October 30, 2023—The portfolio diet—a plant-based diet designed to lower unhealthy cholesterol, emphasizing plant proteins (legumes), phytosterols (nuts and seeds), viscous fiber (oats, barley, berries, apples), and plant-based monounsaturated fatty acids (avocado)—may lower the risk of heart disease and stroke, according to a new study co-authored by researchers at Harvard T.H. Chan School of Public Health.
The study was published on October 25 in Circulation.
While previous studies have pointed to the portfolio diet’s potential to lower unhealthy cholesterol, no research had been conducted on the diet’s long-term effects, particularly on the risk of heart disease. Additionally, according to Andrea Glenn, postdoctoral research fellow in the Department of Nutrition and one of the study’s authors, the portfolio diet is relatively unknown compared to the DASH and Mediterranean diets. While the three are similar, the portfolio diet places more emphasis on plant-based foods and excluding meat.
To fill these gaps, the researchers examined data on the diets of 210,240 adults who enrolled in long-term health studies in the mid-1980s and early 1990s. The participants—none of whom had heart disease at the start of the studies—completed questionnaires about their diets every four years, while their various health outcomes were recorded. The researchers gave each participant’s diet a score based on its compliance with the portfolio diet, then compared the scores with health outcomes after 30 years of follow-up. They found that those with higher scores, indicating higher adherence to the portfolio diet, had a 14% lower risk of heart disease and stroke compared to participants with lower scores.
In an October 25 article about the study, Glenn told the American Heart Association that she hopes more attention will soon be paid to the portfolio diet.
“It’s not an all-or-nothing approach. You can take your own diet and make a few small changes and see cardiovascular benefits,” Glenn said. “You also do not have to follow it as a strict vegan or vegetarian diet to see benefits, but the more of the foods (from the portfolio diet) that you eat, the greater your heart disease risk protection, as we saw in the current study. We need to get the word out.”
Other Harvard Chan co-authors included JoAnn Manson and Eric Rimm, professors in the Department of Epidemiology, and members of the Department of Nutrition: Marta Guasch-Ferre, adjunct associate professor; Vasanti Malik, adjunct assistant professor; Walter Willett, professor; Qi Sun, associate professor; and Frank Hu, professor and department chair.
Read the American Heart Association article: Ever heard of the portfolio diet? It may lower risk for heart disease and stroke