Is It OK to Drink Caffeine During Chemotherapy?

If you're undergoing chemotherapy for cancer and happen to be a coffee lover, you may wonder if you can still enjoy your morning cup of joe. Because each chemo drug is tailored to specific cancers and comes with various side effects, you might have to alter your caffeine habit during treatments.

Caffeinated beverages like coffee, tea and some sodas may be allowed, but it's important to talk to your doctor about your diet, because you might be counseled to restrict certain beverages or foods based on your condition and treatment plan.

Here's more about the importance of fluids during chemotherapy, the potential side effects of caffeine during chemotherapy and the best drinks for the most healthful cancer treatment journey.

According to the University of Pittsburgh Medical Center (UPMC), it's important to increase the amount of fluids you drink when receiving chemo treatments. The reason? Some chemo drugs can cause dehydration, and certain chemotherapy side effects, such as diarrhea and vomiting, may also contribute to this condition, per BreastCancer.org.

"In fact, the American Cancer Society recommends drinking at least eight 8-ounce servings of liquids per day," reports Adil Akhtar, MD, an oncologist, palliative care expert and an associate professor at the Oakland University-William Beaumont School of Medicine in Auburn Hills, Michigan. Per UPMC, good fluids to keep you hydrated during chemo include water, juice, broth-based soups, ice cream, ice pops, milk and gelatin.

As for caffeinated beverages, such as soda, coffee and tea, their dehydrating effects aren't as strong as once believed. According to the Mayo Clinic, drinking beverages that contain caffeine can add to your regular fluid intake and play a role in a healthful lifestyle without causing significant fluid loss. Dr. Akhtar agrees. "Caffeine is safe during chemo as long as it's consumed in moderation," he confirms.

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Although caffeinated drinks may help you increase your fluid intake, you might be counseled to cut back or avoid these beverages if they worsen your chemotherapy side effects. "There is no set limit on how much caffeine one should consume, but moderation is key," says Dr. Akhtar.

Still, side effects are possible when you drink caffeine during chemo treatments. "Sometimes caffeine can cause headaches in those on chemo, and caffeine can interfere with sleep, which makes chemotherapy-associated insomnia worse," he notes.

Got a finicky nose? The smell and taste of coffee may also bother those who have nausea or changes in their ability to taste and smell due to chemotherapy.

A good rule of thumb: If you're having trouble sleeping during your chemo treatments, avoid caffeine after 5 p.m., UPMC advises. And if you can't seem to eat much or you've lost your appetite during chemotherapy, certain higher-calorie drinks like juice, milk shakes, instant breakfast drinks or hot chocolate might be recommended over low-calorie options like coffee or tea.

"Caffeine in general is a weak diuretic, which means it can cause fluid loss due to increased urination, but for it to cause a case of dehydration, you'd have to consume a large amount of it," says Dr. Akhtar. Still, caffeine may sometimes aggravate diarrhea and digestive problems caused by chemotherapy, and too much caffeine can make chemotherapy-induced dehydration worse, he adds.

Speak with your doctor about your daily intake of caffeine, and then learn the signs and symptoms of dehydration so you can identify a potential problem before it begins. Per the Cleveland Clinic, you may be dehydrated if you lightly pinch your skin and it remains bunched up in place. Other signs of dehydration include dry mouth, having little or no urine, dark urine, headache and/or dizziness.

"For those people who are already at risk for dehydration on chemotherapy, my advice would be to avoid caffeinated drinks," says Dr. Aktar.

Read more: Long-Term Effects of Caffeine

To combat dehydration, make sure you're taking in an adequate amount of fluids during chemotherapy treatments. Keep drinking water and know that broth-based soups, milk and even ice cream count toward your fluid intake, according to the American Cancer Society (ACS). But be sure to limit or avoid alcohol as well as acidic or spicy drinks, as they may further irritate an already dry mouth.

In addition to staying well hydrated, make sure your overall diet is nourishing your body. Some cancer drugs work even better in people who are getting enough calories and protein, ACS points out. Of course, that can be easier said than done, as food can be difficult to negotiate when you're experiencing treatment side effects. ACS suggests having several small snacks a day instead of three large meals. High-calorie, high-protein beverages like milkshakes and canned liquid supplements may also be a good option.