Activity: Competency Development

Gehring J, Touvier M, Baudry J, Julia C, Buscail C, Srour B, et al. Consumption of Ultra-Processed Foods by Pesco-Vegetarians, Vegetarians, and Vegans: Associations with Duration and Age at Diet Initiation. The Journal of Nutrition. 2020;151(1):120-31. 

Relevant to: 

All Dietitians-Nutritionists.   

Question: 

This study assessed the intake of ultra-processed foods (UPFs) and unprocessed foods within a group of meat eaters and vegetarians (pesco-vegetarians, vegetarians, and vegans) in France. The nutritional quality of the plant-based foods was also assessed, as well as the determinants of UPF consumption for the vegetarians.  

Bottom line for nutrition practice: 

In this study, vegetarians – and even moreso, vegans – consumed more energy from ultra-processed foods (UPFs) than meat eaters. This was driven particularly through the consumption of commercial plant-based meat and dairy alternatives, but vegetarians also had a higher UPF intake through the consumption of salty snacks and biscuits. On the other hand, the proportion of energy from unprocessed foods was higher for vegetarians than for meat eaters, and vegetarians also had lower intakes of alcoholic beverages and sweet and fatty foods.  

 The study showed that consuming UPFs is linked to a lower intake of whole plant-based foods, and could therefore decrease the nutritional quality of the diet. Those who had been vegetarians for a shorter time or had a young age when initiating the diet had an increased consumption of UPFs. In this study, vegetarians demonstrated a diversity of diets (e.g., differing in their intake of UPFs, and in the nutritional quality of their choices). The results show that all plant-based diets are not equally beneficial to health; the health benefits of a plant-based diet could be compromised if diets are composed of a high amount of processed foods. The authors therefore recommend guidelines for vegetarians and vegans to limit their consumption of UPFs, similar to those recommended for the general population.  

Abstract: 

Background: There is a growing availability of industrial plant-based meat and dairy substitutes that can be classified as ultra-processed foods (UPFs). Very little is known about the consumption of UPFs by vegetarians. 
Objective: The aim of this cross-sectional study, from the NutriNet-Santé cohort, was to describe the contribution of UPFs to different vegetarian diets, in relation to the nutritional quality of their diet, and determinants of UPF consumption, including duration and age at vegetarian diet initiation. 
Methods: The study population (n = 21,212) was divided into 4 groups: 19,812 meat eaters, 646 pesco-vegetarians, 500 vegetarians, and 254 vegans. Daily food intakes were collected using repeated 24-h dietary records. Vegetarian diets were described by the proportion of energy from UPFs and the nutritional quality of the diet using healthy and unhealthy plant-based diet indices (PDIs). In a subsample without meat eaters (n = 1,400), a multivariable linear regression model was performed to study the association between UPF consumption and its determinants. 
Results: Higher avoidance of animal-based foods was associated with a higher consumption of UPFs (P < 0.001), with UPFs supplying 33.0%, 32.5%, 37.0%, and 39.5% of energy intakes for meat eaters, pesco-vegetarians, vegetarians, and vegans. The nutritional quality of diets was also associated with the level of animal-based foods avoidance (P < 0.001), with healthy PDIs at 53.5, 60.6, 61.3 and 67.9 for meat-eaters, pesco-vegetarians, vegetarians, and vegans. Short duration and young age at diet initiation were associated with an increased consumption of UPFs (βage at initiation = −0.003, P = 0.001; βduration = −0.002, P < 0.001). 
Conclusions: Not all vegetarian diets necessarily have health benefits, because of potential adverse effects of UPFs on nutritional quality and healthiness of diet. UPF consumption by vegetarians and their diet characteristics should be considered in future studies on the links between vegetarianism and health.  

Details of results: 

The authors used a cross-sectional design of over 20,000 adults sampled from the French NutriNet-Santé (a French prospective observational cohort launched in May 2009). Participants were classified into four groups according to their diets: meat eaters, pesco-vegetarians, vegetarians, and vegans.  

Foods were classified by the NOVA categories “ultra-processed foods” (UPFs) and “unprocessed or minimally processed foods” (see “of additional interest” for more details). The NOVA UPFs include a wide range of foods from industrial plant-based substitutes such as vegetable patties or nuggets and plant-based dairy alternatives to packaged snacks, frozen or shelf-stable ready to eat meals, sweetened beverages, and foods made predominantly from sugar and fat. Foods were further classified by “healthy” and “unhealthy” plant-based diet indices (PDI), which assessed the nutritional quality of the foods.  

Each participant was assigned a UPF indicator related to the proportion of energy from UPFs in the diet, as well as an indicator related to the proportion of energy from unprocessed foods. Within the group of vegetarians, the authors separated out the contribution of plant-based meat and dairy alternatives to their UPF intake (i.e., textured soy protein foods, vegetarian patties, and plant-based drinks). Participants were also assigned healthy PDI and unhealthy PDI scores.  
 
All vegetarian groups except for pesco-vegetarians had a higher energy intake from UPFs than meat eaters, whose UPF intake was 33% of total energy consumed. Vegans were particularly high at 39.5% of total energy consumed. Within the group of vegetarians, vegans by far consumed the most industrial plant-based milk or dairy substitutes. Vegans also had a significantly higher percentage of total energy intake from unprocessed foods (31.2%) than meat eaters (29.0%).   

When examined through the lens of a plant-based nutrition index, the study found that average healthy PDI and unhealthy PDIs scores were both significantly higher for vegetarians than meat eaters. This suggests that a higher number of vegans and vegetarians favoured unhealthy plant-based foods over healthy plant-based foods than meat eaters, but that they also favoured healthy plant-based foods over unhealthy plant-based foods. The authors suggest that this somewhat contradictory result illustrates the heterogeneity of the diets of the vegetarians studied. When the proportion of energy from UPFs was correlated with the healthy and unhealthy diet indices, results demonstrated that when UPF intake increased, the unhealthy diet index increased and the healthy diet index decreased.  

The authors suggest that the observed increased consumption of UPFs for those who had been vegetarians for a shorter time or had initiated the diet at a young age might be explained by previous studies showing that vegetarians seem to include healthier plant based foods over time. The authors conclude by suggesting that all plant-based diets are not equally beneficial to health; the health benefits of a plant-based diet could be compromised if diets are composed of a high amount of processed foods.  

Of additional interest: 

The four NOVA levels of food by level of processing include: 1. Unprocessed and minimally processed foods; 2. Processed culinary ingredients; 3. Processed foods; and 4. Ultra-processed foods. 

For more information on the NOVA classification see: Monteiro, C.A., Cannon, G., Lawrence, M., Costa Louzada, M.L. and Pereira Machado, P.2019. Ultra-processed foods, diet quality, and health using the NOVA classification system. Rome, FAO. http://www.fao.org/3/ca5644en/ca5644en.pdf 

Editor’s comment:  

While this study focused on vegetarians, some of the findings are relevant to those following a plant-based diet – in particular, the need to limit the consumption of UPFs.  

Additionally, while the study noted that the higher intake of UPFs by vegetarians and vegans was driven by a higher consumption of plant-based meat and dairy substitutes, it is important to note that not all meat and dairy alternatives are equally healthy (or unhealthy). Dietitians-Nutritionists can assist the population to choose the healthiest alternatives among these processed products. 

Open access link to article: 

N/A 

Conflict of interest/ Funding:  

No conflicts reported 

External relevant links:  

Corresponding author: 

b.alles@eren.smbh.univ-paris13.fr