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A study published in the Lancet Regional Health – Europe looks at plant based ultra-processed foods and cardiovascular disease risk.
Sarah Nájera Espinosa, Nutrition & climate change researcher and PhD Candidate in the Department of Population Health; Dr Pauline Scheelbeek, Associate Professor in Nutritional Epidemiology & Planetary Health; and Prof Rosie Green, Professor of Environment, Food and Health; all at the London School of Hygiene & Tropical Medicine, said:
Does the press release accurately reflect the science?
“Some people could get the impression from the first paragraph of the press release that the study only looked into meat alternatives, when in fact, it considered many other UPF products such as industrial breads, biscuits, confectionery, etc.
Is this good quality research? Are the conclusions backed up by solid data?
“It’s a very large sample size with good detailed dietary information, and the conclusions are backed up by the data presented. However, I have some reservations about the findings (particularly the diversity of categories included in plant-based UPF) and the inclusion of alcohol in only the plant-sourced foods (both UPF and non UPF) to estimate health outcomes.
“Furthermore, the terminology used and the classification system (i.e., NOVA) are misleading. First, during the development of the NOVA classification, nutrition was not at its core, and this classification is currently debated by many experts. Second, the study speculates regarding ‘the rising trend of new plant-sourced UPF products,’ suggesting that meat alternatives may be negative for our health, when the results from the study are not focused solely on meat alternatives. Since emerging evidence shows contrasting outcomes for these specific products, the UPF health studies need further classification to understand the outcomes of UPFs better.
How does this work fit with the existing evidence?
“Findings from this study add to the existing evidence on the negative associations of the consumption of UPFs. However, the separation between animal and plant-based UPFs is misleading, as most studies investigating UPFs would have a similar proportion of plant-based foods included in their analyses if the UPF category also included ‘all products’ such as cakes, industrial bread, confectionery, etc. This is because these products are generally made from plant-sourced ingredients (e.g., flour, plant-based oils, sugar).
“Although the study mentions plant-based meat alternatives (i.e., plant-based sausages, nuggets) in the introduction, there are no strong associations of their findings to these specific products, given that the proportion of the total energy intake was only 0.2% (as reported in Table 2). Previous studies have disaggregated meat alternatives, industrial bread, and cereals from other UPF categories and found contrasting evidence1. This study does not mention the importance of further disaggregating plant-based UPFs to separate specific foods such as plant-based alternatives to meat and dairy, which generally do not have the same nutritional outcomes as other products (i.e. cakes and biscuits). This would be very helpful to further understand which foods are negative for human health.
Have the authors accounted for confounders? Are there important limitations to be aware of?
“The authors have accounted for confounders, particularly nutrients of interest in UPF products such as sodium, fat, and sugar. In the study, the category of plant-based UPFs included various foods such as cakes, biscuits, industrial bread, and meat alternatives to meat and dairy.
What are the implications in the real world? Is there any overspeculation?
“This study may lead to more confusion in the real world. There is already misunderstanding and debate related to the NOVA classification, UPFs, UPF labels, and the healthiness of plant-based alternatives to meat and dairy among technical experts, consumers and other stakeholders. Emerging evidence has shown positive outcomes for plant-based meat alternatives and studies that do not segregate health outcomes from different UPF categories become misleading. Furthermore, the application of the NOVA may be beneficial in certain circumstances, however, in the nutrition/health context NOVA classification to individual food products involves a degree of subjectivity on some concepts that are loosely defined (i.e., “wholesome,” “natural,” “mass-produced,” and “raw”) but do determine whether a food should be labelled as UPFs.”
1 Cordova R, Viallon V, Fontvieille E, et al. Consumption of ultra-processed foods and risk of multimorbidity of cancer and cardiometabolic diseases: a multinational cohort study. Lancet Reg Health Eur. Dec 2023;35:100771. doi:10.1016/j.lanepe.2023.100771.
Dr Hilda Mulrooney, Reader in Nutrition & Health, London Metropolitan University, said:
“It makes very interesting reading. It is impressive in terms of the size of the study and it has used a wide range of statistical methods to demonstrate an effect. It will undoubtedly cause a stir I think. It is an area well worth exploring; I don’t agree with the premise that just because something is ‘plant-based’, it is automatically healthy. However, I also don’t think when people think of ‘plant-based’ they think of bread, cereals etc. I imagine they think more of meat, fish and dairy product alternatives. This study takes all foods and drinks into account, classifying them as either plant or non plant-based; meat alternatives only contribute 0.2% within the UPF plant-based category and meat products only 2.8% within the ultra-processed meat-based category. The greatest contributor to the ultra-processed plant-based foods are not meat alternatives but bread, pastries, buns, cakes, and biscuits, which arguably are not good markers of a plant-based diet, since many people consuming meat will also be consuming those products. I know the study authors take this into account by categorising the foods people in the study consume and then looking at the proportions consumed, but it seems an unusual way of classifying a diet as plant-based. Arguably, high intakes of many of those products are markers of generally poorer diets and are likely to be associated with lower intakes of fruit and vegetables for example. This may well be due to the higher costs relatively speaking of healthier foods like fruit and vegetables; the Food Foundation has done work on this.
“The study remains limited to showing associations and causality cannot be demonstrated. It also relies entirely on the NOVA classification system and a number of concerns about this have been raised – particularly that it assumes that the health implications of a foodstuff are based only on the degree of processing, rather than their nutritional content. For example, breakfast cereals are classed as ultra-processed and therefore should be avoided according to the rationale of the authors, but we know from the NDNS in the UK that breakfast cereals are important contributors to intakes of several nutrients. That being said we don’t have to go far within any supermarket to see examples of breakfast cereals that are far from ideal, so care is needed in making recommendations to the public including parents and carers – but that advice is already out there and that is what dietitians and registered nutritionists do. Although some may assume the message of this study is that all ultra-processed plant-based foods are bad for health, I think that in fact what the evidence in the study actually shows is that poor diets are associated with increased risk of chronic diseases. Too high an intake of any one group of foods is likely to result in imbalance, and I would have far more concern that healthy foods are made more affordable. Consuming lower quality foods is the only option for many people due to cost-of-living pressures.”
Rachel Richardson, Methods Support Unit Manager, Evidence Production and Methods Directorate, Cochrane, said:
“This is an important study and makes a valuable contribution to the research in this field. The nature of this type of research means that it is impossible to randomise people to different interventions, in this case different diets. We cannot therefore be sure that we have accounted for all the factors that may influence health outcomes such as cardiovascular disease. For this reason it will be important that findings such as these are examined further in other studies to build up a evidence base with which we can make health policy decisions.”
Prof Peter Scarborough, Professor of Population Health, University of Oxford, said:
“This paper adds to the growing literature that shows that UPF consumption is associated with poor health. In the introduction and discussion the authors suggest that the findings from this paper show that plant-based meat alternatives are bad for health. However, UPF is a very broad term that captures many food groups. Table 2 in the paper shows that plant-based meat alternatives make up only 0.5% of all the plant-based UPFs included in this paper. The main sources of plant-based UPFs studied in this paper are industrialised packaged breads, pastries, buns, cakes and biscuits (which make up 53% of the plant-based UPFs studied in the paper). It is therefore very difficult to conclude from this paper that plant-based meat alternatives are bad for your health.”
Dr Duane Mellor, Dietitian and Spokesperson for British Dietetic Association; and Honorary Academic Fellow at Aston University, said:
“This is an interesting paper – unfortunately people could possibly assume from the press release that the association with cardiovascular disease risk is specific to meat and dairy replacement plant-based foods such as plant-based sausages, nuggets and burgers. This is not what the paper shows. It explored the effects of all plant based ultra-processed foods – although this included plant-based meat alternatives, these only made up 0.2% of the energy from ultra-processed foods consumed by participants who were followed during the study. The main foods which were considered as plant-based ultra-processed foods were processed baked foods including packaged breads, pastries and cake and biscuits along with crisps and soft drinks.
“So this study possibly highlights the problem that many foods that do not contain animal products, which includes biscuits, crisps, confectionary and soft drinks, are technically plant based but would not be considered essential as part of a healthy diet by the majority of people. So, it is important to emphasise that just because a food or drink is technically plant based, it does not mean it is healthy.
“Therefore this study, which looked at the association between ultra processed foods in the UK Biobank, which included 118,000 people, showed that a dietary pattern high in foods high in fat, salt and sugar was associated with a higher risk of heart disease. It also suggested that a dietary pattern high in fresh, frozen or tinned fruits and vegetables along with legumes and cereals was associated with a lower risk of heart disease. As such this does not really show anything new, only that perhaps we can’t always assume plant-based means healthy, as after all sugar is plant based. What we need to try to do is eat a diet that is mainly vegetables, fruits, legumes, nuts and seeds with wholegrain.
“When looking at how the researchers classified what was ultra-processed and non-ultra-processed in my view this has to cast further doubt on the usefulness of the research – for example, tofu was classified as ultra-processed whereas beer and wine were classed as unprocessed. Tofu can be made at home by soaking and pressing soy beans. Often wine has additives in the form of sulphites and some commercially produced beers contain flaked malted barley which is a processed ingredient (this is before considering no public health expert would suggest that drinking beer and wine as they are not ultra-processed is a good way to improve health!). Overall, this suggests to me a lack of understanding of principles of food production and nutrition in the classification system, as essentially tofu, here classified as ultra-processed can be made in a way similar to cheese which the researchers said was non-ultra-processed.
“If these messages are taken superficially it could suggests drinking beer is associated with lower risk of heart disease than eating tofu – this would go against the other available evidence and in my view would be nutritional nonsense. The importance of a reliable way of classifying ultra-processed foods and plant based foods based on clear criteria based on nutrition and culinary factors is key, as currently the concept of ultra-processed food is dogged by inconsistencies in how foods are classified, risking invalidating the whole concept of ultra-processed foods.”
Prof Gunter Kuhnle, Professor of Nutrition and Food Science, University of Reading, said:
“The results of the latest study on ultra-processed food are not surprising, as “plant-based ultra-processed foods” include foods that are well known to have an adverse effect on health: foods that are high in sugar, fat and salt. The foods included are for example “pastries, buns and cakes”, “confectionary” and “soft drinks” – and their impact on health has been well known before the concept of ultra-processing has been popular.
“This might cause confusion among casual readers, as it could be misunderstood as plant-based alternatives to animal products such as plant-based drinks or meat alternatives. However, these foods appear to contribute only a small amount of total “UPF” intake in this study.
“Unsurprisingly, the study finds an association between the consumption of all plant based UPF, including cakes and pastries, and a higher risk of disease and early death, but it is impossible to attribute this to processing or ultra-processing. It is therefore also not surprising that the consumption of non-ultra-processed plant based food is associated with a reduced risk of disease – because these are mainly fruits and vegetables. In their paper, the authors confirm that food composition is a likely explanation for the observed results.
“There is no unambiguous definition for “ultra-processed foods” and the term is often wrongly used synonymously with “junk food” or food high in fat, salt and sugar. The results of this paper suggest that focusing on composition instead of processing in dietary recommendations is likely to be sufficient.”
Prof Tom Sanders, Professor emeritus of Nutrition and Dietetics, King’s College London, said:
“This new study has attempted to investigate the association between ultra processed plant-based food intake and risk of cardiovascular disease using the UK Biobank data base. Previous research on this data base has found a healthy dietary pattern to be associated with a lower risk of cardiovascular disease, it has also reported that the risk of cardiovascular disease is lower among vegetarians than meat-eaters. This study reports dietary intake assessed more recently on this cohort using two 24-hour dietary recalls and have assessed the intake of ultra-processed food using the Nova classification. It has followed up the participants, who were on average 55 years old, for 9 years and have recorded incident cardiovascular disease.
“The main findings were that the intake of non-ultra-processed plant-based foods was associated with a lower risk of cardiovascular disease whereas the risk was greater with ultra processed plant-based foods. A strength of the study is that it did use two measures of dietary intake. However, what remains concerning is that the individuals who consumed the highest amounts of ultra processed food, were not as fat (lower body mass index) and reported lower intakes of food energy, fat and sugar and higher intake of dietary fibre which is opposite to what might be predicted. These difference in nutrient intake severely question the credibility of dietary data which was obtained by dietary recall and email questionnaires. Unhealthy dietary patterns and lifestyle are strongly associated with social factors which have a huge influence on risk of cardiovascular disease. Those who consumed the highest amount of ultra processed food differed were more like to be smokers/ex-smokers, to have higher levels of physical activity, more likely to live in London. The statistical analysis has made some adjustments for these confounding factors. However, a major weakness is the use of postcode to measure deprivation. Previous studies on this cohort have used the Townsend Index which is more robust and includes non-home ownership, non-car ownership, household overcrowding and unemployment. Other social factors such as men living alone also have not been considered.
“The main source of ultra processed food reported were bread, cakes, biscuits, confectionery, deep fried potatoes products and margarine. Industrially produced bread (mainly white) has accounted for most bread consumed in the UK for the past fifty years, over which period cardiovascular disease incidence has fallen by 70%. It is, therefore, unlikely that industrially produced bread has anything to do with risk of CVD, especially as salt levels are now only around 0.9 g/100g compared with 1.8 g/100g in the 1970s. Margarine in the UK contains less saturated fat than butter and has been virtually free from trans fatty acids since about 2000 and thus unlikely to contribute to risk. As a nutritionist I find the term “plant-based ultra processed food” confusing and not helpful in formulating dietary advice to the public. It is well accepted that well-balanced plant-based diets such as the Mediterranean or DASH diets are favourable for cardiovascular health and these already emphasise avoiding unhealthy foods such as crisps etc., sugar sweetened beverages, cakes, biscuits and confectionary. These latter foods are unhealthy regardless of whether they are made industrially or home-made.”
‘Implications of food ultra-processing on cardiovascular risk considering plant origin foods: an analysis of the UK Biobank cohort’ by Fernanda Rauber et al. was published in The Lancet Regional Health – Europe at 23:30 UK time on Monday 10 June 2024.
DOI: 10.1016/j.lanepe.2024.100948
Declared interests
Sarah Nájera Espinosa, Dr Pauline Scheelbeek, and Prof Rosie Green: “No conflicts to declare.”
Dr Hilda Mulrooney: “I have no conflicts of interest to declare.”
Rachel Richardson: “No conflicts of interest for me. No conflicts of interest either from Cochrane – we’re an independent international non-profit and we do not accept commercial or conflicted funding. More info here – www.cochrane.org/about-us.”
Prof Peter Scarborough: “I am currently funded by ESRC, Wellcome Trust and NIHR to conduct research on healthy, sustainable diets. I don’t have any conflicts of interest to declare.”
Dr Duane Mellor: “I have discussed and been a consultant about the concept of UPF for EUFIC, APPGs (both unpaid as part of my previous academic role) and members of the food industry (including Mars and Danone as a paid independent consultant).”
Prof Gunter Kuhnle: “https://kuhnle.co.uk/coi.html
Employment
Research funding
Committee membership
Scientific organisations
Others
Prof Tom Sanders: “Member of the Science Committee British Nutrition Foundation. Honorary Nutritional Director HEART UK.
Before my retirement from King’s College London in 2014, I acted as a consultant to many companies and organisations involved in the manufacture of what are now designated ultraprocessed foods.
I used to be a consultant to the Breakfast Cereals Advisory Board of the Food and Drink Federation.
I used to be a consultant for aspartame more than a decade ago.
When I was doing research at King’ College London, the following applied: Tom does not hold any grants or have any consultancies with companies involved in the production or marketing of sugar-sweetened drinks. In reference to previous funding to Tom’s institution: £4.5 million was donated to King’s College London by Tate & Lyle in 2006; this funding finished in 2011. This money was given to the College and was in recognition of the discovery of the artificial sweetener sucralose by Prof Hough at the Queen Elizabeth College (QEC), which merged with King’s College London. The Tate & Lyle grant paid for the Clinical Research Centre at St Thomas’ that is run by the Guy’s & St Thomas’ Trust, it was not used to fund research on sugar. Tate & Lyle sold their sugar interests to American Sugar so the brand Tate & Lyle still exists but it is no longer linked to the company Tate & Lyle PLC, which gave the money to King’s College London in 2006.”