Pre-schoolers who eat French fries frequently have a much higher risk of breast cancer as adults, US researchers say.

A study of American nurses found that one additional serving of fries per week at ages three to five increased the risk of breast cancer by 27 percent.

"Researchers are finding more evidence that diet early in life could play a role in the development of diseases in women later in life," Dr Karin Michels, of Brigham and Women's Hospital in Boston and Harvard Medical School, was quoted as saying by the AAP.

"This study provides additional evidence that breast cancer may originate during the early phases of a woman's life. Eating habits during that phase may be particularly important to reduce future risk of breast cancer."

Writing in the International Journal Of Cancer, the researchers said they looked at the women's diets and at questionnaires filled out by the mothers of the participants.

One risk factor for breast cancer stood out: women whose mothers who said their daughters ate French fries had a higher risk of breast cancer. This increased 27 percent for each weekly serving reportedly eaten.