摘要：Objectives . To review the contribution of the Nurses’ Health Studies (NHSs) to diet assessment methods and evidence-based nutritional policies and guidelines. Methods . We performed a narrative review of the publications of the NHS and NHS II between 1976 and 2016. Results . Through periodic assessment of diet by validated dietary questionnaires over 40 years, the NHSs have identified dietary determinants of diseases such as breast and other cancers; obesity; type 2 diabetes; cardiovascular, respiratory, and eye diseases; and neurodegenerative and mental health disorders. Nutritional biomarkers were assessed using blood, urine, and toenail samples. Robust findings, from the NHSs, together with evidence from other large cohorts and randomized dietary intervention trials, have contributed to the evidence base for developing dietary guidelines and nutritional policies to reduce intakes of trans fat, saturated fat, sugar-sweetened beverages, red and processed meats, and refined carbohydrates while promoting higher intake of healthy fats and carbohydrates and overall healthful dietary patterns. Conclusions . The long-term, periodically collected dietary data in the NHSs, with documented reliability and validity, have contributed extensively to our understanding of the dietary determinants of various diseases, informing dietary guidelines and shaping nutritional policy. Diet includes multiple interacting components and varies for individuals over time, 1 making it challenging to measure in large, free-living populations. In the Nurses’ Health Studies (NHSs), we dealt with this challenge by using semiquantitative food frequency questionnaires (SFFQs) for diet assessment, conducting substudies to compare their validity with that of more detailed assessment methods (e.g., multiple-week weighed diet records) and biomarkers, and further developing measurement error correction techniques to improve the validity of diet–disease association findings. The NHSs have also assessed nutritional biomarkers using biospecimens, including blood, urine, and toenail samples. Together, these approaches enable the assessment of long-term diet and, thus, the investigation of dietary etiologies of major chronic diseases. These detailed investigations, together with evidence from other large cohorts and randomized dietary intervention studies, have formed the evidence base for developing current nutritional policies and dietary guidelines to reduce the risk of many chronic diseases.
