Eat more plant‐based food, less meat, for better heart health

By Dr. Liji Thomas, MDAug 12 2019

What many scientists been saying for decades turns out to be most likely true, according to a recent study that looked at diet. Eating more food from the plant category and less animal-based food could benefit your heart and reduce your odds of dying of a stroke.

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The current research looked at data on eating habits from a study called the ARIC (Atherosclerosis Risk in Communities) study that involved over 10,000 US adults of middle age, gathered over 30 years. None of the participants had any cardiovascular disease at their entry into the study.

The data was then stratified based on the relative proportion of plant-based and animal-based foods. This was compared to the subsequent development of cardiovascular disease, including stroke and heart attacks, and heart failure.

The analysis of dietary patterns used four indices: the overall plant-based diet index, the provegetarian diet index, the health plant-based diet index, and the less healthy plant-based index. The scoring was as follows: in the first two, participants got higher scores if they ate more plant foods in general or from selected categories. An overall plant-based diet covered a broad category of foods, including fruit juices, refined flours, sweets and desserts, and sugary beverages.

In the third, only eating more of the healthy plant foods earned them higher scores, while conversely, with the last index, a higher intake of unhealthy plant foods resulted in higher scores. Increased intake of animal foods was always associated with lower scores.

Healthy plant-based foods are those which are nutrient-dense and have less refined sugars. They include whole grains, plant proteins, and vegetables.

Previous studies have examined plant-based vs animal-based diet impacts in specific groups such as vegetarians, or predominantly vegan groups like the Seventh Day Adventists. These have shown that cardiovascular health is generally benefited by eating mostly plant-based foods.

This is an early attempt to explore the effect of these different dietary approaches in the general population. The results were interesting. People with the highest adherence to overall plant-based or provegetarian diets had between 4 and 5 servings of fruit and vegetables a day, and less than one serving of red or processed meat a day. In contrast, those with the highest intake of less healthy plant-based foods ate about 2 servings of fruits and vegetables, and 1.2 servings of red and processed meat, every day.

Those in the highest quintile for overall plant-based foods or provegetarian diets reduced their cardiovascular risk significantly with respect to those who had the lowest, even after adjusting for the lower rates of numerous confounding factors like obesity, smoking, drinking, cholesterol levels and diabetes mellitus.

The former had;

• 16% reduction in cardiovascular disease
• 32% lower risk of death from cardiovascular disease
• 25% reduction in all-cause mortality (dying from any cause)

When it came to the healthy plant-based food index, the risk of dying from cardiovascular disease or from any cause was reduced by 19% and 11% respectively. There was no reduction in the incidence of new cardiovascular disease with this diet. This included heart attacks requiring hospitalization, fatal coronary heart disease, definite or probable stroke, and heart failure with hospitalization or death.

There was no observable trend with the intake of less healthy plant-based foods. When individual foods were examined, it was found that potato intake was surprisingly associated with a lower incidence of heart disease and stroke, as well as death from all causes.

Since these were only observed effects, it is impossible to prove that eating a higher proportion of plant-based foods had anything to do with the improved heart health. Nonetheless, researcher Casey Rebholz sums up: “You don't have to give up foods derived from animals completely. To reduce cardiovascular disease risk people should eat more vegetables, nuts, whole grains, fruits, legumes and fewer animal-based foods. These findings are pretty consistent with previous findings about other dietary patterns, including the Dietary Approaches to Stop Hypertension, or DASH diet, which emphasize the same food items.”

Plant foods are also classified by dietary specialists as healthy and unhealthy. The American Heart Association (AHA)’s Mariell Jessup endorses this view, saying, “French fries or cauliflower pizza with cheese are plant based but are low in nutritional value and are loaded with sodium (salt). Unprocessed foods, like fresh fruit, vegetables and grains are good choices.”

However, one significant finding from the present study is that overall dietary patterns play a stronger role in heart health than individual foods within the diet. This means it is more important to examine diet in toto than to focus on single nutrients or foods, as foods work together or antagonize one another to produce health or disease. The researchers hope that this will spark future studies on specific types of plant foods, and how they impact the risk of death and cardiovascular disease.

The study was published in the Journal of the American Heart Association on August 7, 2019.