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  • Joanna Injore

Anti-cancer diets?? Top tips to spot fact from fiction

Nutrition is a very newsworthy topic and just a quick browse online and you will see there is a wealth of information and recommendations of specific foods and diets to follow.

When it comes to cancer, there is great deal of info on what you should and shouldn’t eat; but how do you know what to believe? If you have been diagnosed with cancer, food can become more than just nourishment, it is often a means maintaining some control over what is happening to you. You may be in the thick of treatments and investigations and food gives you a means to take charge and have an influence on what is happening to you.

I get that.

But it is vital that your body needs good nutrition during and after cancer treatment so it is important that the advice you are following is safe and actually works! I have put together my top tips when reading about nutrition and cancer or anti-cancer diets to help you spot the reliable information from the myths.

Top tips to spot fact from fiction

Anti-cancer diets top tips

Top Tip No. 1. The who?

Check who is making the claims. What are the qualifications of the person providing advice? Do they hold qualifications in Nutrition? There are a lot of medical doctors that talk about nutrition and whist they may be experienced in their field of medicine; their education does not include comprehensive nutrition training. Whereas Registered Dietitians are the regulated by the Health & Care Professional Council (HCPC) and undergo extensive academic and practical training in nutrition.

Top Tip No. 2. Check the details

Are research or studies quoted? That is a good thing right. Yes and no. There are a few details in the research that we need to examine to see if this information is actually useful.

References and research

Do they have references for their claims? Dig a little digger into these. Are they quoting animal studies or lab based ‘cell studies as evidence for their recommendations? Remember that animal studies or lab-based cell studies may not be applicable to us humans. We are complex beings and unfortunately what happens in a test tube or in an animal cannot often be replicated in the human body. These studies may hint at possible new developments but they need further testing before translating this guidance to humans.

The numbers

Are they quoting research from a single study or the effect of their claim has only been noted in very small numbers of people? Unless the effect is observed in large groups of people it is difficult to conclude that this is a true effect.

Types of studies

There are a few different types of study designs and some are more comprehensive than others. A lot of research in nutrition is based on observational studies where you ‘observe’ a group of people and measure a particular outcome, to see if there are any links. Observational studies only suggest a link or association which does not mean that it CAUSES something to happen.

Let’s take a fictitious example to work through this idea. In our study we are observing a group of women over time and asking them about their tomato intake and then recording whether they develop cancer. Now if the results identify that in women who ate more tomatoes they had a lower incidence of cancer, this does not mean that definitely eating tomatoes lowers your risk of cancer. All we have identified is an observation. On it’s own this information may not be helpful but if it is combined with other evidence from other types of studies such as systematic reviews (which analysis the data from several sources to try to answer a specific questions) we may be able to draw stronger conclusions. The WCRF cancer prevention recommodifications do just that, regularly undertaking a ‘comprehensive review of a range of evidence to draw conclusions and make recommendations’.

Top Tip No. 3. Does it sound too good to be true?

Proceed with caution with if you are reading about a diet or food that ‘cures cancer’ or other such claims. These wide sweeping statements are very unlikely to be true and can be harmful especially if it advises going against medical treatments.

Top Tip No. 4. Are they selling you a product or supplement?

Are they recommending that you buy their product to solve x? Their interest may be more financial rather than health.

Top Tip No. 5. Are they advising limiting whole food groups?

Diets that recommend cutting out whole food groups without adequate replacement is potentially dangerous especially if you are undergoing cancer treatment. If you cut out foods without replacing them your diet could be lacking in vital nutrients.

So where can I find reliable information:

The following website below for reliable information on cancer and nutrition and are usually a good place to start. British Dietetic association provides useful ‘Food fats’ on popular nutrition topics. provides information and support for people affected by cancer. They produce information on treatments, nutrition, social/emotional and financial help. produces update information in cancer prevention research related to diet, nutrition and activity. provide information and support on cancer prevention, diagnosis and treatments. - further guidelines on ‘how to read health news’

Take home message
Nutrition is a hot topic and will always be in the news so when reading about nutrition and cancer or anti-cancer diet procedure with caution and question the writers claims.
As an experienced Oncology/cancer Dietitian I can help you navigate through the information and answer your specific questions about cancer nutrition and diet. Click here if you have questions and would like support fact checking anything you have read.

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