Doctoral Dissertation Improvement : Early Life Growth and Nutrition and Milk Composition in Adulthood

本论文研究的是菲律宾妇女母乳特征和婴儿生长的代际预测因素。过去的研究表明，母亲在子宫内对后代的营养投入受到女性自身早期生活营养经历的影响，随着胎儿生下更大的后代，女性得到的营养更好。这项研究将调查妇女早年的营养经历是否继续影响出生后的营养转移，这反映在她产生的母乳的组成和她的后代的生长速度上。根据先前的营养经验调整对后代的投资的能力，可以通过允许设定与当地营养可获得性相匹配的后代生长速度来发挥适应功能。此外，现在已经知道，婴儿的喂养方式和饮食结构可以对成人患糖尿病等疾病的风险产生持久的影响。为了澄清这些问题，本研究有以下目的：1)记录牛奶中常量营养素的自然变化；2)调查妇女早期生命营养和生长与成年后所产牛奶成分之间的关系；3)探索牛奶成分对其后代生长和身体成分的可能影响。这些目标将与一项研究合作进行，该研究自1983年以来对居住在菲律宾宿务市的妇女及其子女进行了大样本跟踪调查。定期收集所有参与者的详细健康、营养和人体测量数据，从生命头两年每两个月进行一次访谈开始。由于这些原始后代现在开始了自己的生殖生涯，这项研究将识别新怀孕并跟踪他们的新生儿，收集出生2个月、4个月和6个月的营养、行为、人体测量学和母乳样本。牛奶将进行营养成分分析。目前的饮食、活动和身体成分与牛奶成分变化的关系，以及早期生命营养和生长速度的可能影响，将使用多元统计技术进行建模。这项研究的主要智力优势是扩大了对母乳变化的自然复杂性和决定因素的理解，同时测试了这种变化的适应性和进化意义。具体地说，它将探索母乳成分变化作为关于母亲慢性或早期生活营养经历的代际“信息”来源的可能作用。由于营养物质流向后代会影响后代的生长速度和成年后代的表型，这种对母亲先前经验的敏感性可能会增加表型与环境的“契合度”。这项研究的更广泛影响包括培养研究生，以及对公共卫生的贡献。饮食和生活方式正在全球范围内发生变化，导致婴儿时期营养不良或发育不良的人肥胖和II型糖尿病增加。母乳喂养和牛奶成分已被证明可以预测未来的疾病风险。这项研究将通过探索牛奶变异是如何产生的，以及它对后代生长的影响来阐明这些问题。

This dissertation research concerns the intergenerational predictors of breast milk characteristics and infant growth in a Philippine women. Past work has shown that maternal investment of nutrients in offspring in utero is conditioned by a woman's own early life nutritional experiences, with women better-nourished as fetuses giving birth to larger offspring. This study will investigate whether a woman's early life nutritional experiences continue to influence nutrient transfer after birth, as reflected in the composition of breast milk that she produces and in the growth rate of her offspring. An ability to adjust investment in offspring in response to prior nutritional experiences could serve an adaptive function by allowing offspring growth rate to be set to match local nutritional availability. In addition, it is now known that mode of infant feeding and diet composition can have lasting effects on adult risk for diseases like diabetes. To clarify these issues, this study has the following aims: 1) document natural variation of milk macronutrients; 2) investigate the association between a woman's early life nutrition and growth and the composition of milk that she produces as an adult; 3) explore the possible influences of milk composition on the growth and body composition of her offspring. These objectives will be addressed in collaboration with a study that has followed a large sample of women and their offspring living in Cebu City (the Philippines) since 1983. Detailed health, nutrition, and anthropometric data have been collected on all participants at regular intervals, starting with bi-monthly interviews during the first two years of life. As these original offspring are now beginning their own reproductive careers, this study will identify new pregnancies and follow up their newborns, collecting nutritional, behavioral, anthropometrics and breast milk samples at two, four and six months of life. Milk will be analyzed for nutritional composition. The associations of current diet, activity, and body composition with variation in milk composition, and the possible influence of early life nutrition and growth velocity, will be modeled using multivariate statistical techniques.This study's primary intellectual merit is in expanding understanding of the natural complexities and determinants of human milk variation, while testing ideas about the adaptive and evolutionary significance of that variation. Specifically, it will explore the possible role of variation in milk composition as a source of intergenerational "information" about the mother's chronic or early life nutritional experiences. Because the flow of nutrients to offspring influences offspring growth rate and the adult phenotype, this sensitivity to the mother's prior experiences could increase the phenotypic "fit" with the environment. The broader impacts of this study include training a graduate student, and contributions to public health. Diet and lifestyle are being transformed globally, with resulting increases in obesity and Type II diabetes in individuals who were malnourished or stunted as infants. Breast feeding and milk composition have been shown to predict future disease risk. This study will illuminate these issues by exploring how milk variation arises and what effects it has on offspring growth.