Nutritional epidemiology is an area of epidemiology that studies the role of nutrition and diet in the etiology of disease such as cancer and heart disease, and monitors nutritional status of populations. It thus involves the assessment of food consumption and nutrient intake, an area referred to as assessment of dietary intake or of dietary exposure. In addition to the use of demographic and psychosocial variables, today nutritional epidemiology also attempts to study nutrition-related diseases by means of clinical trials and to monitor nutrient intake with biochemical markers (Margetts and Nelson, 1997).

The field of nutritional epidemiology can often be traced back to 1747, when James Lind (1753) observed that fresh fruits and vegetables could be used to cure scurvy. His observation represents one of the earliest clinical trials. The cause of the scurvy disease was later found to be vitamin C deficiency (see, e.g., Sandstead, 1973). Then in 1884, Kanehiro Takaki (1887) linked Japanese sailor’s diet of polished rice to the disease beriberi (which is due to vitamin B1 deficiency). The disease was eliminated when he added milk and vegetables to the soldiers’ diet.

The relationship between nutritional epidemiology and health risk assessment is quite unique in that the consumption of too much or too little nutrients of certain kind may lead to some chronic diseases. The measure of nutritional status is also unique since socioeconomics, education, and cultural habit can have a great influence on an individual as well as a population’s nutrient or dietary intake.