The health benefits of tea are primarily attributed to its polyphenols content. Flavonoids are polyphenolic compounds that appear in tea, cocoa, fruits, vegetables and wine. Flavonoids contribute significantly to taste and color, and help maintain certain normal, healthy body functions.
A diet rich in flavonoids is generally associated with helping to maintain normal, healthy heart function. All teas from the Camellia Sinensis plant, such as black, green, oolong and white (but not herbal) teas naturally contain between 100 to 300 mg of flavonoids per serving. Though tea is a natural source of flavonoids, it is not a substitute for fruits or vegetables, which provide a wide range of nutrients such as flavonoids and essential vitamins and minerals.
The type and quantity of flavonoids found in different types of teas depends on processing steps that the tea leaves undergo. A major step in tea production is the halting of the oxidation process at a predetermined stage, depending on the type of tea. For example, black tea is well oxidized compared to green and Oolong tea.
Black, green, white and oolong teas are rich natural sources of flavonoids. The majority of flavonoids are infused from the tea leaves to the brew after 4 minutes of brewing (without stirring or squeezing).
Teas come from the same plant, but their flavonoid profile is not the same. The processing of tea determines the amount of flavonoids found within each cup. Green tea undergoes a very minimal fermentation process and is often referred to as the unfermented tea. Black tea is called the fully fermented tea because it undergoes the whole fermentation process. During fermentation, black tea develops different types of flavonoids. Unfermented teas are rich in catechins which research has shown contain anti-cancer properties while fermented teas are high in enzymatically polymerized catechins, which have proven cardiovascular disease fighting properties. These flavonoids have antioxidant abilities and they may help prevent heart disease and some types of cancer. White and green tea have a large percentage of flavonoids called catechins. As the leaves ferment to become black tea, some of the original flavonoids change. Black tea retains a small amount of the same catechins as green tea, but its primary flavonoids are theaflavins and thearubigins. About 70 percent of the total flavonoids in black tea are thearubigins.
However, research is ongoing and more studies are needed to confirm black tea’s health benefits.
One of the primary reasons for Green tea’s rise in popularity as “the” drink of choice for today’s health conscious consumers is due to its assumed anti-cancer effect due to the high level of catechins found within. Chemically speaking, catechins are simple forms of flavonoids. On the other hand, black tea is known for its anti-cardiovascular disease effect because it is rich in complex catechins such as theaflavins and thearubigins, which lowers cholesterol in the body and speeds metabolism.
Note that while tea is a natural source of flavonoids, it is not a substitute for fruits or vegetables, which provide a wide range of nutrients such as flavonoids and essential vitamins and minerals. Please consult your doctor regarding a diet/nutritional plan that is right for you.
The flavonoids in black tea are acknowledged as antioxidants, but research into their specific effects on your body is relatively new. For example, a review of research published in 2011 noted that the role of flavonoids in black tea had not been thoroughly investigated. Their potential ability to contribute to your health was illustrated in a study published in the journal “Molecules” in March 2007. Researchers used several different methods to extract flavonoids from black tea. While some extracts retained more flavonoids than others did, each one was tested and showed antioxidant and antibacterial activity.
Although it was once thought that the antioxidant activity of the tea flavonoids may also decrease the risk of many cancers and neurodegenerative diseases such as Alzheimer’s disease, scientists now believe that it is the ability of tea flavonoids to control gene expression that may prevent such diseases. Tea flavonoids can bind with non-heme iron — the main form found in plants, dairy products and most nutritional supplements — and reduce its absorption. Therefore, it is best to drink tea well before or after a meal if you are concerned with iron absorption.