Two of the five servings should be fruit – the other three should focus on vegetables, the study found.
“This amount probably offers the most benefits in the prevention of serious chronic diseases and is a relatively achievable intake for the general public,” said lead author, dr. Dong Wang, an epidemiologist and nutritionist at Harvard Medical School and Brigham and Women’s Hospital in Boston, in a statement.
However, there were differences in benefits depending on the fruits or vegetables involved.
“We also found that not all fruits and vegetables offer the same benefits, although current nutritional recommendations generally treat all types of fruits and vegetables, including starchy vegetables, fruit juices and potatoes, the same,” Wang said.
Peas, maize, potatoes and other starchy vegetables, for example, are not associated with a reduced risk of death or specific chronic diseases.
Green leafy vegetables rich in beta-carotene and vitamin C, such as spinach, leafy lettuce and kale, as well as carrots, have shown benefits.
“The totality of the evidence in the study ‘should convince health workers to eat more fruits and vegetables as an important dietary strategy, and that citizens should accept it,’ said Dr. Naveed Sattar and dr. Nita Forouhi wrote in an accompanying editorial. will publish in April.
Sattar is Professor at the Institute of Cardiovascular and Medical Sciences at the University of Glasgow; Forouhi leads the nutrition epidemiology program of the MRC Unit for Epidemiology at the University of Cambridge. None were involved in the new study.
‘The biggest gain can come from encouraging those who rarely eat fruit or vegetables as diets rich in even modest higher fruit and vegetable consumption are beneficial, ”they wrote.
Association, no cause and effect
The study, published Monday in AHA’s journal Circulation, was large and in two parts. The first was an analysis of data from the Nurses’ Health Study and the Health Professionals Follow-Up Study, which followed more than 100,000 American men and women for up to 30 years. At the beginning of the studies, all participants completed a questionnaire for food habits; those questionnaires are updated every two to four years. This information was then compared with health and mortality rates collected during the long-term studies.
The second part of the study was a meta-analysis of aggregated data from 26 studies covering nearly 2 million participants from 29 countries and territories in Asia, Africa, Australia, Europe and North and South America. These studies also compared the self-reported intake of fruits and vegetables with mortality rates.
People who ate five servings of fruits and vegetables a day had a 13% lower chance of death due to people eating only two servings of fruits and vegetables a day.
Eating five servings was also linked to a 12% lower risk of dying from cardiovascular disease, including heart disease and stroke.
They also had a 10% lower risk of cancer death and a 35% lower risk of respiratory diseases, such as chronic obstructive pulmonary disease (COPD), than those who ate only two servings.
Only five servings?
Oddly enough, the study found no benefit in prolonging life by eating more than five servings of fruits and vegetables a day, which is inconsistent with previous research in animals and humans.
“The eight to nine servings a day were where we saw the best effect (on immunity),” said Dr. Simin Meydani, senior scientist and leader of the nutritional immunology team at Tufts University, Jean Mayer USDA Human Nutrition Research Center. Aging.
Meydani pointed out that the new study relied on reported food intake, which relied on the ability of participants to remember what they ate and to be true. Therefore, the new study could only show a link between five servings and better health – not a cause and effect.
“It is mainly based on observational studies and dietary intake records, which in my opinion do not have the sensitivity to distinguish and determine the required dose,” said Meydani, who was not involved in the study.
“To recommend that five servings of fruits and vegetables be the best dose, they should conduct a randomized controlled trial of disease outcomes or biomarkers for health, which has not been done in a systematic way,” Meydani said.
Few of us eat our fruits and vegetables
Dietary guidelines say that adult women should eat at least 1.5 cups of fruit and 2.5 cups of vegetables every day. Men need more – daily 2 cups of fruit and 3.5 cups of vegetables.
“The American Heart Association recommends filling at least half of your plate with fruits and vegetables at each meal,” said Dr. Anne Thorndike, who chairs the American Heart Association’s nutrition committee, said in a statement.
“This research provides strong evidence for the lifelong benefits of eating fruits and vegetables and indicates a target amount to consume daily for ideal health,” added Thorndike, who is also an associate professor of medicine at Harvard Medical School.