Not All Plant-Based Diets Protect the Heart—Study Reveals the Critical Difference

A large-scale study has found that not all plant-based diets protect against heart disease. Researchers tracked over 63,000 French adults for more than nine years, revealing stark differences in cardiovascular risk based on food quality and processing. The results challenge the assumption that simply eating plant foods guarantees better heart health.

The study, published in The Lancet Regional Health - Europe, analysed data from 63,835 participants in the NutriNet-Santé cohort. Over an average of 9.1 years, those who ate mostly high-quality, minimally processed plant foods—such as fresh fruits, vegetables, and whole grains—showed a 40% lower risk of cardiovascular disease.

By contrast, adults whose diets relied on low-quality, ultra-processed plant foods—like industrial breads, ready meals, and sugary snacks—faced a 40% *higher* risk compared to those eating minimally processed options. Even processed foods marketed as healthy, such as store-bought wholemeal breads or canned soups, failed to reduce heart risks when compared to diets containing more animal products. The findings highlight that the benefits of plant-based eating depend on more than just avoiding meat. Nutritional quality and processing levels played a decisive role, with whole, unprocessed foods offering the strongest protection. This aligns with recent updates to global dietary guidelines, including the WHO's 2023 emphasis on nuts and legumes and the American Heart Association's 2021 warning against ultra-processed foods. The research suggests that a balanced diet—considering both plant and animal sources, along with food processing—is key to lowering cardiovascular risk.

The study underscores that plant-based diets are not inherently heart-healthy unless they prioritise whole, minimally processed foods. Ultra-processed alternatives, even those labelled as nutritious, provided no clear advantage over diets with more animal products. These results reinforce current guidelines urging reduced intake of processed foods for long-term cardiovascular protection.