This article is reviewed, corrected, and approved by: Dr. Benjamin McLean M.D. | FCPS | FRCP | MPH

If you or someone you know has breast cancer, you might want to know about a treatment called Anastrozole. It works by blocking an enzyme that fuels cancer cells, which can help slow or even stop their growth.

This medication is perfect for treating hormone receptor-positive breast cancer because it targets the hormones that feed those cancer cells. It's a pretty effective way of reducing the risk of recurrence, too! Today, I am about to share with you some foods you should avoid while taking Anastrozole.

What is Anastrozole?

Anastrozole is classified as an aromatase inhibitor drug. It blocks the aromatase enzyme, which converts androgens to estrogen in postmenopausal women. This can help to reduce estrogen levels and treat breast cancer.

Breast cancer cells may grow faster when estrogen is present in the body. Women with a certain kind of breast cancer, where the cancer cells have special parts on their surface called estrogen and progesterone receptors, often get treated with Anastrozole.

These receptors are like switches that can make cancer grow. Anastrozole helps to turn off these switches and slow down cancer growth.

How Does Anastrozole Work in the Body?

By inhibiting aromatase activity, our body produces less estrogen when Anastrozole is taken. As a result, hormone receptor-positive breast cancer cells grow slower or even cease to grow. Unlike other treatments that directly interfere with estrogen receptors, Anastrozole addresses the source of estrogen production, making it particularly effective for postmenopausal women with lower levels of circulating estrogen.

Foods to Avoid When Taking Anastrozole

Here are some foods that you should avoid when taking Anastrozole

1. Grapefruit and Grapefruit Juice

When Anastrozole is taken with grapefruit or its juice, the enzyme inhibition can slow down the breakdown of the medication, causing it to stay in the body longer than intended. This prolonged presence of Anastrozole might lead to a higher concentration of the drug, which could potentially amplify its effects, including both therapeutic benefits and potential side effects.

Grapefruit can interact with medication, including Anastrozole, by inhibiting liver enzymes. As a result, side effects can occur, or effectiveness can be altered, depending on the level of medication in the bloodstream.

2. High-Fat Dairy Products

High-fat content in dairy products, including whole milk, cheese, and butter, may indirectly affect estrogen levels in the body. As estrogen is stored in fat tissue, higher levels of body fat can cause an increase in estrogen levels, which may offset the effects of Anastrozole in reducing estrogen production.

While the impact of dietary fats on Anastrozole's effectiveness may not be as direct as that of grapefruit, it's still recommended to choose low-fat dairy options or dairy substitutes to maintain a balanced diet that supports the medication's intended effects.

3. Soy Products

Foods made from soy, like tofu, soy milk, and edamame, have phytoestrogens. As estrogen receptor binders, these compounds have a structure similar to estrogen.

There is a concern among doctors and researchers that women with hormone receptor-positive breast cancer may want to avoid consuming phytoestrogens as they may mimic estrogen and potentially promote the growth of cancer cells.

It is possible that consuming soy in moderation may not have negative effects on hormone receptor-positive breast cancer. However, it is important to exercise caution and consult a healthcare provider if you take Anastrozole and consider incorporating soy into your diet. Making informed decisions and practicing moderation is key when consuming soy with this medication.

4. Cruciferous Vegetables

The body's natural detoxification processes are stimulated by cruciferous vegetables, such as broccoli, cauliflower, and Brussels sprouts. However, these vegetables contain glucosinolates, which can produce substances that could influence estrogen metabolism.

While the impact of cruciferous vegetables on Anastrozole's effectiveness is considered minimal, it's worth being mindful of their consumption. These vegetables are undeniably nutritious and provide various health benefits, so excluding them from the diet is unnecessary.

Instead, patients can continue enjoying cruciferous vegetables as part of a well-rounded diet while maintaining a reasonable balance to support their treatment plan.

Adjust your diet as per the doctor's recommendations when taking Anastrozole for hormone receptor-positive breast cancer since medical conditions and responses to medicine vary.

5. Avoid Alcohol

Consuming alcohol can elevate the levels of estrogen in the body, which can potentially negate the benefits of Anastrozole.

It's recommended to avoid consuming beef and red meat, chamomile tea, and corn oil as they are often high in carcinogens that can increase the risk of cancer. Also, avoiding any grilled, BBQ, or smoked meat or fish is wise since they may interact with Anastrozole.

How to Take Anastrozole?

Anastrozole is a medicine that comes in the form of a pill that you take by mouth or orally. Doctors usually prescribe it to treat a certain type of breast cancer that grows because of certain hormones in the body. Anastrozole is one part of a bigger plan to treat this type of cancer, including surgery, radiation, or other medicines.

The goal of using Anastrozole is to target the hormones that help the cancer grow, to make the treatment more successful and to lower the chance of the cancer coming back. Doctors determine the appropriate anastrozole dosage based on the patient's medical condition.


Maintaining a balanced diet is essential when using Anastrozole. During Anastrozole treatment, it's crucial to remain conscious of particular dietary factors that can influence the medication's efficacy. It is important to avoid consuming ions while taking Anastrozole, as they can affect the medication's absorption, concentration, and overall effectiveness.

Frequently Asked Questions

Q: Is it possible for Anastrozole to lead to blood clot?

A: Anastrozole may increase the risk of blood clots, but the risk is generally lower than with other treatments for breast cancer.

Q: What are the common side effects associated with Anastrozole?

A: Common side effects of Anastrozole are joint pain, hot flashes, bone weakening, fatigue, and mood changes.

Q: When to take Anastrozole with testosterone?

A: Anastrozole is typically prescribed to postmenopausal women for breast cancer treatment. If you are considering taking it with testosterone, you should talk with a health expert first.