1. contains antioxidants, including polyphenols such as epigallocatechin gallate (EGCG), which can powerfully quench damaging “free radicals,” metabolic byproducts that are chemically reactive and can damage cells.
2. The effect of oolong tea on blood sugar has been tested in several studies. Investigators with the U.S. Agricultural Research Service (ARS) conducted a pilot study in 2001 with eight volunteers, all with type 2 diabetes. They found that by drinking six cups of oolong daily for eight weeks, the volunteers were able to lower their blood sugar levels by 15 to 20 percent. Another study, from Taiwan, published in Diabetes Care in 2003, seemed to show that drinking oolong tea (while also taking drugs to lower blood sugar) significantly lowered blood sugar when compared to drinking water. The researchers concluded that the combination was more effective than the drugs alone.
3. In 2011, ARS researchers published results of a study showing that drinking oolong tea did not improve glucose metabolism in non-diabetic adults.
4. The possibility that oolong tea can boost fat oxidation comes from an investigation of the long-held Chinese belief that this tea can help control body weight. In 2001, ARS researchers tested four different beverages on 12 male volunteers for three consecutive days. The researchers found that the energy expenditure of the volunteers was higher and that their subjects burned 67 more calories per day when they drank tea instead of an equal amount of plain water. Also, the volunteers’ fat oxidation was 12 percent higher after they drank tea.
5. In an animal study, those given antioxidants from oolong tea were found to have lower bad cholesterol levels