强化燕麦饮品对北京郊区儿童体格和智力相关因素的影响

【作者】 赵静；

【导师】 胡小琪；

【作者基本信息】 中国疾病预防控制中心 ， 营养与食品卫生学， 2010， 硕士

【摘要】 研究背景2002年中国居民营养与健康状况调查结果显示,我国儿童的膳食和营养状况有了明显的改善,但某些微量营养素摄入不足的现象仍然存在,其中钙、铁缺乏是我国儿童普遍存在的问题。尤其是农村地区,6-12岁儿童膳食钙摄入量仅为中国营养学会推荐摄入量(800mg～1000mg／d)的32～34%。由缺铁导致的缺铁性贫血已成为普遍关注的公共卫生问题。目前,我国5～11岁农村儿童贫血患病率为13.7%,贫血不仅会影响儿童的身体健康,还会影响其学习能力和智力发育。通过食物强化补充微量营养素是公认的经济而有效的改善营养素缺乏的措施之一。国内外有许多通过在牛奶中强化钙、铁改善儿童钙铁营养状况的研究,但是对于乳糖不耐受者和食物过敏者,通过牛奶补充改善儿童微量营养素状况受到较大限制。因此,有必要探讨和研究通过在其他食物中强化微量营养素,以改善包括乳糖不耐受儿童在内的学生膳食和营养状况。本研究中所用的燕麦饮品是以燕麦为原料的液体植物性食物,生产加工过程营养素损失较少,是强化各种微量营养素的良好基质。本研究在燕麦饮品中强化了钙和铁,以观察补充钙和铁对北京郊区儿童体格发育及智力相关因素的影响。研究目的观察补充强化钙和铁的燕麦饮品对北京郊区儿童体格生长、体成分、骨骼发育及智力发育影响,为改善北京郊区儿童营养状况提供科学依据。研究对象及方法本研究为随机对照干预研究。选取北京市怀柔区2个乡镇,每个乡镇各选随机取1所小学,二至四年级的健康学生,共409名作为研究对象。随机分为干预组：209人,分别于上午和下午课间给予强化钙和铁的燕麦饮品200ml各一次；对照组：200人,正常膳食不给予燕麦饮品。对干预组学生进行为期1年的燕麦饮品补充。通过问卷调查收集研究对象的社会经济背景、家庭环境状况、膳食摄入情况、身体活动情况及智力情况等,检查生长发育状况。用双能X线吸收仪(Dual Energy X-ray Absorptiometry, DEXA)测定全身、前臂远端1／3处(前臂近端)、前臂远端1／10处(前臂远端)和桡骨远端1／3处骨矿物含量(Bone Mineral Content, BMC)、骨矿物密度(Bone Mineral Density, BMD)和骨面积(Bone Area, BA),同时测定全身体成分。取晨起空腹血,检测钙代谢相关指标：血清骨碱性磷酸酶(Bone Alkaline Phosphatase, BAP)、抗酒石酸盐酸性磷酸酶(Tartrate-Resistant Acid Alkaline Phosphatase, TRAP)、胰岛素样生长因子1(Insulin Like Growth Factor-1, IGF-1)和铁代谢相关指标：血清铁、转铁蛋白和可溶性转铁蛋白受体(Soluble Transferrin Receptor, sTfR)含量。所有测量在干预开始前和结束后各进行一次。t检验、卡方检验、秩和检验用于比较组间差异,采用多元线性回归分析体格、骨量、体成分、智力及学习成绩的影响因素,混合线性模型用于分析干预效果。研究结果干预前,研究对象平均年龄为8.9±0.9岁,两组间性别和年龄无显著差异。干预过程中,干预组学生共补充燕麦饮品366天,平均每天补充365ml(提供365mg钙和5.5mg铁)。有32人失访,失访率为7.8%,干预组与对照组失访率分别为7.2%和9.9%,两组分布无统计学差异。膳食摄入、身体活动、早期营养状况、青春发育及家庭环境没有显著性差异,但干预组的家庭经济状况和父母受教育程度高于对照组。干预后,干预组男生体质指数(Body Mass Index, BMI)增量比对照组高50%(P<0.05),干预组男生体重增量比对照组高18.4%(P=0.064)。用混合线性模型调整混杂因素后,男生BMI的干预效应显著意义(P<0.05)；体重有干预效应,但未达到显著性(P=0.058)。男生身高以及女生体格指标干预前后组间无显著差异。干预组男生前臂近端和桡骨BMC增量分别比对照组高16.9%和12.3%(P<0.05);全身BMC增量比对照组高10.3%(P=0.08)。但调整混杂因素后,干预效应显著性消失。女生上肢、前臂近端及桡骨BMC增量分别较对照组高出27.1%、26.4%和24.1%(P<0.05)；调整混杂因素后,干预效应仍有显著意义(P<0.05)。两组男生各部位BMD增量无组间差异,但调整混杂因素后,男生前臂近端和桡骨BMD有显著干预效应(P<0.05)。干预组女生上肢BMD增量显著高于对照组(P<0.05),且调整混杂因素后,干预效应仍有显著意义。干预组男生血清IGF-1增量和血清BAP、TRAP降低显著高于对照组(P<0.05),调整混杂因素后,干预效应仍有显著意义。干预组女生血清IGF-1增量和血清TRAP降低显著高于对照组,调整混杂因素后,干预效应仍有显著意义(P<0.05)。干预组女生血清sTfR浓度降低0.87nmol/L,而对照组上升了3.58 nmol/L,两组间有显著差异(P<0.01)。干预后,干预组女生的血清sTfR浓度显著低于对照组。调整混杂因素后,干预效应仍有显著意义(P<0.05)。按智力评分划分智力等级,干预前,对照组男生智力中上及优秀者所占比例高于干预组(P<0.05)；干预后,两组男生的智力等级分布无显著差异。骨面积、体成分、血清铁和转铁蛋白以及智力评分和学习成绩无显著干预效果。结论通过一年的燕麦饮品补充实验证明,补充钙、铁能促进男生身高和BMI增长,对女生的体格发育促进作用不显著；补充钙通过刺激骨增长、降低骨转换而促进骨量的增加；补充铁对女生铁营养状况有一定的改善作用,但是对儿童智力的影响不显著。更多还原

【Abstract】 BackgroundAccording to 2002 China National Nutrition and Health Survey (CNNHS,2002), on the one hand, the nutritional status of children and adolescents in China has been improved markedly; on the other hand, inadequate intakes of micronutrients in Chinese children and adolescents are still exists, such as low calcium intake and iron deficiency.The intakes of calcium and iron in chinese children are quite low, especially in rural area. The average calcium intake of rural children aged 6～12 years was only 32～34% of the RNI (800～1000 mg/day, CNNHS). Iron deficiency still exist among children and adolescents in China, the prevalence of anemia in 5～11 years children was 13.7% in rural area(CNNHS,2002). Though iron intake of children and adolescents is not low, our diet is mainly based on plant food, results in limited iron absorption and utilization. Iron deficiency anemia has become a universal public health problem, anemia will affect study abilities and intellectual development of children and adolescents.Micronutrients supplementation through food fortification is recognized as the economic and effective measures to improve the nutrient deficiencies. There are many studies at home and abroad fortified calcium and iron in milk to improve nutritional status of children. But for the ones, who are lactose intolerance and food allergy, through the milk fortification to improve the micronutrient status of children, are restricted. It is necessary to find other food to fortified micronutrients to improve the students nutritional status.The oat drinks is liquid plant food based on the oat as raw material, which of the production process is less nutrients loss, oat drinks is also the better vehicle for nutrient fortification. The oat drinks used in this study was fortified with calcium and iron, in order to observe the effect of calcium and iron fortified oat drinks on physical and mental development in children in suburban district in Beijing.ObjectiveIn order to improve calcium and iron nutrition status of children in suburban district in Beijing and promote their healthy development, as well as to observe the effect of calcium and iron fortified oat drinks on physical development, bone development, body composition and IQ in children. To provide a scientific basis for improving the nutritional status of children in suburban district in Beijing.MethodThe design was randomized controledl intervention trail.Select two small towns from a Huairou District, Beijing, and one primary schools select randomly from each small town. Total 409 health pre-pubertal children in 2nd-4th grade were recruited. All subjects were randomly divided into two groups by individual:intervention group:209 subjects, who supplied with 200 ml fortified oat milk twice per day; control group:200 subjects, who maintained day-to-day diet, without supplementation of oat drinks.Collect subjects’socio-economic background, family environments, dietary intake, physical activity, children intelligence through a questionnaire survey. The anthropometric and pubertal development was examined. Bone mineral content (BMC), bone mineral density (BMD), and bone area (BA) of distal forearm (DF), proximal forearm (PF), proximal radius(PR) on the left arm and total body(TB) were measured by DEXA(Norland XR-46 densitometer), as well as the whole body composition measured. Overnight fasting blood samples were obtained in the morning for biochemical measurements, including serum bone alkaline phosphatase (BAP), tartrate-resistant acid alkaline phosphatase (TRAP) and insulin-like growth factor-1(IGF-1) for calcium metabolism; serum iron, transferrin, and soluble transferrin receptor for iron nutrition status. All measurements were carried out at baseline and 12 months later. The differences between two groups were analyzed with t-test, chi square test, wilcoxon. The influnencing factors of bone mass, body composition, intelligence were analyzed with multivariable linear regression. The intervention effects were analyzed with mixed linear modle.Results409 subjects were recruited from suburban of Beijing, the mean age of subject was 8.9±0.9 years old. There were 209 subjects in study group and 200 subjects in control group. There was no significant difference of age, gender distribution. During the intervention, in total, the average daily intake over the 12month study period was 365 ml oat milk (containing 365 mg calcium and 5.5 mg iron) for study group, after correcting for compliance. Total 32 of 409 subjects withdrew the study,7.2% in study group vs 9.9% in control group (P>0.05). No significant difference was observed between follow-up and withdrawal subjects. There was no significant difference between two groups on nutrient intake, physical activity level, pubertal development, early nutrition status, and family environment during the study; while family income and parent education level of subjects in study group were slightly but significantly higher than those of the control group.After intervention, the average Body Mass Index (BMI) gain in boys of the study group were 50% higher than that of control group(P<0.05); after adjusted for confounding factors in linear mixed models, this effect is still significant. The average weight gain in boys of the study group were 18.4% higher than that of control group (P=0.064); after adjusted for confounding factors in linear mixed models, this effect is still not significant. However, no significant difference were observed between groups in other anthropometric indicators, or in girls.The accretion BMC in boys of study group was higher by 16.9% and 12.3% at the proximal forearm and radius (P<0.05) and by 10.3% at total body (P=0.08) than those of control group during intervention; while the intervention effect was disappeared after adjustment of confounding factors. In girls, the accretion of BMC at upper limb, proximal forearm and radius was 27.1%,26.4% and 24.1% higher than those of control group (P< 0.05), so did after adjustment of confounders.There was no significant difference between two groups for accretion BMD at each position after intervention, while after adjusting for confounding factors, the intervention effects of BMD at proximal forearm and radial in boys was significant. In girls, the accretion BMD at upper limb of study group was significantly higher than of control group(P<0.05), and after adjusting for confounding factors, the intervention effect was still significant.As to the biomarkers of bone turnover, for boys, the mean gain of serum IGF-1 and the mean decrease of serum BAP and TRAP in study group were significantly higher than those of control group (P<0.05); the intervention effect was still significant after adjusting for confounding factors. For girls, the mean gain of serum IGF-land the mean decrease of serum TRAP of study group was significantly higher than that of control group (P<0.05), with or without adjustment. The serum sTfR in girls of study group decreased 0.87nmol/L, while that of control group increased by 3.58 nmol/L (P <0.01). After the intervention, the serum sTfR in girls of study group was significantly lower than that of control group. After adjusting for confounding factors, the intervention effect was still significant (P<0.05).Both in boys and girls, body composition indices, the serum iron and transferrin, IQ were not observed significant difference between groups before or after intervention.ConclusionsThe findings of this study shows that calcium and iron fortified oat milk supplementation can promote the physical development in boys living in Chinese rural areas, but not in girls. The supplementation of calcium can benefit bone mass accrual by stimulating growth and decreasing bone turnover. However, the effect of iron supplement on iron status is limited in girls, but not in boys, the effect on intelligence is not obvious in Chinese rural children either.更多还原