As long as you don’t count French fries and soda as healthy choices, it’s never too late to increase your longevity and cut your risk of heart disease death by adding fruits and vegetables to your diet, according to preliminary research presented at the American Heart Association’s Epidemiology and Prevention | Lifestyle and Cardiometabolic Health Scientific Sessions 2019, a premier global exchange of the latest advances in population based cardiovascular science for researchers and clinicians.

“Not all plant-based diets are equal, but boosting the intake of high-quality plant-based foods over time lowers the risk of death even among people who started off with poor-quality diets,” said Megu Y. Baden, M.D., Ph.D., lead author of the study and postdoctoral research fellow in the department of nutrition at the Harvard T.H. Chan School of Public Health in Boston.

Previous studies have shown that eating a high-quality plant-based diet can reduce the risk of diabetes and heart disease, but this is the first to look at how positive or negative changes in diet may influence a person’s risk of dying – no matter where they started. In the current study, researchers developed three diet scales that took into account the overall consumption of plant-based foods, the consumption of healthful plant-based foods (such as whole grains, fruits, vegetables and nuts), and the consumption of lower-quality plant-based foods (such as fruit juices, refined grains, potatoes and sweets).

The study included 47,983 women (average age 64 years) participating in the Nurses’ Health Study and 25,737 men (average age 64 years) participating in the Health Professionals Follow-Up Study. None had a history of heart disease or cancer when they entered the study in 1998. Using dietary reports, participants were assessed on changes in their diet over the 12 years prior to entering the study.

Compared to those who had fairly stable diets, during a 12-year follow-up period (1998-2014) the researchers found that deaths from all causes were:

• 8 percent lower in those with the biggest increase in an overall plant-based diet;
• 10 percent lower in those with the biggest increase in a healthy plant-based diet;
• 11 percent higher in those with the biggest increase in an unhealthy plant-based diet.

A 10-point increase in score on the healthy plant-based diet scale (which can be achieved for example by replacing 1 serving/day intake of refined grains with whole grains, increasing fruit intake by 1 serving/day and vegetable intake by 1 serving/day, and decreasing sugary beverage intake by 1 serving/day) was associated with a 10 percent lower risk of death from cardiovascular disease, while a 10-point increase in score on the unhealthy plant-based diet scale was associated with a 6 percent high risk of cardiovascular-disease death.

“Over a period of time, consuming more whole grains, fruits, vegetables, while decreasing your intake of refined grains, sweets and desserts, and animal foods such as animal fat meat, and miscellaneous animal-based foods, may lower your risk of death from heart disease and other causes,” Baden said.

Results were adjusted for several factors, including age, race, initial diet score, body mass index, weight change, family history of diabetes, heart attack, or cancer, heart disease risk factors, medications, menopausal status and hormone use, initial and changes in smoking and other lifestyle influences, and weight change. Because the study was not a randomized trial, it cannot prove a cause-and-effect relationship between the dietary changes and the risk of death. Although there is no reason to think that consuming high-quality plant foods would not be good for everyone, these results in health professionals who were predominantly of European ancestry might not be generalizable to other groups of people.

The most recent dietary guideline, by the American Heart Association and American College of Cardiology, recommends that adults follow a dietary pattern that emphasizes vegetables, fruits, and whole grains; includes low-fat dairy products, poultry, fish, legumes, non-tropical vegetable oils, and nuts; and limits intake of saturated fats, sodium, sweets, sugar-sweetened beverages and red meats.