Google
 
Web www.vitaminlore.com
www.eniva.com
. 

Estradiol

Also indexed as: Alora®, Climara®, Dalergen®, Delestrogen®, Depo-Estradiol®, Depogen®, DepoGynogen®, E-Cypionate®, Escalim®, Esclim®, Estinyl®, Estrace®, Estraderm®, Estragyn LA 5®, Estring®, Estro-Cyp®, Estro-L.A.®, Ethinyl Estradiol®, FemPatch®, Gynodiol®, Gynogen L.A.®, Menaval®, Noven®, Vagifem®, Vivelle®

Combination drugs: Adgyn Combi®, Climagest®, Climesse®, Cyclo-Progynova®, Elleste-Duet®, Esstrapak-50®, Estracombi®, Evorel®, Femapak®, Femostan®, Indivina®, Kliofem®, Kliovance®, Nuvelle TS®, Nuvelle®, Tridestra®, Trisequens Forte®, Trisequens®

Estradiol is a semisynthetic human estrogenic hormone used to treat menopausal symptoms, to prevent osteoporosis in postmenopausal women, and as replacement therapy in other conditions of inadequate estrogen production.

Estradiol is available as an oral drug, a transdermal (skin) patch, and as a vaginal cream.

Interactions with Dietary Supplements

Quercetin
Studies have shown that grapefruit juice significantly increases estradiol levels in the blood.1 2 One of the flavonoids found in grapefruit juice is quercetin. In a test tube study, quercetin was found to change estrogen metabolism in human liver cells in a way that increases estradiol levels and reduces other forms of estrogen.3 This effect is likely to increase estrogen activity in the body. However, the levels of quercetin used to alter estrogen metabolism in the test tube were much higher than levels found in the body after supplementing with quercetin.

There is evidence from test tube stuudies that another flavonoid in grapefruit juice, naringenin, also has estrogenic activity.4 It has yet to be shown that dietary or supplemental levels of quercetin (or naringenin) could create a significant problem.

Vitamin D
In controlled studies, the addition of 300 IU per day of vitamin D3 (cholecalciferol) did not improve the bone-preserving or fracture-preventing effects of hormone replacement with estradiol plus a progestin (a synthetic form of progesterone) in postmenopausal women without osteoporosis.5 6 However, in a controlled study of osteoporotic women, only those receiving both hormone replacement and vitamin D had increases in bone density of the hip; no improvement occurred in the hip with hormones alone.7 More research is needed to determine conclusively when vitamin D is important to add to hormone replacement.

Interactions with Foods and Other Compounds

Grapefruit
In a small, controlled study of women with surgically removed ovaries, estradiol levels in the blood were significantly higher after estradiol was taken with grapefruit juice than when estradiol was taken alone.8 These results have been independently confirmed,9 suggesting that women taking oral estradiol should probably avoid grapefruit altogether.

Summary of Interactions for Estradiol

Depletion or interference None known
Adverse interaction Grapefruit*
Quercetin*
Side effect reduction/prevention None known
Supportive interaction None known
Reduced drug absorption/bioavailability None known
Other (see text) Vitamin D

For the convenience of the reader, the information in the summary is categorized as follows: “Depletion or interference” indicates the drug may deplete or interfere with the absorption or function of the supplement or herb. “Adverse interaction” indicates that the supplement or herb used together with the drug may result in undesirable effects. “Side effect reduction/prevention” indicates the supplement or herb may reduce the likelihood and/or severity of a potential side effect caused by the drug. “Supportive interaction” indicates the supplement or herb may support or aid the function of the drug. “Reduced drug absorption/bioavailability” indicates that the supplement or herb may decrease the absorption and/or activity of the drug in the body. An asterisk (*) next to an item in the summary indicates that the interaction is supported only by weak, fragmentary, and/or contradictory scientific evidence.

References:

1. Schubert W, Cullberg G, Edgar B, Hedner T. Inhibition of 17 beta-estradiol metabolism by grapefruit juice in ovariectomized women. Maturitas 1994;20:155–63.

2. Weber A, Jager R, Borner A, et al. Can grapefruit juice influence ethinylestradiol bioavailability? Contraception 1996;53:41–7.

3. Schubert W, Eriksson U, Edgar B, et al. Flavonoids in grapefruit juice inhibit the in vitro hepatic metabolism of 17 beta-estradiol. Eur J Drug Metab Pharmacokinet 1995;3:219–24.

4. Kuiper GG, Lemmen JG, Carlsson B, et al. Interaction of estrogenic chemicals and phytoestrogens with estrogen receptor beta. Endocrinology 1998;139:4252–63.

5. Komulainen M, Kroger H, Tuppurainen MT, et al. Prevention of femoral and lumbar bone loss with hormone replacement therapy and vitamin D3 in early postmenopausal women: a population-based 5-year randomized trial. J Clin Endocrinol Metab 1999;84:546–52.

6. Komulainen MH, Kroger H, Tuppurainen MT, et al. HRT and Vit D in prevention of non-vertebral fractures in postmenopausal women; a 5 year randomized trial. Maturitas 1998;31:45–54.

7. Tuppurainen MT, Komulainen M, Kroger H, et al. Does vitamin D strengthen the increase in femoral neck BMD in osteoporotic women treated with estrogen? Osteoporos Int 1998;8:32–8.

8. Schubert W, Cullberg G, Edgar B, Hedner T. Inhibition of 17 beta-estradiol metabolism by grapefruit juice in ovariectomized women. Maturitas 1994;20:155–63.

9. Weber A, Jager R, Borner A, et al. Can grapefruit juice influence ethinylestradiol bioavailability? Contraception 1996;53:41–7.