Tea leaves have long been associated with good health.
Now researchers are investigating the relationship between tea leaves and a range of health conditions, from obesity and cancer to cardiovascular disease and diabetes.
The new study, published online July 16 in the journal PLoS One, found that a variety of tea leaves were more likely to contain flavonoids, the compounds found in some green tea leaves that help people fight inflammation.
A wide range of studies have linked the compounds to a wide range and range of beneficial health effects, but the exact composition of those compounds is still unknown.
“In this new study we looked at all types of tea and we focused on the flavonoid content of all tea leaves, so we were able to get a pretty good look at what was in each leaf,” said lead author Daniel Pappas, a research associate in the School of Chemistry and Biochemistry at the University of Southern California.
The study also examined how different types of green tea leafs reacted to different kinds of antioxidants, to see whether they were better or worse at fighting some diseases.
For instance, some green teas were more resistant to the effect of a substance called dihydrofolate reductase (DFR), which helps cells produce more free radicals, the chemical group of molecules that are known to cause inflammation.
Other green tea leaves, however, were more vulnerable to an antioxidant called anthocyanins, which help cells make more of the compound that helps fight inflammation, the researchers found.
The researchers also looked at the effects of certain types of antioxidants on the activity of enzymes in the liver and pancreas.
The findings suggest that some tea leaves might have a positive effect on the metabolism of certain compounds that help cells detoxify themselves, according to the authors.
The authors also examined whether some tea leaf types were better at killing certain kinds of cancer cells.
“It’s really interesting to see how different tea leaves react to different types and types of compounds and how that might impact how these compounds interact with the body,” said Pappos.
“The different types seem to be a good source of a variety and variety of benefits.”
The study was led by lead author Jonathan P. Janssen, a graduate student in the Department of Chemistry at USC.
The research was supported by the National Institute on Drug Abuse (grant numbers U01DA018271, U01AI077243, U23DA082531, U24DA092492, U25DA068774, and U31DA107575) and the National Institutes of Health (grants R01DA016664 and U01HD017523).
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Sources: The American College of Nutrition, U.S. Department of Agriculture, The University of California at Berkeley, The Harvard School of Public Health, The National Institutes on Drug Administration, The USDA National Agricultural Statistics Service, The U.K. Food Standards Agency, The United Kingdom Ministry of Agriculture and Food, The Department of Health, Education and Welfare, The Centers for Disease Control and Prevention, and The National Institute of Food and Agriculture.