So they designed this analysis to study how drinking soda might affect hormones. Women who drank more than a cup of regular (not diet) soda a day had higher levels of estrogen than those who drank less regular soda, diet soda, or fruit juice.
Alcohol can change the way a woman's body metabolizes estrogen (how estrogen works in the body). This can cause blood estrogen levels to rise. Estrogen levels are higher in women who drink alcohol than in non-drinkers . These higher estrogen levels may in turn, increase the risk of breast cancer .
A Cedars-Sinai study published in 2012 in the Journal of Women's Health challenged the belief that all types of alcohol consumption heighten the risk of developing breast cancer. Doctors determined long ago that alcohol increases the body's estrogen levels, fostering the growth of cancer cells.