New study shows some plant-based diets may raise heart disease risk

When plant foods are ultra-processed, the advantage disappears—and can even backfire

INRAE - National Research Institute for Agriculture, Food and Environment

Previous studies have indicated that eating large amounts of ultra-processed foods^[1] is linked with a higher likelihood of developing cardiovascular diseases. Other research^[2] has found that diets centered on plant-based foods can lower this risk when those foods offer balanced nutrition and are consumed in appropriate proportions.

To explore how nutrition relates to cardiovascular health in more detail, scientists from INRAE, Inserm, Université Sorbonne Paris Nord, and Cnam examined more than whether foods came from plant or animal sources. Their assessment also incorporated the nutritional makeup of foods, including factors such as carbohydrate, fat, and antioxidant vitamin and mineral content, along with the level of industrial processing involved.

How the Study Evaluated Diets and Food Choices

The team evaluated data from 63,835 adults enrolled in the French NutriNet-Santé cohort. Participants were followed for an average of 9.1 years, with some tracked for as long as 15 years. Information on what they ate and drank (collected over at least three days) was gathered through online questionnaires. This detailed approach allowed researchers to classify diets based on the share of plant-based and animal-based foods, while also considering both nutritional quality and processing level.

The findings showed that adults who consumed more plant-based foods of higher nutritional quality (lower in fat, sugar, and salt) and with minimal industrial processing had about a 40 percent lower risk of cardiovascular disease compared with those who ate fewer nutritious plant-based foods and more animal-based products^[3].

However, people who ate larger amounts of plant-based foods that were nutritionally higher quality but ultra-processed, including items such as industrial whole meal breads, store-bought soups, ready-made pasta dishes, or commercially prepared salads with dressing, did not experience a reduced cardiovascular risk relative to individuals who consumed fewer of these products and more animal-based foods.

Ultra-Processed Plant Foods and Increased Heart Disease Risk

A notably higher risk emerged for adults whose diets were dominated by plant-based foods that were both lower in nutritional quality and ultra-processed. These items included crisps, sweetened fruit drinks or sodas made from plant extracts, chocolate-based sweets or confectionery, sugary breakfast cereals, and savory biscuits. Their cardiovascular disease risk was roughly 40 percent higher than that of people who consumed more plant-based foods of good nutritional quality with little or no industrial processing.

Why Processing Level Matters for Plant-Based Eating

Overall, the results show that understanding the relationship between diet and cardiovascular health requires considering the nutritional quality of foods and how heavily they are processed, in addition to the balance of plant-based and animal-based components. These findings support public health recommendations that encourage the consumption of plant-based foods that are both nutritionally high quality and minimally processed (such as fresh, frozen, or high-quality canned fruits and vegetables without added fats, salt, sugar, or additives).

Notes

[1] According to the NOVA classification, these are foods that have undergone significant biological, chemical, or physical processing (such as extrusion, pre-frying, hydrolysis, or ultra-high-temperature heating), and/or whose formulation includes certain food additives not necessary for the product's food safety (such as colourings, emulsifiers, or sweeteners), or industrial substances such as hydrogenated oils, glucose/fructose syrup, hydrolysed proteins and inverted sugar.

[2] Rauber F., da Costa Louzada M.L., Chang C. et al. (2024). Implications of food ultra-processing on cardiovascular risk considering plant origin foods: an analysis of the UK biobank cohort. The Lancet Regional Health-Europe, DOI: https://doi.org/10.1016/j.lanepe.2024.100948 Daas M.C., Vellinga R.E., Pinho M.G.M. et al. (2024). The role of ultra-processed foods in plant-based diets: associations with human health and environmental sustainability. European Journal of Nutrition. DOI: https://doi.org/10.1007/s00394-024-03477-w

[3] That is, with a consumption of about 280 g per day of fruits and vegetables -- half the recommendation of the French National Health and Nutrition Plan (PNNS) -- 54.1 g per day of red meat (about 380 g per week),

The NutriNet-Santé study is a public health initiative coordinated by the Nutritional Epidemiology Research Team (CRESS-EREN, Inserm/INRAE/Cnam/Université Sorbonne Paris Nord/Université Paris Cité). Thanks to the commitment and long-term participation of over 180,000 "nutrinauts," the study is helping advance research into the links between nutrition (diet, physical activity, nutritional status) and health. Launched in 2009, it has already led to over 300 international scientific publications. Recruitment of new participants is ongoing, to continue supporting public research into the relationship between nutrition and health.

By spending just a few minutes each month on the secure platform etude-nutrinet-sante.fr to complete questionnaires on diet, physical activity, and health, participants are helping build knowledge toward healthier and more sustainable eating habits.