Foods to Avoid

Foods to avoid while taking letrozole

You don't need to avoid any specific foods while taking letrozole. However, you may want to reduce your consumption of certain foods to improve your experience of this drug, such as alcohol and spicy food.

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Last updated and fact checked:
Foods to avoid while taking letrozole
  • Letrozole treats certain types of breast cancer, such as early breast cancer.
  • There are no specific foods to avoid while taking letrozole, but healthy choices can reduce side effects.
  • Avoid alcohol and caffeine to reduce any adverse side effects of letrozole.
  • Sticking to a healthy diet can help you look after yourself on letrozole.

Foods to avoid with letrozole: FAQs

  • What should you not take with letrozole?

    Limit your intake of refined carbohydrates to improve insulin resistance and balance your hormone levels. Reducing your consumption of spicy foods, saturated fats, processed foods and packaged foods can promote a healthy lifestyle.

  • What reduces the side effects of letrozole?

    Whilst there are no specific foods to avoid while taking letrozole, you may want to avoid alcohol, smoking and some processed foods and packaged foods to help limit side effects such as hot flushes. Eating smaller meals can also help feelings of vomiting.

  • Do you always gain weight on letrozole tablets?

    No, not everyone gains weight on letrozole - but it is a possibility, as this drug affects your hormone levels. Aromatase inhibitors can cause a loss of appetite or feelings of nausea. If you experience these side effects, try eating smaller meals and taking letrozole with food.

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Letrozole is a medicine used to treat breast cancer and help prevent cancer cells from coming back. It can also be used as a treatment for fertility if you have polycystic ovary syndrome (PCOS).

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By choosing healthy foods and following key lifestyle changes, you can reduce the adverse side effects of letrozole and improve your quality of life while taking this drug.

The list of foods you should avoid while taking letrozole includes:

  • Foods high in phytoestrogens and xenoestrogens.
  • Spicy foods.
  • High-sodium food products.
  • Beans and legumes.
  • Refined carbohydrates.

Let’s look at these in more detail.

Foods high in phytoestrogens and xenoestrogens

Some foods can affect oestrogen production in the body, which, in turn, can interact with letrozole and reduce its effectiveness. For example, consuming high levels of dietary phytoestrogens may affect your prescription. This includes foods such as:

  • Kidney beans.
  • Sunflower seeds.
  • Peanuts.
  • Barley.
  • Soybeans.

You may also want to avoid xenoestrogens while taking letrozole. Xenoestrogens are oestrogen-mimicking compounds, and there may be an interaction between these compounds and palbociclib/letrozole - a common combination of drugs used to treat breast cancer.

Foods affected by environmental pesticides may contain xenoestrogens, such as fruits and vegetables. You can avoid exposure by choosing organic produce and thoroughly washing fruits and vegetables before eating. Make sure to speak to your doctor before altering your diet or lifestyle.

Spicy food

You may find avoiding spicy or rich food helpful, as this can reduce hot flashes and menopause-like symptoms. These foods can also exacerbate any feelings of sickness or nausea while taking letrozole.

High-sodium food products

Letrozole can lead to reduced bone density, particularly if you're taking this drug on a long-term basis. You may want to avoid high-sodium foods, such as:

  • Cured meats.
  • Salty snacks.
  • Processed and packaged foods.

Processed foods with a high sodium level can result in a loss of calcium and further bone loss.

Beans and legumes

Letrozole can cause an increased risk of osteoporosis, so it’s important to look after your bones. You may want to consider how many legumes and beans you include in your diet, such as kidney and pinto beans, as these foods contain a lot of phytates. This can reduce calcium absorption in the body, negatively affecting bone health.

Speak to your healthcare provider for dietary advice and support if you're worried about bone loss or fractures.

Refined carbohydrates

If you're taking letrozole as a fertility treatment, reducing your consumption of saturated fat and refined carbohydrates can help to improve your insulin resistance and lead to more stable hormone levels.

Refined carbohydrates typically contain a lot of sugar. In particular, consider how many sweets, desserts, white bread products and sugary drinks you include in your diet, as these products could start to affect your insulin resistance.

Should I include any new foods in my diet while taking letrozole?

It’s not necessary to include any new foods in your diet while taking letrozole. However, by following a healthy diet, you can ease uncomfortable side effects such as nausea. It's also important to look after yourself and enjoy a good quality of life on letrozole.

Let's take a look at a few dietary changes that can support your letrozole prescription.

Plant-based diet

Choosing a primarily plant-based diet may help if you have breast cancer, allowing you to reduce your cholesterol levels and follow a balanced, healthy lifestyle.

Many people like to choose a Mediterranean diet, as this includes a lot of vegetables, fruits, and whole grains - all typically healthy foods, whether you're taking letrozole or chemotherapy drugs or a breast cancer survivor.

You may also want to introduce lean protein into your diet, such as fish, chicken or eggs. Letrozole can lead to high cholesterol, so choosing foods with low saturated fats may help to manage your prescription.

Healthy unsaturated fats

Unsaturated fats, such as omega-3 fatty acids, help to support your heart health and cognitive functions.

Certain foods contain these fats, including:

  • Avocados.
  • Oily fish, such as salmon or mackerel.
  • Nuts and seeds.

Adding these foods to your diet while taking letrozole can support hormonal balance, nutrient absorption and overall well-being.

Calcium-rich foods

It's important to look after your bone health while taking this medication, particularly if you need to take letrozole long-term. This medication may contribute to reduced bone density, leading to osteoporosis. In fact, if you’re a menopausal woman, you’re more likely to develop this condition whether you take letrozole or not, as low oestrogen levels can reduce bone strength.

You can protect your bone health by eating foods with high levels of calcium, such as:

  • Dairy products, including milk, cheese or yoghurt.
  • Fortified cereals.
  • Green vegetables.
  • Soya products, such as tofu.

By introducing high-calcium foods into your diet, you can avoid bone fractures or further bone loss while taking this drug.

Will I experience a change in appetite while taking letrozole?

You may lose your appetite or experience feelings of sickness while taking this drug. If you're dealing with nausea or vomiting, eating smaller meals may be helpful. Make sure to stay hydrated, as this can reduce nausea or constipation, both common side effects of letrozole. This can also help you avoid dehydration if you're being sick.

Letrozole can also cause weight gain. Speak to your doctor for a comprehensive diet or exercise plan, and follow any medical guidance to stay a healthy weight while you take this drug.

Can I drink alcohol with letrozole?

According to the NHS, it's safe to consume alcohol at the same time as letrozole. However, this substance can lead to increased side effects, such as hot flashes or sweating. For this reason, you may want to consider your alcohol consumption while taking letrozole.

Smoking may also make aromatase inhibitors like letrozole less effective.

Can I drink caffeinated drinks?

You can drink caffeine with letrozole, but it may exacerbate your side effects. Many foods and drinks contain caffeine, including:

  • Tea and coffee.
  • Soft drinks.
  • Energy drinks.
  • Chocolate.

Reduce your caffeine intake to ease uncomfortable letrozole side effects, such as difficulty sleeping.

Should I exercise while taking letrozole?

Exercise can help you cope with tiredness, weight gain and constipation while on letrozole. Try doing some light exercise when you feel able, such as going for a daily walk.

Although it's safe to drive when taking letrozole, this drug can cause tiredness and blurred vision. Avoid exercises like cycling if you're struggling with these side effects. You may also want to stop driving until you feel better.

Why might I need to take letrozole?

Letrozole treats breast cancer, and it can also prevent breast cancer from coming back. In particular, letrozole treats hormone-dependent breast cancer, as it's a form of hormone, or endocrine, therapy.

You'll take letrozole after other breast cancer treatments, such as surgery, radiotherapy or chemotherapy. This is a long-term drug, with most breast cancer survivors taking it for at least five years.

You may also take letrozole if you’ve had early breast cancer treated by tamoxifen or you’re postmenopausal with unknown advanced breast cancer. In some cases, premenopausal women - and men - can take this drug, too.

If you have PCOS, you can use letrozole as a fertility drug, as it may induce ovulation. Although this drug has a 25-30% success rate when used to induce ovulation, you should note that the pharmaceutical company has not officially licensed letrozole for this use.

How does letrozole work?

Letrozole belongs to a group of drugs called aromatase inhibitors, used in treating hormone receptor-positive breast cancers by reducing oestrogen levels in the body. Even after menopause, an enzyme called aromatase still produces some oestrogen. Elevated oestrogen levels can contribute to breast cancer, stimulating the growth and mutation of breast tissue.

Letrozole works by blocking this enzyme, reducing the chances of breast cancer cells growing. It is also used in infertility treatment to stimulate ovulation.

How do I take letrozole?

Letrozole is available in 2.5mg tablets. You should take your tablet at the same time every day, but it doesn't matter when you take it. Set an alarm or build your prescription into your daily routine.

If you miss your dose, take it as soon as you remember, unless your next dose is due in the next two or three hours, in which case skip your missed dose and take your tablet at the usual time.

You can take this drug with or without food. However, if you're experiencing nausea as one of your side effects, it might be best to wait until you have food in your stomach before you take it.

Who can't take letrozole?

Letrozole has age and pregnancy restrictions. Your healthcare provider can suggest alternative options if you're under 18, still have periods, are pregnant, or are breastfeeding.

If you've ever had an allergic reaction to letrozole or another medication, or you have kidney or liver disease, make sure to speak to your doctor before taking your prescribed letrozole. This drug affects your bone health, so you may not be able to take this drug if you already have brittle bones, also known as osteoporosis.

Will I experience side effects while taking letrozole?

Common side effects of letrozole include: 

  • Hot flushes.
  • Sweating.
  • Aching muscles or bones.
  • Joint pain.
  • Sleepiness or fatigue.
  • Dry or itchy vagina.
  • Nausea or vomiting.
  • Weight gain.

There are also some more serious side effects of letrozole. If you notice swelling along a vein, seek medical advice, as this may indicate a blood clot. You may also experience muscle weakness or joint pain while taking your prescription.

Your doctor will monitor your cholesterol, bone density and blood pressure while you take this medication, as long-term use of letrozole can affect these aspects of your health.

Will letrozole interact with my other medications?

There aren’t many known interactions between letrozole and other medications. 

However, it’s important to note that you can't take hormone replacement drugs, such as HRT, at the same time as letrozole, as this can influence your hormone levels and stop the medication from doing its job properly.

Speak to your doctor if you’re currently taking any other drugs, with or without a prescription. 

Herbal remedies and supplements

As osteoporosis is a potential side effect of letrozole, it might help to take a Vitamin D or calcium supplement with your prescription. This can support your bone health and reduce the chance of fractures.

However, it's important to discuss any supplements with your healthcare provider. You should also avoid taking herbal remedies without consulting your doctor, as there is little scientific or medical research about these products.

You also shouldn't take any remedies for menopause symptoms while taking letrozole, as these supplements can affect the drug's effectiveness at treating and preventing breast cancer.

Do I need to use contraception while taking letrozole?

Letrozole can affect your fertility if you're using this medication as a breast cancer drug. Although you may have been through menopause before taking letrozole for breast cancer treatment, this drug can restart your periods again. So, you may need to start using contraception to prevent pregnancy.

You should speak to your doctor about your contraception needs. This is especially important as letrozole isn't typically safe to use during pregnancy.

Following a balanced diet while taking letrozole

Letrozole is a common aromatase inhibitor used to treat breast cancer. Although there are no foods to avoid while taking letrozole, it's important to understand how to ease any side effects of this drug and enjoy a healthy quality of life.

Above all, look after yourself on letrozole and always seek medical advice before changing your diet.

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The content on is provided for informational and educational purposes only and should not be construed as professional medical advice or guidance. Should you need professional medical advice or guidance, you should consult with such a professional in their relevant field. Likewise, you should always seek professional medical advice before starting a diet, exercise regime or course of medication, or introducing or eliminating specific elements from your lifestyle. We strive to write accurate, genuine and helpful content, and all views and opinions expressed within this article are specifically the views of the author.
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