Those eating too few fruits and vegetables are on a path to premature death, according to a Swedish study published in the American Journal of Clinical Nutrition.
Nearly 72,000 people aged 45 to 83 recorded what they ate and researchers checked on death data in 13 years of follow-up.
Those who ate:
Five servings of fruit and vegetables a day lived three years longer than those who ate none.
One serving of fruit a day lived 19 months longer than those who ate none.
Three servings of vegetables a day lived 32 months longer than those who ate none.
One serving is roughly what fits in one palm, such as a medium-sized apple weighing 130g or half a cup of stewed fruit or three heaped tablespoons of cooked vegetables (although potatoes don't count); a child's serving is based on the child's palm.
A New Zealand study in 2003 - whose findings the Health Ministry says cannot be compared to the Swedish research - estimated that up to 9000 deaths a year in this country reflected poor diet. That included 1559 deaths that were attributable to inadequate fruit and vegetable intake, with an average loss of 10.6 years of life for each death.
Eating too few fruits and vegetables was ranked eighth on a list of causes of death that was topped by smoking and on which obesity was number five.
After that study, one of the authors said if everyone in New Zealand ate one more apple a day, it would save "a couple of hundred lives a year".
Public health researcher Rob Quigley said eating plenty of fruit and vegetables helped to reduce sodium (salt) intake and to obtain many vitamins and minerals and fibre.
"They are nutrient dense and energy poor," Mr Quigley said. "There's a lot of stuff in fruit and vegetables that we don't know a lot about, so when people try to put them in a pill, they don't work too well."
The Cancer Society says antioxidants in fruit and vegetables but not in other foods help to protect cells from damage.
"Perhaps even more important than the antioxidants in fruit and vegetables is the way they help maintain a healthy body weight when they replace other foods high in sugar, fat and energy. Being overweight or obese increases the risk of many chronic diseases like [type 2] diabetes, heart disease, stroke and some kinds of cancers."
Obesity is linked to an elevated risk of bowel, breast and other cancers.
What they contain
*Vitamin C in broccoli, spinach, kiwifruit, strawberries, oranges and melon.
*Folate in spinach and oranges.
*Thiamin in dried peas and beans.
*Calcium in broccoli and spinach.