Effects of prune consumption on the ratio of 2-hydroxyestrone to 16alpha-hydroxyestrone.
BACKGROUND
A higher urinary ratio of the biologically inactive estrogen metabolite, 2-hydroxyestrone (2OHE1), to the biologically active metabolite, 16alpha-hydroxyestrone (16alphaOHE1), may be associated with a lower risk of breast cancer. High fiber intake is also associated with decreased breast cancer risk.


OBJECTIVE
We investigated the effects of prunes, which are naturally rich in both soluble and insoluble fiber, on the concentrations of 2OHE1 and 16alphaOHE1 and on the ratio of 2OHE1 to 16alphaOHE1.


METHODS
Nineteen healthy premenopausal women consumed their habitual diets for 3 menstrual cycles and then consumed 100 g prunes/d for the next 3 cycles. Concentrations of urinary 2OHE1 and 16alphaOHE1 were determined during the follicular and luteal phases.


RESULTS
Prune supplementation increased total and soluble fiber intakes by 4 and 2 g/d, respectively (P < 0.001). Mean (+/- SEM) luteal 2OHE1 excretion decreased from 3.92 +/- 0.79 to 2.20 +/- 0.40 nmol/mmol creatinine during the third cycle (P = 0.017). Luteal 16alphaOHE1 excretion decreased from 1.38 +/- 0.24 to 0.87 +/- 0.10 and 0.87 +/- 0.15 nmol/mmol creatinine during the first and third cycles, respectively (P = 0.018 for both values). Follicular 16alphaOHE1 excretion decreased significantly only during the first cycle (from 0.82 +/- 0.12 to 0.45 +/- 0.09 nmol/mmol creatinine; P = 0.005). The 2OHE1-16alphaOHE1 ratio did not change significantly after prune supplementation.


CONCLUSIONS
Prune supplementation significantly decreased the excretion of 16alphaOHE1 during the follicular phase of the first menstrual cycle and during the luteal phases of both the first and third menstrual cycles. The 2OHE1-16alphaOHE1 ratio did not change significantly. The potential significance of the decrease in 16alphaOHE1 excretion, without a change in the 2OHE1-16alphaOHE1 ratio, on the prevention of estrogen-dependent cancers remains to be determined.
Kasim-Karakas
Sidika E
SE
Department of Internal Medicine, Division of Endocrinology, Clinical Nutrition, and Vascular Medicine, University of California, Davis, CA 95817, USA. sekarakas@ucdavis.edu
Almario
Rogelio U
RU
Gregory
Laura
L
Todd
Heather
H
Wong
Rodney
R
Lasley
Bill L
BL
D001823:Body Composition; D001824:Body Constitution; D015992:Body Mass Index; D001835:Body Weight; D004032:Diet; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D004041:Dietary Fats / Q000008:administration & dosage; D004043:Dietary Fiber / Q000008:administration & dosage*; D004044:Dietary Proteins / Q000008:administration & dosage; D002149:Energy Intake; D005498:Follicular Phase; D005638:Fruit; D006894:Hydroxyestrones / Q000652:urine*; D008183:Luteal Phase; D017697:Premenopause; D027861:Prunus
D004040:Dietary Carbohydrates; D004041:Dietary Fats; D004043:Dietary Fiber; D004044:Dietary Proteins; D006894:Hydroxyestrones; C026702:16-hydroxyestrone; C024980:2-hydroxyestrone