Letrozole (Femara) is a medication often used to treat a specific type of breast cancer called hormone receptor-positive breast cancer. It works by reducing levels of the hormone estrogen in the body. This, in turn, helps stop the spread of certain cancer cells that rely on estrogen to grow.

Some common side effects of letrozole include lower bone density, higher cholesterol levels, and fatigue. Being mindful of your diet and lifestyle while taking letrozole can help minimize the risk of certain side effects and help you feel your best.

Check out three foods you may want to avoid while taking letrozole. Note that what you eat doesn’t change how your body absorbs letrozole.

1. Grapefruit

Grapefruit and grapefruit juice contain compounds that can interfere with the enzymes responsible for breaking down several medications. The manufacturers of letrozole don’t list grapefruit as causing a drug interaction with the medication, but combination therapies containing letrozole and ribociclib do interact with grapefruit juice.

If you’re a fan of grapefruit, double-check with your health care provider to see if it’s safe to consume with your medication.

2. High-Fat Dairy Products

Getting enough calcium is essential to your overall health — and people taking letrozole should be especially mindful of their calcium intake because the drug can weaken your bones over time. Regular exercise can also help reduce your risk of osteoporosis (a disease that causes bones to weaken) and fractures. Ask your oncology provider about what types of exercise are safe for you.

However, it’s important to find calcium sources that don’t include a lot of extra saturated fat. High-fat dairy products like ice cream and cheese may cause high cholesterol levels, which is already a concerning side effect of letrozole. It’s generally a good idea to choose leaner sources of dairy, like low-fat Greek yogurt and cottage cheese, to maintain a healthy heart.

Your health care provider will also monitor your cholesterol while you’re on letrozole to watch for elevated levels and recommend additional treatment if needed.

3. Alcoholic Beverages

Consuming alcohol (which some sources classify as a food) can be risky if you’re taking letrozole. Alcohol can affect liver function and modify how your body processes medications, including letrozole. Additionally, alcohol might worsen certain side effects of letrozole, such as hot flashes. During your treatment, you may find it best to minimize alcohol intake or avoid it altogether. This includes over-the-counter medications, like some cough syrups, that contain alcohol.

Additional Tips To Keep in Mind

It’s crucial to communicate openly with your health care provider about your diet and any supplements you’re considering. They can provide personalized guidance based on your medical history and treatment plan.

If you’re struggling with unpleasant side effects, your doctor may be able to switch you to another treatment. “I was miserable on letrozole with pain and insomnia. My oncologist switched it to anastrozole, and I’m much better. They are very similar meds, but, he says, one of the meds might be easier for some people,” explained a MyBCTeam member.

Other members found that they just needed to give their bodies some time to adjust. “I found that letrozole side effects evolve over time,” another member wrote. “I’ve been on it for 2.5 years, and at the four- to six-month mark, I think my body finally adjusted, and the side effects didn’t bother me so much. I do exercise and stretch daily, which helps.”

Regardless of where you are in your breast cancer journey, always strive to maintain a well-rounded, nutrient-rich diet that supports your overall health and well-being. Focus on whole foods, fruits, vegetables, lean proteins, and whole grains. In addition, drinking plenty of water can help support your body’s normal metabolic processes, including the breakdown and elimination of medications.

If you’re having trouble planning healthy meals, a registered dietitian nutritionist can help. Ask your doctor for a referral or call your health insurance company to find providers in your network.

Talk With Others Who Understand

MyBCTeam is the social network for people with breast cancer and their loved ones. On MyBCTeam, more than 65,000 members come together to ask questions, give advice, and share their stories with others who understand life with breast cancer.

Did you experience any serious side effects from letrozole? How did your food choices change during breast cancer treatment? Share your experience in the comments below, or start a conversation by posting on your Activities page.