Word of Caution: Despite all of these health benefits of rooibos tea, there can be a downside for some people. Since rooibos is so powerful, it can interfere with treatments for various conditions, including chemotherapy for cancer patients. Also, rooibos has shown estrogenic activities in certain studies, so it might not be a good idea to use if you have hormone-sensitive cancer like breast cancer.
In 2009, King’s College researchers found that epicatechin may protect brain cells through mechanisms unrelated to its antioxidant ability, as epicatechin is one of the few flavonoids that can cross the blood-brain barrier. The King’s College researchers reported that somehow epicatechin protects brain cells from the negative effects of beta-amyloid plaques, although the exact mechanism of how this works is still not entirely know. (9)
“Red tea” is the name the Chinese use for what we in the west call “black tea.” All true tea comes from the same plant, Camellia sinensis. The differences between types of tea result from different methods of processing the leaves. For green tea, the tea leaves are steamed, rolled and dried, a method that preserves the content of polyphenols, antioxidant compounds that confer the well-known health benefits of tea. For black tea, the leaves undergo a process of oxidation that changes the color and flavor and reduces the content of polyphenols. Oolong is intermediate between green and black tea – in color, flavor and polyphenol content.
Green tea is a longtime treasure of China and Japan that is gaining popularity in America. It’s easy to understand why: the best green tea leaves are heated or steamed right after harvest, preserving their all-natural flavor and resulting in a nourishing beverage containing antioxidants. With about half the caffeine of black tea, you get the health benefits of green tea in every gentle cup. You can buy green teas in either loose-leaf or green tea bags.

African red tea's naturally sweet taste makes it easy to keep your added sugar intake low. According to the American Heart Association, most Americans consume too much added sugar in their diet, which can lead to weight gain and obesity. The association recommends consuming no more than 6 to 9 teaspoons of added sugar a day. Added sugar, and especially drinks high in added sugar such as sodas, have no nutritional benefits whatsoever, unlike rooibos, which has a number of associated health benefits.

Gardenias were originally found only in China and Japan, but today there are over 200 different species of gardenia, mostly hybrids, throughout the world. Gardenia fruit is used extensively in Traditional Chinese Medicine (TCM), where it is known as zhi zi. TCM uses gardenia primarily to promote calm, but it is also used to support bladder and urinary tract health.

To make green tea, the leaves are quickly steamed or heated to stop oxidation, the chemical process that causes browning. To make black tea, the leaves are crushed, torn, curled, or rolled and allowed to oxidize before being dried. This additional processing step degrades some of the flavonoids. As a result, black tea has slightly lower amounts of flavonoids than green tea.
The Alzheimer's Society commented that "this study adds to previous research that suggests green tea might help to reduce the risk of Alzheimer's disease. However, the researchers used a far higher dose of the active green tea chemical than would ever be found in the human body. More research is needed to see whether green tea is protective at a much lower dose, and to understand the mechanism involved."
Tea culture of Korea was actively suppressed by the Japanese during the Japanese forced occupation period (1910‒1945), and the subsequent Korean War (1950‒1953) made it even harder for the Korean tea tradition to survive.[70] The restoration of the Korean way of tea began in the 1970s, around Dasolsa.[70] Commercial production of green tea in South Korea only began in the 1970s,.[71] By 2012 the industry was producing 20% as much tea as Taiwan and 3.5% as much as Japan.[72][73] Green tea is not as popular as coffee or other types of Korean teas in modern South Korea. The annual consumption per capita of green tea in South Korea in 2016 was 0.16 kg (0.35 lb), compared to 3.9 kg (8.6 lb) coffee.[74] Recently however, as the coffee market reached saturation point, South Korean tea production doubled during 2010‒2014,[75] as did tea imports during 2009-2015,[76] despite very high tariff rate (513.6% for green tea, compared to 40% for black tea, 8% for processed/roasted coffee, and 2% for raw coffee beans).