Short-term studies have shown that drinking tea may improve vascular reactivity—a measure of how well your blood vessels respond to physical or emotional stress. There's also evidence that drinking either black or green tea may lower harmful LDL cholesterol levels. Blood pressure may also dip slightly in people who drink tea, but results from these studies have been mixed.
Others credit various Buddhists in the 500s BC and subsequent centuries for the discovery of tea. Buddhists would travel between India and China spreading their religion, culture and ritual of tea. Buddhist monks grew, harvested and produced tea much like their Catholic counterparts in European monasteries did with grapes and wine. The monks’ habit of tea drinking for physical refreshment, to aid meditation and as a substitute for alcohol developed into a spiritual and social practice that spread across China.
Because matcha is made from high-quality tea, and the whole leaves are ingested, it’s a more potent source of nutrients than steeped green tea. In addition to providing small amounts of vitamins and minerals, matcha is rich in antioxidants called polyphenols, which have been tied to protection against heart disease and cancer, as well as better blood sugar regulation, blood pressure reduction, and anti-aging. Another polyphenol in matcha called EGCG has been shown in research to boost metabolism, and slow or halt the growth of cancer cells.
Scientists have also discovered that the antioxidants flavonoids may also protect the brain from oxidative stress. The scientists extrapolated that a human would need to drink about three liters of liquid infused with 0.5 percent of the catechins to get similar effects. However, because humans ingest other antioxidants in the form of vitamins and plant polyphenols, it’s likely that a much lower quantity could be effective in protecting memory.

When I was conducting research into South Africa’s native herbs, I was served rooibos everywhere I went. Red in the cup, fragrant to the nose and pleasing to the palate, rooibos soon became a favorite. In every meeting, I looked forward to that red tea, which is one of the only native herbs of South Africa to achieve significant commercial status.  My wife and I keep it in the tea cupboard at home, and we often turn to rooibos when we want a cup of tea without caffeine.
The risks associated with green tea are the same as those associated with any other kind of tea (common black tea, White Tea etc.) and are primarily due to the content of caffeine and tannin. The contraindications may vary with the percentage of caffeine and tannins in it. Most people might be familiar with these adversities, but it is still important to review and summarize the components responsible, as well as the associated risks.
Observational studies found a minor correlation between daily consumption of green tea and a 5% lower risk of death from cardiovascular disease. In a 2015 meta-analysis of such observational studies, an increase in one cup of green tea per day was correlated with slightly lower risk of death from cardiovascular causes.[13] Green tea consumption may be correlated with a reduced risk of stroke.[17][18] Meta-analyses of randomized controlled trials found that green tea consumption for 3–6 months may produce small reductions (about 2–3 mm Hg each) in systolic and diastolic blood pressures.[18][19][20][21] A separate systematic review and meta-analysis of randomized controlled trials found that consumption of 5-6 cups of green tea per day was associated with a small reduction in systolic blood pressure (2 mmHg), but did not lead to a significant difference in diastolic blood pressure.[22]
Rooibos contains polyphenols that have anti-inflammatory, antiviral, and antimutagenic qualities. Polyphenols are organic chemicals that are often praised for their antioxidant capabilities. Studies suggest that regularly drinking organic red rooibos tea provides the liver with potent antioxidants, helping the organ to improve detoxification. Antioxidants act as scavengers of free radicals throughout the body, which are detrimental byproducts of cell metabolism that can cause cancer and heart diseases. Aspalathin and nothofagin are two other vital antioxidants that rooibos tea contains, making it a great beverage to boost your immune system and protect your body against all types of diseases.
Update... I made this tea cold and it was amazing! I read that another reviewer said that it had no flavor? All I can imagine is that maybe he/she is not letting the bag seep long enough? Or maybe using too much water? For my cold brew, I boil 4 cups of water and seep 6 bags for about 30 min. I then add 1 Tbsp honey and about 4-6 Tbsp fresh lemon juice. I keep that in the fridge in a glass container. When I want a drink, I fill a tall glass with ice and pour it over. As the ice melts, it dilutes the tea and is the perfect flavor! Add a sprig of fresh mint in your glass and it's even better! This is my everyday drink... delicious hot or cold!
Green tea, however, is considered to have originated in China. It is said that even today the word “tea” in China refers only to green tea, not to the general category of tea as it does in the West. China’s Yunnan province is considered to be the original home of the Camellia sinensis plant species. In fact, 260 of the world’s 380+ varieties of tea can be found in Yunnan.