Why public health warnings could backfire

Premature warnings to consumers to avoid consuming all ultra-processed food products likely have social costs and may harm the health of people facing food poverty, at least in the short term.

That’s the clear message to policymakers in a recently published perspective article by Professors Alexandra Johnstone of the Rowett Institute of Nutrition and Health at the University of Aberdeen and Eric Robinson of the University of Liverpool.

They say that until the link between ultra-processed foods (UPF) and poor health is better understood, official public advice should remain focused on preventing known threats: high fat, sugar and salt.

Issuing formal warnings about UPF in the UK – which other countries have done – could be counterproductive, leading some people to turn to alternatives that are not classed as ultra-processed but are less nutritious than what they consumed before, they say. .

And they highlight the “potential social cost to many people with more limited resources” of removing practical options and the possible negative impacts on the mental health of “those who worry about their health or live with mental health disorders.” diet, particularly if social circumstances make it difficult to avoid UPF.” “

The article—published in PLOS Medicine as part of a collection on the subject of UPFs – concludes: “Based on the balance of current evidence, we do not believe it is appropriate to advise consumers to avoid all UPFs and we expect additional evidence to enlighten consumers on the need to limit the consumption of specific foods based on their degree or type of processing.

“We know for sure that foods high in energy and/or high in saturated fat, salt or sugar are harmful to health and we should continue to advise consumers to limit the consumption of these foods. Likewise, we should encourage the consumption of healthy products. promote foods such as fruits, vegetables and whole grains.

“Mechanical uncertainty over food processing and health should not prevent immediate and much-needed public health policy to regulate the food industry to significantly reduce the advertising, availability and dominance of energy-dense foods and/or or saturated fat, salt or sugar in national diet markets.

“However, mechanistic uncertainty is expected to determine how the public is communicated and play a central role in determining public advice and emerging national dietary guidelines on UPF and food processing health risks.”

Pressure to issue guidelines against the consumption of UPF – which make up a significant portion of the national diet – has intensified in the media and elsewhere due to consistent evidence from a growing number of observational studies that they are linked to poor health outcomes.

But many UPFs are also high in fat, sugar and salt and, at present, the Food Standards Agency believes that other possible causes of health problems linked to their consumption “have not yet been fully explained by science”, and therefore specific public guidelines have not been given. issued.

Food Standards Scotland (FSS) warned in March that “there is a risk that the focus on ultra-processed foods will distract from key food issues where there is strong evidence for action, namely foods high in fat, salt and sugar, providing additional impetus for the FSS to provide clear messages to consumers on this issue.

The FSS has since published its organizational position on the subject, as well as advice for consumers, reaffirming these findings.

Professor Johnstone said: “We must guard against the possibility that those in our society who are already most at risk of not being able to afford to eat healthily will not be placed in an even worse situation as we continue to investigate the links between certain ultra-processed foods and poor health.

“We need higher quality mechanistic research in humans, using controlled diets, to determine the effects of nutrient profile and ultra-processing per se. Diet reformulation and diet quality are two key aspects of our food environment and, alongside affordability, they remain food system challenges.

Professor Robinson said: “Foods classified as ultra-processed that are high in fat, salt and/or sugar should be avoided, but a number of ultra-processed foods are not. We should think very carefully about the advice that is given to consumers. the public, instead of providing simplified and potentially misleading messages that grab headlines. »