WASHINGTON (CNN) – Five is your new lucky number.
That’s the number of servings of fruits and vegetables you need to eat each day to live longer., according to a new study published by the American Heart Association that analyzed data representing nearly 2 million adults worldwide.
Two of those five servings must be fruit; the other three should focus on vegetables, the study found.
“This amount probably offers the greatest benefit in terms of preventing major 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 fruit or vegetable in question.
“We also found that not all fruits and vegetables offer the same degree of benefit, although current dietary recommendations generally treat all types of fruits and vegetables, including starchy vegetables, fruit juices, and potatoes, in the same way. “said Wang.
Peas, corn, potatoes, and other starchy vegetables, for example, were not associated with a reduced risk of death or a specific chronic disease.
Green leafy vegetables rich in beta-carotene and vitamin C, such as spinach, green leafy lettuce, and kale, along with carrots, showed benefits.
In the fruit category, fruits full of beta-carotene and vitamin C, such as berries of all kinds and citrus fruits, also helped reduce the risk of death and chronic disease. However, the fruit juice did not. Previous research has found that it is the fiber in the whole fruit that is the key to any benefit.
“The totality of the evidence in the study should convince healthcare professionals to promote the consumption of more fruits and vegetables as a key dietary strategy, and for citizens to adopt this,” wrote Dr. Naveed Sattar and the Dr. Nita Forouhi in an accompanying editorial to be published in April.
The biggest benefits may come from encouraging those who rarely eat fruits or vegetables, as diets rich in even modestly higher fruit and vegetable consumption are beneficial.
-Dr. Naveed Sattar and Dr. Nita Forouhi
Sattar is Professor at the Institute of Cardiovascular and Medical Sciences at the University of Glasgow; Forouhi directs the nutritional epidemiology program of the MRC Epidemiology Unit at the University of Cambridge. Neither of them participated in the new study.
“The greatest benefits may come from encouraging those who rarely eat fruits or vegetables, as diets rich in even modestly higher consumption of fruits and vegetables are beneficial,” they wrote.
Association, without cause and effect
The study, published Monday in the AHA journal Circulation, was comprehensive and divided into 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 over a period of up to 30 years. All participants completed a questionnaire on eating habits at the beginning of the studies; these questionnaires were updated every two to four years. This information was then compared with the health and death records collected during the long-term studies.
The second part of the study was a pooled data meta-analysis of 26 studies covering nearly 2 million participants from 29 countries and territories in Asia, Africa, Australia, Europe, and North and South America. Those studies also compared self-reported fruit and vegetable intake with mortality rates.
People who ate five servings of fruits and vegetables a day had a 13% lower risk of death from any cause than people who only ate two servings of fruits and vegetables a day.
Eating five servings was also linked to a 12% lower risk of death from cardiovascular disease, including heart disease and stroke.
They also had a 10% lower risk of death from cancer and a 35% lower risk of death from respiratory disease, such as chronic obstructive pulmonary disease, than those who ate just two servings, the study found.
5 servings only?
Interestingly, the study found no benefit in prolonging life from eating more than five daily servings of fruits and vegetables, which is contrary to previous research in both animals and people.
A 2017 study found a significant reduction in the risk of heart attack, stroke, cancer, and premature death by eating 10 servings of fruits and vegetables each day. Animal studies found much lower immune responses in animals that were fed two to three servings of fruits and vegetables a day than in animals that ate five to nine servings a day.
“Eight to nine servings a day was where we saw the best effect (on immunity),” said study author Dr. Simin Meydani, senior scientist and team leader for nutritional immunology at the Jean Human Nutrition Research Center. Mayer from USDA at Tufts University on Aging.
Meydani pointed to the fact that the new study was based on self-reported food intake, which boasts the participants’ ability to remember and be honest when recording what they ate. Therefore, the new study was only able to show an association between five servings and better health, not cause and effect.
“It’s mainly based on observational studies and dietary intake records, which I don’t think has the sensitivity to differentiate and determine the exact dose needed,” said Meydani, who was not involved in the study.
“To recommend that five servings of fruits and vegetables is the best dose, they will need to conduct a randomized controlled trial looking at disease outcomes or health biomarkers, which has not been done consistently,” Meydani said.
Few of us eat our fruits and vegetables
The dietary guidelines say that adult women should eat at least 1.5 cups of fruit and 2.5 cups of vegetables a day. Men need more: 2 cups of fruit and 3.5 cups of vegetables a day.
However, only 9% of American adults eat the suggested servings of vegetables and only 12% eat the recommended amount of fruit, according to the US Centers for Disease Control and Prevention.
“The American Heart Association recommends filling at least half your plate with fruits and vegetables at every meal,” said Dr. Anne Thorndike, chair of the American Heart Association’s nutrition committee, in a statement.
“This research provides strong evidence for the lifetime benefits of eating fruits and vegetables and suggests a target amount to consume daily for ideal health,” added Thorndike, who is also an associate professor of medicine at Harvard Medical School.
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