Compared with infant cereals based on refined grains, an infant cereal containing whole grains (WGs) and pulses with adequate amounts of ascorbic acid to protect against absorption inhibitors could ...be a healthier source of well-absorbed iron. However, iron absorption from such cereals is uncertain.
We measured iron bioavailability from ferrous fumarate (Fefum) added to commercial infant cereals containing 1) refined wheat flour (reference meal), 2) WG wheat and lentil flour (WG-wheat-lentil), 3) WG wheat and chickpea flour (WG-wheat-chickpeas), and 4) WG oat flour (WG-oat) and from ferrous bisglycinate (FeBG) added to the same oat-based cereal (WG-oat-FeBG).
In a prospective, single-blinded randomized crossover study, 6- to 14-mo-old Malawian children (n = 30) consumed 25-g servings of all 5 test meals containing 2.25 mg stable isotope-labeled iron and 13.5 mg ascorbic acid. Fractional iron absorption (FIA) was assessed by erythrocyte incorporation of isotopes after 14 d. Comparisons were made using linear mixed models.
Seventy percent of the children were anemic and 67% were iron deficient. Geometric mean FIA percentages (–SD, +SD) from the cereals were as follows: 1) refined wheat, 12.1 (4.8, 30.6); 2) WG-wheat-lentil, 15.8 (6.6, 37.6); 3) WG-wheat-chickpeas, 12.8 (5.5, 29.8); and 4) WG-oat, 9.2 (3.9, 21.5) and 7.4 (2.9, 18.9) from WG-oat-FeBG. Meal predicted FIA (P ≤ 0.001), whereas in pairwise comparisons, only WG-oat-FeBG was significantly different compared with the refined wheat meal (P = 0.02). In addition, FIAs from WG-wheat-lentil and WG-wheat-chickpeas were significantly higher than from WG-oat (P = 0.002 and P = 0.04, respectively) and WG-oat-FeBG (P < 0.001 and P = 0.004, respectively).
In Malawian children, when given with ascorbic acid at a molar ratio of 2:1, iron bioavailability from Fefum-fortified infant cereals containing WG wheat and pulses is ≈13−15%, whereas that from FeBG- and Fefum-fortified infant cereals based on WG oats is ≈7−9%.
1 Nestle Water Institute, 88804 Vittel;
2 Mass Spectrometry Unit, Institut National de la
Santé et de la Recherche Médicale, 31024, Toulouse, France; and
3 Western Human Nutrition Research Center, ...United
States Department of Agriculture, University of California, Davis, California
95616
Submitted 9 December 2002
; accepted in final form 22 May 2003
The aim of this study was to build a compartmental model of magnesium (Mg)
kinetics by using data collected from six healthy adult men after oral
administration of 26 Mg and intravenous administration of
25 Mg. Blood, urine, and feces were collected for 12 days after
administration of the isotopes. Isotopic ratios were determined by inductively
coupled plasma-mass spectrometry. Data were analyzed for each subject using
SAAMII. We began with a compartmental model previously proposed (Avioli LV and
Berman M. J Appl Physiol 21: 1688-1694, 1966) and developed an
alternative approach to resolve the discrepancy between model-predicted curves
and experimental data. This analysis enables the exploration of 25% of total
body Mg that exchanges rapidly from plasma compartment with two extraplasma
pools. One of the extraplasma compartments contains 80% of the exchangeable Mg
with a transport rate of 48 ± 13 mg/h. The second exchanges 179
± 88 mg of Mg/h. The model permitted estimation of kinetic parameters
as well as fractional Mg absorption and fecal endogenous excretion.
magnesium absorption; magnesium fecal endogenous excretion; inductively coupled plasma-mass spectrometry
Address for reprint requests and other correspondence: M. J. Arnaud, Nestle
Water Institute, BP 101, 88804, Vittel Cedex, France.
Purpose
An iron-enriched yeast able to lyse at body temperature was developed for iron fortification of chilled dairy products. The aim was to evaluate iron (Fe) absorption from iron-enriched yeast ...or ferrous sulfate added to fresh cheese.
Methods
Two stable isotope studies with a crossover design were conducted in 32 young women. Fe absorption from fresh cheese fortified with iron-enriched yeast (2.5 mg
58
Fe) was compared to that from ferrous sulfate (2.5 mg
57
Fe) when ingested with fresh cheese alone or with fresh cheese consumed with bread and butter. Iron absorption was determined based on erythrocyte incorporation of isotopic labels 14 days after consumption of the last test meal.
Results
Geometric mean fractional iron absorption from fresh cheese fortified with iron-enriched yeast consumed alone was significantly lower than from the cheese fortified with FeSO
4
(20.5 vs. 28.7 %;
p
= 0.0007). When the fresh cheese was consumed with bread and butter, iron absorption from both fortificants decreased to 6.9 % from the iron-enriched yeast compared to 8.4 % from ferrous sulfate. The relative bioavailability of the iron-enriched yeast compared to ferrous sulfate was 0.72 for the cheese consumed alone and 0.82 for cheese consumed with bread and butter (
p
= 0.157).
Conclusions
Iron from iron-enriched yeast was 72–82 % as well absorbed as ferrous sulfate indicating that the yeast lysed during digestion and released its iron.
The two objectives were 1) to evaluate the solubility of two iron casein complexes (ICCs) under a condition mimicking gastric pH, 2) to evaluate the impact of ascorbic acid (AA) on the in vitro iron ...absorption of ICCs after incorporation in reconstituted whole milk powder.
The in vitro solubility was determined over time after addition of diluted HCl (pH 1.7), ultracentrifugation and measurement of iron appearing in the supernatant by ICP-OES (n = 2). The impact of AA on iron uptake from the Fe compounds in reconstituted milk was determined using the in vitro digestion coupled with the Caco-2 cell model and the measurement of ferritin/total protein produced by the cells (n = 3). The molar ratio of AA to iron of 2 to 1 recommended by the WHO for iron absorption optimization has been tested with an iron level corresponding to 3.3 mg Fe/serving of milk. Ferrous sulfate (FeSO4), the reference compound for iron bioavailability and micronized ferric pyrophosphate (FePP), main salt used for milk fortification were used as references.
The dissolution test showed a rapid solubilization of iron from the ICCs i.e., >75 ± 19.3% at 5 min and >89 ± 0.3% at 90 min. The kinetics of soluble iron from the complexes were like that from FeSO4. The solubility of FePP was only 37.6 ± 4.7% at 90 min. Without AA, the iron uptake from FeSO4 was lower than expected translating into a relative in vitro bioavailability (iRBA) of FePP and of the two ICCs to FeSO4 of 66, 169 and 215%. This might be explained by a rapid conversion of soluble iron from FeSO4 into Fe3+ and insoluble iron hydroxide when the pH increased from 2 to >7 during in vitro digestion. However, with the addition of AA in the milk, iron uptake by the cells was found to be increased to levels of 341.8 ± 8.9, 124 ± 12.2, 403.1 ± 117.8 and 362.9 ± 36.9 ng ferritin/mg protein for FeSO4, FePP and the two ICCs respectively. This translates into iRBAs to FeSO4 of 36% for FePP and of 118 and 106% for the two ICCs.
The solubility and the demonstrated impact of AA on Fe uptake suggest that ICCs are absorbed to a similar amount as FeSO4 and thus provide an excellent source of Fe.
Société des Produits Nestlé, NPTC Konolfingen, Switzerland.
Dietary bioactive compounds (vitamin E, carotenoids, polyphenols, vitamin C, Se and Zn) have beneficial effects on skin health. The classical route of administration of active compounds is by topical ...application direct to the skin, and manufacturers have substantial experience of formulating ingredients in this field. However, the use of functional foods and oral supplements for improving skin condition is increasing. For oral consumption, some dietary components could have an indirect effect on the skin via, for example, secondary messengers. However, in the case of the dietary bioactive compounds considered here, we assume that they must pass down the gastrointestinal tract, cross the intestinal barrier, reach the blood circulation, and then be distributed to the different tissues of the body including the skin. The advantages of this route of administration are that the dietary bioactive compounds are metabolized and then presented to the entire tissue, potentially in an active form. Also, the blood continuously replenishes the skin with these bioactive compounds, which can then be distributed to all skin compartments (i.e. epidermis, dermis, subcutaneous fat and also to sebum). Where known, the distribution and mechanisms of transport of dietary bioactive compounds in skin are presented. Even for compounds that have been studied well in other organs, information on skin is relatively sparse. Gaps in knowledge are identified and suggestions made for future research.
It is generally considered that the absorption of Mg is inversely related to the ingested dose. The objective of the present study was to determine if the mode of administration (bolus v. consumption ...throughout the day) could influence Mg bioavailability from Mg-rich natural mineral water comparing the same nutritional Mg amount (126 mg). Using a 2 d cross-over design, twelve healthy men were asked to drink 1·5 litres Mg-rich mineral water either as 2 × 750 ml or 7 × 212 ml throughout the day. Two stable isotopes (25Mg and 26Mg) were used to label the water in order to distinguish both regimens. Fractional apparent Mg absorption was determined by faecal monitoring and Mg retention was determined by measuring urinary excretion of Mg isotopes. Higher Mg absorption (50·7 (sd 12·7) v. 32·4 (sd 8·1) %; P = 0·0007) and retention (47·5 (sd 12·9) v. 29·0 (sd 7·5) %; P = 0·0008) from Mg-rich mineral water were observed when it was consumed in seven servings compared with larger servings. Thus, regular water consumption throughout the day is an effective way to increase Mg bioavailability from Mg-rich mineral water.
Background: The double-labeling (DL) method for determining magnesium absorption is less cumbersome than is the fecal monitoring method, which has been used most often, but it has not been validated. ...Objective: The aim of this study was to compare methods and several sampling protocols for determining magnesium absorption to establish a simple and reliable alternative to the fecal monitoring approach. Fecal monitoring was used as the standard against which the DL methods based on urine data (DLU), plasma data (DLP), and plasma kinetics with the use of a deconvolution analysis (DP) were compared. Design: Six healthy adult men received 70 mg 26Mg orally and 30 mg 25Mg intravenously. Multiple blood samples and complete urine and fecal samples were collected over 12 d. Stable-isotope ratios were determined by inductively coupled plasma mass spectrometry. Results: Results from DLU were not significantly different from the fecal monitoring reference value (0.48 +/- 0.05; x̄ +/- SD) when based on 3-d urine pools from 72 to 144 h (0.54 +/- 0.04) and when based on the 24-h urine pools from 48 to 72 h (0.49 +/- 0.06), 72 to 96 h (0.51 +/- 0.11), and 96 to 120 h (0.50 +/- 0.06). Results with the DLP method 72 h after isotope administration also compared well with those with the fecal monitoring method (0.54 +/- 0.09). Magnesium absorption was 0.47 +/- 0.06 with the DP method, which also agreed with the fecal monitoring value. Conclusions: The DL methods are an alternative to fecal monitoring when applied within the appropriate time intervals. Therefore, DLU-the simplest and least invasive approach-is recommended for determining magnesium absorption.
The double-labeling (DL) method for determining magnesium absorption is less cumbersome than is the fecal monitoring method, which has been used most often, but it has not been validated.
The aim of ...this study was to compare methods and several sampling protocols for determining magnesium absorption to establish a simple and reliable alternative to the fecal monitoring approach. Fecal monitoring was used as the standard against which the DL methods based on urine data (DLU), plasma data (DLP), and plasma kinetics with the use of a deconvolution analysis (DP) were compared.
Six healthy adult men received 70 mg 26Mg orally and 30 mg 25Mg intravenously. Multiple blood samples and complete urine and fecal samples were collected over 12 d. Stable-isotope ratios were determined by inductively coupled plasma mass spectrometry.
Results from DLU were not significantly different from the fecal monitoring reference value (0.48 ± 0.05; x̄ ± SD) when based on 3-d urine pools from 72 to 144 h (0.54 ± 0.04) and when based on the 24-h urine pools from 48 to 72 h (0.49 ± 0.06), 72 to 96 h (0.51 ± 0.11), and 96 to 120 h (0.50 ± 0.06). Results with the DLP method 72 h after isotope administration also compared well with those with the fecal monitoring method (0.54 ± 0.09). Magnesium absorption was 0.47 ± 0.06 with the DP method, which also agreed with the fecal monitoring value.
The DL methods are an alternative to fecal monitoring when applied within the appropriate time intervals. Therefore, DLU—the simplest and least invasive approach—is recommended for determining magnesium absorption.
The aim of this study was to build a compartmental model of magnesium (Mg) kinetics by using data collected from six healthy adult men after oral administration of 26Mg and intravenous administration ...of 25Mg. Blood, urine, and feces were collected for 12 days after administration of the isotopes. Isotopic ratios were determined by inductively coupled plasma-mass spectrometry. Data were analyzed for each subject using SAAMII. We began with a compartmental model previously proposed (Avioli LV and Berman M. J Appl Physiol 21: 1688-1694, 1966) and developed an alternative approach to resolve the discrepancy between model-predicted curves and experimental data. This analysis enables the exploration of 25% of total body Mg that exchanges rapidly from plasma compartment with two extraplasma pools. One of the extraplasma compartments contains 80% of the exchangeable Mg with a transport rate of 48 ± 13 mg/h. The second exchanges 179 ± 88 mg of Mg/h. The model permitted estimation of kinetic parameters as well as fractional Mg absorption and fecal endogenous excretion.
Magnesium intakes in many industrialized countries are below recommended daily allowances. Magnesium-rich mineral water may contribute to coverage of magnesium requirements by providing significant ...amounts of natural, energy-free, bioavailable magnesium.
The objectives were to determine magnesium bioavailability from magnesium-rich (110 mg/L) mineral water in healthy subjects when consumed alone and to evaluate the effect of simultaneous meal consumption.
Magnesium bioavailability was measured in 10 healthy women with the use of a crossover design. Stable magnesium isotopes (25Mg and 26Mg) were administered orally with mineral water, which was consumed with or without a meal. Apparent magnesium absorption was determined by fecal monitoring, and magnesium retention was determined from urinary excretion of magnesium isotopes.
The mean (±SD) magnesium absorption from mineral water consumed alone was 45.7 ± 4.6% (range: 40.2–55.5%) and was significantly greater (P = 0.0001) when it was consumed with a meal (52.3 ± 3.9%; 46.2–60.2%), a relative difference of 14.4%. Magnesium retention also was significantly greater (P = 0.0004) when mineral water was consumed with a meal (41.5 ± 4.2%; 35.2–50.6%) than when consumed alone (37.4 ± 4.0%; 33.1–47.0%), a relative difference of 11.0%.
In healthy young women, ≈50% of the magnesium from magnesium-rich mineral water was absorbed when consumed alone. Magnesium bioavailability from mineral water is enhanced when the water is consumed with a meal, perhaps because of a slower gastrointestinal transit time, the presence of digestion products from the meal, or both. Regular consumption of magnesium-rich mineral water could make a valuable contribution to magnesium requirements.
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