Addressing Concerns on Diet During Breast Cancer Treatment

Facing a cancer diagnosis or undergoing treatment, including for breast cancer, often raises critical questions about how to support the body through challenging physical side effects. Patients frequently seek clarity on managing treatment-induced digestive issues, navigating the "sugar feeds cancer" misconception, and maintaining hydration amidst their cancer therapy. Therefore, having reliable, medical guidance on these topics is essential for optimizing recovery from treatment and enhancing quality of life.

In a recent webinar titled, Bite Back! How Your Plate Can Help You Fight Breast Cancer Risk, Dr. Roshani Patel, a breast surgical oncologist, as well as medical director of the breast program at Hackensack Meridian Health’s Jersey Shore University Medical Center, addressed the most pressing nutritional and lifestyle concerns shared by patients.

From managing diarrhea caused by immunotherapies like Keytruda (pembrolizumab) to understanding why non-scale victories are important during muscle gain, she provided targeted answers linked with actionable advice.

I have diarrhea due to Keytruda. What specific diet can I follow?

Patel: Dealing with diarrhea from chemotherapy like Keytruda is challenging. Patients should focus on bland foods during treatment weeks. Yogurt is one of my favorites, and bananas tend to irritate the mouth a little bit less, but you replenish potassium and some of the other electrolytes with that, as well as rice. While you're undergoing this [colitis] episode, we recommend bowel rest and hydration and gently getting things back to normal.

Should I avoid sugar completely during chemotherapy? Will eating sugar "feed" my cancer?

Consuming more sugar does not feed cancer cells, but the concern is that it does cause inflammation in the body if you're eating excess sugar in your diet. It is those inflammatory changes that are thought to increase cancer risk and the risk of diabetes and cardiovascular disease.

Are there herbal supplements or vitamins that can help fight cancer?

It’s a tough question, because I don't know the medications that the patient is on. I don't know the exact details of what happened or what the chemo regimen was, but again, you can try to balance your diet and hydrate well during chemo. It helps most patients. Unfortunately, there's no magical supplement or anything in the diet that will help reverse anything.

Before I was diagnosed with breast cancer, I added collagen peptides to my diet for joint and skincare. I currently do not add any supplements to my diet, and I have arthritis. Is there any supplement I can safely take to support my healthy lifestyle?

It's OK to have collagen; collagen is going to be broken down into amino acids, which help with building protein in the body. That being said, it is a good source of protein, and there's nothing against taking that. If you feel good with the collagen supplement that you're taking, that's fine, really.

The only thing I recommend is a multivitamin with iron. If you take that with four ounces of 100% food juice, you'll absorb more of the iron. Then, there are some patients who may be vitamin D deficient — for those, you should be taking vitamin D with calcium. Sometimes, those may need to be prescribed by somebody.

I don't recommend any specific supplements. There are a lot of companies that are making these turmeric supplements, mushroom supplements and everything else. To be perfectly honest with you, they're expensive, they're not approved by the FDA, and a lot of times they're chemically modified. You can get a lot of these herbs and things naturally in your diet. For turmeric and cinnamon, you should have no more than one teaspoon a day, especially if you're taking tamoxifen; it can interfere with the medications that you're taking, and during chemotherapy, you have to be aware of potential interactions. 

I eat sweets sometimes. I eat out once a week. Should I not eat out at all, and only eat in my house, since I'm the one cooking the food?

I don't think there's any issue with you eating out; I tell my patients that when they're feeling better. For most of my patients, the weeks that they're getting their medications, that's when I tell them to eat more of the bland diet.

[It’s OK to eat out] as long as the food is cooked properly. You don't want to get any raw type of food or anything from outside, because you don't know how that's been prepared. You should clean [fresh fruits and vegetables] at home.

I have no objection to you eating sweets, I tell my patients: 85% good [food], 15% bad. If you feel like you need it, you deserve it. It's just that I don't want every single meal to be a cupcake for you, right? For the weeks that you're feeling better, the more protein and the more balanced plate that you can get, the better; then, the weeks that you're feeling lousy, sticking with the bland diet will help. 

I try to take a one-hour walk least three times per week. Is that good, or should I be doing more?

That's one of the best things that you can do for yourself. It’s hard when you're getting chemo; there's going to be times when you feel lousy and you want to be in bed and you want to rest, and you should do that. But the more that you can walk and the more active you are, it's going to help you through your treatment, and you're going to be better prepared for when it's time for your surgery.

One of the worst things I see for my patients who cannot do much during chemotherapy is that they're completely deconditioned when it comes to surgery time, so they have a harder time recovering. You’re something good for yourself, but you don’t want to push yourself too hard to if you're going to pass out or something, right? You want to walk as much as you can tolerate.

Editor’s Note: The “Bite Back! How Your Plate Can Help You Fight Breast Cancer Risk” webinar was sponsored by The Hennessy Institute for Cancer Prevention & Applied Molecular Medicine, which provides personalized cancer risk assessments and genetic tests to help patients understand their unique profile and take control of their health.

For more news on cancer updates, research and education, don’t forget to subscribe to CURE®’s newsletters here.