Green tea comes from the dried leaves of the Camelia sinensis shrub. Side effects are possible with green tea, and many of these effects are due to its caffeine content. Caffeine also interacts with a number of drugs and herbal preparations. Talk to your physician or pharmacist before using green tea extract to avoid unforeseen interactions.
Side Efffects
Healthline, reporting Natural Standard information on green tea, indicates that the drink’s caffeine-related side effects include central nervous system stimulation, insomnia, and increased urination with possible loss of sodium and potassium. People with incontinence can see worsening of this problem. Caffeine’s tendency to increase stomach acidity may aggravate gastric ulcers. Heart rate and blood pressure tend to increase with ingestion of caffeine, so people with cardiac problems and high blood pressure should avoid caffeinated green tea. The tannin in the tea also can cause constipation when taken in large amounts. Excessive caffeine use can also result in increasing tolerance to the substance and physical dependence. Withdrawal can provoke symptoms such as headache and irritability.
Natural Standard also reports conflicting information on the effects of green tea on blood glucose levels. Some information indicates that blood sugar levels may increase, while some preliminary studies indicate that green tea can lower blood glucose. People with diabetes should use green tea or its extract cautiously and monitor their blood sugars carefully.
According to Natural Standard, very early research in animals posits possible links between caffeine and multiple sclerosis, and also between caffeine and effects on blood clotting. Early animal studies have also suggested that there may be a link between the tannins in green tea and an increased cancer risk. To date, the possibility of similar links has not been studied in humans.
Side Effects in Children
Infants receiving caffeine through breast milk may have difficulty sleeping. In addition, children who ingest drinks like green tea which contain tannin may develop iron deficiencies. Infants ingesting tea can also develop microcytic anemia.
Allergic Side Effects
Persons with allergies or hypersensitivities to tea should not use green tea or its extract. Natural Standard, reporting through the Healthline website, says that the tannins and caffeine in green tea can cause allergic reactions. Caffeine allergy is specifically associated with rashes. Discontinue use of the tea or extract if you have allergic symptoms such as itching, hives, rashes or other symptoms. If you experience chest pain or tightness, difficulty breathing, or swelling of the mouth, lips or throat, seek medical help immediately.
Toxicity
Caffeine can build up to toxic levels with chronic overuse of green tea or in people who are unable to clear the substance metabolically. The University of Maryland Medical Center lists abdominal spasms, nausea, vomiting, loss of appetite and diarrhea a symptoms of toxicity. Should such symptoms occur, seek medical care immediately. People with liver conditions should consult with their physicians prior to trying green tea.
Member Comments