There are pros and cons to drinking coffee during chemotherapy for breast cancer. Because treatment affects everyone differently, it’s best to ask your cancer care team whether coffee or decaf is OK for you.

Some people who drink coffee regularly try to cut back or switch to decaf. Others lose interest in coffee while undergoing treatment because their tastes change.

Members of MyBCTeam have shared a range of experiences with drinking coffee during chemo. “I could drink iced coffee during chemo, but not before my vitals and finger stick,” shared one member.

Another wrote, “On chemo days, I would stay away from coffee because my heart rate was always high, and caffeine didn’t help. … I’d have decaffeinated coffee occasionally, though.”

Here are some factors to consider when deciding whether to drink coffee during chemo.

Caffeine can make it harder to get a good night’s sleep. Some people also have trouble sleeping during chemotherapy, so avoiding caffeinated coffee may help improve sleep during treatment.

One of the most common side effects of chemotherapy is fatigue (extreme tiredness). Although coffee can give you a boost during the day, it won’t be much help if it’s also keeping you awake at night.

Timing Matters

A 2023 review of 24 studies found that drinking an 8-ounce cup of caffeinated coffee less than 8.8 hours before bedtime may reduce total sleep time. If you generally go to bed at 10:30 p.m., you may want to avoid regular coffee after about 1:30 p.m. to help protect your sleep.

Details on Decaf

You may consider switching to decaf to see if that helps. According to the National Coffee Association, the decaffeination process removes about 97 percent of caffeine from coffee beans.

The actual amount of caffeine in decaf may vary by brand. But remember, decaf isn’t completely caffeine-free. An 8-ounce cup of regular coffee typically has about 95 milligrams of caffeine, while an 8-ounce cup of decaf usually has about 2 to 15 milligrams.

Your body may associate coffee with a surge of energy. If so, drinking decaf coffee may still make it harder for some people to relax at bedtime.

Coffee drinking doesn’t worsen all chemotherapy side effects. In fact, coffee and chemo can be a good combination for certain issues, particularly constipation (difficulty having a bowel movement).

Chemotherapy drugs and pain medication can lead to constipation, adding more discomfort to cancer treatment.

Hydration

Coffee can contribute to your daily fluid intake. Although caffeine can have a mild diuretic effect (meaning it may make you pee more), the fluid in coffee usually balances this out at typical caffeine levels. Staying hydrated helps support regular bowel movements.

Many people aim for 8 to 10 cups (8 ounces each) of total fluid per day. However, your oncology team may give you different guidelines. Fluid needs can change with kidney disease, heart issues, or certain side effects of chemo, like diarrhea.

Urge To Go

Coffee stimulates the digestive system and triggers bowel movements for some people. Decaf coffee can have similar effects, but they’re generally not as strong.

However, people who drink coffee all the time may become less sensitive to this effect. You can ask your oncologist about stool softeners or other constipation remedies if coffee doesn’t help enough.

Gut Bacteria

Studies suggest that both regular and decaf coffee may affect the body’s natural gut bacteria in similar ways. Other compounds in coffee besides caffeine may play a role.

Gut bacteria help digest food. They also support the gut-brain axis, the connection between the digestive system and the brain, which may influence mood and brain function.

Some people find it difficult to eat enough during chemo. Nausea and taste changes can make food unappealing. As a result, you may miss out on important nutrients your body needs during treatment.

Separating Food and Drinks

Your cancer care team may suggest drinking beverages between meals instead of with them. This can help you avoid filling up on less nutritious drinks, including coffee. Instead of drinking coffee with a meal, you may want to have it on its own.

Losing Interest in Coffee

Some MyBCTeam members say they didn’t feel like drinking coffee during chemo. “I was offered coffee and tea during chemo,” explained one member. “But my taste for coffee went, and it really hasn’t returned. I have a very small 4-ounce cup of coffee with coconut creamer.”

People are often surprised when a familiar or comforting cup of coffee starts to taste different or doesn’t “sit right.” It’s normal for eating habits and preferences to change during chemo. Listen to your body and choose foods and drinks you can tolerate and enjoy.

When trying to cut back on coffee, many people assume green tea is a healthier option. But it’s best to ask your oncology team before changing your beverage or supplement habits.

Potential Interactions

The compounds in green tea can have mixed effects on breast cancer treatment. Brewed green tea may not be a concern for everyone, but concentrated green tea extracts and epigallocatechin gallate (EGCG) supplements may interact with some cancer drugs.

EGCG, a compound found in green tea, has been shown in lab studies to interfere with bortezomib, a drug used for some blood cancers. Studies on green tea supplements and tamoxifen have had mixed results, so ask your oncology team what’s safe for you.

Caffeine Intake

When it comes to caffeine, regular green tea usually has less than regular coffee, but it’s not caffeine-free. An 8-ounce cup of green tea may have 40 to 70 milligrams of caffeine, compared with about 80 to 100 milligrams in an 8-ounce cup of coffee.

Deciding for Yourself

If you want to swap coffee for tea, caffeine-free herbal teas might be a better option, depending on your medications. You could also consider hot cocoa or a fruit smoothie as a replacement “treat” beverage.

Before changing your drinking or supplement habits, ask your oncology team if there are any medication interactions you should know about.

Chemotherapy-associated taste changes can limit your interest in food. But if you like the taste of coffee, you can use it as a base for chilled smoothies with nutritious frozen berries, vanilla Greek yogurt, and nutrient-dense nut butters.

Adding Protein to Coffee

Some people require extra protein during chemotherapy, but you might not always be in the mood for protein-rich foods like steak or eggs. Mixing flavored protein powders or drinks into cool coffee can be a nice treat that provides additional protein and amino acids (building blocks of protein).

Whey protein isolate may help improve muscle strength during chemotherapy, especially in people who are malnourished or at risk of malnutrition. This may be especially important if you’re underweight before treatment or if you’re not interested in food as a result of chemo side effects.

Protein Precautions

Ask your oncologist about meeting with a registered dietitian nutritionist. They can review your diet to make sure you’re getting the right amount of protein during chemo.

Added protein isn’t right for everyone. You may need to be careful with protein if you have kidney problems or take other supplements.

Only you and your healthcare team can decide whether you should cut back on coffee during breast cancer treatment. For many people, moderate coffee may be OK after treatment, as long as their clinician agrees.

The jury is still out on coffee’s potential pros and cons for various health conditions. Some observational studies have linked coffee intake with a lower risk of breast cancer, but this doesn’t prove that coffee prevents breast cancer. Intake of regular coffee (and decaf to a slightly lesser extent) has also been linked to better survival after breast cancer in some studies.

There’s no guarantee that coffee will improve cancer outcomes. After finishing chemo, many people can continue drinking coffee if their care team says it’s OK and they feel up to it.

Potential Benefits of Coffee

Coffee has compounds called polyphenols (plant-based substances) that act as antioxidants (substances that help protect cells from damage). Regular and decaf coffee have been linked in some studies to lower rates of heart disease, type 2 diabetes, and some cancer types

Discuss Caffeine and Decaf With Your Doctor

Your quality of life during and after cancer treatment is important. If you don’t want to give up regular coffee during chemo, ask your healthcare provider whether it’s OK for you. The choice may come down to what helps you manage side effects and feel your best.

Your oncology care team can help you balance your coffee intake with chemo side effects so you can stay healthy and maintain your quality of life. They can also help you determine whether decaf is a good alternative for managing issues such as sleep problems or digestive symptoms.

Join the Conversation

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

What are your thoughts on drinking coffee and chemo? Let others know in the comments below.