Caffeine has been linked to varying oestrogen levels among women of different races. A study at the National Institutes of Health and other institutions found that Asian women who consume an average of 200mg or more of caffeine a day have elevated oestrogen levels compared to women who have less. Black women also have higher oestrogen levels. Conversely, white women who consume 200mg or more caffeine on a daily basis have slightly lower oestrogen levels than women who consume less. However, findings differed slightly when the source of caffeine was considered singularly. Total caffeine intake was calculated using coffee, black tea, green tea and caffeinated soda. It was found that consumption of more than one cup each day of caffeinated soda or green tea created higher estrogen levels in Asians, whites, and blacks. Caffeine and estrogen also effect the development of Parkinson's disease risk in postmenopausal women. Find the nearest Barchester care home.