Veggies really are good for you, and taste good too
American
Heart Association
Eating a plant-centered diet during young adulthood is associated with a lower risk of heart disease in middle age, according to a long-term study with about 30 years of follow-up.
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.
One study, titled "A Plant-Centered Diet and Risk of Incident Cardiovascular Disease during Young to Middle Adulthood," evaluated whether long-term consumption of a plant-centered diet and a shift toward a plant-centered diet starting in young adulthood are associated with a lower risk of cardiovascular disease in midlife.
"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,"
said Yuni Choi, Ph.D., lead author of the young adult study and a postdoctoral
researcher in the division of epidemiology and community health at the
University of Minnesota School of Public Health in Minneapolis.
Choi and colleagues 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.
"As opposed to existing diet quality scores that are usually based on small numbers of food groups, APDQS is explicit in capturing the overall quality of diet using 46 individual food groups, describing the whole diet that the general population commonly consumes.
Our scoring is very comprehensive, and it has many
similarities with diets like the Dietary Guidelines for Americans Healthy
Eating Index (from the U.S. Department of Agriculture's Food and Nutrition
Service), the DASH (Dietary Approaches to Stop Hypertension) diet and the
Mediterranean diet," said David E. Jacobs Jr., Ph.D., senior author of the
study and Mayo Professor of Public Health in the division of epidemiology and
community health at the University of Minnesota School of Public Health in
Minneapolis.
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.
"A
nutritionally rich, plant-centered diet is beneficial for cardiovascular
health. A plant-centered diet is not necessarily vegetarian," Choi said.
"People can choose among plant foods that are as close to natural as
possible, not highly processed. 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."
Because this
study is observational, it cannot prove a cause-and-effect relationship between
diet and heart disease.
Other co-authors
are Nicole Larson, Ph.D.; Lyn M. Steffen, Ph.D.; Pamela J. Schreiner, Ph.D.;
Daniel D. Gallaher, Ph.D.; Daniel A. Duprez, M.D., Ph.D.; James M. Shikany,
Dr.P.H.; and Jamal S. Rana, M.D., Ph.D.
The study was
funded by the National Heart, Lung and Blood Institute of the National
Institutes of Health; Healthy Food Healthy Lives Institute at the University of
Minnesota; and the MnDrive Global Food Ventures Professional Development
Program at the University of Minnesota.
In another
study, "Relationship Between a Plant-Based Dietary Portfolio and Risk of
Cardiovascular Disease: Findings from the Women's Health Initiative (WHI)
Prospective Cohort Study," researchers, in collaboration with WHI
investigators led by Simin Liu, M.D., Ph.D., at Brown University, evaluated
whether or not diets that included a dietary portfolio of plant-based foods
with U.S. Food and Drug Administration-approved health claims for lowering
"bad" cholesterol levels (known as the "Portfolio Diet")
were associated with fewer cardiovascular disease events in a large group of
postmenopausal women.
The "Portfolio 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 and canola oil and avocadoes; along with limited consumption of saturated fats and dietary cholesterol.
Previously, two randomized trials
demonstrated that reaching high target levels of foods included in the
Portfolio Diet resulted in significant lowering of "bad" cholesterol
or low-density lipoprotein cholesterol (LDL-C), more so than a traditional
low-saturated-fat National Cholesterol and Education Program diet in one study
and on par with taking a cholesterol-lowering statin medication in another.
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.
"These results present an important opportunity, as there is still room for people to incorporate more cholesterol-lowering plant foods into their diets. 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.
Still, an 11% reduction is clinically
meaningful and would meet anyone's minimum threshold for a benefit. The results
indicate the Portfolio Diet yields heart-health benefits," said John
Sievenpiper, M.D., Ph.D., senior author of the study at St. Michael's Hospital,
a site of Unity Health Toronto in Ontario, Canada, and associate professor of
nutritional sciences and medicine at the University of Toronto.
The researchers
believe the results highlight possible opportunities to lower heart disease by
encouraging people to consume more foods in the Portfolio Diet.
"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," said Andrea J. Glenn, M.Sc., R.D., lead
author of the study and a doctoral student at St. Michael's Hospital in Toronto
and in nutritional sciences at the University of Toronto.
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.
Co-authors are
Kenneth Lo, Ph.D.; David J. A. Jenkins, M.D., Ph.D.; Beatrice A. Boucher,
M.H.Sc.; Anthony J. Hanley, Ph.D.; Cyril W.C. Kendall, Ph.D.; JoAnn E. Manson,
M.D., Dr.P.H.; Mara Z. Vitolins, Ph.D.; Linda G. Snetselaar, Ph.D.; and Simin
Liu, M.D., Ph.D.
The study was
funded by the National Heart, Lung, and Blood Institute of the National
Institutes of Health and Diabetes Canada.
