Green tea originates from China and has been an important part of many Asian cultures. It is made from the leaves of Camellia sinensis and grown in other countries like Taiwan, Japan, Indonesia, and Vietnam as well. Green tea has been closely examined during recent years for its innumerable perceived health benefits.
Health Benefits of Green Tea
Studies have shown that regular green tea drinkers have lower chances of developing certain types of cancer along with a reduced risk of heart disease. More recent studies indicate green tea may play a part in weight loss as well. WebMD notes the limited studies that show green tea's role in lowering cholesterol, burning fat, preventing diabetes and stroke, and possibly even warding off dementia.
Green Tea's Antioxidants
Catechins are the antioxidants in green tea that scavenge for free radicals that can damage DNA and contribute to cancer, blood clots, and atherosclerosis. Green tea undergoes minimal processing as the leaves are withered and steamed versus fermentation like an oolong or black tea. By steaming the leaves, the tea does not undergo oxidation. The enzymes in tea convert the good polyphenols into a different compound, with different pharmacological effects. Catechins are a type of flavonoids, which is the major polyphenols in green tea.
EGCG is one of green tea's unique catechins and is highly concentrated. EGCG is the primary catechin linked to the health and anti-aging benefits. It can improve overall health due to its ability to repair and strengthen cells.
Green Tea in Extract Form
Green tea extract is the herbal derivative from the green tea leaves, capturing the catechins and antioxidants that are sought after for their innumerable health benefits. This herbal version of green tea is standardized to ensure a certain percentage of the active ingredients are still present in the final form.
In extract form, green tea is believed to be better in improving cardiovascular circulation and reducing bad cholesterol (LDL). Other marketing claims of green tea extract include appetite suppression and an improvement in oxidation of fat. Acceptance of these claims is mixed amongst professionals in the scientific community as human studies are limited.
The recommendation for green tea extract products should be at least 55% EGCG and 90% polyphenols. A daily dose correlates to approximately two cups of green tea per day, or 200-400mg of EGCG per day.
Possible Side Effects and Warnings on Green Tea Extract
Green tea extract has not been evaluated by the DFA for safety or its effectiveness, therefore all potential risks may not be known yet. According to Drugs.com, those with the following conditions should talk to their health care provider before using green tea:
- heart problems or high blood pressure
- kidney disease
- an overactive thyroid (hyperthyroidism)
- an anxiety or nervous disorder, or
- a bleeding or blood clotting disorder or if you take a blood thinner such as warfarin (Coumadin).
Excess caffeine from green tea extract can be a problem for some people, especially those with the conditions listed above. Women who are pregnant or lactating and those with allergies (especially to plants) should talk to their doctor or health care professional prior to using green tea extract as well.
The caffeine in green tea can also cause anemia and other problems in children and should not be given to any child without first talking to the pediatrician.
Allergic reactions to green tea extract include difficulty breathing, throat closing, swelling of lips, tongue, or face, or hives. Prolonged use of green tea may be associated with esophageal cancer.
Less serious potential side effects as listed by Drugs.com include the following:
- heartburn
- upset stomach
- loss of appetite
- constipation or diarrhea
- nervousness, irritability, or anxiety
- sleeplessness
- irregular heartbeats, or
- headache
Green tea extract can have a variety of positive health benefits, but should be used in moderation, and any health concerns should be discussed with a medical provider prior to using on a regular basis.
Erin De Santiago - Erin is a freelance travel, food/wine, & Disney writer in Taipei, Taiwan, who has traveled within 40+ different countries to date.
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