Green tea intake is associated with urinary estrogen profiles in Japanese-American women.

Abstract

SCOPE:

Intake of green tea may reduce the risk of breast cancer; polyphenols in this drink can influence enzymes that metabolize estrogens, known causal factors in breast cancer etiology.

METHODS AND RESULTS:

We examined the associations of green tea intake (<1 time/week, 1-6 times weekly, or 7+ times weekly) with urinary estrogens and estrogen metabolites (jointly EM) in a cross-sectional sample of healthy Japanese American women, including 119 premenopausal women in luteal phase and 72 postmenopausal women. We fit robust regression models to each log-transformed EM concentration (picomoles per mg creatinine), adjusting for age and study center. In premenopausal women, intake of green tea was associated with lower luteal total EM (P trend=0.01) and lower urinary 16-pathway EM (P trend=0.01). In postmenopausal women, urinary estrone and estradiol were approximately 20% and 40% lower (P trend=0.01 and 0.05, respectively) in women drinking green tea daily compared to those drinking<1 time/week. Adjustment for potential confounders (age at menarche, parity/age at first birth, body mass index, Asian birthplace, soy) did not change these associations.

CONCLUSIONS:

Findings suggest that intake of green tea may modify estrogen metabolism or conjugation and in this way may influence breast cancer risk.

• Authors: Barbara J Fuhrman, Ruth M Pfeiffer, Anna H Wu, Xia Xu, Larry K Keefer, Timothy D Veenstra, Regina G Ziegler
• Journal: Nutrition journal (Nutr J) Vol. 12 Pg. 25 (Feb 15 2013) ISSN: 1475-2891 [Electronic] England
• PMID: 23413779 (Publication Type: Journal Article, Research Support, N.I.H., Intramural, Research Support, U.S. Gov't, Non-P.H.S.)

Chemical References

• Estrogens
• Polyphenols
• Tea

Topics

• Adult
• Asian
• Body Mass Index
• Breast Neoplasms (prevention & control)
• Cross-Sectional Studies
• Estrogens (urine)
• Feeding Behavior
• Female
• Humans
• Linear Models
• Middle Aged
• Multivariate Analysis
• Polyphenols (administration & dosage)
• Postmenopause (physiology)
• Premenopause (physiology)
• Risk Factors
• Specimen Handling
• Surveys and Questionnaires
• Tea
• Young Adult