Scientific and public health rationale for the Dietary Guidelines for Americans.

The Dietary Guidelines for Americans, published by DHHS and USDA in 1980, have recently been reviewed by an expert committee that has recommended only minimal changes to scientifically update them. Initial efforts to develop dietary guidelines for prevention of diseases were fraught with controversy, some of which has continued. This controversy exemplifies a larger issue concerning the role that contemporary science, and specifically government, has in assuring and maintaining public health. Two broad questions need to be asked: what is the government's role in facilitating application of contemporary nutrition knowledge to public health, and what standard of scientific surety should be the basis for its application? Government's role in assuring public health and safety indirectly through information is well established. In deciding when the data are sufficient to inform the public, public health scientists must, at some point, make the leap of faith, even though some doubts may remain.