Los Angeles: Grapefruit raises levels of oestrogen and could increae the risk of breast cancer by nearly a third, says a joint study from the universities of Southern California and Hawaii.

Raised levels of the mainly female hormone oestrogen have been implicated in an increased cancer risk for women.

According to the researchers, eating as little as a quarter of a grapefruit a day raises the danger by 30 per cent among older post-menopausal women.

This is the first report of a commonly consumed food that may increase the risk of breast cancer among post-menopausal women.

The report published in the British Journal of Cancer says: “Whole grapefruit intake was significantly associated with breast cancer in the present study generally a 30 per cent increase among women who consume the equivalent of one quarter of a grapefruit or more per day. There is evidence that grapefruit increases plasma oestrogen concentrations.

“Since it is well established that oestrogen is associated with breast cancer risk, it is plausible that regular intake of grapefruit would increase a woman’s risk of breast cancer.’ The study, carried out by the universities of Southern California and Hawaii, was based on more than 50,000 postmenopausal women from five ethnic groups, including 1,657 with breast cancer.”

A number of lifestyle factors are also linked to breast cancer risk. For example, alcohol. fat and junk food consumption are said to increase the risks.