Home Story How To Eat Right To Ease Side Effects In Cancer Patients

How To Eat Right To Ease Side Effects In Cancer Patients

This extract from 'Food Matters: The Role Your Diet Plays in the Fight Against Cancer,' written by Dr Shubham Pant examines how to deal with constipation, a frequent side effect of cancer.
Dr Shubham Pant | Jan 07, 2021

The book cover of Food Matters: The Role Your Diet Plays in the Fight Against Cancer Harper Collins Publishers

Constipation is a frequent side effect in cancer patients and is a source of great discomfort and can lead to belly pain, swelling, bloating, gas, and even nausea. In general, constipation occurs as the stool takes a longer time to travel through the large intestine (also known as the colon) which allows more water to be absorbed, leading to hard, dry stool. Interestingly, one can have constipation and diarrhoea at the same time as liquid stool can pass behind the obstructing, solid stool. Medicines like morphine (which belongs to a class of medicines called opioids) bind to receptors in the gastrointestinal system and slow down the transit time in the gut, leading to constipation. As with anything in life, it pays to be proactive as it is easier to prevent constipation than to treat it once it has occurred. Below are a few recommendations that can help with constipation:

  • Eating high-fibre foods, such as whole-wheat chapatti, wholegrain and bran breads/cereals, oats, fruits, vegetables, prunes, lentils, beans, peas, nuts, and seeds in meals and snacks daily can help prevent constipation. There are two kinds of fibre: insoluble and soluble. Many foods contain both but are usually richer in one type than the other. Soluble fibre absorbs water, making stool softer and improving its form and consistency, which makes it easier to pass through your intestines. Examples of soluble fibre include oats, apples, beans, peas. Insoluble fibre adds bulk to your stool, easing its passage through the intestines, and can help in the movement of material through the digestive system and helps expel stool rapidly. Examples include the skin of fruits, whole wheat flour, brown rice. Remember that the increase in fibre should be gradual and not sudden as that can result in gas, bloating, and abdominal pain.
  • Drinking adequate amount of water will also help. Patients with constipation should have a goal of eight cups of total fluids each day.Try warm water and prune juice.
  • Try and avoid foods and drinks that cause gas, such as cabbage and carbonated beverages.
  • Avoid chewing gum and drinking with a straw as it can cause gas and abdominal discomfort.
  • Above all, it is important to exercise and stay active as this can help movement of food in the gut.

Diarrhoea is, unfortunately, another side effect which is just as problematic as constipation. It can be a consequence of cancer therapy like chemotherapy, immunotherapy, radiation or even surgery if some parts of the gut are removed. Patients can also develop diarrhoea if they get infections or if the cancer itself secretes hormones. For example, a disease called the carcinoid syndrome is a serious problem as patients can become dehydrated and have electrolyte abnormalities like low potassium in the blood. The tips below may be helpful for management of diarrhoea:

  • Avoid foods with high fibre, such as raw fruits and vegetables, whole grains, peas, etc which can make diarrhoea worse. Once diarrhoea subsides, you can slowly go back to foods with fibre.
  • Avoid high fat and fried foods including cakes, cookies, pastries.
  • Avoid alcoholic drinks, caffeine and spicy foods.
  • Stay hydrated. Drink plenty (at least 8–12 cups) of non-alcoholic, non-caffeinated and non-carbonated (no fizz) beverages each day. Try drinking the majority of fluids between meals rather than with meals. Take your time, slowly sip on the fluids.
  • You can lose essential electrolytes like sodium and potassium with diarrhoea. Try and eat high sodium (salted) foods like crackers and soups, broths at room temperature and high potassium foods like potatoes (without skin), bananas, papayas, and coconut water.
  • Eat small, frequent meals during the day.
  • It may be hard to process dairy products like milk. Try to limit your intake or avoid these foods until your diarrhoea stops. Yoghurt and buttermilk may be better tolerated.
  • Try easy to digest foods like bananas, applesauce and dry toast. You can remember the acronym: The BRAT diet, which includes bananas, white rice, applesauce, and dry toast.


(Dr Shubham Pant is a graduate from Maulana Azad Medical College in New Delhi, who is currently an Associate Professor in the Department of Investigational Cancer Therapeutics and the Department of Gastrointestinal Medical Oncology at the University of Texas MD Anderson Cancer Center in Houston, Texas. This is his first book)

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