Health & Wellness

Top 13 Foods to Avoid while taking Letrozole

You might wonder what foods to avoid while taking letrozole if you recently took this medicine. It’s essential to pay attention to what you eat and drink when taking any medication since some foods can interfere with the medication’s absorption and reduce its effectiveness. This is important for those taking letrozole, a medication frequently used to treat several kinds of breast cancer. Because letrozole inhibits the body’s estrogen production, it may not be as effective when used with certain foods that imitate or interfere with estrogen production.

This article will discuss what foods interact with letrozole to ensure optimal treatment outcomes and minimize potential interactions.

In This Article

  1. What is Letrozole used for
  2. Foods to Avoid while taking Letrozole
  3. Foods to avoid while taking letrozole for fertility
  4. What reduces the side effects of Letrozole

What is Letrozole used for

A medication called letrozole is used to treat several kinds of breast cancer, including hormone receptor-positive breast cancer in postmenopausal women. Letrozole prevents the body from producing estrogen, which slows or stops the growth of cancer cells since this kind of breast cancer responds to estrogen.

Letrozole is categorized as an aromatase inhibitor, which prevents the body from converting androgens (male hormones) into estrogens (female hormones) by blocking the activity of the aromatase enzyme. Letrozole decreases estrogen levels by inhibiting this enzyme, which can help hormone-sensitive breast cancer develop more slowly or not at all.

Foods to Avoid while taking Letrozole

Here is the list of foods to avoid when on letrozole

Foods to Avoid while taking Letrozole

1. Grapefruit

Grapefruit and grapefruit juice can interfere with the metabolism of many medications, including letrozole. Grapefruit and its juice contain compounds that can increase the levels of letrozole in the bloodstream. This can lead to a higher risk of side effects such as nausea, vomiting, headache, and dizziness.

2. Pomegranate

Compounds in pomegranates can also interact with letrozole. Similar negative effects to those from grapefruit may result from this.

3. Soy products

Phytoestrogens, which are plant-based substances that can mimic the actions of estrogen in the body, are present in soy products. Consuming soy products can reduce the efficiency of letrozole.

4. Dairy products

Letrozole can bind to calcium and other minerals in dairy products, which can lessen its absorption into the bloodstream. The medicine may become less effective as a result.

5. High-fat foods

Foods to avoid while taking letrozole are high-fat foods. Foods heavy in fat can also hinder the digestive tract’s ability to absorb letrozole, decreasing the efficacy of the medicine.

6. Alcohol

Letrozole can cause liver damage as a rare side effect. Drinking alcohol can increase the risk of liver damage, so it is best to avoid alcohol while taking letrozole.

7. Caffeine

Caffeine can hinder the gastrointestinal tract’s ability to absorb letrozole, decreasing the drug’s effectiveness.

8. Licorice

Letrozole’s metabolism in the liver may be inhibited by substances found in licorice root, which could result in higher blood levels of the drug and undesirable side effects.

9. Fennel

Consuming fennel while taking letrozole may interfere with the drug’s effectiveness and reduce its ability to treat breast cancer. Therefore, avoiding fennel and fennel-containing products is recommended while taking letrozole.

10. Red clover

Red clover is another plant-based compound that contains phytoestrogens that can mimic the effects of estrogen in the body. This can counteract letrozole’s effects.

11. Sage

Sage can counteract the effects of letrozole, which works by blocking estrogen production. Consuming sage while taking letrozole may interfere with the drug’s effectiveness and reduce its ability to treat breast cancer.

12. Flaxseeds

If you are considering consuming flaxseed, it is important to remember that it can also affect the absorption of medications, including letrozole.

13. St. John’s Wort 

 St. John’s Wort is a herbal supplement that may prevent the liver from properly metabolizing letrozole. This can lead to decreased levels in the bloodstream and potentially reduce the drug’s effectiveness.

Foods to avoid while taking letrozole for fertility

Foods high in salt and sugar should be avoided when using letrozole for fertility. The effectiveness of the medication may be affected by these.

Foods that have been processed or canned should also be avoided since they can have salts or sugars hidden in them that could interfere with your treatment plan.

While taking this medication is also advised to avoid dairy items like cheese and milk due to their hormone concentration, which can reduce their effectiveness.

What reduces the side effects of Letrozole

Some strategies that may help reduce the side effects of letrozole include Staying hydrated by drinking plenty of water, engaging in regular exercise, eating a balanced and healthy diet, getting adequate sleep and relaxation, and managing stress.

Managing side effects can also benefit some people from alternative therapies, including acupuncture, massage, or relaxation. It is essential to discuss any adverse effects you have with your doctor since they can suggest particular treatments or dosage adjustments to help you manage them.


In conclusion, it is important to avoid certain foods while taking letrozole. Foods high in fat, such as fried and processed foods, should be avoided. Additionally, alcohol should also be avoided when taking letrozole as it can interfere with the drug’s effectiveness.

Eating a balanced diet of fruits and vegetables and lean proteins will help ensure you get all the nutrients your body needs while avoiding any potential negative interactions from consuming certain types of food when using this medication.

Be sure to read:


  1. Precautions for Patients Taking Aromatase Inhibitors 
  2. Prolonged use of letrozole causes morphological changes on gonads in Galea spixii
  3. Effect of High-Fat Diet on the Intestinal Flora in Letrozole

Dr Maria

MD. Board Certified physician. Fellowship In Family Medicine UK. 8 years of medical experience in Lifestyle-related health disorders. Graduated from AIIMS – All India Institute Of Medical Science, INDIA

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