Studies representing nearly two million adults worldwide show that eating about five daily servings – two of which are fruits and three vegetables – is likely the optimal amount for longer life, according to new research. This research was published in the American Heart Association’s flagship journal Circulation.
Diets rich in fruits and vegetables help reduce the risk for numerous chronic health conditions that are leading causes of death, including cardiovascular disease and cancer. Yet, only about one in 10 adults eat enough fruits or vegetables, according to the U.S. Centers for Disease Control and Prevention.
Lead study author Dong D. Wang, along with his colleagues, analyzed data from the Nurses’ Health Study and the Health Professionals Follow-Up Study, two studies including more than 100,000 adults who were followed for up to 30 years. Both datasets included detailed dietary information repeatedly collected every two to four years. For this analysis, researchers also pooled data on fruit and vegetable intake and death from 26 studies that included about 1.9 million participants from 29 countries and territories in North and South America, Europe, Asia, Africa, and Australia.
Analysis of all studies, with a composite of more than two million participants, revealed:
- Intake of about five servings of fruits and vegetables daily was associated with the lowest risk of death. Eating more than five servings was not associated with an additional benefit.
- Eating about two servings daily of fruits and three servings daily of vegetables was associated with the greatest longevity.
- Compared to those who consumed two servings of fruit and vegetables per day, participants who consumed five servings a day of fruits and vegetable had a 13% lower risk of death from all causes; a 12 percent lower risk of death from cardiovascular disease, including heart disease and stroke; a 10 percent lower risk of death from cancer; and a 35 percent lower risk of death from respiratory diseases, such as chronic obstructive pulmonary disease (COPD).
- Not all foods that one might consider to be fruits and vegetables offered the same benefits. For example, starchy vegetables, such as peas and corn, fruit juices, and potatoes were not associated with reduced risk of death from all causes or specific chronic diseases.
On the other hand, green leafy vegetables, including spinach, lettuce, and kale, and fruit and vegetables rich in beta carotene and vitamin C, such as citrus fruits, berries, and carrots, showed benefits.
Wang said this study identifies an optimal intake level of fruits and vegetables and supports the evidence-based, succinct public health message of ‘5-a-day,’ meaning people should ideally consume five servings of fruit and vegetable each day.
“This amount likely offers the most benefit in terms of prevention of major chronic disease and is a relatively achievable intake for the general public,” he said.
“We also found that not all fruits and vegetables offer the same degree of benefit, even though current dietary recommendations generally treat all types of fruits and vegetables, including starchy vegetables, fruit juices, and potatoes, the same,” added Wang.
A limitation of the research is that it is observational, showing an association between fruit and vegetable consumption and risk of death; it does not confer a direct cause-and-effect relationship.