with the normal procedure (P < 0.05). Moreover, other factors, such as digestion time, mixing and filtration pressure, also affected the availability. Recovery tests yielded mean values of 94 +/- 3% for calcium, 109 +/- 9% for iron and 106 +/- 4% for zinc. Mean intra- and inter-batch precision of the availability procedure was 4.1 CV% and 6.6 CV% for calcium, 14.5 CV% and 19.2 CV% for iron, and 4.0 CV% and 13.6 CV% for zinc. The method provides adequate accuracy, acceptable precision and good recovery. It offers the advantage of being simple, rapid and inexpensive, since it takes only 1 day to run the whole availability procedure (including four replicates per sample), and the low costs of the dialysis equipment. It can therefore be considered as suitable for predicting the availability of essential elements from foods used during the first months of infancy.

Analysis of Variance↗

PubMed2001

In vitro availability of calcium, iron, and zinc from first-age infant formulae and human milk.

BACKGROUND: Variation in the bioavailability of calcium (Ca), iron (Fe), and zinc (Zn) occurs because of interactions of food components in the gastrointestinal microenvironment. Bioavailability is preferably determined by in vivo tests, but these are expensive, labor-intensive, time consuming, and often unethical. As an alternative, in vitro methods can be used to predict bioavailability of nutrients from foodstuffs. METHODS: A continuous-flow dialysis model with preliminary intraluminal digestive phase, adapted to the gastrointestinal conditions of infants younger than 6 months, was used. Human milk was the reference standard. Ca, Fe, and Zn content of samples and dialysates after digestion were analyzed by atomic absorption spectrometry. RESULTS: Ca availability is similar in human milk (13.1%+/-0.8%), whey (13.3%+/-1.2%), and soy-based formulae (13.0%+/-1.2%; P > 0.05), and higher in casein-predominant formula (21.2%+/-0.6%; P < 0.05). Availability of Fe is highest in human milk (8.12%+/-0.27%: P < 0.05). Fe availability in whey (1.28%+/-0.28%) and soy formulae (1.48%+/-0.28%) is similar (P > 0.05), but availability is lower in casein-predominant formula (0.48%+/-0.22%; P < 0.05). Zn availability is also highest in human milk (13.1%+/-0.7%; P < 0.05). However, Zn availability is similar in whey (6.7%+/-0.6%) and casein formulae (8.5%+/-1.6%; P > 0.05), but lower in soy formula (2.3%+/-0.4%; P < 0.05). CONCLUSIONS: Our observations are in agreement with previous data from in vivo studies in term infants. This in vitro procedure is an inexpensive, simple, rapid, and reliable method that predicts the bioavailability of Ca, Fe, and Zn in foods.

Biological Availability↗

PubMed2001

Binding of mineral elements to locust bean gum influences availability in vitro.

Experiments were conducted to evaluate the extent to which element binding of locust bean gum (LBG) affects the availability of calcium, iron, and zinc in the gut. Infant formula was supplemented with increasing amounts of LBG and subjected to an intraluminal digestion procedure. Element binding was measured by eliminating the complexes by twofold centrifugation. Availability of the elements was determined using a validated continuous-flow dialysis technique. Elemental content of the samples, supematants, and dialysates was analyzed with validated atomic absorption spectrometry. LBG provided small amounts of intrinsic calcium (1.13+/-0.02 mg/g) and trace amounts of iron (0.02+/-0.00 mg/g) and zinc (0.01+/-0.00 mg/g), which were strongly bound to the LBG molecule (respectively: 76.6+/-3.3%, 83.4+/-1.2%, 96.7+/-6.6%). Correlation analysis, between percent element bound by LBG after centrifugation and percent trapped after dialysis, yielded significant correlation only for the data of zinc (r = 0.93). For calcium and iron, no correlation could be demonstrated; however, for iron a similar trend was observed. These findings suggest that element binding of LBG has a major influence on the availability of zinc and maybe of iron. For calcium, other factors might also be involved, affecting availability.

Biological Availability↗

PubMed2000

Thickening infant formula with digestible and indigestible carbohydrate: availability of calcium, iron, and zinc in vitro.

BACKGROUND: Regurgitation is common in infants and is usually due to gastroesophageal reflux. Often parental reassurance and dietary management by feeding thickened formulas are the only therapeutic steps necessary. Adding fibers may interfere with the absorption of micronutrients. METHODS: A continuous-flow dialysis in vitro method with a preliminary intraluminal digestive phase, modified to simulate the conditions of infants less than 6 months of age and children from 6 months of age on, was used to study the availability of calcium, iron, and zinc from thickened and nonthickened first-and second-age infant formulas. Pooled mature human milk was used as the reference standard. The elemental content of the samples and dialysate fractions of calcium, iron, and zinc after digestion was determined by atomic absorption spectrometry. RESULTS: In human milk, calcium, iron, and zinc were highly available for absorptive processes. Availability of calcium, iron, and zinc from nonthickened first- and second-age infant formulas tends to be significantly better than in the corresponding products thickened with locust bean gum. Thickening infant formulas with pregelatinized rice starch, however, does not affect the availability of calcium, iron, and zinc. CONCLUSIONS: It appears that human milk provides optimal conditions for the availability of calcium, iron, and zinc. Availability of calcium, iron, and zinc seems to lower when infant formulas are thickened with indigestible carbohydrates, whereas it does not by adding digestible carbohydrates.

Biological Availability↗

PubMed2000

Indication of silicon essentiality in humans: serum concentrations in Belgian children and adults, including pregnant women.

Serum silicon concentrations were determined in Belgian healthy children and adults, including pregnant women, by electrothermal atomic absorption spectrometry. Serum levels appeared to be significantly higher in healthy children (1-18 yr) than in healthy adults (19-60 yr). Especially, levels in infants (< 1 yr) were higher than in any other group. Compared to age-matched nonpregnants, the serum silicon content was very low in pregnant women. In addition to the fact that this study for the first time provides serum silicon values in adults and children in Belgium, the most important observation is that these serum profiles might be an indication of silicon essentiality in man.

Adolescent↗

PubMed1996

Daily dietary chromium intake in Belgium, using duplicate portion sampling.

Daily dietary chromium intake in Belgium has been evaluated by sampling duplicate portions of food, heating them at an acidic pH in a microwave oven and then quantifying the chromium by atomic absorption spectrometry. The mean intake value (53 +/- 31 micrograms/day) is similar to levels found for most other countries and is situated at the lower end of the recommended range for a safe and adequate daily dietary intake.

Belgium↗

PubMed1995

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.

Adult↗

PubMed1995

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).

Adult↗

PubMed1994

Copper, zinc, manganese, iron, lead, cadmium, mercury and arsenic in fish from Lake Tanganyika, Burundi.

Atomic absorption spectrometric determination of copper, zinc, manganese, iron, lead, cadmium, mercury and arsenic in two fish species from Lake Tanganyika, Burundi, provide values that are lower than most literature data, especially for cadmium, arsenic and mercury. Tissue analysis of Lates stapersii reveals that liver accumulates the highest amount of most elements. The data illustrates that Lake Tanganyika is still a non-polluted area at the time of analysis.

Animals↗

PubMed1994

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.

Adult↗

PubMed1994

Actual daily dietary intake of selenium in Belgium, using duplicate portion sampling.

The dietary selenium (Se) intake in Belgium has been re-evaluated. Duplicate meal collection, wet acid destruction and flow injection hydride generation atomic absorption spectrometry were used as techniques. The daily intake ranged from 28.4 micrograms (Liège, Walloon part of the country) to 61.1 micrograms (Vilvoorde, central part of the country). Compared with intakes recently published for other countries, the actual Belgian value corresponds to intermediate ranges of Se intake.

Belgium↗

PubMed1994

Selenium concentration in serum of healthy Greek adults.

Serum selenium levels of 160 healthy Greeks were determined by Zeeman-effect background-corrected atomic absorption spectrometry. Mean value for 101 men (70.7 +/- 16.2 micrograms/L) tended to be higher, but not statistically significant, compared to the mean value for 59 women (64.9 +/- 14.7 micrograms/L). When the subjects were divided into various age groups there appeared to be some increase as a function of age. Compared to the extensive literature data on serum Se levels for various countries healthy Greeks proved to be at the lower concentration range. The scarce, but conflicting literature data on serum Se values for Greeks is discussed.

Adult↗

PubMed1990

Direct selenium determination in human whole blood by graphite furnace atomic absorption spectrometry with deuterium correction using a L'vov-platform, a Pd/Mg matrix modification and appropriate dilution.

A mixture of palladium/magnesium nitrate was used as matrix modifier in graphite furnace atomic absorption spectrometry for the direct determination of selenium in human whole blood Addition of HCl up to 0.2 M, a twenty-five fold diluted sample and an appropriate furnace program are necessary to eliminate the interference of iron. Reproducibility of less than 3% at the 95 micrograms/L level, a detection limit of 10 micrograms/L and good accuracy, as determined by intercomparison runs and recovery of spiked samples, are obtained. The proposed method can be used for analysing 4 blood samples per hour.

Deuterium↗

PubMed1990

Selenium concentration levels in whole blood of Belgian blood bank donors, as determined by direct graphite furnace atomic absorption spectrometry.

Direct graphite furnace atomic absorption spectrometry after appropriate sample dilution is applied to whole blood of Belgian blood bank donors from different geographical areas. Highest values were obtained for the northern part of the country (Flanders). Different consumption habits may explain the significant difference in selenium level found for the two cultural communities (Flemish and Walloon). No sex difference was obtained in both parts of the country and no influence of age was observed for the two communities. Values obtained are compared with literature data on whole blood selenium content for other European countries.

Adult↗

PubMedDate not supplied

Selenium content of livers from sex-linked dwarf and normal broiler breeders. Influence of a thyrotropin-releasing hormone-induced growth hormone release.

Plasma concentrations of cGH, T3, and T4 were not different between dwarf and normal broiler breeders. Normal hens had a liver selenium content of 710 +/- 35 ng/g, and dwarf hens 656 +/- nine ng/g (n = 8). Following injections into a wing vein of different doses (1.5, 3, 6, 12, and 24 micrograms/kg) of the hypothalamic hormone TRH, GH was increased after 15 min. This effect seemed to last longer in dwarf chickens. Plasma concentrations of T3 increased significantly 1 h after TRH in normal hens, but TRH was ineffective in raising T3 levels in dwarf animals. The selenium content of livers obtained following decapitation after 2 h was also increased in normal hens up to 902 +/- 42 ng/g using the highest dose of TRH (24 micrograms/kg). This seemed not to be the case for dwarf animals. A much smaller number of hepatic cGH receptors was also found in dwarf hens, whereas the affinity of the hepatic GH receptor was not influenced by the genotype. It is concluded that the sex-linked dwarf hens are unable to increase their hepatic T4 into T3 conversion following a TRH challenge probably because of a deficiency in hepatic GH receptors. The lower content of selenium in dwarfs and their inability to increase its uptake after TRH seem therefore to support the hypothesis that selenium has a direct role in the activity of the 5'-deiodinase complex.

Animals↗