Risk of infection (reduced immunity)

Cancer or cancer treatments may increase your risk of infection. Some treatments can temporarily lower the number of white blood cells in your body. These cells help fight infection. Having a lower number of white blood cells than normal is called neutropenia.

Most people having cancer treatment will not need to change their diet. If you are having high-dose chemotherapy, you may be advised to avoid foods that might contain harmful bacteria. You may also need to be extra careful with food hygiene. This is called a ‘clean diet’. It can help reduce your risk of getting an infection. Your specialist nurse will talk with you about this.

Foods to avoid if your immunity is low

If your immunity is very low, you might need to avoid certain foods. Your doctor, nurse or dietitian will be able to tell you whether you need to avoid any foods. Different hospitals will have different recommendations. Your doctor or nurse will give you more details and advise you how long you should avoid these things for after treatment.

Foods to avoid may include:

  • cheese or other foods or drinks made from unpasteurised milk
  • mould-ripened and blue-veined cheeses
  • meat and fish pate
  • yoghurt or other products that contain probiotics
  • raw or undercooked meats, poultry, fish and shellfish
  • cold meats that have been smoked but not cooked, such as salami
  • runny eggs, and any product containing raw egg – such as homemade mayonnaise.
  • Unwashed fruit, vegetables and salad.

Preparing food

If your immune system is weak, you are more at risk of getting food poisoning. This is because you are less able to fight infection. You may also be less able to cope with the symptoms of food poisoning.

To reduce this risk, you should:

  • use fresh ingredients
  • check the use-by dates on food
  • store food and drink at the correct temperature – look at the packaging for instructions
  • rinse all fruit and vegetables in cold running water before eating or cooking
  • cook food thoroughly
  • throw away mouldy food.

In the kitchen, you should:

  • wash your hands before you touch food
  • clean cooking utensils and chopping boards thoroughly
  • wipe worktops with hot, soapy water or an anti-bacterial spray – this is very important if you have prepared raw meat or eggs
  • wash or replace dishcloths and tea towels regularly
  • keep pets out of the kitchen.

Leftovers

If you decide to store food to eat later, let it cool down completely and then store it in the fridge or freezer.

Freezing extra portions can save you time later. It is a useful thing to do before starting cancer treatment. You must defrost food fully before reheating it. This is very important if you have low immunity because of treatment.

Only reheat food once, and make sure it is hot all the way through before you eat it. Do not reheat cooked rice. Eat rice as soon as it is cooked. Take care not to burn your mouth or tongue if you are reheating food.

Eating out

It is best to avoid eating out and takeaway food if your immunity is low. If you eat out, try to choose somewhere where you know the food will be freshly prepared and properly cooked. Avoid eating food from salad bars, buffets and street vendors because it is difficult to know how fresh the food is. Also avoid having ice-cream from an ice-cream van.

About our information

  • References

    Below is a sample of the sources used in our healthy eating information. If you would like more information about the sources we use, please contact us at cancerinformationteam@macmillan.org.uk

    Fang X et al. Quantitative association between body mass index and the risk of cancer: A global Meta-analysis of prospective cohort studies. International Journal of Cancer. 2018 Oct 1;143(7):1595-1603.

    British Nutrition Foundation website www.nutrition.org.uk (accessed December 2019).

    Bhaskaran K et al. Body-mass index and risk of 22 specific cancers: a population-based cohort study of 5·24 million UK adults. The Lancet, August 2014..

    The Eatwell Guide: Helping you eat a healthy, balanced diet, Food Standard Scotland, October 2019.



  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Chief Medical Editor, Professor Tim Iveson, Consultant Medical Oncologist.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.