Dietary patterns in transition can inform health risk, but detailed assessments are needed to guide recommendations

Authors: Tucker, Katherine

Submitted to: International Journal of Epidemiology
Publication Type: Other
Publication Acceptance Date: 4/18/2007
Publication Date: 5/28/2007
Citation: Tucker, K. 2007. Dietary patterns in transition can inform health risk, but detailed assessments are needed to guide recommendations. International Journal of Epidemiology. doi:10.1093/ije/dym105.

Interpretive Summary:

Technical Abstract: Most research on diet and health has historically focused on single nutrients or foods and their effect on disease outcomes. In recent years, this focus has shifted to include the total dietary pattern as a risk factor in epidemiologic studies. This change has occurred for several reasons. First, as we have moved from a focus on deficiency conditions to one of risk of chronic disease, the etiology has become more complex. Methodologically, as well, it has been recognized that diets contain components that are highly collinear—so that observations of a single nutrient with a disease outcome could often be explained by other dietary factors. More than that, however, has been the realization that it may not be enough to simply adjust for other dietary components as they are likely to interact in complex ways. The importance of this point has reached a larger audience since the limitations of several large nutrient specific clinical trials have become evident. For example, despite strong epidemiologic evidence of protective effects of beta-carotene against lung cancer in observational studies, the alpha-tocopherol beta-carotene (ATBC) trial in Finland, where beta-carotene was provided as a supplement, showed increased risk rather than protection. In the Women’s Health Initiative, modification of total fat intake did not have the expected or desired result, and it has since been acknowledged that other aspects of the diet needed consideration as well. At the same time, a more complex total diet intervention, the DASH study showed multiple improvements in health and the benefits of the Mediterranean diet were being confirmed. These and other such large studies have taught an important lesson—nutritional exposures are complex and dietary research needs a broader paradigm than the "pharmaceutical" model that most studies have followed.