Study Compares Low-Fat With Plant-Centered Diets for CVD

There has been a long-standing debate on whether a low-fat or a plant-centered diet is better at lowering the risk of CVD. A new study that followed more than 4,700 people over 30 years found that a plant-centered diet was associated with a lower long-term risk of CVD. However, both diets were linked with lower LDL cholesterol levels.

“Since 1980, dietary guidelines in the United States and in Europe have recommended eating low amounts of saturated fat because of the high rates of heart disease in these regions,” says research team leader David Jacobs, PhD, from the University of Minnesota. “This isn’t necessarily wrong, but our study shows that plant-centered diets also can lower bad cholesterol and may be even better at addressing heart disease risk.”

The plant-centered diet emphasizes fruit, vegetables, legumes, whole grains, nuts and seeds, low-fat dairy, and fish. It also limits high-fat red and processed meats, salty snacks, sweets, and sugar-sweetened soft drinks. The low-fat diet is based on the Keys Score, which measures saturated fat, polyunsaturated fat, and cholesterol in the diet.

Yuni Choi, PhD, a postdoctoral fellow in Jacobs’ lab, presented the research as part of NUTRITION 2021 LIVE ONLINE, a virtual conference hosted by the American Society for Nutrition.

“Our findings show that it’s important to view diet quality from a holistic perspective,” Choi says. “Targeting just single nutrients such as total or saturated fat doesn’t take into account the fats that are also found in healthful plant-based foods such as avocado, extra-virgin olive oil, walnuts, and dark chocolate—foods that also have cardioprotective properties and complex nutrient profiles.”

The new research is based on participants in the four US clinics of the Coronary Artery Risk Development in Young Adults study, which enrolled 5,115 Black and white men and women in 1985 and 1986. During more than 30 years of follow-up, there were 280 cases of CVD, 135 cases of coronary heart disease, and 92 cases of stroke among the study participants.

To assess eating patterns, the researchers conducted three detailed diet history interviews over the follow-up period. These diet history questionnaires determined what participants ate and then asked them to list everything consumed in that category. For example, participants who reported eating meat in the past 30 days would be asked what meat items and how much they consumed. This was repeated for around 100 areas of the diet. Based on this information, the researchers calculated scores for all participants derived from both the Keys Score and the A Priori Diet Quality Score (APDQS), which captured the plant-centered diet.

After accounting for various factors including socioeconomic status, educational level, energy intake, history of CVD, smoking, and BMI, the researchers found that having a more plant-centered diet (higher APDQS Scores) and consuming less saturated fat (lower Keys Scores) were both associated with lower LDL levels. However, lower LDL levels didn't necessarily correlate with lower future risk of stroke. Higher APDQS scores, but not lower Keys Scores, were strongly associated with a lower risk of coronary heart disease and stroke.

“Based on our study, we suggest people incorporate more nutritionally rich plant foods into their diets,” Choi says. “One way to do this is to fill 70% of your grocery bag with foods that include vegetables, fruits, whole grains, nuts, legumes, coffee, and tea.”

The researchers are carrying out a variety of studies looking at how the APDQS diet score relates to various health outcomes. They're also interested in studying how different diets affect gut bacteria, which are known to influence many aspects of health and disease.

— Source: American Society for Nutrition