Nutritional Epidemiology

Nutritional epidemiology is concerned with describing the distribution and variation in the nutritional behavior of individuals and relates that behavior to health outcomes. A key aspect of the topic is defining and measuring food and nutrient intakes. Challenges exist around measuring these aspects with accuracy, free from bias. Because diet and other behaviors are complex and interrelated, it is important, both in the design and interpretation of studies, to understand how this complexity may affect the results of the study. In this chapter, nutritional exposures are defined and methods of dietary exposure measurement are described, including the importance of having a clear research question to drive the choice of method. New technologies for measuring diet show a promising way forward. Accurate food composition tables are critical to accurate measurements. Measurement error and calibration of dietary intake are discussed. Statistical approaches including energy adjustment and dietary pattern analysis are highlighted. The importance of accurate measures in national surveys and public health nutrition is discussed. There are many health outcomes for where nutrition plays a direct or an indirect role in causation and therefore in disease prevention. Worldwide, there is a complex mix of problems of over- and undernutrition, often stratified by education or economic groups. The methods of nutritional epidemiology guide that evidence-base and our ability to support public health.