Also, green tea might increase the risk of birth defects associated with folic acid deficiency. In women who are nursing, caffeine passes into breast milk and can affect a nursing infant. Nursing mothers should closely monitor caffeine intake to make sure it is on the low side (2-3 cups per day).
High intake of caffeine by nursing mothers can cause sleep problems, irritability, and increased bowel activity in breast-fed infants. "Tired blood" (anemia) : Drinking green tea may make anemia worse. Anxiety disorders : The caffeine in green tea might make anxiety worse. Bleeding disorders : Caffeine in green tea might increase the risk of bleeding. Don't drink green tea if you have a bleeding disorder. Heart conditions : Caffeine in green tea might cause irregular heartbeat. Diabetes : Caffeine in green tea might affect blood sugar control.
If you drink green tea and have diabetes, monitor your blood sugar carefully. The caffeine in green tea, especially when taken in large amounts, can worsen diarrhea. Glaucoma : Drinking green tea increases pressure inside the eye. The increase occurs within 30 minutes and lasts for at least 90 minutes. High blood pressure : The caffeine in green tea might increase blood pressure in people with high blood pressure. However, this effect might be less in people who consume caffeine from green tea or other sources regularly. Irritable bowel syndrome (IBS) : Green tea contains caffeine. The caffeine in green tea, especially when taken in large amounts, might worsen the diarrhea some people have with IBS. Liver disease : Green tea extract supplements have been linked to rare cases of liver damage. Talk to your doctor before taking a green tea extract. Tell your doctor if you have signs of liver damage such as yellowing skin, dark urine, or abdominal pain. Keep in mind that drinking green tea as a beverage is normal amounts is still probably safe. Weak bones (osteoporosis) : Drinking green tea can increase the amount of calcium that is flushed out in the urine. If you have osteoporosis, don't drink more than 6 cups of green tea per day. Taking calcium supplements may help make up for calcium that is lost. If you are generally healthy and getting enough calcium from your food or supplements, taking up to 400 mg of caffeine (about 8 cups of green tea) per day doesn't seem to increase the risk of getting osteoporosis. Stimulant drugs such as amphetamines speed up the nervous system. By speeding up the nervous system, stimulant medications can make you feel jittery and increase your heart rate. The caffeine in green tea might also speed up the nervous system. Taking green tea along with stimulant drugs might cause serious problems including increased heart rate and high blood pressure. Stimulant drugs such as cocaine speed up the nervous system. By speeding up the nervous system, stimulant medications can make you feel jittery and increase your heart rate. The caffeine in green tea might also speed up the nervous system. Taking green tea along with stimulant drugs might cause serious problems including increased heart rate and high blood pressure. Caffeine (contained in green tea) and ephedrine are both stimulant drugs.
Taking green tea along with ephedrine might cause too much stimulation and sometimes serious side effects and heart problems. Do not take caffeine-containing products and ephedrine at the same time. The caffeine in green tea might block the affects of adenosine (Adenocard).
Adenosine (Adenocard) is often used by doctors to do a test on the heart. Stop consuming green tea or other caffeine-containing products at least 24 hours before a cardiac stress test. Antibiotics (Quinolone antibiotics) interacts with GREEN TEA. Some antibiotics might decrease how quickly the body breaks down caffeine.