Folate

Supplementation Possibly Helpful

Some evidence suggests that estrogen may interfere with the absorption of folate. 1 Since folate deficiency is fairly common even among those not taking estrogen, taking a folate supplement on general principle is probably a good idea.

Ipriflavone

Potential Benefits and Risks

When the two are taken together, ipriflavone may increase estrogen's ability to protect bone. 2-6 This may allow you to use a lower dose of estrogen and still receive its beneficial effects.

However, there may be risks involved. Although ipriflavone itself probably does not affect tissues other than bone, some evidence suggests that when it is combined with estrogen, estrogen's effects on the uterus are increased. 7,8 This might mean that risk of uterine cancer would be elevated by the combination.

It should be possible to overcome this risk by taking progesterone along with estrogen, which is standard medical practice. However, this finding does make one wonder whether ipriflavone-estrogen combinations raise the risk of breast cancer as well, an estrogen side effect that has no easy solution. At present, there is no available information on this important subject.

Other Nutrients

Supplementation Possibly Helpful

Estrogen use may decrease blood levels of magnesium , vitamin C , and zinc . 9,10 This may mean that supplementation is advisable.

Boron

Theoretical Harmful Interaction

In some studies, boron has been found to elevate levels of the body's own estrogen. 11,12 This might lead to an increased risk of estrogen side effects if boron is combined with estrogen therapy.

Resveratrol

Possible Harmful Interaction

The supplement resveratrol has a chemical structure similar to that of the synthetic estrogen diethylstilbestrol and produces estrogenic-like effects. 14 For this reason, it should not be combined with prescription estrogen products.

Rosemary

Possible Harmful Interaction

Weak evidence hints that the herb rosemary may enhance the liver’s rate of deactivating estrogen in the body. 20 This could potentially interfere with the activity of medications that contain estrogen.

Indole-3-Carbinol

Theoretical Harmful Interaction

Indole-3-carbinol (I3C) is a substance found in broccoli that is thought to have cancer preventive effects. One of its mechanisms of action is thought to involve facilitating the inactivation of estrogen, as well as blocking its effects on cells. 13,17-18 The net result could be decreased effectiveness of medications containing estrogen.

Chasteberry

Theoretical Harmful Interaction

Because of its effects on the pituitary gland, chasteberry might unpredictably alter the effects of estrogen-replacement therapy.

Dong Quai

Interaction Unlikely or Probably Insignificant

The herb dong quai (Angelica sinensis) is used for menstrual disorders.

Because dong quai contains beta-sitosterol, a phytoestrogen, 15 there have been concerns that taking the herb with estrogen might add to estrogen-related side effects. However, a 24-week, placebo-controlled study of 74 postmenopausal women found no estrogen-like effects or reduction of menopausal symptoms associated with taking dong quai. 16

Therefore, dong quai seems unlikely to increase estrogen-related side effects.