When you are going through cancer treatment, your attention naturally goes towards scans, medicines, surgery, chemotherapy, radiation and follow up appointments. But there is another part of your body quietly working in the background throughout this journey: your gut.
Gut health can have an important role in how you feel during treatment. The digestive system is responsible not only for breaking down food, but also for absorbing nutrients, supporting the immune system and maintaining a healthy balance of microorganisms. During cancer treatment, all of these functions can be affected.
For someone undergoing breast cancer treatment, taking care of the gut is therefore not simply about avoiding stomach problems. It is about helping the body receive the nutrition and support it needs during recovery.
How cancer treatment can affect your gut
Chemotherapy can affect rapidly dividing cells, including some of the cells lining the digestive tract. This can contribute to symptoms such as nausea, diarrhoea, constipation, mouth sores or changes in appetite.
Some medicines used during treatment can also affect bowel habits. Antibiotics, pain medicines and other medications may alter the balance of bacteria in the gut or cause constipation and diarrhoea.
Radiation treatment involving areas close to the abdomen or pelvis can affect digestion as well. While this is less relevant to most breast cancer radiation treatments, every patient's treatment plan is different.
These symptoms may seem like minor inconveniences, but persistent digestive problems can make it harder to eat and drink enough. Over time, this may contribute to weakness, dehydration or inadequate nutrition.
Your gut and your immune system
A large part of the body's immune activity is closely connected with the digestive system. The gut contains trillions of microorganisms, collectively known as the gut microbiome. These microorganisms interact with the intestinal lining and the immune system.
Cancer treatment can sometimes disturb this microbial balance. Research is continuing to explore how the gut microbiome may influence treatment response, inflammation and immunity.
However, this is an area where patients should be cautious about online claims. There is currently no single "gut health diet" or probiotic supplement that has been proven to improve breast cancer treatment outcomes for everyone.
The goal should be to support overall digestive and nutritional health rather than trying to manipulate the microbiome with unproven products.
What can you do to support gut health?
The simplest approach is often the most useful.
Eat a varied diet when you can. Vegetables, fruits, whole grains, pulses, nuts and seeds can provide fibre and a range of nutrients. But during certain stages of treatment, high fibre foods may worsen diarrhoea or bloating. Your diet may need to be adjusted according to your symptoms.
Include enough protein. Protein is important for maintaining muscle and supporting tissue repair. Eggs, fish, chicken, dairy products, pulses, soy and other protein rich foods can be included according to your preferences and dietary needs.
Stay hydrated. Water and other suitable fluids can become especially important if you have vomiting, diarrhoea or constipation.
Pay attention to food safety. During periods when your immune system is weakened, foodborne infections can be more serious. Properly wash produce, cook foods thoroughly and avoid foods that may carry a higher risk of infection if your cancer care team has advised you to do so.
Do not start supplements without asking your doctor. Probiotics, herbal products and high dose vitamins are often marketed as ways to improve immunity or "heal the gut". Some may not be appropriate during cancer treatment and some supplements can interact with medicines.
Listen to your symptoms
There is no need to simply accept ongoing digestive problems as an unavoidable part of treatment. Tell your oncology team if you have persistent diarrhoea, constipation, vomiting, abdominal pain, difficulty eating or significant changes in bowel habits.
A dietitian may also be able to help you adjust your meals according to your symptoms, treatment stage and nutritional requirements.
Dr. Pragati Singhal
