Coffee is one of the most popular beverages worldwide. More than 30 percent of breast cancer survivors report drinking a lot of coffee or tea after a breast cancer diagnosis.

If you’re a coffee lover, you may wonder how your coffee consumption can affect your prognosis (expected outcome) and treatment with triple-negative breast cancer (TNBC). TNBC is an aggressive subtype of breast cancer.

In TNBC, breast cancer cells lack estrogen and progesterone receptors and don’t have much of a protein called HER2. Between 10 percent and 15 percent of all breast cancers are TNBC.

🗳️ Since being diagnosed with breast cancer, do you:

Drink more coffee

Drink less coffee

Drink the same amount of coffee as before

Thanks! You've successfully submitted your vote.

Sign up to view the results!

Continue with Facebook

Continue with Google

Continue with Email

By joining, you accept our Terms of Use, and acknowledge our collection, sharing, and use of your data in accordance with our Health Data and Privacy policies.

Already a member? Log In

In general, making healthy lifestyle changes can decrease your risk of breast cancer recurring (coming back) and improve your chances of survival. But what about drinking coffee with TNBC? Read on to find out.

It may be cold comfort if you’re already diagnosed with TNBC, but several studies have linked drinking coffee with lower rates of breast cancer.

One international study found that among women who’d gone through menopause, coffee drinkers had a lower risk of all types of breast cancer.

Another review of studies said coffee may be slightly protective against breast cancer, but only for women who drink large amounts of it. Other large studies found no association.

Coffee is rich in plant compounds that act as antioxidants. Researchers have theorized that these coffee compounds may naturally help protect cells in the body against damage that can lead to cancer and other diseases.

These associations are interesting, but it’s important to remember that they aren’t proof that coffee lowers the risk for cancer.

It’s easy to forget that caffeine is a drug — it’s the active ingredient that’s responsible for coffee’s stimulant effect. Within five to 30 minutes after you’ve had a cup of coffee, caffeine can start to affect your body, including impacting:

• Heart rate
• Breathing rate
• Mental alertness
• Physical energy

Like other drugs, caffeine can potentially interact with medications, such as chemotherapy (chemo) for TNBC.

Caffeine and Chemo

Researchers looking at TNBC cells in a U.S. laboratory found that caffeine may boost the effects of the chemotherapy drug cisplatin, a potential TNBC treatment option for some people. However, more research is needed to understand the effect of combining caffeine and chemo drugs in humans.

Although there’s some evidence that caffeine may help some chemo drugs work, it may interact negatively with others.

Paclitaxel (available as Abraxane and formerly sold as Taxol in the U.S.) is a first-line treatment for TNBC. Studies have found that consuming caffeine while on paclitaxel may inhibit the drug’s ability to kill cancer cells. However, it hasn’t been proven that the typical amount of caffeine in a cup or two of coffee would be a problem.

Ask your cancer care team if your TNBC treatment plan has any potential dietary interactions. For instance, are there recommendations against a high coffee intake, or are there any foods you should avoid?

If you’ve been diagnosed with TNBC, you may wonder if drinking coffee during your treatment can change your prognosis. Studies have found that, in general, regular consumption of coffee after a breast cancer diagnosis isn’t associated with a worse outcome.

A 2021 study followed 8,900 women with stage 1 to stage 3 breast cancer for up to thirty years. Results found that those who drank more than 3 cups of coffee a day had a lower risk of dying from breast cancer or any other cause.

In a 2022 study of more than 3,700 people with stage 1 to stage 3 breast cancer, researchers found that drinking more than 3 cups of coffee or tea a day wasn’t associated with worse survival outcomes. Limited studies about coffee have included participants with stage 4 breast cancer.

Chemotherapy is the main treatment for TNBC. Although side effects differ for everyone, common side effects of chemo include:

• Hair loss
• Nail changes
• Mouth sores
• Decreased appetite and weight loss
• Nausea, vomiting, and diarrhea
• Fatigue
• Menopausal symptoms (such as hot flashes and vaginal dryness)
• Nerve damage

Some MyBCTeam members have described how drinking coffee helped with chemo side effects. One said, “I gave up caffeinated coffee, except occasionally, about a year before my diagnosis. I discovered quickly that one cup a day on no chemo days is the best way for me to fight the morning fatigue and get me moving.”

Another member shared, “I’ve been in chemo for over a year. The side effects are terrible! I get dizzy, nauseous, irritated, etc.! Drinking iced coffee helps my mood. Always decaf!”

Is Coffee Bad for Cancer?

While caffeine can help ease fatigue by increasing mental and physical energy, you should be aware of the possible side effects of high caffeine consumption, such as:

• Dehydration
• Nausea
• Dizziness
• Headache
• Rapid heart rate
• Restlessness
• Anxiety
• Poor sleep

Some side effects of caffeine may make chemo side effects worse. For example, staying hydrated during chemotherapy is often recommended to manage side effects.

Caffeine can have a mild diuretic effect (making you pee more often). Also, if you’re quenching your thirst with coffee drinks, you may not be drinking as much water.

Other side effects of caffeine may overlap with chemo side effects, such as nausea and dizziness.

According to the U.S. Food and Drug Administration (FDA), a daily caffeine intake of 400 milligrams — the amount in about two to three 12-ounce cups of coffee — is safe for most healthy adults. Talk to your cancer care team about how much caffeine is safe for you to drink each day with your breast cancer treatment regimen.

Some breast cancer survivors have a higher risk of developing a second type of cancer. The specific type depends on several risk factors, such as genetics, family history, and the type of TNBC treatment received.

Healthy lifestyle changes such as eating a balanced diet, engaging in physical activity, avoiding tobacco, and limiting alcohol are important for cancer prevention. Cancer research studies have also linked coffee consumption to a decreased risk of certain cancers, such as liver cancer and endometrial (uterine) cancer.

If you’re concerned about increased risk factors for developing second cancers, talk to your healthcare providers.

Join the Conversation

On MyBCTeam, people share their experiences with breast cancer, get advice, and find support from others who understand.

Have your coffee drinking habits changed since being diagnosed with TNBC? Let others know in the comments below.