Eating more nutritious, plant-based foods is heart-healthy at any age, according to two research studies published today in the Journal of the American Heart Association, an open access journal of the American Heart Association.

In two separate studies analyzing different measures of healthy plant food consumption, researchers found that both young adults and postmenopausal women had fewer heart attacks and were less likely to develop cardiovascular disease when they ate more healthy plant foods.

The American Heart Association Diet and Lifestyle Recommendations suggest an overall healthy dietary pattern that emphasizes a variety of fruits and vegetables, whole grains, low-fat dairy products, skinless poultry and fish, nuts and legumes and non-tropical vegetable oils. It also advises limited consumption of saturated fat, trans fat, sodium, red meat, sweets and sugary drinks.

Researchers examined diet and the occurrence of heart disease in 4,946 adults enrolled in the Coronary Artery Risk Development in Young Adults (CARDIA) study. Participants were 18- to 30-years-old at the time of enrollment (1985-1986) in this study and were free of cardiovascular disease at that time. Participants included 2,509 Black adults and 2,437 white adults (54.9% women overall) who were also analyzed by education level (equivalent to more than high school vs. high school or less). Participants had eight follow-up exams from 1987-88 to 2015-16 that included lab tests, physical measurements, medical histories and assessment of lifestyle factors. Unlike randomized controlled trials, participants were not instructed to eat certain things and were not told their scores on the diet measures, so the researchers could collect unbiased, long-term habitual diet data.

After detailed diet history interviews, the quality of the participants diets was scored based on the A Priori Diet Quality Score (APDQS) composed of 46 food groups at years 0, 7 and 20 of the study. The food groups were classified into beneficial foods (such as fruits, vegetables, beans, nuts and whole grains); adverse foods (such as fried potatoes, high-fat red meat, salty snacks, pastries and soft drinks); and neutral foods (such as potatoes, refined grains, lean meats and shellfish) based on their known association with cardiovascular disease.

Participants who received higher scores ate a variety of beneficial foods, while people who had lower scores ate more adverse foods. Overall, higher values correspond to a nutritionally rich, plant-centered diet.

Researchers found:

• During 32 years of follow-up, 289 of the participants developed cardiovascular disease (including heart attack, stroke, heart failure, heart-related chest pain or clogged arteries anywhere in the body).

• People who scored in the top 20% on the long-term diet quality score (meaning they ate the most nutritionally rich plant foods and fewer adversely rated animal products) were 52% less likely to develop cardiovascular disease, after considering several factors (including age, sex, race, average caloric consumption, education, parental history of heart disease, smoking and average physical activity).

• In addition, between year 7 and 20 of the study when participants ages ranged from 25 to 50, those who improved their diet quality the most (eating more beneficial plant foods and fewer adversely rated animal products) were 61% less likely to develop subsequent cardiovascular disease, in comparison to the participants whose diet quality declined the most during that time.

• There were few vegetarians among the participants, so the study was not able to assess the possible benefits of a strict vegetarian diet, which excludes all animal products, including meat, dairy and eggs.

The study analyzed whether postmenopausal women who followed the Portfolio Diet experienced fewer heart disease events. The study included 123,330 women in the U.S. who participated in the Women's Health Initiative, a long-term national study looking at risk factors, prevention and early detection of serious health conditions in postmenopausal women. When the women in this analysis enrolled in the study between 1993 and 1998, they were between 50-79 years old (average age of 62) and did not have cardiovascular disease. The study group was followed until 2017 (average follow-up time of 15.3 years). Researchers used self-reported food-frequency questionnaires data to score each woman on adherence to the Portfolio Diet.

The researchers found:

• Compared to women who followed the Portfolio Diet less frequently, those with the closest alignment were 11% less likely to develop any type of cardiovascular disease, 14% less likely to develop coronary heart disease and 17% less likely to develop heart failure.

• There was no association between following the Portfolio Diet more closely and the occurrence of stroke or atrial fibrillation.

The researchers believe the results highlight possible opportunities to lower heart disease by encouraging people to consume more foods in the Portfolio Diet.

Although the study was observational and cannot directly establish a cause-and-effect relation between diet and cardiovascular events, researchers feel it provides a most reliable estimate for the diet-heart relation to-date due to its study design (included well-validated food frequency questionnaires administered at baseline and year three in a large population of highly dedicated participants). Nevertheless, the investigators report that these findings need to be further investigated in additional populations of men or younger women.