The benefits of eating five portions of fruit and vegetables a day have been drummed into us all for years.

But it seems that many parents still aren't getting the message.

A new poll has found that more than a third of parents (34 per cent) don't know about the five-a-day recommendation, and that five-in-six children are not eating five portions of fruit and vegetables daily.

In fact, the survey by Notcutts Garden Centres, which is trying to encourage people to grow their own fruit and veg, found that 35 per cent of parents say their children are eating just one or two portions a day.

Part of the problem may be that parents aren't eating enough fruit and vegetables themselves — only 18 per cent of the mums and dads surveyed ate five-a-day themselves, and two-thirds of parents said they were worried about passing on their own bad eating habits to their children.

Healthy eating consultant Lucy Thomas, who runs classes to encourage young children to eat fruit and vegetables (www.mangetoutkids.com), says: “Parents are crucial in getting children engaged with fruit and vegetables.

“If a parent wants their child to eat broccoli but won't touch the stuff themselves, success is unlikely.”

Certainly, the research found that almost half of parents thought eating more fruit and vegetables themselves would encourage their kids to eat more greens, with two-thirds saying they would like to be more adventurous with their own food choices.

“Parents should revisit foods that they wrote off as children — our tastebuds develop over time and it can take as many as 10 or 15 tries before we get used to new tastes,” explains Thomas.

“Adults may be surprised to find that they now enjoy fruit or vegetables they always thought they hated.”

The Government advises both adults and children to eat five portions of fruit and vegetables a day because they are rich in antioxidants, vitamins and minerals, high in fibre and low in calories.

Studies have consistently shown that populations with a high intake of fruit and vegetables have a lower incidence of heart disease, some cancers and other health problems.

The recommended portion size for an adult is 80g, but the amount a child needs varies with age, body size and physical activity. As a rough guide, one portion is the amount they can fit in the palm of their hand.

Rick Wilson, director of Nutrition and Dietetics at King's College Hospital, London, and a spokesman for the British Dietetic Association, points out that official calculations suggest that if most people ate five-a-day, avoidable deaths in the UK would be reduced by 62,000.

He says: “It doesn't surprise me that a lot of people aren't eating five-a-day — getting everyone to do that is very difficult to achieve.”

He points out that fresh, frozen, tinned or dried fruit all count as a five-a-day portion.

Wilson suggests that if children have a glass of fruit juice with their breakfast, a sandwich with cucumber and/or tomatoes in it and a piece of fruit for lunch, a portion of vegetables in the evening with their hot meal, and another piece of fruit as a snack during the day, they have had their five-a-day.