||Caffeine, found in tea, coffee, cocoa, and some carbonated drinks, stimulates the cardiovascular system, and may cause abnormal heart rhythms, palpitations, and raised blood pressure. Boiled filtered coffee has been associated with raised blood cholesterol. Intakes of caffeine-rich drinks should be limited to no more than six cups a day.
Caffeine stimulates the nervous system and may worsen PMS symptoms such as irritability. It may also contribute to infertility if it is consumed in excessive amounts. This is possibly because caffeine reduces the circulating levels of the pituitary hormone prolactin. Low levels of prolactin are associated with infertility.