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Eating a mostly plant-based diet linked to lower risk of cardiovascular disease

The study’s participants come from four U.S. communities, including Minneapolis.

Devoting a greater proportion of our diet to foods derived from plants and a smaller proportion to foods derived from animals may help us live healthier and longer lives.
Photo by Dan Gold on Unsplash

Middle-aged people who eat mostly plant-based foods are at reduced risk of developing cardiovascular disease, including heart attack and stroke, later in life, according to a study published in the Journal of the American Heart Association.

They are also likely to live longer than their peers who consume fewer fruits and vegetables.

This study isn’t the first to make such findings. But it is one of the first to examine the effects of a plant-based diet on cardiovascular health in a general population. Most previous studies that have linked plant-based diets to better heart health have involved people who are vegetarians or vegans.

“Not everyone is going to go vegetarian,” pointed out Lyn Steffen, one of the study’s authors and an associate professor of epidemiology and community health at the University of Minnesota, in an interview with MinnPost.

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The new study suggests we don’t have to, she added. It suggests instead that devoting a greater proportion of our diet to foods derived from plants (fruits, vegetables, nuts, legumes and whole grains) and a smaller proportion to foods derived from animals (meat, eggs, dairy products and seafood) may help us live healthier and longer lives.

Cardiovascular disease — sometimes just called heart disease — is the leading cause of death in both men and women in the United States, killing more than 610,000 people each year. It is also a major cause of disability in the country.

How the study was done

For their study, Steffen and her colleagues analyzed data collected from 12,168 middle-aged participants in the Atherosclerosis Risk in Communities (ARIC) study, a long-running research project funded by the National Heart, Lung and Blood Institute. Those participants come from four U.S. communities, including Minneapolis.

Lyn Steffen
Lyn Steffen
The data included health information on the participants from the time they joined ARIC in the late 1980s, when they were aged 45 to 64, until 2017, when they were in the 70s, 80s or 90s. At the start of the study, none had cardiovascular disease.

The participants filled out a lengthy dietary questionnaire at enrollment and then again at their third follow-up session, which was around five years later. The researchers took the information from those questionnaires to score the quality of each participant’s diet. They assessed the diets using four different dietary indexes. In general, the more plant-based foods consumed, the higher the score.

The use of those indexes is important because not all plant-based diets are healthy. Filling up on French fries and tortilla chips isn’t the same as eating broccoli and blueberries.

“Just because someone says they’re a vegetarian doesn’t mean that they’re eating a healthy vegetarian diet,” said Steffen, “although I must say it’s probably healthier than people who are eating a lot of meat.”

Key findings

Over the three decades of the study, 5,436 of the participants died, including 1,564 from cardiovascular disease. A total of 4,381 of the participants had some kind of cardiovascular “event,” such as a heart attack or stroke, or were diagnosed with coronary heart disease.

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The researchers looked to see if there were any associations between those illnesses and deaths and the participants’ dietary scores. They found that compared with the people who scored in the bottom 20 percent of the dietary indexes, those who scored in the top 20 percent — in other words, those who ate the greatest proportion of plant-based foods — were 16 percent less likely to have developed cardiovascular disease.

They were also 32 percent less likely to have died from a cardiovascular disease and 25 percent less likely to have died from any cause.

The study also found that a higher consumption of meat and other animal-based foods was linked to an increased risk of all three outcomes.

“Results from our study suggest that progressively increasing the intake of plant foods by reducing the intake of animal foods is associated with benefits on cardiovascular health and mortality risk,” the study’s authors conclude.

Limitations and implications

This research was observational, so it can’t prove that plant-based diets offer protection against heart disease. Other factors may explain the results. It could be, for example, that people who eat more plant-based foods are more likely to have additional healthy behaviors, such as regular exercise.

Furthermore, the findings are based on self-reported accounts of dietary habits, and such reports are prone to error.

Still, as Steffen and her co-authors explain in their paper, the study’s findings are in line with a growing body of other research that supports the health benefits of a plant-based diet. Earlier this month, for example, researchers reported in JAMA Internal Medicine that eating a plant-based diet was associated with a lower risk of developing type 2 diabetes.

“There have been lots and lots of studies out there that show consuming more fruits and vegetables and whole grains and less meat products — particularly red and processed meat — are related to a lower risk of cardiovascular disease,” said Steffen.

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And although this study suggests you don’t have to give up on meat altogether, it does support making it a much smaller proportion of your daily diet.

In the study, the people who had the healthiest diets — whose risk of death from cardiovascular disease was a third lower than those with the unhealthiest diets — consumed, on average, four to five servings of fruits and vegetables daily and less than an ounce of meat a day.

An ounce of meat is a very small amount — one-fourth cup tuna or ground beef, one-half small chicken leg or thigh, or a matchbox-sized piece of steak or ham.

Of course, eating more plant-based foods and fewer animal-based ones is not all that’s required of a heart-healthy lifestyle. We should also make sure our diets are low in sugar and sodium (salt), said Steffen.

“And, of course, get out there and walk around the block,” she added.

FMI: You can read the study on the Journal of the American Heart Association’s website. For specific tips on how to make your diet more heart healthy, go to the AHA’s website.