Eating loads of fruit and vegetables - 10 portions a day - might give us longer lives, say UK researchers.
Photo: RNZ
The study, by Imperial College London, calculated such eating habits could prevent 7.8 million premature deaths each year.
The team also identified specific fruit and vegetables that reduced the risk of cancer and heart disease.
The analysis showed even small amounts had a health boon, but more was even better.
A portion was counted as 80g of fruit or vegetables - the equivalent of a small banana, a pear or three heaped teaspoons of spinach or peas.
The conclusions were made by pooling data on 95 separate studies, involving two million people's eating habits.
Lower risks of cancer were linked to eating:
Lower risks of heart disease and strokes were linked to eating:
The results, published in the International Journal of Epidemiology, also assessed the risk of dying prematurely. Compared with eating no fruit or vegetables a day, it showed:
The researchers did not know if eating even more fruit and vegetables would have even greater health benefits as there was little evidence out there to review.
Dr Dagfinn Aune, one of the researchers, said: "Fruit and vegetables have been shown to reduce cholesterol levels, blood pressure, and to boost the health of our blood vessels and immune system.
"This may be due to the complex network of nutrients they hold ... For instance, they contain many antioxidants, which may reduce DNA damage and lead to a reduction in cancer risk."
Five-a-day target 'achievable'
However, many people struggled to even eat the five a day (400g) recommended by the World Health Organisation.
In the UK, only about one in three people ate enough.
Dr Aune said the findings did not mean the five-a-day message needed to change.
He told the BBC: "There are many different considerations if changing policy, it's not just the health effects - is it feasible?
"But our findings are quite clear in that they do support five a day, but there are even some further benefits for higher intakes."
Dr Alison Tedstone, chief nutritionist at Public Health England, said: "The five-a-day target is the foundation of a healthy balanced diet and is an achievable way to help prevent a number of diseases.
"Whilst consuming more than five portions of fruit and vegetables a day may be desirable... adding pressure to consume more fruit and vegetables creates an unrealistic expectation."
Not all of the 95 studies that were analysed fully accounted for other aspects of lifestyle, such as exercise levels, that could also play a role in prolonging lives.
However, Dr Aune said the conclusions were "quite robust".
- BBC