Nutrient Green Tea Extract

According to MedlinePlus, a service of the U.S. National Library of Medicine, green tea can be prepared as an extract and used as a medicine. Green tea is made up of the Camellia sinensis plant. Green tea extract can be used to improve thinking and mental alertness. It has also been used to help treat headaches, osteoporosis and solid tumor cancers. Green tea may help prevent cancers, such as breast cancer, lung cancer, colon cancer and gastric cancer. Some people have had success from using green tea extract for improved weight loss.

Caffeine

According to the American Council on Exercise, green tea extract contains 50 mg of the alkaloid, caffeine. MedlinePlus states that, "green tea contains 2 to 4 percent caffeine, which affects thinking and alertness, increases urine output, and may improve the function of brain messengers important in Parkinson's disease." Caffeine may stimulate your heart, nervous system and muscles by elevating the release of some neurotransmitters in your brain. If you take green tea extract in the morning, you may notice an immediate increase in your energy from its caffeine content and sustained energy throughout the day.

Catechins

The University of Maryland Medical Center, or UMMC, states that green tea contains six catechin compounds -- catechin, gallaogatechin, epicatechin, epigallocatechin, epicatechin gallate, and apigallocatechin gallate or EGCG. EGCG is the most active polyphenol in green tea extract and acts as an antioxidant in your body. UMMC reports that a clinical study found that the catechins in green tea may be one of the primary weight loss agents in the herb. "The Journal of Nutrition" found similar conclusions in their controlled study of overweight people and catchin consumption. The group that consumed catchins had greater weight loss than the group that had no catchins. Along with weight loss, the catchins in green tea can be beneficial to the treatment of genital warts. MedlinePlus states that a specific green tea extract ointment provides 15 percent kunecatechins and is an effective topical treatment for the external warts.

L-theanine

The University of Maryland Medical Center states that green tea contains L-theanine -- an amino acid in green tea extract that has been shown to have a calming effect on the nervous system. L-theanine may reduce physiological and psychological stress responses. Consult your doctor before you begin use of green tea extract, and let him know the other medications and supplements you are taking because green tea may interfere with the absorption of other medicines.

Expert Insight

The Mayo Clinic explains that the caffeine in green tea may be helpful in improving airflow to the lungs. However, more research needs to be done to conclude caffeine and tea use effectiveness on people with asthma. MedlinePlus states that if you consume too much green tea you could get side effects from the caffeine that can range from, "headache, nervousness, sleep problems, vomiting, diarrhea, irritability, irregular heartbeat, tremor, heartburn, dizziness, ringing in the ears, convulsions and confusion."

Warning

MedlinePlus states that "green tea is likely safe for most adults. Green tea extract is possibly safe for most people for short-term use." Green tea has been reported for causing nausea and constipation while green tea extracts may cause liver problems in rare cases. Consult your health care practitioner before you consume green tea extract. Green tea may interfere with certain medications so inform your doctor of your current medications and supplements.