• Journal of Nutrition and Health
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• v.26 no.6
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• pp.703-714
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• 1993

The iron content of 178 food items were analyzed by ICP to provide database to calculate dietary intake of iron in Korea. The analysis data showed significant deviations of iron contents in some food items compared with Food Composition Table of KRNI which is most widely used at present. Three day dietary intake records were collected from 96 female college students to estimate mean daily iron intake and bioavailability of dietary iron. Mean daily intake of total iron in the study subjects was 13.2mg and heme iron intake was 0.94mg, 6.7% of total iron intake. BGioavailability of dietary iron was calculated by two methods. Total absorbable iron was calculated by the method of Monsen, body iron storage of the subjects being estimated with serum ferritin concentrations, was 1.21mg and bioavailability of dietary iron was thus 9.3%. Bioavailability calculated with the method by Hallberg was 11.22%. Two values of dietary iron bioavailability of the present study are lower than the reported values in adult women consuming typical western diets but within the range estimated for vegetarians. Considering high prevalence of iron deficiency based on serum ferritin concentrations and low bioavailability of diet in young adult Korean women, more efforts should be made to increase the content and bioavailability of iron in diet of Korea adult women.

• Korean Journal of Community Nutrition
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• v.9 no.2
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• pp.142-150
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• 2004

To increase both iron and enhancers for iron absorption through diets should be a basic strategy to sufficiently provide increased iron for pregnancy. Previous studies reported that iron intakes of Korean pregnant women were short and their iron status deteriorated as pregnancy progressed. However, there is little data about the bioavailability of dietary iron during pregnancy. Therefore, this study was conducted to determine the changes of dietary iron intakes, its bioavailability and iron status during pregnancy longitudinally in Korean women. A total of 151 pregnant women in their first trimester of pregnancy voluntarily participated. Among them, 72 women finished the research protocol during the second trimester and 55 did it during the third trimester. Dietary intakes of total iron, both non-heme and heme iron, as well as enhancers, both MPF (meat, poulty, and fish) and vitamin C, increased significantly as pregnancy progressed. As the results, bioavailability of dietary iron and iron absorbed increased significantly as pregnancy progressed. However, the amount of iron absorbed at each trimester did not meet considerably the iron needed during pregnancy. All five indices examined in the study, Hb level, Hct, serum concentrations of ferritin and sTfR (soluble transferrin receptor), and sTfR: ferritin ratio, showed that iron status of the subjects deteriorated as pregnancy progressed. The rate of anemia of the subjects increased as pregnancy progressed although more than 80% of the subjects took iron supplements after the 20th week of pregnancy. These results imply that it is needed to provide more iron especially, heme iron and dietary enhancers to prevent the deterioration of iron status during pregnancy. Future research on bioavailability of supplemental iron should be performed to determine the iron balance precisely.

• Archives of Pharmacal Research
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• v.26 no.10
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• pp.874-879
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• 2003

The present study was carried out to examine the stability of microencapsulated ascorbic acid in simulated-gastric and intestinal situation in vitro and the effect of microencapsulated ascorbic acid on iron bioavailability. Coating materials used were polyglycerol monostearate (PGMS) and medium-chain triacylglycerol (MCT), and core materials were L-ascorbic acid and ferric ammonium sulfate. When ascorbic acid was microencapsulated by MCT, the release of ascorbic acid was 6.3％ at pH 5 and 1.32％ at pH 2 in simulated-gastric fluids during 60 min. When ascorbic acid was microencapsulated by PGMS, the more ascorbic acid was released in the range of 9.5 to 16.0％. Comparatively, ascorbic acid release increased significantly as 94.7％ and 83.8％ coated by MCT and PGMS, respectively, for 60 min incubation in simulated-intestinal fluid. In the subsequent study, we tested whether ascorbic acid enhanced the iron bioavailability or not. In results, serum iron content and transferring saturation increased dramatically when subjects consumed milks containing both encapsulated iron and encapsulated ascorbic acid, compared with those when consumed uncapsulated iron or encapsulated iron without ascorbic acid. Therefore, the present data indicated that microencapsulated ascorbic acid with both PGMS and MCT were effective means for fortifying ascorbic acid into milk and for enhancing the iron bioavailability.

• Journal of Nutrition and Health
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• v.36 no.3
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• pp.262-269
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• 2003

The effect of dietary supplementation of the two oriental medicinal prescriptions, Sypjeondaebotang or Jahyulyanggeuntang, on iron bioavailability was evaluated in rats which were depleted of iron by being fed an irondeficient diet for 4 weeks. Seventy two iron-depleted rats were randomly divided into 3 groups (n = 24) , and fld one of the following experimental diets for 4 (n = 8), 12 (n = 8), and 25 days (n = 8) : Control diet (CD), Sypjeondaebotang-supplemented diet (SD), Jahyulyanggeuntang -supplemented diet (JD). The CD contained 20 mg Fe/kg diet as FeSO4, and the SD or JD was identical except that the respective oriental medicinal prescription extract was included at the level of 4 g/kg diet. Animals fed the SD and JD for 25 days consumed significantly less food (p＜0.001), but showed no change in food efficiency ratio compared to those that were fed the CD. Serum iron concentration and transferrin saturation values were significantly higher in rats fed the SD for 25 days compared to those that were fed the CD for the same period (p < 0.05). The values of serum UIBC (p < 0.05) and TIBC (p > 0.05) were lower in rats fed the SD compared to those fed the CD. Dietary supplementation of Sypjeondaebotang during the period of iron repletion significantly increased blood levels of hemoglobin (p < 0.05) and hematocrit (p < 0.01) measured at day 12, and increased mean corpuscular volume (p < 0.05) measured at day 25, compared to the values for the CD rats. Regression analyses of hemoglobin-repletion bioassay data from rats fed the SD and JD showed the relative biological values of 123% and 99%, respectively, calculated against the slope for the CD rats. Apparent iron absorption and retention values were also significantly lower (p < 0.05) in rats fed the SD for 25 days than those for the CD rats. Based on the results from diverse biochemical indices of iron status and the chemical balance study, the effect of Jahyulyanggeuntang on iron bioavailability appears to be less prominent than that for Sypjeondaebotang. Taken together, these results indicate that Sypjeondaebotang has a positive effect in restoring iron depletion by increasing the iron bioavailability in rats.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.7
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• pp.1120-1126
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• 2007

An iron-fortified whey protein concentrate (Fe-WPC) was prepared by addition of ferric chloride to concentrated whey. A large part of the iron in the Fe-WPC existed as complexes with proteins such as ${\beta}$-lactoglobulin. The bioavailability of iron from Fe-WPC was evaluated using iron-deficient rats, in comparison with heme iron. Rats were separated into a control group and an iron-deficiency group. Rats in the control group were given the standard diet containing ferrous sulfate as the source of iron throughout the experimental feeding period. Rats in the iron-deficiency group were made anemic by feeding on an Fe-deficient diet without any added iron for 3 wk. After the iron-deficiency period, the iron-deficiency group was separated into an Fe-WPC group and a heme iron group fed Fe-WPC and hemin as the sole source of iron, respectively. The hemoglobin content, iron content in liver, hemoglobin regeneration efficiency (HRE) and apparent iron absorption rate were examined when iron-deficient rats were fed either Fe-WPC or hemin as the sole source of iron for 20 d. Hemoglobin content was significantly higher in the rats fed the Fe-WPC diet than in rats fed the hemin diet. HRE in rats fed the Fe-WPC diet was significantly higher than in rats fed the hemin diet. The apparent iron absorption rate in rats fed the Fe-WPC diet tended to be higher than in rats fed the hemin diet (p = 0.054). The solubility of iron in the small intestine of rats at 2.5 h after ingestion of the Fe-WPC diet was approximately twice that of rats fed the hemin diet. These results indicated that the iron bioavailability of Fe-WPC was higher than that of hemin, which seemed due, in part, to the different iron solubility in the intestine.

• Korean Journal of Community Nutrition
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• v.2 no.1
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• pp.23-32
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• 1997

To evaluate iron nutritional status of female college students, fasting blood samples were taken from 76 female students of Kangnung National University. Hemoglobin(Hb), hematocrit(Hct), serum iron(Fe), total iron binding capacity(TIBC) and serum ferritin concentrations were measured and transferrin saturation was calculated. Mean values for Hb, Hct, Fe, TIBC, TS and serum freeitin were 13.64$\pm$1.42g/dl, 40.99$\pm$4.31%, 103.0$\pm$33.3$\mu\textrm{g}$/이, 395.3$\pm$9.07$\mu\textrm{g}$/dl, 26.58$\pm$9.07$\%$and 26.76$\pm$17.5ng/ml, respectively. Prevalence of iron deficiency greatly varied by indices from 6.8% when judged by Hct to 26.0$\%$ by serum ferritin concentration. The Hb concentration was positively correlated with hematocrit (r=0.5402), serum iron(r=0.2819) and transferrin saturation(r=0.2777)(p<0.05). on the other hand, serum ferritin concentration showed significantly negative correlation with TIBC(r=-0.3196). Two-day dietary intake records were collected from subjects to estimate mean daily iron intake and bioavailability of dietary iron. Mean daily intake of iron was 13.15mg and heme iron intake was 0.83mg which was 6.4% of total iron intake. Total absorbable iron calculated by the method of Monsen was 1.27mg and bioavailability of dietary iron was 9.6%. In the light of high prevalence of iron deficiency based of serum ferritin concentration and low bioavailability of iron in the diet, guidelines about diet should be made to increase the content and bioavailability of iron in the diet if female college students.

• Journal of Nutrition and Health
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• v.27 no.5
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• pp.451-459
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• 1994

This study was performed to investigate the effect of sources of protein on iron bioavailability in 10 healthy young Korean women. The 18-day metabolic study consisted of a 6-day adaptation period, 6-day moderate protein(60g protein/day, 18mg Fe/day) and 6-day high protein period(90g protein/day, 18mg Fe/day). During the moderate and high protein period, 5 subjects were fed the high plant protein meals(80% plant protein). Fecal excretion of dietary iron was significantly higher(p<0.05) in high protein high plant diet group(HPP, 9.48$\pm$1.61mg/day) than in high protein high animal diet group (HPA, 14.40$\pm$0.89mg/day). Apparent absorption and bioavailability of iron was also significantly higher(p<0.10) in HPA(40.7$\pm$5.3%, 6.46$\pm$1.61mg/day) than in HPP(14.4$\pm$5.3%, 2.39$\pm$0.89mg/day). But there was no significant difference between the high animal protein group and high plant protein group in moderate protein period. Serum iron concentration and transferrin saturation increased as animal protein intake increased, from 106.0$\pm$5.1ug/이 and 30.6$\pm$1.5% for MPA to 129.1$\pm$6.7ug/이 and 37.1$\pm$1.3% for HPA. Statistically positive correlations were shown not only between the level of dietary heme iron and apparent absorption(r=0.95, p<0.05), but also between serum iron concentration and apparent absorption(r=0.64, p<0.05). Negative iron balance was shown in two subjects fed the moderate protein meals. These results suggest that recommanded dietary allowances of iron may be under the need to maintain the positive balance, and iron bioavaliability increase by only high level of animal protein intake.

• Journal of Nutrition and Health
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• v.37 no.8
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• pp.645-654
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• 2004

This study examined the effect of excess calcium (Ca) on the iron (Fe) bioavailability and bone growth of marginally Fe deficient animals. Two groups of weanling female SD rats were fed either normal Fe (35 ppm) or Fe deficient diet (8 ppm) for 3 weeks. Then each group of animals were assigned randomly to one of three groups and were fed one of six experimental diets additionally for 4 weeks, containing normal (35 ppm) or low (15 ppm) Fe and one of three levels of Ca as normal (0.5%), high (1.0%), or excess (1.5%). Feces and urine were collected during the last 3 days of treatment. After sacrifice blood, organs, and femur bone were collected for analysis. Final body weight and average food intake were not affected by either the levels of dietary Ca or Fe. Low Fe diet significantly reduced the level of serum ferritin, however, for Hb, Hct, and TIBC no difference was shown than those in the normal Fe group. TIBC increased slightly by high and excess Ca intake in low Fe groups. For both normal and low Fe groups, high and excess Ca intakes reduced the apparent absorption of Fe and Fe contents of liver significantly (p < 0.05). Calcium contents in kidney and Femur of rats that were fed high and excess levels of Ca were significantly greater than those of normal Ca groups. However, weight, length, and breaking force of the bone were not affected by increased Ca intakes. Both in control and low Fe groups, high and excess intakes of Ca decreased the apparent absorption of Ca. These results indicate that the excess intakes of calcium than the normal needs would be undesirable for Fe bioavailability and that the adverse effects be more serious in marginally iron deficient growing animals. In addition bone growth and strength would not be favorably affected by high Ca intakes, though, the long term effect of increased Ca contents in bone requires further examination.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.9
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• pp.1266-1270
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• 2004

Humic substances include several biological active and inactive compounds that are commonly used for improving soil fertility. Use of humic substances in swine diets is a novel concept. Humic substances contain 8,700 mg/kg of iron but its bioavailability is unknown. This study was conducted to test the bioavailability of iron in humic substances for nursery pigs. One hundred twenty five pigs (Newsham, Colorado Springs, CO) were not given supplemental iron while nursing for 21 d. Pigs were weaned on d 21 and allotted to one of five treatments (four control treatments with different levels of supplemented iron; 0, 30, 70 and 88 mg/kg from ${FeSO}_4$ and one treatment with 70 mg/kg iron from humic substances). Pigs were fed diets for 5 wk ad libitum and water was accessible freely. Body weight and feed intake were measured weekly. Blood samples were taken from pigs on d 28 to measure the number of red blood cells and hemoglobin concentration. Pigs fed a diet with the humic substances grew faster (p<0.05) during the first week postweaning, but performance was not different during the entire 5 wk period. Feed intake and gain/feed were the same among treatments. The slope ratio technique was used to estimate relative iron bioavailability. The concentration of blood hemoglobin did not respond to dietary iron levels using this model. However, the number of red blood cells (106/$\mu$l) was modeled by 4.438+0.017${\times}$ 'ron (mg/kg) from ${FeSO}_4$'0.012${\times}$'ron (mg/kg) from the humic substances' Based on the comparison between the slopes (0.012 from humic substances and 0.017 from ${FeSO}_4$), iron in humic substances was 71% as available as the iron in ${FeSO}_4$. The slopes for dietary feed intake of ${FeSO}_4$ and the iron in humic substances did not differ (p>0.05). Humic substances can replace ${FeSO}_4$ as an alternative iron source for pigs at 71% relative bioavailability.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.3
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• pp.349-358
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• 1993

Iron deficiency is still a common nutritional disorder in the world. In developing countries, the bioavailability of dietary iron is often very low, mainly due to a low content of factors facilitating nonheme iron absorption. The iron content of the diet, iron status of subjects, and the actual composition of the diet are the major factors that influence the absorption of food iron. Inadequate dietary intake of iron often results from low-calorie diets, food restrictions, or single food diets. Ascorbic acid and MFP (meat, fish and poultry) are the quantitatively most important enhancers of nonheme iron absorption found in the diet. Ascorbic acid and meat have consistently been shown to enhance iron bioavailability. Major inhibitors of nonheme iron absorption are dietary fiber, phytate, and polyphenols. The availability of nonheme iron can be highly influenced by components of foods ingested concomitantly, Therefore, consumption of food in combinations can either enhance or inhibit nonheme iron absorption.