ABSTRACT
BACKGROUND: Vitamin A deficiency disorders (VADD) is a healthy problem of children in the world, especially in the west of China and remote areas, and the nutritional intervention is needed.OBJECTIVE: To compare the improved effects of biscuits fortified with three different doses of vitamin A on the vitamin A status in children aged 3-6 years and explore ap ideal dose of vitamin A supplement for preventing VADD.DESIGN: Randomized controlled observation.SETTING: Health Surveillance Institute, Chongqing Municipal Health Bureau; Staff Room of Nutrition and Food Hygiene, College of Public Health, Chongqing University of Medical Sciences; Center for Children Nutrition, Children's Hospital, Chongqing University of Medical Sciences.PARTICIPANTS: The investigation was done between March and December 2002. 753 children aged 3-6 years from 8 kindergartens in Banan district of Chongqing city were enrolled with the agreement of their guardians. They were divided randomly into 4 groups: 30% recommended intake group, 100% recommended intake group, 20 000 international unit (IU) and 200 000 IU groups.METHODS: ① The biscuits fortified with 30% recommended intake of vitamin A (500 IU) were once given to people of the 30% recommended intake group (177 cases) every day. ②The biscuits fortified with 100% recommended intake of vitamin A (1666 IU) were once given to people of the 100% recommended intake group (173 cases) every day. ③The biscuits fortified with 20 000 IU of vitamin A were once given to people of the 20 000 IU group (209 cases) every week. ④The soft gelatin capsule with 200 000 IU of vitamin A were once given to people of the 200 000 IU group (194 cases).Height, body mass, serum retinal, prealbumin, haematoglobin and retinal binding protein of all children were measured before intervention and after intervention for 3 months. Above indexes were rechecked after supplement for 9 months in 87 children of 30% recommended intake groupMAIN OUTCOME MEASURES: ①Prevalence rate of VADD before in-tervention and after intervention for 3 months in children of every group.② Serum retinal, serum prealbumin, serum retinal binding protein,haematoglobin, height and body mass of children before intervention and after interventional for 3 months in every group.RESULTS: Because of lose of samples and detective technology, only 580 children' examination results were got by rechecking. ①Comparison of the prevalence rate of VADD of children in every group: Three months supplementation later, the prevalence of VADD in every group all decreased sig nificantly [1.48%,1.42%,1.21%, 2.16% ;6.78%,6.54%,8.61%,8.25%(χ2=3.86-8.57, P ＜ 0.05-0.01 )]. ②Comparison of serum retinal, serum prealbumin, serum retinal binding protein, haematoglobin, height and body mass of children of every group: After supplement for 3 months, except prealbumin and haematoglobin in the 30% recommended intake group ,other indexes in each group all increased significantly (t=2.52-37.44, P＜ 0.05-0.01 ). The increase of serum vitamin A in the 20 000 IU group was larger than that in the other groups (F=4.62,P＜ 0.01 ). The increases of haematoglobin, prealbumin and height in the 30% recommended intake group were less than those in the other groups (F=5.04-7.78 ,P ＜ 0.01 ).After supplement for 9 months, the increases of haematoglobin and prealbumin in the 30% recommended intake group were larger than those in the other groups (F= 11.62,10.21 ,P ＜ 0.01). The increase of serum retinal was still lower than that in the 20 000 IU group (F=4.21 ,P ＜ 0.01 ).CONCLUSION: Supplement with biscuits fortified with 3 different doses of vitamin A and capsule with 200 000 IU of vitamin A can improve obviously the nourished status of vitamin A and the level of ferrohemoglobin, in which 30% recommended intake and 100% recommended intake have small risk, and everyday supplement can maintain stably the level of vitamin A. That may be suitable for the long-term supplement for children, and the effect of 30% recommended intake was better than that of 100% recommended intake.