76% of online breast cancer nutrition claims not supported by evidence, study finds

Study author Negin Amin, a PhD candidate at Adelaide University’s School of Pharmacy and Biomedical Science, and her team wanted to know what nutrition information patients would find online. 

They analysed more than 150 nutrition claims from eight platforms including Facebook, X, Instagram, TikTok, YouTube, Pinterest, Google, and ChatGPT, and found that overall, over 87% of information had weak to no supporting evidence.

“The chance of finding this unsubstantiated advice is much higher on X or TikTok, where up to 76% are not backed up by science,” said Ms Amin.

“Our clinical study is breast cancer specific. But a lot of what we found would be relevant across cancer and cancer treatments.”

Analysing online nutrition claims

The researchers evaluated claims against current scientific evidence, including nutritional guidelines such as ESPEN practical guideline: clinical nutrition in cancer, Australian Dietary Guidelines, and several others. 

“Rather than categorising the information based on information and misinformation or good or bad, we wanted to know whether it was evidence-based or not.”

“We categorised the claims according to whether they were evidence-based, low evidence, weak evidence, and no evidence. That's important because many of the claims that we collected were not evidence-based at the moment, but maybe in five years, [they may have evidence].”

“So, they are not necessarily wrong or misinformation.” 

Of the claims, 8.6% were evidence-based or had strong evidence in favour of the claim, while 4.0% had evidence against.

The platforms containing the most accurate information were Google (33.33%) and ChatGPT (30%), though even the quality of information on these platforms was relatively poor.

The most common unsupported claims included ‘avoid dairy and animal protein during cancer treatment,’ ‘the sugar in fruits feeds cancer cells,’ and ‘olive oil can cure cancer.’

Health care professionals more reliable, but less active online

The researchers found that claims from health professionals were more likely to be consistent with evidence (29%).

“People who introduced themselves as health professionals shared the least amount of weak evidence and no evidence information, which is good.”

“But the other side of that is that the overall amount of content provided by health professionals was much less than the personal accounts, bloggers, and influencers.”

“Societies and health professionals could be becoming more active in that way and delivering their messages in these different ways, for people to access.”

Content creators were coded as ‘health professionals’ if they identified themselves as oncologists, nurses, dietitians, nutritionists, general practitioners, etc. It was not possible to verify the validity of the creators’ credentials.

“We want to be careful not to say that it's misinformation, coming from those societies,” said co-author Associate Professor Tania Crotti, a medical researcher from Adelaide University’s School of Pharmacy and Biomedical Science.

“It’s more that they're not as active; there's not as much [of their] information out there.”

Patients need more accessible information

The study suggested that breast cancer patients need more accessible information that is evidence based. 

“Our study shows that non-evidence-based nutrition information is being shared widely online. This could be putting cancer patients at risk of malnutrition, which can be associated with serious consequences and lower quality of life,” said Associate Professor Crotti.

“It’s critical that we find a way to differentiate between both reliable and unreliable sources to give cancer patients access to the right health advice.”

“For patients, the best thing is to refer to the Cancer Council or The Clinical Oncology Society of Australia (COSA); they have handy and guidelines that are designed for patients with more understandable language.”

“There is a lot more now coming through about survivorship, and support during cancer. The Multinational Association of Supportive Care in Cancer (MASCC) has information on how to manage eating when you've got severe diarrhoea, for example.”

“And it gives tips to help the patient in a way that's understandable.”

Ms Amin is undertaking a second study with patients to find what the gaps are regarding dietary intake.

“In terms of knowledge available and the science behind it, I think that we have a long way to go,” said Ms Amin.

“We currently don't have specific dietary guidelines for breast cancer patients. So that's a huge gap. Most of the guidelines for patients are general, and they probably do not satisfy the need that patients have for the information.”

“Cancer Council has a specific website on which patients can post questions, and they get an answer back with evidence-based information. So, I think that's a great start.”

“The damage from the unsupported information could be direct, and indirect. The direct damage is food-drug interaction, or the encouragement to give up on their main treatment and go only with a specific diet.”

“But those claims are limited. The indirect effect is the confusion that all this different, and contradictory, information provides for patients. Confusion is really tiring for patients.”

“If I, as a patient, scroll Instagram and see one post say, ‘go keto,’ and the next said ‘use alkaline diets,’ and the next one said, ‘use plant-based diets,’ I may not use any of that information, but it creates confusion.”

“Giving patients the opportunity to fact-check the information that they find would be a better approach.”

The role of GPs in nutrition advice

They researchers suggested that this is an opportunity for GPs and specialists.

“For GPs, it’s tricky to just refer to general guidelines because the Australian Clinical Nutrition Guidelines are not specific to cancer patients,” said A/Prof Crotti. 

“And they also don't necessarily allow for a patient who’s lost their appetite, who might have ulcers in their mouth because they've got mucositis, and are not even able to eat.”

A/Prof Crotti and Ms Amin both say that it is the relationship that health care professionals, and in particular GPs, have with their patients that is so important.

“It's making sure what are your patients able to eat, what are they eating, and where they are getting information so that you know if they've all of a sudden changed their diet that they may be now risking malnutrition or lack of nutrients,” said A/Prof Crotti.

“But also, we can't just say, ‘follow general guidelines.”

“What’s really important is the way information is being delivered to patients, as well as the evidence behind them,” said Ms Amin.