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

本论文研究了菲律宾妇女母乳特征和婴儿生长的代际预测因子。过去的研究表明，母亲在子宫内对后代的营养投入是由女性自己早期的营养经历决定的，当胎儿生出更大的后代时，女性的营养状况会更好。这项研究将调查妇女早期的营养经历是否会继续影响出生后的营养转移，这反映在她所产的母乳的成分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，可以通过使后代的生长速度与当地的营养供应相匹配，从而发挥适应性功能。此外，现在已经知道，婴儿喂养方式和饮食构成可能对成人患糖尿病等疾病的风险产生持久影响。为了澄清这些问题，本研究的目的如下：1)记录牛奶宏量营养素的自然变化；2)调查妇女早期营养和生长与她成年后产生的乳汁成分之间的关系；3)探讨乳成分对子代生长和体成分可能产生的影响。这些目标将与一项研究合作进行，这项研究自1983年以来对生活在宿务市（菲律宾）的大量妇女及其后代进行了跟踪调查。每隔一段时间收集所有参与者的详细健康、营养和人体测量数据，从出生后两年内每两个月进行一次访谈开始。由于这些原始的后代现在开始了自己的生殖生涯，这项研究将确定新的怀孕，并跟踪他们的新生儿，收集营养，行为，人体测量学和母乳样本在2个月，4个月和6个月的生命。牛奶的营养成分将被分析。目前的饮食、活动和身体组成与牛奶成分变化的关系，以及早期生活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价值在于扩大了对母乳变化的自然复杂性和决定因素的理解，同时测试了有关这种变化的适应性和进化意义的想法。具体来说，它将探索牛奶成分变化作为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的表型，这种对母亲先前经历的敏感性可能会增加与环境的表型“契合度”。这项研究的更广泛影响包括培养一名研究生，以及对公共卫生的贡献。在全球范围内，饮食和生活方式正在发生转变，导致婴儿时期营养不良或发育迟缓的人群中肥胖和II型糖尿病的人数增加。母乳喂养和母乳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乳汁变化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.