Development of an updated phytoestrogen database for use with the SWAN food frequency questionnaire: intakes and food sources in a community-based, multiethnic cohort study.
Phytoestrogens, heterocyclic phenols found in plants, may benefit several health outcomes. However, epidemiologic studies of the health effects of dietary phytoestrogens have yielded mixed results, in part due to challenges inherent in estimating dietary intakes. The goal of this study was to improve the estimates of dietary phytoestrogen consumption using a modified Block Food Frequency Questionnaire (FFQ), a 137-item FFQ created for the Study of Women's Health Across the Nation (SWAN) in 1994. To expand the database of sources from which phytonutrient intakes were computed, we conducted a comprehensive PubMed/Medline search covering January 1994 through September 2008. The expanded database included 4 isoflavones, coumestrol, and 4 lignans. The new database estimated isoflavone content of 105 food items (76.6%) vs. 14 (10.2%) in the 1994 version and computed coumestrol content of 52 food items (38.0%), compared to 1 (0.7%) in the original version. Newly added were lignans; values for 104 FFQ food items (75.9%) were calculated. In addition, we report here the phytonutrient intakes for each racial and language group in the SWAN sample and present major food sources from which the phytonutrients came. This enhanced ascertainment of phytoestrogens will permit improved studies of their health effects.
Division of Geriatrics, Geffen School of Medicine at UCLA, University of California, Los Angeles, California, USA. mhuang@mednet.ucla.edu
Mei-Hua
MH
Huang
Jean
J
Norris
Weijuan
W
Han
Torin
T
Block
Ellen
E
Gold
Sybil
S
Crawford
Gail A
GA
Greendale
D000328:Adult; D015331:Cohort Studies; D003375:Coumestrol / Q000008:administration & dosage / Q000032:analysis; D016208:Databases, Factual; D004032:Diet / Q000208:ethnology*; D005260:Female; D005502:Food; D005504:Food Analysis; D006801:Humans; D007529:Isoflavones / Q000008:administration & dosage / Q000032:analysis; D017705:Lignans / Q000008:administration & dosage / Q000032:analysis; D008137:Longitudinal Studies; D016239:MEDLINE; D008875:Middle Aged; D048789:Phytoestrogens / Q000008:administration & dosage / Q000032:analysis*; D012111:Residence Characteristics; D011795:Surveys and Questionnaires; D014481:United States; D016387:Women's Health
D007529:Isoflavones; D017705:Lignans; D048789:Phytoestrogens; D003375:Coumestrol