Cancer-related fatigue 

Lady on sofa with cancer-related fatige

Cancer-related fatigue (CRF) is the most commonly reported treatment-related side effect with 9 out of 10 people experiencing fatigue for months or even years after treatment has ended. 

CRF can be not only frustrating, but it can be debilitating causing brain fog, depression, sleep disturbances and a significant impact on quality of life.  

This article looks to see why cancer-related fatigue occurs and what role diet plays in improving it. 


There are many causes of cancer-related fatigue and you may find that you’re experiencing one or several. 

In some cases, individuals had fatigue before they received their cancer diagnosis. The fatigue is exacerbated by the cancer itself, as well as by the treatment. Causes of fatigue pre-diagnosis can include vitamin D deficiency, anaemia, heart conditions, diabetes, psychiatric conditions or psychological factors. Often medications to treat some of these conditions also have fatigue listed as a side effect. 

Another factor that can contribute to CRF is pain, either from the cancer itself or as an effect of treatment. Chronic or acute pain can make it more difficult to rest and sleep, and it also takes significant physical and emotional energy to deal with pain, which exacerbates the issue. 

We also know that many experience a loss of appetite, a sore mouth or taste changes during cancer treatment, all of which can mean a suboptimal intake of nutrition. Fatigue will occur or be worsened if the body isn’t getting enough calories to cover the energy required for our most basic functions. The risk of deficiencies may be increased especially in nutrients that help prevent fatigue such as vitamin D, iron, vitamin B12 and folate. 

There is evidence in the role of inflammation in CRF. The cancer itself, as well as the treatment can induce inflammation in the body, triggering fatigue. Several mechanisms contribute to this, including dysregulation of cortisol (a stress hormone) levels in the blood. Altered cortisol levels are also associated with disruption of the circadian rhythm and disturbed sleep patterns, which are often experienced during cancer treatment. Less sleep equals more fatigue. We also know that cancer treatments can cause a disruption in our energy metabolism which can lead to a loss in skeletal muscle which could, in turn, lead to an increased risk of fatigue. 


Large scale scientific studies found that in comparison to interventions such as exercise, nutrition and psychological support, medical interventions are the least effective at treating CRF. 

Physical activity for cancer-related fatigue

Scientific studies found that aerobic exercise is associated with reduced CRF both during and after cancer treatment. A high quality scientific study found that CRF was improved to a greater extent when aerobic exercise lasted for 50 minutes per session vs 20-30 minutes per session. Other studies have shown that group-based or personal training sessions/programs may have an added benefit of improving adherence, and therefore CRF levels. 

My advice is to seek the support of an oncology specialist physiotherapist such as Louise Malone or one of the team at Perci Health if you’re not able to access the service through your NHS oncology unit. 

Psychological interventions for cancer-related fatigue

Talking therapies can be incredibly helpful as they can help you reduce internal ‘noise’ and physical symptoms that interrupt your sleep as well as help you reframe your perspective about your fatigue and improve your coping skills.

There are different types of talking therapies that have been shown to help reduce CRF. For example, cognitive behavioural therapy (CBT) can be effective at reducing CRF especially when provided after active treatment has ended. CBT can also be effective in addressing insomnia which often co-exists with CRF. 

Mindfulness can be particularly helpful in the short term, where individuals are supported with coping with uncertainties and anxieties resulting from cancer and its treatment. This could be a self-guided mindfulness practice, or with a practitioner. 

My advice is to seek the support of an oncology psychologist or mindfulness practitioner. Your oncology team may be able to put you in touch with someone. 

It’s worth noting that complementary therapies such as massage, yoga and aromatherapy can also indirectly help with cancer-related fatigue as they target both the body and mind with the aim of inducing relaxation which can calm the central nervous system to help us get into “rest and digest” mode. Another common complementary therapy, acupuncture, can be effective at reducing pain which may also lead to a reduction in fatigue. 

Dietary interventions for cancer-related fatigue

Nutrition counselling from an oncology dietitian can help to manage treatment related side effects that may contribute to cancer-related fatigue such as nausea, vomiting, taste changes and loss of appetite. A dietitian would also assess the nutritional status of an individual to identify and address any underlying nutritional deficiencies that are contributing to CRF. In some cases the cancer itself, or its treatment can cause nutrient malabsorption which requires dietetic and often medical support to correct and manage. 

It is generally thought that a diet that is anti-inflammatory is beneficial for the whole population, but in particular those experiencing fatigue where inflammation may be an underlying component of its cause. The term anti-inflammatory diet is a little misleading because there’s no specific diet that is proven to be anti-inflammatory. That being said, there are some key nutrients that have anti-inflammatory properties which come from a range of dietary sources.


Protein is of particular importance to the cancer patient as requirements are increased due to increased protein turnover and loss of skeletal muscle. A lack of protein has been associated with the development of CRF. Therefore, protein requirements should be assessed by a dietitian and tailored advice provided to ensure needs are being met through diet. 

Of particular interest is the amino acid (a building block for protein) called glutamine. A recent study found that glutamine levels are reduced in cancer patients and are associated with CRF. Another study found that supplementation with glutamine may help with mucositis which affects some cancer patients. Glutamine is within in a variety of foods including eggs, beef, milk, tofu, rice and corn. 

We generally don’t need to supplement with glutamine or other proteins, instead focus on getting enough overall protein in the diet. This can be from both animal and plant sources and includes meat, fish, eggs, dairy products, lentils, beans, chickpeas and tofu. 

Fatty Acids

Fats are necessary for many processes in the body including absorbing vitamins, producing hormones, and providing us with energy. Saturated fats (found in butter, cheese, fatty meats and products made with those such as cakes and biscuits etc) are associated with inflammation in many organs of the body. A diet low in saturated fats is associated with reduced CRF. 

We can’t make omega-3 or omega-6 fats – we obtain them from our diet. The intake of omega-3 and omega-6 fatty acids, as well as the ratio of those in our diet may be associated with inflammation and fatigue. A 2017 study found that a diet containing increased amounts of omega-3 rich foods, as well as a reduction in foods high in saturated fats significantly reduced fatigue over a 3 month period. 

Omega-6 is pro-inflammatory. Foods containing this type of oil include sesame oil, avocado oil and sunflower oil as well as walnuts and pumpkin seeds. These foods are not bad for us (in fact they’re incredibly healthy) so we don’t need to avoid them. But the balance of the types of oils we use in our diet, alongside our intake of omega-3 is what is important. 

Omega-3 is anti-inflammatory. It is found predominantly in oily fish. Vegetarian sources include flaxseeds, chia seeds, hemp seeds, walnuts, edamame beans, and kidney beans. Some individuals benefit from an omega-3 supplement (I usually recommend an algae based one). This should be discussed on a case-by-case basis. 

Vitamin D

Vitamin D is a fat-soluble vitamin which plays an important role in not only our bone health but also in supporting the immune system. Low levels of vitamin D can lead to someone feeling achey and tired, and so optimising your level of vitamin D is important to the whole population, and especially to those experiencing CRF. 

For more information about vitamin D see this article


Polyphenols are beneficial chemicals in plants, so within the foods that we eat. There’s lots of different types of polyphenols, for example flavones, isoflavones, flavanols, flavonoids, and anthocyanidins. Many of them have been studied and shown to have antioxidant and anti-inflammatory functions, meaning they can play a protective role in our diet to support our overall health. 

I don’t recommend supplements of polyphenols, especially during active cancer treatment as it may even interfere with the cancer treatment. Instead, I recommend including plenty of these foods in the diet. 

Polyphenols are found in fruits, vegetables, cereals, herbs & spices, and beverages. So by having a varied diet you’re going to be naturally consuming some. Here’s my top 10 foods (in no particular order) which have beneficial polyphenols you may wish to include:

  1. Tofu
  2. Green tea
  3. Red grapes 
  4. Turmeric
  5. Onions
  6. Kale
  7. Cherry tomatoes
  8. Broccoli
  9. Blueberries
  10. Apples

Additional dietary & lifestyle tips to help manage cancer-related fatigue

  • Small frequent meals or snacks can often be easier to manage than large meals which can help improve the quantity and quality of your overall intake. 
  • If you’re regularly too tired in the evening to cook, try having your main meal at lunchtime. 
  • If you’re having a good day, then perhaps optimise this by batch cooking with a slow cooker or casserole so that you have some portions in the fridge/freezer ready. 
  • Accept help of others in preparing food/meals, and don’t be afraid to rely on some frozen meals. FieldDoctor has a wonderful range of ready meals which are full of beneficial plants and fibre, without any of the nasties. You can use the discount code GreenLightNutrition15 to receive 15% off your first order. 
  • Try to maintain a sleep routine so that you’re getting at least 7 hours of sleep per night. If you need to take a nap during the day then do, but limit it to 30 minutes so that it doesn’t disrupt your bedtime. 
  • Ensure you’re drinking enough as dehydration can contribute to fatigue. Aim for at least 2L per day. Water, herbal teas, squashes, cordials and tea/coffee all count. 

For more information about what foods you could include in your diet, please see this article


Cancer related fatigue is incredibly common, and whilst we may not be able to prevent it, there are some dietary and lifestyle measures that we can take to potentially improve symptoms. 

Don’t be afraid to ask for help if you’re struggling with fatigue – your oncology team will likely have some resources they can share with you or signpost you to healthcare professionals who can support you. 


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