Oolong tea is a semi-fermented tea, somewhere between green and black tea. In the west, oolong tea makes up a small percentage of overall tea consumption. It is prized for its complex flavor and ability to hold flavor over multiple steepings.
As a semi-fermented tea, it has antioxidants found in both green and black teas. Theoretically, it should have a wider range of health benefits. However, the science is less established than it is with green or black tea.
Oolong and Weight Loss
According to a preliminary US Agricultural Research Service study, oolong tea consumption results in a higher energy expenditure, with more calories burned and oxidized.
Physiologist Dr. William Rumpler, of the US Agriculture Research Services’ Diet and Human Laboratory, investigated oolong tea’s weight loss benefits. Participants in the study noted higher energy expenditure, with more calories burned, and fat oxidized:
- Energy expenditure (EE) levels were about 3% higher when they drank either the full strength oolong tea or the caffeinated water versus the non caffeinated water.
- Participants burned an average of 67 more calories per day when drinking the full strength oolong tea.
- Participants increased fat oxidation (fat burning) by 12% after consuming the full strength oolong tea versus the caffeinated water.
A 2003 Japanese study compared the benefits of oolong tea and green tea on weight reduction. This small, preliminary study found that drinking oolong tea resulted in greater energy expenditure than green tea.
When identifying why oolong performed better, they found that although green tea had higher caffeine and EGCG content, the concentration of polymerized polyphenols was significantly higher in oolong tea.
These findings show that it’s the polymerized polyphenols, highest in oolong tea, that link tea to burning fat, not just the caffeine or just the combination of caffeine and EGCGs. Furthermore, the rest of the compounds compared in the teas were similar or equal to one another with no marked differences, reinforcing the results.
Oolong and Heart Disease
In a population study published in 2010, oolong tea consumption was associated with a reduced risk of mortality from cardiovascular disease. 76,979 adults, from 40 to 79, were free of stroke, heart disease, and cancer at the start of the study. When participants were asked about their beverage consumption, the researchers determined that those who drank coffee, green tea, and/or oolong tea on a regular basis had a lower risk of heart disease.
Other Health Benefits of Oolong
Other health benefits attributed to drinking oolong are inferred by the antioxidants that are shared with green and black teas. Tea in general is associated with antioxidant and anticancer activity. The mineral content found in tea promotes healthy bone structure. In addition, the caffeine content in oolong helps improve focus and concentration.
- U.S. Department of Agriculture: Brewing Up the Latest Tea Research http://www.ars.usda.gov/is/ar/archive/sep03/tea0903.htm
- Komatsu T, Nakamori M, Komatsu K, Hosoda K, Okamura M, Toyama K, Ishikura Y, Sakai T, Kunii D, Yamamoto S. Oolong tea increases energy metabolism in Japanese females.J Med Invest. 2003 Aug;50(3-4):170-5.
- Chung S. Yang and Zhi-Yuan Wang. Tea and Cancer. JNCI J Natl Cancer Inst (1993) 85 (13): 1038-1049 doi:10.1093/jnci/85.13.1038
- Wu C, Yang Y, Yao W, Lu F, Wu J, Chang C. Epidemiological Evidence of Increased Bone Mineral Density in Habitual Tea Drinkers. Arch Intern Med. 2002;162(9):1001-1006. doi:10.1001/archinte.162.9.1001.
- Mineharu Y, Koizumi A, Wada Y, Iso H, Watanabe Y, Date C, Yamamoto A, Kikuchi S, Inaba Y, Toyoshima H, Kondo T, Tamakoshi A; and the JACC study Group. “Coffee, green tea, black tea and oolong tea consumption and risk of mortality from cardiovascular disease in Japanese men and women.” J Epidemiol Community Health. 2010 Jul 14.