| Objective:To evaluate the effect of a milk and egg supplementation on growth and evelopment,body composition,IQ status,physical development,biochemical indicators,dietary intake of rural primary school students in Tianyang county,Guangxi Autonomous,where height and weight of children are below national averagesMethods:This 2-yr intervention trail was conducted from April 2013 to March 2015.In April 2013,2014,and 2015,the investigations were carried out separately for baseline,1st year and 2nd year data.Four intervention schools and four control schools were selected randomly from Tianyang County of Guangxi Autonomous Region.Both intervention schools and control schools were similar in social-economic level,teaching standards,and school size.The two-year intervention of the milk and egg supplementation involved 955 healthy students aged 6-13 year.Students in the intervention group(538 total)received 200 g milk and a 50g soy flavored egg every school day while students in the control group(417 total)received no supplement.Nutritional status was determined through height,weight.Body composition was measured by bioelectrical impedance method.Standing long jump and 50×8 meters run was assessed the results of physical fitness.Collected venous blood to determine hemoglobin and serum trace element levels.Self-made questionnaire and 3-day 24 hours dietary questionnaire was used to evaluate nutrients and dietary intake.Students' intelligence was determined by Raven Intelligence Test questionnaire.Mixed linear model with repeated measures analyzed the efficacy of the intervention,and the significant level is 0.05.Results:Out of 955 children enrolled in baseline investigation.No differences were seen in dietary energy and calcium intake between the intervention group and the control group.(P>0.05).The intervention group achieved a higher protein,fat,VitB1,VitB2,Fe,Zn intake.(P<0.05)In final investigation,769 children were follow-up for the two years intervention study.The follow-up rate is 80.5%.In 2st years the intake of energy,protein,fat,vitamins B1,VitB2,Ca,Fe,Zn,Ka between intervention group and control group was significant difference.The nutrients' intake in intervention group was higher.In aspect of growth and development,for males the weight of the intervention group gained 0.6kg more(t=3.75,P<0.001)after one year of intervention,and increased 0.7kg(t=1.99,P=0.046)more after two years of intervention.Lean body mass in the intervention group gained 0.5kg more(t=3.66,P<0.01)at one year.In terms of body fat,the intervention group gained 0.2kg more after one year(t = 2.12,P = 0.034)and 0.5kg more after two years(t = 3.23,P = 0.001)compared to the control group.Statistically significant were seen between the two groups.Differences in body fat or lean body weight in males between intervention and control group were still present after controlling age,height and weight.At the same time,those effects on lean body mass were only found among males with low and medium baseline weight level,and the effects on body fat were found among boys with high weight level.For female student,after one and two years of the intervention,no significant effect occurred in height,weight or body composition as well as males height.In aspect of nutritional status,males' proportion of malnutrition in intervention group was lower than the control group after the two-year milk and egg supplementation.(P=0.014)The difference was statistically significant.While no difference was seen between female students and students overall.However,the proportion of malnutrition overall in the intervention group decreased 7.5%compared with the baseline.In aspect of micronutrient nutritional status,the subclinical deficiency and deficiency of vitamin D in the intervention group and control group was not statistically significant in final investigation.But proportion of vitamin D deficiency and subclinical deficiency in intervention was significantly lower than baseline.In aspect of physical development,both male and female students' in intervention group and control group achievement improved in standing long jump and 50m×8 meters run after two years of intervention.But the intervention group increased more.The difference was statistically significant.The results of 2nd year were better than 2014 Chinese student physical and health research report data in the same age.Conclusion:After two-year intervention implemented,the supplementation with eggs and milk had a certain effect on students' physical development,body composition and nutritional status.It can promoted males weight especially lean body mass in low and medium weight levels.It can improve malnutrition and reduce malnutrition rates.Intervention measures had reduced the vitamin D deficiency rate and improved the students' physical condition.However,two years intervention time had no obvious effect on long-term observation indicators such as height.The nutrition improvement of students should continuous carry out. |
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