Depending on which variant of a certain gene a woman has, a coffee consumption rate of at least two-three cups a day can either reduce the total risk of developing breast cancer or delay the onset of cancer. This is shown in new research from Lund University and Malmo University in Sweden.
The effect of coffee is related to estrogens, female sex hormones. Certain metabolic products of these hormones are known to be carcinogenic, and various components of coffee can alter the metabolism so that a woman acquires a better configuration of various estrogens. What's more, coffee contains caffeine, which also hampers the growth of cancer cells.
The cancer researcher Helena Jernström and her associates have studied the coffee-drinking habits of nearly 460 breast cancer patients being treated in Lund. The results show that the effect of coffee varies depending on which variant the women have of a gene called CYP1A2, which codes for an enzyme that metabolizes both estrogen and coffee. Half of the women had a variant called A/A, while the others had either A/C or C/C.
"Those women who had one of the C variants, and who had drunk at least three cups of coffee a day, developed breast cancer considerably more seldom than women with the A/A variant with the same coffee consumption. Their cancer risk was only two thirds of that of the other women.
A/A women who had drunk two or more cups of coffee a day received more ambiguous help from their coffee consumption. On the one hand, their cancer appeared considerably later than among women who had seldom or never drunk coffee at a mean age of 58 years instead of 48 years, unless they had taken hormone replacement therapy for menopausal symptoms, says Helena Jernström.. On the other hand, nearly 15 percent of these women had estrogen-insensitive (ER negative) tumors, which are more difficult to treat.