Two studies separately analyzed different assessments of healthy plant food consumption. The researchers from both studies found that young adults and postmenopausal women had fewer heart attacks, and were less likely to develop cardiovascular disease (CVD) when they ate more nutritious plant foods.
In the first study, titled “A Plant-Centered Diet and Risk of Incident Cardiovascular Disease during Young to Middle Adulthood,” lead author Yuni Choi, Ph.D., a postdoctoral researcher at the University of Minnesota School of Public Health in Minneapolis, investigated if long-term consumption of a plant-focused diet and shifting toward plant-centered diet in early adulthood contribute in lowering the risk of heart disease in midlife (Choi et al., 2021).
In the second study (Glenn et al., 2021), titled “Relationship Between a Plant-Based Dietary Portfolio and Risk of Cardiovascular Disease: Findings from the Women’s Health Initiative (WHI) Prospective Cohort Study,” lead author Glenn, M.Sc., R.D in collaboration with WHI investigators led by Simin Liu, M.D., Ph.D., at Brown University, evaluated whether consumption of the ‘Portfolio Diet,’ approved by the United States Food and Drug Administration for health claims—lowering “bad” cholesterol levels—is associated with lower heart disease events in a big group of postmenopausal women.
Choi and colleagues, in their study, examined the consumption of diet and the occurrence of heart disease in 4,946 adult participants enrolled in the Coronary Artery Risk Development in Young Adults (CARDIA). At the time of enrollment, the participants were 18- to 30-years-old and were free of cardiovascular disease. Among the participants, 2,509 were Black adults, and 2,437 were white adults (54.9% women overall).
During 1987-88 to 2015-16, all participants had eight follow-up exams, including lab tests, physical measurements, medical histories, and assessment of lifestyle factors. The researchers were able to collect unbiased, long-term habitual diet data as the participants were not instructed to eat certain things. Also, they were not told their scores on the diet measures,
- During 32 years of follow-up, 289 participants developed CVD (including heart failure, heart attack, stroke, heart-related chest pain, or clogged arteries.
- Participants who scored in the top 20% mainly consumed healthy plant-based foods, and fewer adversely rated animal products) were 52% less likely to develop heart disease.
- During 7 to 20 years of the study, when participants were between 25 to 50 of age and had improved diet quality by eating more beneficial plant foods and fewer unhealthy animal origin foods, they were 61% less likely to develop subsequent CVD in comparison to the participants whose diet quality excluded the recommended dietary pattern in the same time.
- Among the participants, there were few vegetarians, so the study could not assess the possible beneficial effects of a strict vegetarian diet, which excludes all animal products, including meat, dairy, and eggs.
In the second study, Glenn and colleagues analyzed consumption of the “Portfolio Diet” and the occurrence of heart disease events in postmenopausal women.
The “Portfolio Diet” includes nuts, plant proteins (source: soy, beans, or tofu), soluble fiber (source: oats, barley, okra, eggplant, oranges, apples, and berries), plant sterols, monounsaturated fats (source: olive, canola oil, and avocadoes) along with less consumption of saturated fats and cholesterol-enriched foods.
The study included 123,330 women who participated in the Women’s Health Initiative, a long-term national study investigating risk factors, prevention, and early detection of severe health conditions in postmenopausal women. The women who were enrolled in the study between 1993 and 1998 were between 50-79 years of an average age of 62 and did not have CVD.
The researchers monitored the study participants until 2017 when the average follow-up time reached almost15.3 years. Using participants’ self-reported food-frequency questionnaires information, researchers scored each woman on her adherence to the ‘Portfolio Diet.’
The researchers found:
- Participants who had the closest alignment to the diet were 11% less likely to develop any CVD, 14% less likely to develop coronary heart disease, and 17% less likely to develop heart failure than the participants who followed the Portfolio Diet less frequently.
- No association was observed between following the Portfolio Diet more closely and the occurrence of CVD: stroke or atrial fibrillation.
The researchers of both studies believe the results highlight possible opportunities to lower heart disease by encouraging people to consume more plant-based foods.
“A nutritionally rich, plant-focused diet is beneficial for heart health. A plant-centered diet is not always necessarily vegetarian,” said Choi, the lead author of the first study.
He continued, “People can choose among plant foods that are as close to natural food as possible, not like a highly processed food. We may consider including animal products in moderation from time to time, such as non-fried poultry, non-fried fish, eggs, and low-fat dairy.”
John Sievenpiper, M.D., Ph.D., a senior author of the second study, said the research results presented a significant opportunity to include more cholesterol-lowering plant foods in the diet.
He continued, “even greater adherence to the Portfolio Diet, one would expect an occurrence of fewer CVD events, perhaps, as much as cholesterol-lowering medications yield.”
The author, also an associate professor of nutritional sciences and medicine at the University of Toronto, further mentioned, “Still, an 11% reduction is clinically important and would meet anyone’s minimum threshold for health benefit. The results demonstrate that the Portfolio Diet yields heart-health benefits.”
The researchers also found a dose-response efficacy in reducing heart disease the study, meaning one can start with adding one component of the Portfolio Diet and gain more health benefit as more components are added, mentioned Andrea J. Glenn, lead author of the second study, also a doctoral student in nutritional sciences at the University of Toronto.
The studies were observational. The results the researchers obtained cannot directly establish a cause-and-effect relationship between diet and cardiovascular events.
According to the researchers, the study provides a most reliable estimate for the diet-heart relationship to date due to the study design including well-validated food frequency questionnaires administered at baseline and after that in a significant number of highly devoted participants. Nevertheless, the researchers report that these findings need to be further investigated in additional men or younger women.