Parents have been urged not to put ham and other processed meat into their children's lunchboxes to avoid them developing a cancer risk later in life.

双亲被建议到不要将火腿和其他处理过的肉类食品放入孩子的午餐盒里，这样可以避免他们早年患癌症的风险。

Just under half of children have fruit in their lunchbox

The World Cancer Research Fund said parents should act now to stop their children developing a taste for smoked, salted or cured（咸的） meats.

Eating too much over decades can raise the risk of bowel¹（肠） cancer, they said.

The UK's Food Standards Agency said processed meat was fine for lunchboxes as long as it was not eaten too often.

It is only in recent years that the link between processed meats and bowel cancer in adults has been made, with some estimates suggesting that thousands of cases could be prevented if everyone limited intake² to 70g a week - equivalent³ to（等于） three rashers（咸肉的薄片） of bacon.

Even though the available evidence looks only at adult diets, rather than child diets, the World Cancer Research Fund believes that bad eating habits can start in childhood.

It wants the likes of ham and salami（意大利香肠） given the chop in favour sandwich-fillers such as chicken, fish or cheese.

Marni Craze, the charity's children's education manager, said: "It is better if children learn to view processed meat as an occasional treat if it is eaten at all."

She also wants to see a crackdown on high calorie snacks in school lunchboxes, as being overweight as an adult can also increase the risk of cancer later in life.

She said: "Putting ham or high calorie snacks in your child's lunchbox may seem like a convenient option, particularly for parents who do not have a lot of time to prepare their child's lunchbox.

"But packed lunches are part of a child's diet that is relatively⁴ easy to control and it does not have to take too much time or effort to prepare a healthy lunch."

'Quality not quantity'

However, Sian Porter, a dietician（营养学家） and spokesman⁵ for the British Dietetic Association, said that ham still had a place during dinner hour.

She said: "Variety is the most important thing, and ham can still be used sometimes - just not every day.

"If you add something healthy to a ham sandwich, such as tomato or salad, then that helps too."

She said that some meats were more heavily processed than others, and these should be avoided.

"My advice would be to buy the best quality ham you can, and eat less of it, or eat it less frequently."

The Food Standards Agency, which advises the public on healthy eating, has published its own list of lunchbox menus - some of which feature ham.

An FSA spokesman said: "Processed meats, such as ham and salami, can form part of a balanced diet and parents shouldn't be concerned about including these in their children's lunchboxes now and again.

"However they can contain high levels of fat, particularly saturated⁶ fat, and salt, so we wouldn't recommend eating them too often. Parents should try to include a variety of sandwich fillings and only use processed meats occasionally."