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The Scientific Advisory Committee on Nutrition (SACN) have published their report providing an overview of the current available evidence on processed foods.
Bridget Benelam, Nutrition Scientist, British Nutrition Foundation, said:
“SACN acknowledged that the observed associations between higher consumption of ultra-processed foods (UPF) and adverse health outcomes are concerning. However, they highlighted some limitations of the research using the NOVA classification system, including the potential for confounding and the difficulty in accurately identifying UPF based on UK dietary survey data.
“The UPF category includes many foods that are high in fat, salt and sugar that we are already advised to limit in the diet. For this reason, much of their association with ill health may already be dealt within our current dietary recommendations. But the UPF classification is broad and also includes foods such as sliced wholemeal bread, wholegrain cereals, low fat fruit yogurts and baked beans, all of which could be included in a healthy diet according to current UK healthy eating advice. SACN made a number of recommendations for future research on UPF and we need better evidence on exactly why high consumption of UPF would lead to ill health to give clearer advice to consumers.”
Prof Tom Sanders, Professor emeritus of Nutrition and Dietetics, King’s College London, said:
“This report by SACN is a scoping review looking at food processing identifying gaps in knowledge. SACN recognises the importance of food processing in feeding the population and making food safe to eat. The main conclusion is that there is no reliable evidence currently available to draw any firm conclusions about the hazards of ultraprocessed foods and the suggestions of adverse effects are based on observational data that is subject to bias and confounding. There are no well-designed randomised controlled trials comparing ultraprocessed foods with an appropriate control.
“SACN notes that the term ultraprocessed is a broad catch all. Among the various proposed measures of food processing, only the NOVA classification met the criteria for comparisons. The NOVA system categorises all processed meat (burgers, bacon, ham, chicken nuggets, sausages etc), cheese and flavoured yogurt, industrially processed fats, ready meals, industrially processed cereal foods, baby milks, alcoholic and sugary drinks as well as any food that contains food additives as ultraprocessed foods. Cereals products are staple foods in most Western countries and constitute the largest category of ultraprocessed foods because they include bread, biscuits, cakes and other bakery products. SACN estimated that 41-68% of the dietary energy came from ultra-processed foods using the NOVA classification in the UK National Dietary and Nutrition Survey. It is unlikely that this proportion has changed much in the past fifty years. Especially as the consumption of bread was higher in the 1960s.
“SACN found the NOVA classification system for ultraprocessed foods was open to bias by investigators. The report noted that 9 out 12 of the reviews purporting to show adverse effects of ultraprocessed foods were written by the same group of authors who in Brazil invented the NOVA classification. The truth is the data on whether foods such as bread are produced industrially at home or by artisans is not available so assumption have been made. Data on food additive intake has also been guessed.
“Some processed foods such deep fried foods, confectionery, and beverages (both sugar containing and alcoholic) contribute more calories than nutrients and fuel obesity. The number of aisles in supermarkets dedicated to these foods indicates their high consumption. Excessive calorie intake is fuelling the obesity epidemic and this is facilitated by the increased availability of tasty foods, that are high in calories and often sold in large portions.
“The SACN review concludes by repeating the mantra of unhealthy foods being high saturated fat, salt and sugar. However, this simplistic view does not differentiate between foods that are nutrient dense from those that provide energy and little else. This is particularly the case for dairy products. Although dairy products are a significant source of saturated fat, they also make important contributions to protein, mineral and vitamin intakes. A landmark study by the PURE investigators (Mentes et al. 2023, https://doi.org/10.1093/eurheartj/ehad269) published last week found a 30% reduction in mortality risk among those with the highest healthy diet score based on fruit, vegetables, nuts, legumes, fish, and dairy products (excluding cream and butter). Most salt in the diet is added during food processing, in cooking and at table. The food industry has reduced the salt content of many food products so that they contain much less than most home prepared food. Indeed, industrially manufactured bread contains much less salt than artisanal bread. Many food manufacturers have also reduced the amount of fat in food products as well as the amount of saturated fat. This contrasts with recipes for home prepared food, often endorsed by celebrity cooks, which more than often contain staggering amounts of added fat, salt and sugar.
“Modern food processing has enabled the feeding of urban populations and eradicated micronutrient deficiencies through fortification. Nutrient fortification of processed foods e.g. bread and breakfast cereals makes a substantial contribution to micronutrient intake, especially in children. Folic acid fortification of cereals has prevented neural tube defects. Margarine and spreads now have a healthier nutritional profile compared to butter and contain fewer calories, less saturated fat and more vitamin E and D. Fortification of plant based foods with vitamin B12, D and calcium have also helped people follow vegan diets. To conclude, food processing plays a critical role in feeding the population. SACN concludes that further research is needed to evaluate whether the regular consumption of specific highly processed foods is harmful.”
Prof Janet Cade RNutr FAfN, lead of the Nutritional Epidemiology Group, University of Leeds, said:
“The overall conclusions show that we don’t know how useful definitions of processed food are in relation to health. Whilst we do know that energy intakes above recommended levels can lead to a range of health problems. The processed food classifications do not consider the nutritional composition of foods which is a major limitation; grouping together a wide range of different foods. Although reviews have found increased risk of adverse health outcomes with higher consumption of UPF, in fact, this potentially simply reflects the often high energy dense nature of these foods rather than anything specifically about processing. This creates confusion in interpretation of the UPF findings and concern over which types of foods to consume. Even experts can’t agree on the definition and classification. We need more accurate and detailed methods of recording food and nutrient intakes (such as online tools like myfood24). This would help us to determine whether it is actually the nutritional composition of the foods which is the important element in relation to health or some other attribute. For now, keeping to definitions of High Fat, Salt and Sugar (HFSS) foods would be simpler and easier for us all to interpret and is clearly linked to evidence around health outcomes.”
Prof Judy Buttriss, Chair of Trustees, Academy of Nutrition Sciences; and Prof Christine Williams, Trustee, Academy of Nutrition Sciences, said:
“The Academy of Nutrition Sciences welcomes the thorough and comprehensive statement on processed foods and health from the Scientific Advisory Committee on Nutrition (SACN), which concludes that the observed associations between higher consumption of (ultra-) processed foods and adverse health outcomes need to be treated with caution owing to limitations in the NOVA classification system, the potential for confounding, and the possibility that the observed adverse associations are covered by existing dietary recommendations. Studies are almost exclusively observational and confounding factors or key variables such as energy intake, body mass index, smoking and socioeconomic status may not be adequately accounted for.
“The SACN statement also highlights the lack of evidence about the mechanism(s) via which processed foods might adversely affect health and the need for good-quality randomised controlled trials that may help establish potential mechanisms, and establish whether they are independent of energy density or other dietary factors. This recommendation is aligned with the message of a recent blog post1 from the Academy, which also highlighted the limitations of the dietary methods used in the observational studies. Furthermore, as the NOVA system does not consider nutrient contribution of foods, it fails to accurately distinguish processed foods with limited nutritional attributes from processed foods with recognised nutritional properties, many of which contribute to the nutrient intakes of families living on tight budgets.”
Prof Pete Wilde, Group Leader (Food structure, colloids and digestion), Quadram Institute Bioscience, said:
“An interesting point is that most food processing classification systems (including NOVA) do not take nutrient composition into account. This will therefore mean that processed foods with a healthy nutrient profile / energy density will be classed as UPF.
“It is good to see that SACN have listed a number of potential mechanisms or hypotheses underpinning the impact of UPFs on health, including high energy density, low nutrient and fibre content, lack of food structure / matrix. However, there is often very little difference in these factors between artisanal or homemade versions of a food compared with commercially manufactured versions. Therefore their health impact is likely to be similar, but only the latter would be regarded as UPF and therefore less healthy.
“Whilst the published studies relating to UPF consumption and health show clear effects, these studies are large scale, population level observational studies. These studies, whilst useful in highlighting the potential adverse effects of consuming high quantities of UPFs, don’t identify the causal relationships and the contribution of confounding factors. Also highlighted is that foods in the UPF category had a very broad range of nutritional profiles, which are highly likely to have a similar range of health impacts. Therefore the call for more mechanistic studies to truly understand how and why certain processed foods can have a detrimental impact on health are welcomed. This should ultimately inform the development of an improved classification system which will also incorporate factors such as nutrient profile and matrix structure.
“This should also inform government and the food industry to help develop healthier foods. Most people eat manufactured or processed foods most of the time, as highlighted by the report (“Estimates of population UPF intake in the UK ranged from 51% to 68% of total dietary energy”). We know from experience that it is difficult to dramatically change consumer behaviour, therefore we need to engage with the food industry to be able to provide healthy, cost effective foods that people want to eat, but have the appropriate nutritional profile and structure and other properties that drive healthier eating behaviour.
“Another factor not mentioned is the amount that people eat. Whilst most studies characterise the proportions of UPFs consumed in a diet, little account of the amount consumed is taken. As suggested above, foods with little matrix structure (soft texture) and high energy density are consumed and digested rapidly, leading to a general overconsumption of energy, leading to weight gain, obesity and other non-communicable diseases (type 2 diabetes, cardiovascular disease etc).”
Dr Ian Johnson, Nutrition researcher and Emeritus Fellow, Quadram Institute, said:
“This careful review comes from a highly reputable advisory group using rigorous methods to analyse the current literature on the relationship between consumption of ultra-processed foods and health. It confirms that dietary patterns defined in this way are often associated with higher risks of non-communicable diseases, but it also illustrates the many uncertainties that arise because the concept of UPF is very broad and poorly defined. This makes it extremely difficult to identify and quantify the mechanisms linking UPF diets and poor health outcomes. The subject requires further research and refinement, and certainly does not deserve to be treated with the levels of dogmatic certainty that one often sees in the popular media.”
Prof Gunter Kuhnle, Professor of Nutrition and Food Science, University of Reading, said:
“There have been a lot of discussions about the health impact of ultra-processed foods, and these discussions have unfortunately been dominated by hyperbole and unnecessary generalisations. It is therefore good to see that SACN has published a detail assessment, especially as SACN members are experts in a wide range of research areas concerning nutrition and health. The statement makes it clear that processed and ultra-processed foods are a much more complex issue than previous reports suggest – and clearly not as dangerous as often implied. The evidence base for adverse effects is based on a small number of observational studies that have known limitations: ultra-processed foods might be an indicator of an overall unhealthy lifestyle. SACN also highlight that many ultra-processed foods would already be considered to be unhealthy as they are energy dense and high in salt, fat and sugar – and are therefore already covered by current dietary recommendations.
“The SACN statement highlights a number of limitations when assessing intake of ultra-processed foods: a lot of the information needed to identify a food as ultra-processed are not generally collected. For example, in most studies it is impossible to distinguish between home-made, artisanal or mass-produced breads, although only the latter is considered “ultra-processed”. In order to be able to estimate the intake of ultra-processed foods in the UK more accurately, this needs to be considered in future rounds of the National Diet and Nutrition Survey (NDNS) which provides detailed information on what we eat.
“SACN clearly sees the importance in monitoring the effects of processing and ultra-processing on health – and this is very welcome. They also highlight current knowledge gaps that need to be addressed by research in order to get more reliable information and conduct a proper risk assessment. However, they also consider the data currently available not strong enough to make dietary recommendations.
“This SACN statement puts many of the often-outrageous claims about ultra-processed foods into context.”
Dr Duane Mellor, Registered Dietitian and Senior Lecturer, Aston Medical School, Aston University, said:
“It is good to see this report from SACN which highlights that although there are consistent findings of associations between consuming of ultra-processed foods with poor health including risk of cardiovascular disease, it clearly also states there are limitations with what is meant by an ultra-processed food. The report states that only the NOVA definitions are robust enough to use when looking at UK diet, but even this approach (which defines foods as minimally processed, ingredients, processed foods (e.g. cooked at home) or ultra-processed (made using ingredients not typically available in a domestic setting)) lacks the precision to identify all foods as being ultra-processed or not in a British dietary pattern.
“It is also good to see that the SACN report acknowledges that in the research they looked at, often individuals who are said to consume more ultra-processed foods would be eating a diet that would be consider to be generally less healthy – which could simply mean that it might be overall nutritional quality of the diet that is the issue, rather than the processing of the food itself. It also highlights the problem that the studies reporting the negative effects of ultra-processed foods, generally have not managed to adequately identify all confounding factors such as income, body weight and smoking status. So, it questions the value of using ultra-processed foods as a definition compared to assessing whether a diet is high in fat, salt and sugar or is generally less healthy. It also makes good recommendations about the need for future research.
“What is missing however, is a focus on what people should be trying to eat more and does not really consider the socio-economic inequities which are often associated with a less healthy diet. Perhaps instead of focusing on what we should be eating less of we should be focusing on how we can enjoy a healthier dietary pattern, that is available to all in an equitable way without judgment.”
https://www.gov.uk/government/publications/sacn-statement-on-processed-foods-and-health
Declared interests
Bridget Benelam: “Funding to support the British Nutrition Foundation’s charitable aims and objectives comes from a range of sources including membership, donations and project grants from food producers and manufacturers, retailers and food service companies, contracts with government departments; conferences, publications and training; overseas projects; funding from grant providing bodies, trusts and other charities. Further information about the British Nutrition Foundation’s activities and funding can be found at http://www.nutrition.org.uk/aboutbnf/.”
Prof Tom Sanders: “I used to be a member of the Scientific Advisory Panel of the Global Dairy Platform (8 years ago). In my research I have been involved working with the food industry developing healthier fats. I used to be a consultant to the Breakfast Cereals Advisory Board of the Food and Drink Federation.”
Prof Janet Cade: “I declare COI with myfood24 (https://www.myfood24.org/), Director of Dietary Assessment Ltd.”
Prof Judy Buttriss and Prof Christine Williams: “The Academy of Nutrition Sciences is a charitable organization set up to provide an authoritative voice advancing and promoting evidence-based nutrition science (www.academynutritionsciences.org.uk).
Biographies for Christine and myself are to be found on the website.”
Prof Pete Wilde: “I have never received any personal funding from the food industry, but in the past, some have my research has received support from Quorn Foods, Mondelez, Unilever, Nestle and PepsiCo.”
Dr Ian Johnson: “No conflicts to declare.”
Prof Gunter Kuhnle: “No CoI.”
Dr Duane Mellor: “No declarations of interest.”
For all other experts, no reply to our request for DOIs was received.