Just three portions of fruit and vegetables a day may be enough to protect against heart disease, according to a study.
Eating fruit and vegetables can reduce the risk of heart disease
In Britain, the government and leading experts advise people to eat five portions each day.
But a study by doctors in Greece involving 1,900 people indicates that three portions may be more than enough.
They told the European Society of Cardiology Congress in Vienna that eating more may have no benefit.
Just one in eight men and one in seven women in Britain eat the recommended five portions of fruit and vegetables each day.
This is despite the insistence of experts that it can significantly reduce their risk of heart disease, stroke and some cancers.
Dr Demosthenes Panagiotakos and colleagues at the University of Athens carried out a study of 848 people with heart disease and 1,078 healthy volunteers last year.
They were each asked how much fruit and vegetables they regularly ate.
Overall, 43% of heart patients and 67% of healthy volunteers said they regularly ate fruit and vegetables.
Of these, the vast majority ate less than two portions a day.
Just 7% of these heart patients and 10% of these healthy volunteers said they ate more than 2.5 portions each day.
The researchers found that people who ate between one and two portions of fruit and vegetables a day had a much lower risk of developing heart disease compared to those who did not eat any.
What's more, they found that this risk fell further with each additional portion they ate.
They found that people who ate more than 2.5 portions per day reduced their risk of heart disease by about 70%.
However, they also discovered that this benefit levelled off at this point. Eating more than three portions did not result in any lower risk of developing heart disease.
The UK's Department of Health said it stood by its recommendation that people should eat five portions of fruit and vegetables each day.
A spokeswoman said: "The World Health Organization and the UK Committee on the Medical Aspects of Food and Nutrition recommendations are based on epidemiological research that states we should consume at least 400g of fruit and vegetables a day - five portions.
"Large studies have shown that the more fruit and vegetables that is consumed the lower the risk of coronary heart disease."
Belinda Linden, cardiac nurse manager for the British Heart Foundation, said people should continue to try to eat at least five portions of fruit and vegetables each day.
"The current five portions a day recommendation is based on evidence from large controlled studies.
"The recent study from Athens University, suggesting we only need to eat three portions of fruit and vegetables a day, was based on a small number of participants over a limited number of time.
"This is not convincing enough to change the current recommendation."