Biomedical subjects

Richard F Hurrell

Publications and source records attributed to Richard F Hurrell.

43 records · Page 3Linked to original sources

PubMed2002

Improving iron, zinc and vitamin A nutrition through plant biotechnology.

Recent understanding of plant metabolism has made it possible to increase the iron, zinc and beta-carotene (provitamin A) content in staple foods by both conventional plant breeding and genetic engineering. Improving the micronutrient composition of plant foods may become a sustainable strategy to combat deficiencies in human populations, replacing or complementing other strategies such as food fortification or nutrient supplementation.

Anemia, Iron-Deficiency↗

PubMed2002

Phytate degradation determines the effect of industrial processing and home cooking on iron absorption from cereal-based foods.

The aim of the present study was to compare Fe absorption from industrially-manufactured and home-cooked cereal foods. Fe absorption was measured using the radiolabelled Fe extrinsic tag technique in thirty-nine adult human subjects from cereal porridges manufactured by extrusion cooking or roller-drying, and from the same cereal flours after home cooking to produce pancakes, chappattis or bread. One series of cereal porridges was amylase-treated in addition before roller-drying. Fe absorption was relatively low from all products, ranging from 1.8-5.5 % for rice, 2.5-3.5 % for maize, 4.9-13.6 % for low-extraction wheat, and <1 % for high-extraction wheat foods. The phytic acid content remained high after drying of the cereal porridges being about 1.20, 1.70, 3.20, 3.30 mg/g in low-extraction wheat, rice, high-extraction wheat and maize products respectively, and could explain the low Fe absorption. There were little or no differences in Fe absorption between the extruded and roller-dried cereals, although amylase pre-treatment increased Fe absorption from the roller-dried rice cereal 3-fold. This was not due to phytate degradation but possibly because of the more liquid nature of the cereal meal as fed. There were similarly few or no differences in Fe absorption between the industrially-processed cereals and home-cooked cereals made into pancakes or chappattis. Bread-making, however, degraded phytic acid to zero in the low-extraction wheat flour and Fe absorption increased to 13.6 %, the greatest from all cereal foods tested. It is concluded that Fe absorption from extruded, roller-dried or home-cooked cereal foods is similarly low and that only those cooking procedures such as bread-making, which extensively degrades phytic acid, or amylase pre-treatment, which substantially liquifies cereal porridges, improve Fe absorption.

Adult↗

PubMed2002

Iron bioavailability from iron-fortified Guatemalan meals based on corn tortillas and black bean paste.

BACKGROUND: Corn masa flour is widely consumed in Central America and is therefore a potentially useful vehicle for iron fortification. OBJECTIVE: The goal was to evaluate the bioavailability of iron from meals based on corn tortillas and black bean paste that were fortified with ferrous fumarate, ferrous sulfate, or NaFeEDTA and to investigate the potential of Na(2)EDTA to increase the bioavailability of iron from ferrous fumarate. DESIGN: With use of a crossover study design, iron bioavailability was measured in Guatemalan girls aged 12-13 y by a stable-isotope technique based on erythrocyte incorporation 14 d after intake. RESULTS: Geometric mean iron bioavailability from test meals fortified with ferrous fumarate was 5.5-6.2% and was not improved significantly by the addition of Na(2)EDTA at molar ratios of 1:1 relative to fortification iron or to the total iron content of the fortified corn masa flour. Geometric mean iron bioavailability from test meals fortified with ferrous sulfate was 5.5% and was significantly higher in test meals fortified with NaFeEDTA (9.0%; P = 0.009, paired t test). CONCLUSIONS: The bioavailability of iron from ferrous fumarate was not improved by the addition of Na(2)EDTA, contrary to what was previously shown for ferrous sulfate in other cereal-based meals. However, the bioavailability of iron from the test meal was significantly enhanced when NaFeEDTA replaced ferrous sulfate. These results support the use of NaFeEDTA in the fortification of inhibitory staple foods such as corn masa flour.

Adolescent↗

PubMed2002

Treatment of iron deficiency in goitrous children improves the efficacy of iodized salt in Côte d'Ivoire.

BACKGROUND: In many developing countries, children are at high risk of both goiter and iron deficiency anemia. Iron deficiency adversely affects thyroid metabolism and may reduce the efficacy of iodine prophylaxis in areas of endemic goiter. OBJECTIVE: The aim of this study was to determine whether iron supplementation in goitrous, iron-deficient children would improve their response to iodized salt. DESIGN: We conducted a randomized, double-blind, placebo-controlled trial in 5-14-y-old children in Côte d'Ivoire. Goitrous, iron-deficient children (n = 166) consuming iodized salt (10-30 mg I/kg salt at the household level) were supplemented with either iron (60 mg Fe/d, 4 d/wk for 16 wk) or placebo. At 0, 1, 6, 12, and 20 wk, we measured hemoglobin, serum ferritin, serum transferrin receptor, whole-blood zinc protoporphyrin, thyrotropin, thyroxine, urinary iodine, and thyroid gland volume (by ultrasonography). RESULTS: Hemoglobin and iron status at 20 wk were significantly better after iron treatment than after placebo (P < 0.05). At 20 wk, the mean reduction in thyroid size in the iron-treated group was nearly twice that in the placebo group (x +/- SD percentage change in thyroid volume from baseline: -22.8 +/- 10.7% compared with -12.7 +/- 10.1%; P < 0.01). At 20 wk, goiter prevalence was 43% in the iron-treated group compared with 62% in the placebo group (P < 0.02). There were no significant differences between groups in whole-blood thyrotropin or serum thyroxine at baseline or during the intervention. CONCLUSIONS: Iron supplementation improves the efficacy of iodized salt in goitrous children with iron deficiency. A high prevalence of iron deficiency among children in areas of endemic goiter may reduce the effectiveness of iodine prophylaxis.

Adolescent↗

PubMed2002

Fortification: overcoming technical and practical barriers.

The main barriers to successful iron fortification are the following: 1) finding an iron compound that is adequately absorbed but causes no sensory changes to the food vehicle; and 2) overcoming the inhibitory effect on iron absorption of dietary components such as phytic acid, phenolic compounds and calcium. These barriers have been successfully overcome with some food vehicles but not with others. Iron-fortified fish sauce, soy sauce, curry powder, sugar, dried milk, infant formula and cereal based complementary foods have been demonstrated to improve iron status in targeted populations. The reasons for this success include the use of soluble iron such as ferrous sulfate, the addition of ascorbic acid as an absorption enhancer or the use of NaFeEDTA to overcome the negative effect of phytic acid. In contrast, at the present time, it is not possible to guarantee a similar successful fortification of cereal flours or salt. There is considerable doubt that the elemental iron powders currently used to fortify cereal flours are adequately absorbed, and there is an urgent need to investigate their potential for improving iron status. Better absorbed alternative compounds for cereal fortification include encapsulated ferrous sulfate and NaFeEDTA, which, unlike ferrous sulfate, do not provoke fat oxidation of cereals during storage. Encapsulated compounds also offer a possibility to fortify low grade salt without causing off-colors or iodine loss. Finally, a new and useful additional approach to ensuring adequate iron absorption from cereal based complementary foods is the complete degradation of phytic acid with added phytases or by activating native cereal phytases.

Biological Availability↗

PubMed2002

Iron deficiency anemia reduces thyroid peroxidase activity in rats.

Studies in animals and humans have shown that iron deficiency anemia (IDA) impairs thyroid metabolism. However, the mechanism is not yet clear. The objective of this study was to investigate whether iron (Fe) deficiency lowers thyroid peroxidase (TPO) activity. TPO is a heme-containing enzyme catalyzing the two initial steps in thyroid hormone synthesis. Male weanling Sprague-Dawley rats (n = 84) were randomly assigned to seven groups. Three groups (ID-3, ID-7, ID-11) were fed an Fe-deficient diet containing 3, 7 and 11 microg Fe/g, respectively. Because IDA reduces food intake, three control groups were pair-fed Fe-sufficient diets (35 microg Fe/g) to each of the ID groups and one control group consumed food ad libitum. After 4 wk, hemoglobin, triiodothyronine (T(3)) and thyroxine (T(4)) were lower in the Fe-deficient groups than in the ad libitum control group (P < 0.001). By multiple regression, food restriction had a significant, independent effect on T(4) (P < 0.0001), but not on T(3). TPO activity (by both guaiacol and iodine assays) was markedly reduced by food restriction (P < 0.05). IDA also independently reduced TPO activity (P < 0.05). Compared with the ad libitum controls, TPO activity per thyroid determined by the guaiacol assay in the ID-3, ID-7 and ID-11 groups was decreased by 56, 45 and 33%, respectively (P < 0.05). These data indicate that Fe deficiency sharply reduces TPO activity and suggest that decreased TPO activity contributes to the adverse effects of IDA on thyroid metabolism.

Anemia, Iron-Deficiency↗

PubMed2002

Addition of microencapsulated iron to iodized salt improves the efficacy of iodine in goitrous, iron-deficient children: a randomized, double-blind, controlled trial.

OBJECTIVE: In many developing countries, children are at high risk for both goiter and anemia. Iron (Fe) deficiency adversely effects thyroid metabolism and reduces efficacy of iodine prophylaxis in areas of endemic goiter. The study aim was to determine if co-fortification of iodized salt with Fe would improve efficacy of the iodine in goitrous children with a high prevalence of anemia. DESIGN AND METHODS: In a 9-month, randomized, double-blind trial, 6-15 year-old children (n=377) were given iodized salt (25 microg iodine/g salt) or dual-fortified salt with iodine (25 microg iodine/g salt) and Fe (1 mg Fe/g salt, as ferrous sulfate microencapsulated with partially hydrogenated vegetable oil). RESULTS: In the dual-fortified salt group, hemoglobin and Fe status improved significantly compared with the iodized salt group (P<0.05). At 40 weeks, the mean decrease in thyroid volume measured by ultrasound in the dual-fortified salt group (-38%) was twice that of the iodized salt group (-18%) (P<0.01). Compared with the iodized salt group, serum thyroxine was significantly increased (P<0.05) and the prevalence of hypothyroidism and goiter decreased (P<0.01) in the dual-fortified salt group. CONCLUSION: Addition of encapsulated Fe to iodized salt improves the efficacy of iodine in goitrous children with a high prevalence of anemia.

Adolescent↗