Determinants of iron status in Malaysian adolescents from a rural community

Iron deficiency anaemia is the most common micronutrient deficiency worldwide. The prevalence of anaemia in the developing countries is three to four times higher than that in the developed countries. The iron status was assessed in 199 apparently healthy male and female adolescents aged 12–19 years living in a fishing community in Sabah, Malaysia. Data on socio-economic characteristics, lifestyles, anthropometry measurements, iron status, and dietary intake were gathered. Dietary intake of energy, iron, and most nutrients (with the exception of protein and vitamin C) were below the recommended levels for Malaysian adolescents. Three-quarters of the iron was derived from plant foods. The mean haemoglobin value for the male was 13.9±1.3 g/dl with 9.5% having less than 12 g/dl, while the respective figures for the female were 12.4±1.6 g/dl and 28.6%. The mean serum ferritin concentrations for male and female adolescents were 21.5 and 15.4 μg/l, respectively; with 25.7% of the males and 49.5% of the females having deficient levels of ferritin. Dietary intake of total energy and iron, and gender were found to be independent determinants of serum ferritin and haemoglobin levels, accounting for over 40% of the variations for each of these iron indicators. In males, but not in females, the intake of dietary protein and iron, and physical activity were also found to be significant determinants of serum ferritin. The age of subjects and household size were significant determinants of haemoglobin levels for male subjects, but not for female subjects. The findings indicate the importance of adequate intake of energy and dietary iron for improving the iron status of adolescents.     

Determinants of iron status in Malaysian adolescents from a rural community

Iron deficiency anaemia is the most common micronutrient deficiency worldwide. The prevalence of anaemia in the developing countries is three to four times higher than that in the developed countries. The iron status was assessed in 199 apparently healthy male and female adolescents aged 12-19 years living in a fishing community in Sabah, Malaysia. Data on socio-economic characteristics, lifestyles, anthropometry measurements, iron status, and dietary intake were gathered. Dietary intake of energy, iron, and most nutrients (with the exception of protein and vitamin C) were below the recommended levels for Malaysian adolescents. Three-quarters of the iron was derived from plant foods. The mean haemoglobin value for the male was 13.9 +/- 1.3 g/dl with 9.5% having less than 12 g/dl, while the respective figures for the female were 12.4 +/- 1.6 g/dl and 28.6%. The mean serum ferritin concentrations for male and female adolescents were 21.5 and 15.4 microg/l, respectively; with 25.7% of the males and 49.5% of the females having deficient levels of ferritin. Dietary intake of total energy and iron, and gender were found to be independent determinants of serum ferritin and haemoglobin levels, accounting for over 40% of the variations for each of these iron indicators. In males, but not in females, the intake of dietary protein and iron, and physical activity were also found to be significant determinants of serum ferritin. The age of subjects and household size were significant determinants of haemoglobin levels for male subjects, but not for female subjects. The findings indicate the importance of adequate intake of energy and dietary iron for improving the iron status of adolescents.     

Iron status of adolescents in a nigerian rural community

The iron status of 72 adolescents from rural peasant farming household was evaluated. The regression analyses showed that a Hb value of 11.0 g/dl and a haematocrit concentration of 34% corresponded with a transferrin saturation of 16% (the lower limit for non anaemic individuals). Based on Hb alone, 19.4% were anaemic (16.7% females and 22.2% males) while 16.7% (8.3% females and 25.0% males) had low transferrin saturation (<16%). Also, transferrin saturation levels decreased with age (P<0.01) in females only. Haematocrit concentration was equally low (<34%) in both sexes (22.2%). About 12.5% of all the subjects had mean corpuscular volume below 80 μm³. A combination of two independent measurements gives a better diagnosis of iron deficiency anaemia than single parameters. Iron supply was inadequate for normal haemopoiesis in some of these adolescents.     

Iron intake and dietary sources of iron in Flemish adolescents

OBJECTIVE: To investigate the dietary iron intake and food sources of iron in Flemish adolescents. DESIGN: Cross-sectional survey; dietary assessment method: a 7-day estimated food record. SETTING: Private and public secondary schools in Ghent, a city in the Dutch-speaking part of Belgium. SUBJECTS: A total of 341 adolescents (129 boys and 212 girls), 13-18 y, randomly selected by a multistage clustered sampling technique. RESULTS: The mean total iron intake (s.d.) for boys was 13.4 (+/- 2.91) mg/day and for girls 10.1 (+/- 2.79) mg/day. A proportion of 38.8% of the boys and 99.5% of the girls had a mean total iron intake below the Belgian Recommended Dietary Allowance and 3.1% of the boys and 71.2% of the girls below the British Estimated Average Requirement. When bioavailable iron intake is considered, 84.5% of the boys and only 16.5% of the girls met the age-specific requirement. The food groups with the highest mean proportional contribution to total iron intake in both males and females were bread, meat and meat products, cereals and potatoes. A comparison of adolescents from the highest tertile of iron intake (mg/day) with adolescents from the lowest tertile showed a significantly higher energy-adjusted intake of brown bread and a significantly lower intake of soft drinks in the former group in both boys and girls. A significantly higher energy-adjusted intake of breakfast cereals in adolescents of the highest tertile than those of the lowest tertile was seen in girls only. Analyses in consumers only did not change this overall picture. CONCLUSIONS: One can conclude that the mean iron intake of Flemish girls is considerably lower than the current recommendations. An increased iron intake in this subgroup of the population is therefore advisable.     

Positive association between dietary iron intake and iron status in HIV-infected children in Johannesburg,South Africa

Anemia is a common complication of pediatric HIV infection and is associated with suboptimal cognitive performance and growth failure. Routine iron supplementation is not provided to South African HIV-infected children. We hypothesized that dietary iron intake without supplementation is sufficient to protect against iron deficiency (ID) in HIV-infected children receiving highly active antiretroviral therapy. In this prospective study, the difference between dietary intakes of iron-deficient children (soluble transferrin receptor >9.4 mg/L) and iron-sufficient children after 18 months on highly active antiretroviral therapy was examined. The association between iron intake and hemoglobin (Hb) concentration was also assessed. Longitudinal data collected for 18 months from 58 HIV-infected African children were assessed by generalized estimation equations, with adjustment for demographic information, dietary intakes, growth parameters, and CD4%. After adjustment for covariates, the longitudinal association between dietary iron intake and Hb concentration remained significant. This association shows that for every 1-mg increase in iron intake per day, Hb increases by 1.1 g/L (P < .001). Mean Hb increased significantly after 18 months of follow-up (106 ± 14 to 129 ± 14 g/L, P < .01), but soluble transferrin receptor also increased (7.7 ± 2.7 to 8.9 ± 3.0 mg/L, P < .01). The incidence of ID increased from 15.2% at baseline to 37.2% after 18 months. Children with animal protein intakes greater than >20 g/d had significantly lower odds for ID at 18 months than did children with lower intakes (odds ratio, 0.40; 95% confidence interval, 0.21-0.77). Dietary iron intake was insufficient to protect against ID, pointing to a need for low-dose iron supplementation for iron-deficient HIV-infected children and interventions to increase the consumption of animal protein.     

Association between major patterns of dietary intake and weight status in adolescents

The relationship between dietary intake and obesity is complex, and dietary pattern analysis may offer new insight. We examined associations between dietary patterns identified in a diverse cohort of adolescents and weight status cross-sectionally and over a 5-year period. Project EAT (Eating Among Teens) (Time 1) collected data on 4746 middle (younger cohort) and high school (older cohort) students in 1998-9. EAT-II (Time 2) resurveyed 2516 of the original cohort in 2003-4. All analyses were run separately by age cohort and sex. The relationship between dietary patterns identified previously (vegetable, fruit, vegetable & fruit, starchy food, sweet & salty snack food, and fast food) and weight status was examined using logistic regression. All analyses were adjusted for socioeconomic status, race/ethnicity and activity level (longitudinal analyses were also adjusted for baseline weight status). In cross-sectional analyses, higher adherence to dietary patterns loading heavily on vegetables was associated with lower risk of overweight/obese weight status in older and younger girls, whereas higher adherence to a 'sweet & salty snack food' pattern was associated with lower risk in older and younger boys. These associations were found prospectively in older boys and girls, but were no longer significant in analyses adjusting for baseline weight status. We did not find consistent or intuitive associations between dietary patterns and weight status. Identified patterns may not capture the elements of diet that are truly important in determining adolescent weight, or diet may not be the primary driver in determining weight status at this age. Methodological difficulties in assessing diet must also be taken into consideration.     

Body composition, dietary intake, and iron status of female collegiate swimmers and divers

This study determined the effect of training on body composition, dietary intake, and iron status of eumenorrheic female collegiate swimmers (n = 18) and divers (n = 6) preseason and after 16 wk of training. Athletes trained on dryland (resistance, strength, flexibility) 3 d/wk, 1.5 h/d and in-water 6 d/wk, nine, 2-h sessions per week (6400 to 10,000 kJ/d). Body-mass index (kg/m2; P = 0.05), waist and hip circumferences (P < or = 0.0001), whole body fat mass (P = 0.0002), and percentage body fat (P < or = 0.0001) decreased, whereas lean mass increased (P = 0.028). Using dual-energy X-ray absorptiometry, we found no change in regional lean mass, but fat decreased at the waist (P = 0.0002), hip (P = 0.0002), and thigh (P = 0.002). Energy intake (10,061 +/- 3617 kJ/d) did not change, but dietary quality improved with training, as reflected by increased intakes of fiber (P = 0.036), iron (P = 0.015), vitamin C (P = 0.029), vitamin B-6 (P = 0.032), and fruit (P = 0.003). Iron status improved as reflected by slight increases in hemoglobin (P = 0.046) and hematocrit (P = 0.014) and decreases in serum transferrin receptor (P < or = 0.0001). Studies are needed to further evaluate body composition and iron status in relation to dietary intake in female swimmers.     

Iron intake, red cell indicators of iron status, and DNA damage in young subjects

Objective

This study evaluated the association between primary DNA damage and chromosomal damage with iron intake and red blood cell parameters of iron status in a sample of healthy children and adolescents from a low-socioeconomic community.

Methods

The level of primary DNA damage was assessed using an alkaline comet assay and the level of chromosomal damage was assessed using the cytokinesis-block micronucleus assay. A automated complete blood count was used to evaluate red blood cell status. The intake of iron was measured using a food-recall questionnaire.

Results

According to hemoglobin levels, only 1 of the 30 subjects evaluated was anemic. Nevertheless, 43% of the sampled subjects showed decreased mean corpuscular volume in addition to an increased amount of primary DNA damage (P < 0.05). Mean corpuscular volume was negatively correlated with primary DNA damage (r = −0.429, P = 0.020) but not with chromosomal damage. The association between iron and primary DNA damage showed a U-shaped curve, indicating that an intake of approximately 15 mg of iron per day (up to two-fold of the dietary recommended intake) could minimize primary DNA damage in this age group. The frequency of micronuclei and nucleoplasmic bridges, indicators of chromosomal breakage/loss and chromosomal end-fusions, respectively, showed a negative correlation with iron intake. These results indicate that an intake of iron >15 mg/d could increase genomic stability in binucleated lymphocytes of the same group.

Conclusion

An intake of iron ≥15 mg/d can decrease DNA damage in young subjects.     

Folacin and iron status of adolescents from low-income rural households (1–3)

The folacin and iron status of 179 black and white adolescents from low-income rural households was evaluated. Red blood cell folacin concentrations were less than 140 ng/ml in 45% of the subjects and 56% of the serum folacin levels were less than 6 ng/ml. Twenty-five percent of all females had low (<16%) transferrin saturation levels in contrast to 12% of the males. Transferrin saturation increased as the male adolescents matured and decreased as the females matured (p<0.05). Anemia (Hb<12 g/dl) was identified in 13% of the black adolescents in contrast to 2% of the whites. Mean cell hemoglobin concentrations and mean cell volumes were lower (p<0.05) in the blacks than in the whites. These findings demonstrate that both folacin and iron inadequacies occur in a significant proportion of this low-income rural adolescent population group.     

贵阳市城乡青少年营养状况调查

摘要:目的　通过膳食营养调查了解贵阳城市、农村青少年膳食营养状况,反映青少年膳食营养状况的地区差异。方法　对贵阳城、乡共1 080名初中学生进行膳食营养调查,应用24 h回顾法采集学生连续3 d的膳食摄入数据,实地测量身高、体重,应用身高标准体重法对营养状况进行评价。结果　贵阳城乡青少年谷薯类摄入量较为合理（日均摄入290.00～351.94 g）,城市地区豆类（日均摄入19.60～21.00 g）、乳类（日均摄入139.75～152.08 g）摄入量较低,农村地区乳类、蔬菜、水果等食物摄入量均低于推荐值;两地区能量（日均摄入2 040.96～2 443.15 kcal）、蛋白质（日均摄入47.62～75.12 g）等营养素摄入偏低;两地区三餐热能分配不合理;城市地区整体营养状况优于农村地区,城市营养状况正常占69%,农村营养状况正常仅占52%。结论　贵阳城乡青少年膳食结构仍有待完善,应加强对青少年及家长的营养教育,特别是在农村地区,应指导学生改善不良的饮食习惯,均衡各类食物的摄入比例。     

Iron status in 2-year-old Icelandic children and associations with dietary intake and growth

OBJECTIVE: To investigate the effects of food and nutrient intake at 2 y and growth from birth on iron status at 2 y in a population with high birth weight. DESIGN: In a cross-sectional study, children's food consumption and body size measurements were recorded and blood samples taken. Weighed 3-day food records were used to analyse food and nutrient intake. SETTING: Children were recruited from across Iceland from the Icelandic National Registry by the University of Iceland, Computing Services. The children in the sample were born over a 1-y period. SUBJECTS: Parents of randomly selected 2-year-old children (n=130) were contacted, and 72% (n=94) participated. Blood samples were analysed in 76% (n=71) of participating children. RESULTS: In total, 9% of the children were iron-deficient (serum ferritin (SF)<12 microg/l and mean corpuscular volume (MCV) <74 fl) and 1.4% were also anaemic (Hb<105 g/l), while 27% of children were iron-depleted (SF<12 microg/l). Iron status indices were negatively associated with cow's milk consumption. Half of children consuming>500 g cow's milk/day (n=10) were iron-deficient, while one child in 58 consuming<500 g cow's milk/day had iron deficiency (P<0.001). In multiple regression analyses, also biscuits and crackers consumption was positively associated with MCV. Weight gain from birth to 2 y was negatively associated with SF (adjusted R(2)=0.15; P=0.002; n=58). Iron-depleted children were heavier than children not iron-depleted (14.7+/-1.3 vs 13.8+/-1.7 kg; P=0.043), had higher BMI (17.7+/-1.5 vs 16.7+/-1.4 kg/m(2); P=0.028) and gained more weight from birth (11.2+/-1.3 vs. 10.0+/-1.6 kg; P=0.011). CONCLUSIONS: The results suggest that cow's milk consumption above 500 g/day should be avoided at the age of 2 y for better iron status. Iron depletion at 2 y is associated with faster growth from birth.     

Vitamin-mineral supplement use: association with dietary intake and iron status of adults

Although vitamin-mineral supplement use is increasing in the United States, few researchers have examined whether supplement users have better nutritional status than do nonusers. Data from 10,515 persons examined in the second National Health and Nutrition Examination Survey (NHANES II) were used to compare mean dietary intakes of several nutrients and food groups, hemoglobin, mean corpuscular volume, transferrin saturation, erythrocyte protoporphyrin, and serum ferritin between regular supplement users and nonusers aged 16 to 74 years. Prevalences of impaired iron status also were compared between user groups. Users consumed more vitamin C and ate fruits and vegetables more frequently than did nonusers in all age/sex groups. No significant differences in mean iron status indicators were observed except in the 65 to 74 year age/sex groups: transferrin saturation among men and mean corpuscular volume, erythrocyte protoporphyrin, and serum ferritin among women. In each case, users had higher values than nonusers in this age group. Prevalences of impaired iron status did not differ between users and nonusers in any age/sex group. In general, iron status was not associated with supplement use.     

Iron intake and iron nutritional status of infants fed iron-fortified beikost with meat

We compared iron intake and iron nutritional status of two groups of healthy term infants who received meat-containing baby foods fortified with ferrous sulphate (2 mg Fe/100 g). One group received an Fe-fortified formula (1.6 mg Fe/100 kcal) and the other a nonfortified formula. Fe intake of the group fed the nonfortified formula was significantly lower (p less than 0.0001). These infants received Fe mainly from fortification Fe with beikost (75-86%) and less than 10% met the recommended intake of 1 mg.kg-1.d-1; whereas 80-85% of the infants fed the Fe-fortified formula did. Hb, Hct, FEP, and ferritin were similar in both groups with the exception of lower ferritin values at age 365 d (p less than 0.05) in the group fed the nonfortified formula. No infant had hemoglobin less than 100 g/L. We conclude that regular consumption of commercially prepared Fe-fortified beikost with meat prevents most healthy term infants from Fe deficiency even if Fe intake is substantially below the recommended intake.     

北京市郊区青春期少年植酸摄入量及其与钙铁锌的摩尔比值研究

目的通过调查农村青春期少年植酸的摄入量及其与钙、铁、锌的摩尔比值,评价其植酸摄入水平,为改善青少年对矿物质的吸收利用提供依据。方法随机选取北京市怀柔区某学校11～16岁中学生304人(男154人、女150人),采用连续3d24h回顾法进行膳食调查,并根据不同食物含量计算植酸及钙、铁、锌的摄入量。结果农村青春期少年植酸摄入量为620.5mg/d(男生670.0mg/d,女生569.6mg/d),性别差异有统计学意义(P<0.05)。植酸与钙、铁、锌的摩尔比值分别为0.1、2.1、4.4,植酸×钙/锌为34.9,性别差异无统计学意义。结论农村青春期少年植酸摄入量低于2002年全国平均水平和其他发展中国家水平,但高于西方发达国家水平,其摄入量可能会影响机体对钙、铁、锌的吸收。