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1.
Although carotenoids are known to be important dietary sources of vitamin A, there have been few epidemiological studies that have characterized the serum concentrations of major dietary carotenoids among preschool children with vitamin A deficiency. We conducted a population-based, cross-sectional study of serum pro-vitamin A carotenoids (alpha -carotene, beta-carotene, beta-cryptoxanthin), non-provitamin A carotenoids (lutein/zeaxanthin, and lycopene), and retinol among 278 children, aged 1-5 y, in the Republic of the Marshall Islands. Vitamin A deficiency was defined as serum retinol <0.70 micromol/L. Geometric mean serum concentrations of carotenoids among children with and without vitamin A deficiency were 0.003 vs 0.006 micromol/L for alpha-carotene (P = 0.0017), 0.011 vs 0.023 micromol/L for beta-carotene (P <0.0001), 0.023 vs 0.034 micromol/L for beta-cryptoxanthin (P = 0.0075), 0.007 vs 0.012 micromol/L for lycopene (P = 0.037), 0.044 vs 0.052 micromol/L for lutein/zeaxanthin (P = 0.2), and 0.045 vs 0.074 micromol/L for total provitamin A carotenoids (P <0.0001) respectively. In a multivariate analysis adjusting for sex, age (Odds Ratio [O.R.] 1.44, 95% confidence interval [C.I.] 1.16-1.78), and serum provitamin A carotenoids (O.R. 0.49, 95% C.I. 0.34-0.71) were associated with vitamin A deficiency, but serum non-provitamin A carotenoids were not associated with vitamin A deficiency (O.R. 0.93, 95% C.I. 0.67-1.28). Preschool children with vitamin A deficiency in the Republic of the Marshall Islands have extremely low serum concentrations of provitamin A carotenoids and interventions are needed to improve the dietary intake of provitamin A carotenoids among Marshallese children.  相似文献   

2.
BACKGROUND: The vitamin A requirements of elderly humans have not been studied. OBJECTIVE: In a cross-sectional study of 60-88-y-old men (n = 31) and women (n = 31) in rural Philippines, we assessed the dietary intakes of elders with adequate (> or = 0.07 micromol/g) or low (< 0.07 micromol/g) liver vitamin A concentrations to estimate vitamin A requirements for this age group. DESIGN: Total-body vitamin A was assessed by the deuterated-retinol-dilution technique; liver vitamin A concentrations were assessed by assuming that liver weight is 2.4% of body weight and that, in this marginally nourished population, 70% of total-body vitamin A is in the liver; serum retinol was measured by HPLC; and dietary intakes were assessed with 3 nonconsecutive 24-h dietary recalls. The mean vitamin A intake + 2 SDs of subjects with adequate liver vitamin A concentrations was used to estimate an acceptable or sufficient vitamin A intake value for elders. RESULTS: The mean (+/- SD) vitamin A intakes of the men and women with adequate vitamin A in liver were 135 +/- 86 and 134 +/- 104 microg retinol activity equivalents (RAE)/d, respectively; intakes of the men and women with low vitamin A in liver were 75 +/- 53 and 60 +/- 27 microg RAE/d, respectively. Total-body vitamin A or liver vitamin A but not serum retinol correlated with dietary RAE, preformed vitamin A, beta-carotene, fat, and protein. An estimated acceptable or sufficient dietary vitamin A intake associated with adequate liver vitamin A concentrations in elders is 6.45 microg RAE/kg body wt; for a reference 76-kg man and a 61-kg woman, these values are approximately 500 and 400 microg RAE/d, respectively. CONCLUSION: The dietary vitamin A intakes of elders with adequate or low liver vitamin A concentrations as estimated by use of the deuterated-retinol-dilution technique are useful for assessing vitamin A requirements.  相似文献   

3.
Dietary intakes and plasma concentrations of retinol and carotenoids were estimated in assessing the vitamin A status of young children in Kwangju, Republic of Korea. Three consecutive 24-hour food recalls and fasting blood samples were obtained from 123 healthy children (58 boys, 65 girls), aged 2-6 years. The daily vitamin A intake (mean +/- SD) was 355.9 +/- 178.1 microg retinol equivalents or 239.0 +/- 111.2 microg retinol activity equivalents. Provitamin A carotenoid intakes were 1211.2 +/- 840.0 microg/day beta-carotene, 234.6 +/- 231.7 microg/day alpha-carotene, and 149.1 +/- 160.7 microg/day beta-cryptoxanthin. Approximately 15-26% of subjects consumed < Korean Estimated Average Requirements (EAR) for vitamin A; whereas, 57-64% consumed < EAR for vitamin A for USA/Canadians. The mean plasma retinol concentration was 1.108 +/- 0.244 micromol/L. There were no significant correlations between intakes and plasma concentrations of retinol and carotenoids. Only 2.4% of children were vitamin A-deficient based on having plasma retinol concentrations <0.70 micromol/L. Plasma retinol concentrations of 42.3% of subjects were 0.70 - <1.05 micromol/L, which is considered indicative of potentially suboptimal vitamin A status. Therefore, some children may be at risk of inadequate vitamin A status in Kwangju, Republic of Korea.  相似文献   

4.
Vitamin A deficiency is a public health problem in the Northeast of Brazil. This study aimed to determine the prevalence of vitamin A deficiency and associated factors among preschool children in Teresina, Piauí, Brazil. We studied the serum retinol levels and socioeconomic and demographic characteristics of 631 children from 36 to 83 months of age. The statistical association between each of the above characteristics and serum retinol levels was investigated by univariate and multivariate linear regression analysis. Mean serum retinol was 1.21 mmol/L (95%CI: 1.17-1.25 micromol/L) and was independent of gender (p = 0.259). Prevalence of vitamin A deficiency (retinol < 0.69 micromol/L) was 15.4% (95%CI: 12.7-18.4), with a tendency to decrease with age. Acceptable but not adequate retinol levels (0.70 to 1.04 micromol/L) were observed in 29% of children (95%CI: 25.2-32.4). There were positive associations between retinol levels and age, income, vitamin A supplementation, and maternal schooling. Vitamin A deficiency appeared as a moderately serious public health problem, emphasizing the importance of strategies to combat this problem in the region.  相似文献   

5.
BACKGROUND: Vitamin A deficiency (VAD) is a major public health problem in the developing world, leading to >3 million eye-related problems in preschool children. Nearly 250 million children have subclinical VAD, resulting in a 23% increase in childhood mortality. Difficulties in obtaining samples to assess VAD have hampered the detection, intervention, and surveillance of VAD. The use of dried blood spots (DBS) could ameliorate many problems of vitamin A assessment. OBJECTIVE: The objective of this study was to validate the use of retinol in DBS for vitamin A assessment by comparing it with venous and capillary serum retinol. DESIGN: Venous and capillary blood specimens were obtained simultaneously from 20 healthy adult volunteers. From each blood specimen, both DBS and liquid serum were prepared (a total of 80 samples). All specimens were maintained at -70 degrees C until HPLC analysis. RESULTS: The mean retinol concentrations in the 4 sample types were as follows: venous serum (2.02 +/- 0.42 micromol/L, or 58 +/- 12 microg/dL), capillary serum (2.06 +/- 0.42 micromol/L, or 59 +/- 12 microg/dL), venous DBS (2.06 +/- 0.49 micromol/L, or 59 +/- 14 microg/dL), and capillary DBS (2.09 +/- 0.45 micromol/L, or 60 +/- 13 microg/dL). Of the 6 possible 2-way combinations, the R(2) values ranged from 0.77 for capillary DBS versus venous DBS to 0.95 for venous serum versus capillary serum. CONCLUSIONS: DBS retinol measured by HPLC is comparable with serum retinol. Thus, it is possible to compare and combine blood retinol concentration data obtained from DBS with current and historic measurements in serum.  相似文献   

6.
BACKGROUND: Vitamin A deficiency is associated with stunting and wasting in preschool children, but vitamin A supplementation trials have not shown a consistent effect on growth. OBJECTIVE: We examined the effect of vitamin A supplementation on height and weight increments among Indonesian preschool children. DESIGN: Data were obtained from a randomized, double-masked, placebo-controlled trial of rural Javanese children aged 6-48 mo. Children received 206000 IU vitamin A (103000 IU if aged <12 mo) or placebo every 4 mo. RESULTS: High-dose vitamin A supplementation modestly improved the linear growth of the children by 0.16 cm/4 mo. The effect was modified by age, initial vitamin A status, and breast-feeding status. Vitamin A supplementation improved height by 0.10 cm/4 mo in children aged <24 mo and by 0.22 cm/4 mo in children aged >/=24 mo. The vitamin A-supplemented children with an initial serum retinol concentration <0.35 micromol/L gained 0.39 cm/4 mo more in height and 152 g/4 mo more in weight than did the placebo group. No growth response to vitamin A was found among children with an initial serum retinol concentration >/=0.35 micromol/L. In non-breast-fed children, vitamin A supplementation improved height by 0.21 cm/4 mo regardless of age. In breast-fed children, vitamin A supplementation improved linear growth by approximately 0.21 cm/4 mo among children aged >/=24 mo, but had no significant effect on the growth of children aged <24 mo. CONCLUSION: High-dose vitamin A supplementation improves the linear growth of children with very low serum retinol and the effect is modified by age and breast-feeding.  相似文献   

7.
BACKGROUND: Persons with cystic fibrosis (CF) and pancreatic insufficiency (PI) are at risk of vitamin A deficiency because of steatorrhea, despite pancreatic enzyme replacement. Long-standing vitamin A supplementation may increase the risk of vitamin A toxicity. OBJECTIVE: The aim was to describe the vitamin A intake and serum retinol concentrations of preadolescent children with CF, PI, and mild-to-moderate pulmonary disease, who were cared for under current practice recommendations. DESIGN: This cross-sectional study evaluated children aged 8.0-11.9 y with CF and PI from 13 US CF centers. Dietary and supplemental vitamin A intakes were compared with the Dietary Reference Intakes (DRIs) for healthy children, CF recommendations, and data from the National Health and Nutrition Examination Survey (NHANES), 1999-2000. Serum retinol concentrations were compared with NHANES data. RESULTS: The 73 subjects with CF had a dietary vitamin A intake of 816 +/- 336 microg retinol activity equivalents (165 +/- 69% of the recommended dietary allowance), which was similar to the NHANES value. The supplement intake provided 2234 +/- 1574 microg retinol activity equivalents/d and exceeded recommendations in 21% of the subjects with CF. Total preformed retinol intake exceeded the DRI tolerable upper intake level in 78% of the subjects with CF. The serum retinol concentration was 52 +/- 13 microg/dL (range: 26-98 microg/dL), which was significantly higher than the NHANES value (37 +/- 10 microg/dL; range: 17-63 microg/dL; P < 0.001). CONCLUSION: Although supplementation helps to prevent vitamin A deficiency in children with CF and PI, their high vitamin A intakes and serum retinol concentrations suggest that usual care may result in excessive vitamin A intake and possible toxicity that would increase the risk of CF-associated liver and bone complications.  相似文献   

8.
This paper focuses on changes in vitamin A (VA) intakes as part of the evaluation of a pilot project on social marketing of red palm oil (RPO) as a VA supplement for mothers and children in central-north Burkina Faso. The objectives of the 30-month project are to demonstrate the feasibility and effectiveness of introducing RPO in non-consuming areas. RPO is collected from women in the South-West region and it is sold in project sites by village volunteers. RPO is promoted by community workers trained in persuasive communication and social marketing. The target population is free to buy and consume RPO. Evaluation design includes data collected at onset, then 12 and 24 months later, from the same sample of 210 mothers and their children randomly selected in seven project sites. Children were 1 to 3 years old at onset. Blood samples were collected at baseline from mothers and children for serum retinol determination by HPLC. VA intakes are estimated by a semi-quantitative food frequency questionnaire, using the conventional beta-carotene to retinol conversion factors and the newly revised lower factors. VA deficiency is a major public health problem in the area: 64% of mothers and 85% of children had serum retinol concentrations < 0,70 mumol/l at baseline. VA came mainly from plant foods, particularly fruits and dark green vegetables which provided more than 90% of the dietary VA at onset of the project. Mean vitamin A intakes are low. We found 138 106 mug ER for the children and 302 +/- 235 microg ER for the mothers with conventional factors and 64 +/- 58 microg ER and 133 +/- 162 microg ER, respectively, with the revised factors. One year later, one third of respondents had consumed RPO in the previous week, and it supplied around 56% of the VA intake of children and 67% of mothers (36% and 46% respectively for the whole group). VA intakes were significantly increased at 510 +/- 493 microg ER and 801 +/- 913 microg ER for the children and their mothers respectively (347 +/- 443 microg ER and 568 +/- 803 microg ER respectively, with the revised factors). Analyzing serum retinol and dietary data collected at baseline, it was found that VA intakes < 62,5% of safe level of intake were highly sensitive to low serum retinol (< 0,70 micromol/l) and using revised conversion factors to assess total VA intake slightly enhanced sensitivity. The proportion of mothers and children at risk of inadequate VA intake changed from nearly 100% at baseline to 60% one year later. The results show that promoting RPO (and other VA rich foods) was effective in improving VA intakes. This improvement will hopefully be sustained and even further enhanced during the remaining 12 months of the project, after which repeated measurement of serum retinol and VA intakes will allow the actual impact of the project to be truly assessed.  相似文献   

9.
目的了解母乳与非母乳喂养儿童中血清维生素A水平是否存在差异以及造成差异可能原因。方法研究数据来自人群为基础的儿童维生素A营养状况横断面调查,共调查401名 0-23月龄儿童。采用改良的荧光方法测定血清中视黄醇含量来反映维生素A水平,通过问卷方法调查儿童的家庭社会经济、围产期保健、2周内患病情况;半定量膳食频率问卷调查前1周内儿童膳食情况。利用SAS 8.1软件进行统计分析。结果 401名2岁内儿童中,母乳喂养率为50.37%;非母乳喂养组维生素A平均水平为(30.67±0.57)μg/dl,母乳喂养组为(27.60±0.56)μg/dl,两组差异有统计学意义(P<0.01);在控制其他因素影响后,调整后的非母乳喂养组均值为(31.82±0.98)μg/dl, 母乳喂养组为(29.46±0.96)μg/dl,差异有统计学意义(P<0.01)。按年龄组分层分析显示,0月龄~、6月龄~、12月龄~和18月龄~组的母乳喂养率分别92.1%、70.1%、32.0%和17.1%。各年龄组内两组间(非母乳喂养组-母乳喂养组)维生素A均值差值及其95%可信区间(CI)分别为4.70 (-2.52-1.92)、0.82(-2.32-3.95)、2.95(-0.68-6.58)和6.05(2.34-9.77)μg/dl;控制其他混杂因素后,调整后的两组均值差值及其95%CI分别为0.00(-7.18-7.19)、1.35(-1.76-4.45)、 2.92(-0.82-6.65)和4.26(0.71-7.81)μg/dl;调整前、后只有18月龄组非母乳喂养组和母乳喂养组维生素A水平差异有统计学意义(P<0.01)。趋势x2检验表明12月龄以后母乳喂养儿童辅食添加频率均比非母乳喂养儿童低。结论与非母乳喂养儿童相比,母乳喂养儿童的体内维生素A水平有所降低,但差别只是局限在18月龄以后儿童中。母乳中维生素A含量不足以及辅食添加不充分可能是造成这种差异潜在原因。控制人群中维生素A缺乏应该采取综合干预措施。  相似文献   

10.
A study of 296 school-age Yaqui Indian children (6-10 y) was conducted in 26 rural communities. Vitamin A status was determined by retinol and carotenoid serum levels according to a method described previously (IVACG, 1982). Serum retinol and carotenoids in children were analyzed according to community size. Vitamin A intake was assessed in a sub-sample by means of a 24 h recall questionnaire. Serum retinol distribution showed that 6.3% of the children were below 10 microg/100 mL (0.35 micromol/L) and 40% were in the range of 10-20 microg/100 mL (0.35-0.70 micromol/L). Differences (p < 0.02) were found between small and large communities (Median, 95% CI): 19.2 (17.1, 20.9) microg/100 mL and 22.9 (20.3, 24.1) microg/100 mL. Serum carotenoid levels were significantly higher in large than in small and medium communities: 72 (68.2, 77.8) microg/100 mL versus 62.4 (53.3, 68.2) and 62.4 (55.7, 69.6) microg/100 mL, respectively. Food staples were wheat flour tortillas, pinto beans, corn tortillas, few animal products and scarce fresh vegetables. Mean vitamin A consumption was 244+/-29 microg RE (34.9% of the US RDA). Iron status showed that only 4 children were classified as anemic, with two of them having iron deficiency anemia. Iron deficient erythropoiesis was observed in 7.8% of the children and iron depletion only in 4.4%. The Yaqui diet seems to provide adequate amounts of iron but not of vitamin A or its precursors, which renders a vitamin A status of sub-clinical deficiency that could be considered a public health problem.  相似文献   

11.
BACKGROUND: Deficiencies of iodine, iron, and vitamin A are the 3 most common micronutrient deficiencies in developing countries, although control programs, when properly implemented, can be effective. OBJECTIVE: We investigated these deficiencies and their possible interaction in preschool children in the southern Blue Nile area of Sudan. DESIGN: Goiter, signs of vitamin A deficiency, and biochemical markers of thyroid, vitamin A, and iron status were assessed in 984 children aged 1-6 y. RESULTS: The goiter rate was 22. 3%. The median urinary iodine concentration was 0.79 micromol/L and 19.3% of the children had a concentration >1.57 micromol/L. Although serum thyroxine and triiodothyronine concentrations were within reference ranges, the median thyrotropin concentration was 3.78 mIU/L and 44% of the children had thyrotropin concentrations above normal. The mean urinary thiocyanate concentration was high (259 +/- 121 micromol/L). The prevalences of Bitot spots and night blindness were 2.94% and 2.64%, respectively, and 32% of the subjects had serum retinol binding protein concentrations <15 mg/L. A significant positive correlation was observed between thyrotropin and retinol binding protein. Whereas 88% of the children had hemoglobin concentrations <1.86 mmol/L, only 13.5% had serum ferritin concentrations below the cutoff of 12 microg/L and 95% had serum transferrin concentrations above the cutoff of 2.50 g/L. CONCLUSIONS: Our results indicate that goiter is endemic in this region of Sudan despite iodine sufficiency and that both anemia and vitamin A deficiency are health problems in the area. Moreover, consumption of millet, vitamin A deficiency, and protein-energy malnutrition are possible etiologic factors in this endemic area.  相似文献   

12.
INTRODUCTION: Although vitamin A deficiency, iron deficiency, and inflammation may contribute to anemia, their relative contribution to anemia has not been well characterized in preschool children in developing countries. OBJECTIVE: To characterize the contributions of vitamin A and iron deficiencies and inflammation to anemia among preschool children in the Republic of the Marshall Islands. SUBJECTS AND METHODS: A community-based survey, the Republic of the Marshall Islands Vitamin A Deficiency Study, was conducted among 919 preschool children. The relationship of vitamin A and iron status and markers of inflammation, tumor necrosis factor-alpha, alpha1-acid glycoprotein, and interleukin-10, to anemia were studied in a subsample of 367 children. RESULTS: Among the 367 children, the prevalence of anemia was 42.5%. The prevalence of severe vitamin A deficiency (serum vitamin A < 0.35 micromol/l) and iron deficiency (serum ferritin < 12 microg/dl) were 10.9 and 51.7%, respectively. The respective prevalence of iron deficiency anemia (hemoglobin < 110 g/l and iron deficiency), anemia with inflammation (anemia with TNF-alpha > 2 pg/ml and/or AGP > 1000 mg/l), and severe vitamin A deficiency combined with anemia was 26.7, 35.6, and 7.6%. In multivariate linear regression models that adjusted for age, sex, and inflammation, both iron deficiency (odds ratio (OR) 1.74, 95% confidence interval (CI) 1.08-2.83, P = 0.023) and severe vitamin A deficiency (OR 4.85, 95% CI 2.14-10.9, P < 0.0001) were significantly associated with anemia. CONCLUSIONS: Both iron and vitamin A deficiencies were independent risk factors for anemia, but inflammation was not a significant risk factor for anemia among these preschool children.  相似文献   

13.
OBJECTIVE: Iron and zinc share common food sources, and children at risk of iron deficiency may also develop zinc deficiency. We determined the prevalence of zinc and copper deficiency and examined factors associated with serum zinc and copper in young children from low-income families at risk of iron deficiency. DESIGN: A cross-sectional study design was used to assess serum zinc and copper, along with an interview-assisted survey to assess factors associated with serum zinc and copper in a convenience sample. SUBJECTS/SETTING: Participants were 435 children aged 12 to 36 months recruited from select clinics of the Special Supplemental Nutrition Program for Women, Infants, and Children in Contra Costa and Tulare Counties, California. STATISTICAL ANALYSES PERFORMED: Frequencies were used to report prevalence. Multiple linear regressions were conducted to examine factors associated with serum zinc and copper, controlling for age, sex, and ethnicity. RESULTS: The prevalence of low serum zinc level (<70 microg/dL [<10.7 micromol/L]) was 42.8%, and low serum copper level (<90 microg/dL [<14.2 micromol/L]) was <1%. Mean+/-standard deviation of serum copper was 150+/-22 microg/dL (23.6+/-3.5 micromol/L) and 140+/-24 microg/dL (22.1+/-3.8 micromol/L) for anemic and non-anemic children, respectively (t test, P=0.026). In multiple linear regression consumption of sweetened beverages was negatively associated with serum zinc level, and consumption of >15 g/day meat was positively associated with serum zinc level, whereas current consumption of breast milk and >15 g/day beans were positively associated with serum copper level. CONCLUSIONS: The prevalence of low serum zinc concentration in the sample was high, and warrants further investigation amongst vulnerable populations.  相似文献   

14.
BACKGROUND: An elevated plasma total homocysteine (tHcy) concentration is associated with an increased risk of cardiovascular diseases. Folate, riboflavin, vitamin B-6, and vitamin B-12 are essential in homocysteine metabolism. OBJECTIVE: The objective was to describe the association between dietary intakes of folate, riboflavin, vitamin B-6, and vitamin B-12 and the nonfasting plasma tHcy concentration. DESIGN: A random sample of 2435 men and women aged 20-65 y from a population-based Dutch cohort examined in 1993-1996 was analyzed cross-sectionally. RESULTS: Univariately, intakes of all B vitamins were inversely related to the plasma tHcy concentration. In multivariate models, only folate intake remained inversely associated with the plasma tHcy concentration. Mean plasma tHcy concentrations (adjusted for intakes of riboflavin, vitamin B-6, vitamin B-12, and methionine and for age, smoking, and alcohol consumption) in men with low (first quintile: 161 microg/d) and high (fifth quintile: 254 microg/d) folate intakes were 15.4 and 13.2 micromol/L, respectively; in women, plasma tHcy concentrations were 13.7 and 12.4 micromol/L at folate intakes of 160 and 262 microg/d, respectively. In men, the difference in the mean plasma tHcy concentration between men with low and high folate intakes was greater in smokers than in nonsmokers (2.8 compared with 1.6 micromol/L) and greater in nondrinkers than in drinkers of >2 alcoholic drinks/d (3.5 compared with 1.4 micromol/L). In women, the association between folate intake and plasma tHcy was not modified by smoking or alcohol consumption. CONCLUSIONS: In this Dutch population, folate was the only B vitamin independently inversely associated with the plasma tHcy concentration. Changing dietary habits may substantially influence the plasma tHcy concentration in the general population.  相似文献   

15.
To explore the influence of dietary factors of iron bioavailability and socio-demographic conditions on blood iron status of married adolescent girls (MAG), a cross-sectional study was conducted in 173 MAG (15-19 years old) from urban slums near Pune city, India. Diet was assessed by two random 24-h recalls. The age, weight, height, education, family size, income, physical work, and number of days of menstrual loss were recorded. Fasting blood was analyzed for hemoglobin and serum ferritin. Mean intakes of micronutrients were 40-75% less than the recommended dietary intakes for Indian adolescent girls. High intake of phytates (171+/-6 mg/day) and low intakes of vitamin C (25+/-1 mg/day) resulted in low bioavailable iron intakes. The mean bioavailable iron intake was 0.76+/-0.3 mg/day, which is one-half of the basal iron requirement of adolescent girls. The prevalence of iron deficiency (serum ferritin<12 microg/l) was 25.1%, and anemia (hemoglobin <12 g/l) was seen in 46.4% of MAG. A multiple regression model adjusted for energy intake indicated that intakes of beta-carotene and riboflavin were associated with hemoglobin (P<0.001) and those of zinc, riboflavin and thiamin associated with serum ferritin (P<0.01). Multiple regressions including socio-demographic factors revealed that the family size, number of menstrual days lost and total bioavailable iron intake were the influencing factors for low iron status. In conclusion, there is a need to increase intakes of vitamin C and other micronutrients of the MAGs and to improve iron bioavailability through diet modifications.  相似文献   

16.
Serum Se concentrations and dietary Se intakes have been determined in relation to age, sex, ethnicity, region and index of deprivation in a nationally representative sample of New Zealand children aged 5-14 years from the 2002 National Children's Nutrition Survey. Dietary intake was assessed from computer-assisted, multiple-pass 24 h diet recall interviews (n 3275). Serum Se concentrations were obtained from a subset of urban-based children (n 1547). Mean (95 % CI) serum Se concentration in children was 0.96 (0.93, 1.00) micromol/l. Males (1.00 micromol/l) had higher serum Se levels than females (0.93 micromol/l; P = 0.027). M?ori children had lower serum Se than Pacific Islands children (P = 0.038) and New Zealand European and Other children (P = 0.005). Children in the Upper North Island (1.06 micromol/l) had higher mean serum Se values than those in the Lower North Island (0.98 micromol/l, P < 0.0005) and South Island (0.79 micromol/l, P < 0.0005), and serum Se in the Lower North Island was higher than that in the South Island (P < 0.0005). Mean dietary Se intake was 36 (34, 37) microg/d. The intakes of children aged 5-6 years (31 microg/d) were lower than those of children aged 7-10 and 11-14 years (35 and 38 microg/d, respectively; P < 0.00 005) and the intakes of 7-10-year-olds were lower than those of 11-14-year-olds (P = 0.002). Serum Se was associated with dietary Se after adjusting for all variables, including region (P = 0.006). The Se status of our children falls in the middle of the international range of serum Se concentrations, but that for children in the South Island is among the lowest values reported and may be a cause for concern.  相似文献   

17.
Hyperhomocysteinemia is considered a risk factor for cardiovascular disease and is prevalent in the elderly. Supplementation with folic acid, vitamin B-6 and B-12 lowers homocysteine levels. In January 2000, the Chilean government initiated a flour folic acid fortification program to decrease the occurrence of neural tube defects. The aim of this study was to evaluate the effect of this program on serum homocysteine and folate levels in elderly subjects after 6 mo. A total of 108 elderly people were studied. We measured serum folate, homocysteine and vitamin B-12 levels before the fortification started and 6 mo later. At baseline, folate deficiency (<6.8 nmol/L) was present in 1.8%, vitamin B-12 deficiency (<165 pmol/L) in 27.6% and hyperhomocysteinemia (>14 micromol/L) in 31% of the sample. Six months later, serum folate levels increased from 16.2 +/- 6.2 to 32.7 +/- 7.1 nmol/L (P < 0.001), homocysteine levels decreased from 12.95 +/- 3.7 to 11.43 +/- 3.6 micromol/L (P < 0.001) and vitamin B-12 levels were unchanged. Flour fortification with folic acid had a moderate lowering effect on homocysteine levels. Given that vitamin B-12 deficiency was more common than folate deficiency, it may be more appropriate to add vitamin B-12 to food, at least in foods for this age group.  相似文献   

18.
Dietary treatment of iron deficiency in women of childbearing age.   总被引:1,自引:0,他引:1  
BACKGROUND: The Australian Iron Status Advisory Panel advocates dietary intervention as the first treatment option for mild iron deficiency [serum ferritin (SF) = 10-15 microg/L]. However, there appear to be no studies on the efficacy of dietary treatment for iron deficiency. OBJECTIVE: We compared the effects of iron supplementation and of a high-iron diet on serum ferritin (SF) and hemoglobin in iron-deficient women of childbearing age. DESIGN: Forty-four iron-deficient women (SF <15 microg/L or SF = 15-20 microg/L plus serum iron <10 micromol/L and total-iron-binding capacity >68 micromol/L) and 22 iron-replete women (hemoglobin > or =120 g/L and SF >20 microg/L) matched for age and parity categories were enrolled and completed 7-d weighed food records at baseline. The iron-deficient women were randomly allocated to receive iron supplementation (105 mg/d; supplement group) or a high-iron diet (recommended intake of absorbable iron: 2.25 mg/d; diet group) for 12 wk. Hematologic and dietary assessments were repeated at the end of the intervention and again after a 6-mo follow-up. RESULTS: Mean SF in the supplement group increased from 9.0 +/- 3.9 microg/L at baseline to 24.8 +/- 10.0 microg/L after the intervention and remained stable during follow-up (24.2 +/- 9.8 microg/L), whereas the diet group had smaller increases during the intervention (8.9 +/- 3.1 to 11.0 +/- 5.9 microg/L) but continued to improve during follow-up (to 15.2 +/- 9.5 microg/L). Mean hemoglobin tended to improve in both intervention groups, but the change was only significant in the supplement group. CONCLUSIONS: In iron-deficient women of childbearing age, a high-iron diet produced smaller increases in SF than did iron supplementation but resulted in continued improvements in iron status during a 6-mo. follow-up.  相似文献   

19.
Five cross-sectional surveys were conducted in African refugee camps to assess the level of iron deficiency anemia and vitamin A deficiency in populations dependent on long-term international food aid and humanitarian assistance. The prevalence of anemia in children [hemoglobin (Hb) <110 g/L] was high, with >60% affected in 3 of 5 camps. Iron deficiency [serum transferrin receptor (sTfR) >8.5 mg/L] was also high, ranging from 23 to 75%; there was also a strong ecological correlation between the prevalence of iron deficiency and anemia among different camps. Within camps, sTfR predicted the concentration of Hb with adjusted R(2) values ranging from 0.19 to 0.51. Although children were more affected, anemia was also a public health problem in adolescents and women. The effect of recent recommendations on Hb cutoff values for African populations was assessed and found to produce decreases in the prevalence of anemia of between 5 and 21%; this did not affect the public health categorization of the anemia problem within the most affected camps. Mean serum retinol in children, after adjustment for infection status, ranged from 0.72 +/- 0.2 to 0.88 +/- 0.2 micromol/L in the 4 camps assessed and vitamin A deficiency (<0.7 micromol/L) was present at levels ranging from 20.5 to 61.7%. In areas in which vitamin A capsule distribution programs were in effect, coverage ranged from 3.5 up to 66.2%. The high level of micronutrient deficiencies seen in long-term refugees argues in favor of further enhancements in food aid fortification and the strengthening of nutrition and public health programs.  相似文献   

20.
BACKGROUND: The Food and Nutrition Board of the National Academy of Sciences states that 95 microg vitamin D/d is the lowest observed adverse effect level (LOAEL). OBJECTIVE: Our objective was to assess the efficacy and safety of prolonged vitamin D3 intakes of 25 and 100 microg (1000 and 4000 IU)/d. Efficacy was based on the lowest serum 25-hydroxyvitamin D [25(OH)D] concentration achieved by subjects taking vitamin D3; potential toxicity was monitored by measuring serum calcium concentrations and by calculating urinary calcium-creatinine ratios. DESIGN: Healthy men and women (n = 61) aged 41 +/- 9 y (mean +/- SD) were randomly assigned to receive either 25 or 100 microg vitamin D3/d for 2-5 mo, starting between January and February. Serum 25(OH)D was measured by radioimmunoassay. RESULTS: Baseline serum 25(OH)D was 40.7 +/- 15.4 nmol/L (mean +/- SD). From 3 mo on, serum 25(OH)D plateaued at 68.7 +/- 16.9 nmol/L in the 25-microg/d group and at 96.4 +/- 14.6 nmol/L in the 100-microg/d group. Summertime serum 25(OH)D concentrations in 25 comparable subjects not taking vitamin D3 were 46.7 +/- 17.8 nmol/L. The minimum and maximum plateau serum 25(OH)D concentrations in subjects taking 25 and 100 microg vitamin D3/d were 40 and 100 nmol/L and 69 and 125 nmol/L, respectively. Serum calcium and urinary calcium excretion did not change significantly at either dosage during the study. CONCLUSIONS: The 100-microg/d dosage of vitamin D3 effectively increased 25(OH)D to high-normal concentrations in practically all adults and serum 25(OH)D remained within the physiologic range; therefore, we consider 100 microg vitamin D3/d to be a safe intake.  相似文献   

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