Specific advice around eating well to reduce and manage cancer.

Advice on foods, supplements, storage and cancer risk

Red meat can provide an important source of protein, iron, zinc and vitamin B12.

However, eating too much red meat and, in particular, processed meat may increase the risk of bowel cancer.

To reduce bowel cancer risk, we recommend: 

  • eating no more than 350-500 grams cooked (or less than 700-750g raw) red meat (beef, lamb, pork) or less than three portions weekly.  A 100g (cooked) serving is equivalent to two slices of meat or one to two chicken drumsticks or ½ cup minced meat
  • limiting or avoiding processed (smoked, cured, fermented, salted) meats, chicken or fish such as frankfurters, corned beef, bacon, ham, sausages, and salami
  • regularly including alternate iron-rich protein such as legumes, lentils, tofu, nuts, seeds, eggs, chicken, fish and seafood.

Cooking beef, pork, fish, or poultry at high temperatures or in direct contact with a flame or a hot surface, such as pan-frying, barbecuing, or grilling, can cause the formation of potentially carcinogenic chemicals.

However, there is not enough data to clearly associate the way meat is cooked with cancer risk to date.

We recommend reducing the risk of carcinogenic chemical formation by:

  • using lower cooking temperatures rather than too much direct exposure to an open flame or a hot metal surface and avoiding prolonged cooking times at high temperatures
  • turning meat, fish and chicken regularly to avoid burning and removing charred portions. 
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When starchy foods, like bread or potatoes, are cooked until they are dark brown, a compound called acrylamide is formed.

Animal studies have found a link between eating overcooked foods such as burnt toast that contains acrylamide and cancer risk. This has not been found in humans.  

We recommend when baking, toasting or roasting starchy foods like potatoes, parsnips and bread to cook only till golden yellow colour. 

Sugar is found in both added and natural forms in our food.

It is naturally occurring in foods like milk, fruit, breads, cereals, rice and potatoes. Added sugars include white, brown and raw sugar, honey and syrups and are often used in processed food and sugary drinks.

During cancer treatment

Some people worry that eating food with sugar will make their cancer grow faster. Sugar itself has not been shown to increase the progression of cancer.

People who have cancer often have eating problems due to the cancer and its treatment. This may cause weight loss. During this time extra fat, protein, and ‘added’ sugar may be needed to increase your calorie intake to help maintain your weight.

You will be guided by your treatment team on the best foods to eat.

After cancer treatment

While limiting sugar in your diet may not prevent cancer, we can all reduce our risk of getting cancer by making healthy choices.

Processed foods and drinks with added sugar, often have no or very limited nutritional value. They can contribute to weight gain.

When you are not going through cancer treatment, limiting added sugar can be a good place to start with making your diet healthier.  This can help lower your weight and provide protection from some weight-related cancers.

For example, try using fresh fruit flavoured water instead of sugary drinks, snack on fresh fruit and choose packaged products with less than 10 grams of sugar per 100grams. 

Learning more about this topic here: 

For more information

Eating a diet low in salt (sodium chloride) is good for your health and protects against cancer risk.

Fresh whole foods such as fresh fruit, vegetables, herbs, spices, fish, legumes and lentils, eggs and milk contain little natural salt but provide enough for your body’s needs.  

However, most processed food such as packaged, canned, fast food and takeaways use added salt to flavour and preserve them and have been linked to greater cancer risk. 

  • Salted preserved fish and pickled vegetables are linked to stomach and nasopharyngeal cancer risk.  
  • Red meat, preserved by salting, fermentation, curing and smoking such as bacon, ham, salami, and sausages, increase colorectal cancer risk.  

Eating mostly fresh, whole, unprocessed foods will help lower your salt intake, cancer risk and support good health. 

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Regularly eating foods high in fibre may protect you from some cancers, especially bowel cancer.

Foods high in fibre include:

  • whole grain bread and cereals
  • a colourful variety of fruit and vegetables (especially non-starchy vegetables)
  • legumes and lentils.

Soybean products such as tofu, tempeh, miso, green soybean (edamame) and soy milk contain chemicals called isoflavones (phytoestrogens). Isoflavones are like human oestrogen but have a much milder effect.

While the use of high amounts of soy in animal studies increased breast cancer risk, this has not been found in humans. In fact, some evidence finds moderate amounts of soy products (but not supplements) can instead provide health benefits and better survival of breast cancer survivors.

Soy products used in moderation add protein, fibre and variety to your diet.

Vitamins and minerals are essential for good health.  You should try to get all the vitamins and minerals you need through what you eat.

Evidence does not support the need for vitamin or mineral supplements (including high dose supplementation) to prevent cancer.

High-dose supplements could increase the risk of cancer in some people.

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Vitamin C comes mainly from fruit and vegetables and has an important role in healing and preventing cell damage.

High-dose vitamin C, given by mouth or into a vein, has been used by some people with cancer. However, this treatment has not been tested in clinical trials and to date there are no proven benefits of vitamin C supplements other than through dietary sources.

While a good intake of vitamin C from fruit and vegetables is recommended, further research is needed into the benefits and harms of high-dose vitamin C therapy.

Concerns have been raised that chemicals in plastic bottles, cling film and food containers used to store or freeze food could cause cancer by seeping into their contents.

However, while pollutants from plastics packaging exist, the amounts are within safe levels and no evidence links them to cancer in humans.

We recommend following the manufacturers reheating and storage instructions to limit expose of any potential risks from plastics. 

Many people want to know if they can fight cancer by eating certain foods or taking vitamins or supplements. There are no studies that prove that any special diet or any combinations of food, can slow or cure or keep cancer from coming back.

These include: macrobiotic, low acid/alkaline, intermittent fasting, ketogenic diets (low carbohydrate, high fat) and diets centered on specific vitamins, minerals, dietary supplements or herbs.

Eating well, keeping active and maintaining a healthy body weight have been shown to reduce the risk of developing some cancers.

Talk to your treatment team if you are unable to eat well, or if you want to learn more about any dietary supplements, herbs or special diets, as they may make cancer treatments less effective.

Last updated: March 21, 2023