Plant-based diets are recommended to reduce the risk of heart disease; however, some plant-based diets are associated with a higher risk of heart disease, according to a study published today in the Journal of the American College of Cardiology.
In prior studies of the impact of a plant-based diet, there were several limitations. Plant-based diets were defined as "vegetarian" which consist of a variety of dietary patterns that exclude some or all animal foods. These studies treat all plant foods equally, even though certain plant foods like refined grains and sugar sweetened beverages are associated with a higher risk of cardio-metabolic disease.
To overcome these limitations, the researchers created three versions of a plant-based diet: an overall plant-based diet which emphasized the consumption of all plant food and reduced (but did not eliminate) animal food intake; a healthful plant-based diet that emphasized the intake of healthy plant foods such as whole grains, fruits and vegetables; and an unhealthful plant-based diet which emphasized consumption of less healthy plant foods such as refined grains.
Researchers used a baseline sample of 73,710 women from the Nurses' Health Study, 92,320 women from the Nurses' Health Study 2 and 43,259 men from the Health Professionals Follow-Up Study. These participants responded to a follow-up questionnaire every two years for over two decades on lifestyle, health behaviors and medical history. Participants with coronary heart disease at baseline were excluded, as were participants with cancer, stroke and coronary artery surgery.
During follow-up, 8,631 participants developed coronary heart disease. Overall, adherence to a plant-based diet was associated with a lower risk of heart disease. A higher intake of a more healthful plant-based diet one rich in whole grains, fruits, vegetables, etc. was associated with a substantially lower risk of heart disease. However, a plant-based diet that emphasized less healthy plant foods like sweetened beverages, refined grains, potatoes and sweets had the opposite effect.