A study has shown that calcium and vitamin D can protect young women against breast cancer
Younger women can cut their risk of breast cancer by eating foods rich in calcium and vitamin D, say experts.
In the past, animal studies have linked calcium and vitamin D intake to a lower risk of breast cancer but human studies have proved inconclusive.
Scientists asked 10,578 premenopausal and 20,909 postmenopausal women how often they ate certain foods, beverages and supplements in the past year.
They found that eating a high amount of calcium and vitamin D was linked to a low risk of breast cancer before but not after the menopause.
A team led by Jennifer Lin at Harvard Medical School Boston says that calcium and vitamin D may exert "anticarciogenic effects" on breast cancer cells that express high levels of insulin like growth factors (IGF).
Since breast cancer cells tend to express lower levels of IGFs after the menopause, this may explain why calcium and vitamin D do not protect older women.
The authors comment: "Further investigation is warranted to study the potential utility of calcium and vitamin D intake in reducing the risk of breast cancer."