Using isothiocyanate excretion as a biological marker of Brassica vegetable consumption in epidemiological studies: evaluating the sources of variability

Public Health Nutrition

James R Hebert¹  Jed W Fahey¹  Katherine K Stephenson¹  Jay H Fowke¹ 

关键词: Isothiocyanate;    Biomarker;    Diet;    Estrogen metabolism;    Dietary assessment;    Brassica;   

DOI  :  10.1079/PHN2000113

学科分类：卫生学

来源: Cambridge University Press

【 摘 要 】

Objective:Brassica vegetable consumption (e.g. broccoli) leads to excretion of isothiocyanates (ITC) in urine. We evaluated the consistency of ITC as a biomarker for dietary Brassica vegetable consumption across the types of vegetables and methods of preparation used in Western societies, and across consumption levels.Design:A single-armed behavioural intervention with duplicate baseline assessment and post-intervention assessment. Urinary ITC excretion and estrogen metabolites were measured from 24-hour urine samples. Dietary intake was measured by a 24-hour recall.Setting:The behavioural intervention facilitated daily Brassica intake among participants by providing peer support, food preparation instruction, guided practice in a teaching kitchen, and other information.Subjects:Thirty-four healthy free-living postmenopausal women who recently had a negative screening mammogram at the University of Massachusetts Medical Center.Results:Urinary ITC excretion and total Brassica intake followed the same pattern over the intervention. The ITC biomarker significantly predicted Brassica intake when Brassica consumption averaged about 100 g day−1, but not when Brassica consumption averaged about 200 g day−1. Urinary ITC levels were somewhat higher when more raw vegetables were consumed as compared to lightly cooked vegetables, while the types of Brassica consumed appeared to have only a small, non-significant effect on urinary ITC levels.Conclusion:Urinary ITC excretion would be a good exposure biomarker among populations regularly consuming a vegetable serving/day, but may be less accurate among populations with greater intake levels or a wide range of cooking practices.

【 授权许可】

Unknown