Methodologic considerations in the study of diet as part of complementary and alternative medicine modalities.

Diet is an essential component of most comprehensive health systems. Food figures prominently in the consciousness of most individuals, and the sensations of taste and smell are fundamentally important in human emotion. Complex configurations of dietary sanctions and strictures exist in virtually every human society, providing additional force to the power of diet. A wide variety of epidemiologic and laboratory-based studies have implicated a number of specific dietary factors in health and disease, with the former producing much in the way of equivocal evidence on most diet-health relationships and the latter often focusing so narrowly as to call into question the relevance of findings to human health. Assessing the role of diet as an important component of complementary and alternative medical treatment and preventive strategies will require a broad understanding of methodologic issues. Careful consideration of what is required to answer substantive questions in this intriguing and important area also will serve to advance the study of complementary and alternative modalities more generally.