Aromatase inhibitors such as Arimidex (anastrozole), Femara (letrozole), and Aromasin (exemestane) suppress the production of estrogen within the body by inhibiting the action of the enzyme aromatase (which converts androgens into estrogens). The growth of ER+ (i.e., estrogen sensitive) breast cancer is promoted by estrogen and decreasing its production is designed to reduce recurrence.
There are also some foods that inhibit aromatase and others that increase it. We cover these and other foods that influence the treatment effects of aromatase inhibitors in Foods to eat & avoid during aromatase inhibitor treatment. Below we list only those foods known to inhibit or promote aromatase activity directly. The purpose is to provide useful information to postmenopausal women who would benefit from aromatase inhibitor treatment, but are unable to undergo it or other anti-estrogen treatment.

Foods that inhibit aromatase activity

Foods that increase aromatase activity

The following foods contain compounds that have been shown to increase aromatase activity, thereby increasing the production of estrogen.
Alcohol
Beef
Corn oil
Grilled, BBQ'd, or smoked meat or fish
Lamb
Peanut oil
Safflower oil
Soybean oil
Sunflower oil
Please see our article on aromatase inhibitors for more information.