For adults both young and old, eating a nutritious, plant-based diet may lower the risk for heart attacks and other types of cardiovascular disease, two new studies show.

Both studies published Wednesday in the Journal of the American Heart Association. One found eating a plant-centered diet in young adulthood lowered the risk in middle age for heart attack, stroke, heart failure and several other cardiovascular conditions. A second found eating plant-based foods that lower cholesterol levels reduced the risk of heart disease in postmenopausal women.

While the research underscores the importance of eating more fruits and vegetables, it doesn't suggest strict vegetarianism is necessary to reap heart-healthy benefits.

"People can choose among plant foods that are as close to natural as possible, not highly processed," lead author of the young adult study, Yuni Choi, said in a news release. Choi is a postdoctoral researcher in the division of epidemiology and community health at the University of Minnesota School of Public Health in Minneapolis. "We think that individuals can include animal products in moderation from time to time, such as non-fried poultry, non-fried fish, eggs and low-fat dairy."

Choi and her team analyzed diet and cardiovascular disease occurrence in 4,946 adults, ages 18 to 30, enrolled in the Coronary Artery Risk Development in Young Adults (CARDIA) study. Information about participants' diets was collected through interviews, and they were not told what to eat.

Based on what is known about their link to cardiovascular disease risk, foods such as fruits, vegetables, beans, nuts and whole grains were considered beneficial, while those such as fried potatoes, high-fat red meat, salty snacks, pastries and soft drinks were considered adverse. Neutral foods included refined grains, lean meats and shellfish.

Those who ate a more beneficial, plant-centered diet, with fewer foods considered adverse, were 52% less likely to develop cardiovascular disease during about 30 years of follow-up.

Those whose diets improved the most as they got older were 61% less likely to develop cardiovascular disease than those whose diets worsened the most.

"Earlier research was focused on single nutrients or single foods, yet there is little data about a plant-centered diet and the long-term risk of cardiovascular disease," Choi said.

In a separate study, researchers analyzed the diets of 123,330 women enrolled in the Women's Health Initiative who were scored on their adherence to eating foods considered part of the "Portfolio Diet," already known to lower "bad" LDL cholesterol. The diet includes nuts; plant protein from soy, beans or tofu; viscous soluble fiber from oats, barley, okra, eggplant, oranges, apples and berries; plant sterols from enriched foods and monounsaturated fats found in olive oil, canola oil and avocado. It also allows a limited amount of saturated fats and dietary cholesterol.

The women, who were between 50 and 79 when they enrolled in the study, were followed for 15 years.

Postmenopausal women who ate the most of these foods were 11% less likely to develop cardiovascular disease of any kind and 14% less likely to develop coronary heart disease, in which plaque builds up in the walls of the arteries leading to the heart. They were 17% less likely to develop heart failure, which occurs when the heart can't pump blood as well as it should. The diet didn't appear to affect stroke risk.

"We also found a dose response in our study, meaning that you can start small, adding one component of the Portfolio Diet at a time, and gain more heart-health benefits as you add more components," lead author Andrea J. Glenn said in the release. Glenn is a registered dietitian and doctoral student in nutritional sciences at the University of Toronto.

The study's senior author, Dr. John Sievenpiper, said in the release that "with even greater adherence to the Portfolio dietary pattern, one would expect an association with even less cardiovascular events, perhaps as much as cholesterol-lowering medications." Sievenpiper is an associate professor of nutritional sciences and medicine at the University of Toronto.

"Still," he said, "an 11% reduction is clinically meaningful and would meet anyone's minimum threshold for a benefit."

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