Foods to avoid during chemotherapy


Foods to avoid during chemotherapy

By Jane Clarke

June 29, 2022

Cancer, Constipation, Diarrhoea, Sore mouth

There are some foods to avoid during chemotherapy because they interact with the drugs and stop them working as effectively. Other foods you may want to avoid because they cause nausea, they hurt an already sore mouth, or because the medication affects how you experience their taste. And then there are some foods that pose a higher risk of infection and food poisoning, and should be avoided if you have low immunity.

High-risk foods for low immunity
Not everyone who is treated with chemotherapy or immunotherapy will become neutropenic – that is, when there is an extremely low number of infection-fighting neutrophil white blood cells. However, if you have or are at risk of low immunity, or simply don’t want to put your body under undue additional stress during your treatment, then certain foods are best avoided.

Nourish Drinks are gently pasteurised so they are safe to enjoy even if you have low immunity. And because they contain a healthy balance of carbohydrates, protein and fats, plus 26 vitamins and minerals, they can help to supplement your nourishment during cancer treatment.

You can also include foods to boost your immune system during cancer and chemotherapy.

Foods that carry a greater risk of food poisoning are best left out of your diet until your treatment is over and your immune system has become stronger. These include:

  • raw or undercooked red and white meat
  • raw fish and seafood, including sushi and sashimi
  • cold or undercooked sausages and hotdogs
  • deli meats and paté
  • smoked fish
  • raw or soft-boiled/undercooked eggs
  • unpasteurised or raw milk
  • soft and raw milk unpasteurised cheeses
  • unpasteurised fruit juice
  • unwashed fresh produce, including bought prepared salads
  • raw sprouts (such as beansprouts and alfalfa)

Foods and supplements that interfere with chemotherapy
A group of enzymes produced by the liver, called CYP enzymes, influence how cancer drugs are broken down in the body. If the drugs are broken down too quickly, they may not be as effective and a higher dose of chemotherapy may be needed. If not enough of the drugs are broken down, you may experience worse side effects and need a smaller dose of treatment.

This is important because certain foods and supplements may affect the levels of CYP enzymes in the body. These are:

  • grapefruit, grapefruit juice and other grapefruit products
  • Seville oranges, Seville orange marmalade and other Seville orange products
  • Herbal supplements including St. John’s Wort
  • black cohosh
  • ginseng
  • gingko biloba
  • goldenseal
  • mistletoe
  • milk thistle

You should inform your doctor if you are taking any supplements, as these and others may affect your treatment. However, if you are instructed to take them by your practitioner, just make sure your cancer team is aware of this.

Foods to avoid if you have nausea and vomiting
If chemotherapy is making you feel nauseous, the thought of eating – or even smelling – food can turn your stomach. But it’s still important to eat to provide you with nourishment and strength.

You can follow our tips on reducing nausea, and focus on avoiding strongly fragranced foods, spicy, fatty or sugary meals that may induce sickness, and highly flavoured options.

Instead, opt for gently flavoured foods such as porridge, soups and pureed fruit. Sip on Nourish Drinks and eat small, more frequent meals if a large meal is too overwhelming. It can also be helpful to suck on ice grapes or berries. And to sip ginger tea, which reduces feelings of nausea.

Foods to avoid if you have taste changes
Chemotherapy and immunotherapy can often leave a ‘metallic’ taste in the mouth that changes the experience of eating. Swapping to non-metallic cutlery (such as bamboo) may help but tweaking the flavours in your meals can also hugely improve your enjoyment of mealtimes.

Adding flavoursome herbs and spices, swapping out sweet ingredients for sharp and tangy flavours, adding punchy condiments such as mustard and pickle, and swapping tea and coffee for herbal teas can all help. Take a look at our Taste Changes blog for more ideas.

What to eat if you have a sore mouth
Cancer treatment can cause your mouth to become sore, which means certain foods will aggravate it further.

Soft foods, soothing soups (not served too hot), cooling puddings (a chilled yoghurt may be less painful than a cold ice cream), and tender tagines and stews can all provide nourishment without hurting. Take a look at our Sore Mouth tips for more ideas.

Why you should reduce alcohol
The liver has to work hard during chemotherapy and immunotherapy treatment, so it’s best to avoid taxing it further by regularly drinking alcohol. A glass of wine or your favourite tipple should be fine (ask your doctor’s advice) but if you want a ‘grown-up’ drink during your treatment, it may be worth switching to one of the many great alcohol-free alternatives available now.

Stay hydrated
Cancer treatments can be hard on the kidneys – you need plenty of fluids in order to process and excrete the medication.

It’s easier to sip fluids regularly, rather than trying to glug down a big cup of water. Keep a water bottle with you, and don’t forget that herbal teas, sparkling water flavoured with lemon or lime, and our Nourish Drinks will all help you to stay hydrated.

How to prepare food during chemotherapy
Good food hygiene is important at any time, but especially if you are having or you are recovering from cancer treatment, or you have low immunity. Follow these guidelines to reduce risk of food-borne infections:

  • Wash your hands with soap and running water immediately before preparing food, and after handling raw meat, poultry, seafood, eggs and unwashed produce.
  • Wipe down and wash or disinfect surfaces, cutting boards and utensils after each use.
  • Use separate chopping boards and knives for uncooked meat, fish and seafood, and fresh produce.
  • Follow your refrigerator storage guidelines and keep all foods separate and in clean resealable containers or bags. Put prepared food in the fridge immediately after preparation if you are not eating it straight away.
  • Always defrost food on a plate in the fridge.
  • Cook all food to the proper temperature to kill bacteria.


Photo by Rayia Soderberg on Unsplash

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