QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Chang, J.-L. Articles by Lampe, J. W. Search for Related Content PubMed PubMed Citation Articles by Chang, J.-L. Articles by Lampe, J. W.

---

Biochemical, Molecular, and Genetic Mechanisms

UGT1A1 Polymorphism Is Associated with Serum Bilirubin Concentrations in a Randomized, Controlled, Fruit and Vegetable Feeding Trial¹

² Interdisciplinary Graduate Program in Nutritional Sciences, Department of Epidemiology, University of Washington, Seattle, WA 98195 and ³ Fred Hutchinson Cancer Research Center, Seattle, WA 98109

^* To whom correspondence should be addressed. E-mail: jlampe{at}fhcrc.org.

UDP-glucuronosyltransferase (UGT) 1A1 glucuronidates bilirubin, estrogens, and exogenous compounds, including dietary carcinogens. The UGT1A1*28 polymorphism, characterized by variation in the number of thymine-adenine repeats in the promoter region, modulates UGT1A1 transcription. Observational and in vitro studies suggest that certain phytochemicals may increase UGT activity. We investigated, in a randomized, controlled, crossover feeding trial, whether 10 servings/d (doses adjusted for body weight) of crucifers, soy, and citrus for 2 wk compared with a fruit- and vegetable-free basal diet affected UGT1A1 activity as measured by serum bilirubin concentrations and whether effects were modulated by the UGT1A1*28 polymorphism. Healthy men (n = 32) and women (n = 31), aged 20–40 y, enrolled based on UGT1A1 genotype, completed the study. We measured bilirubin in blood collected at d 8 and d 15 of each feeding period. Overall, fruit and vegetables (F&V) did not affect serum bilirubin; however, among 7/7 individuals, d 8 total (P = 0.057) and indirect (unconjugated) (P = 0.051) bilirubin tended to be lower when individuals consumed the F&V diet (28.97 ± 2.36 µmol/L and 25.97 ± 2.15 µmol/L) compared with the basal diet (32.46 ± 2.63 µmol/L and 29.31 ± 2.43 µmol/L). We no longer detected this difference at d 15, by which time bilirubin had also decreased when participants consumed the basal diet. Additionally, intervention effects on bilirubin were restricted to women with 7/7 genotype (P = 0.002). These results suggest that serum bilirubin glucuronidation is modulated by dietary intervention, but factors such as UGT1A1 genotype and sex may affect the response to diet.