Even organically grown green teas have been shown to contain lead, which is absorbed by the plant from the environment, particularly tea grown in China. When traditional green tea is steeped, about 90% of the lead stays in the leaf, which is discarded. With matcha, since the whole leaf is consumed, you will ingest more lead. One independent group, ConsumerLab.com, which tested teas, estimates that a cup of matcha may contain as much as 30 times more lead than a cup of green tea. Therefore, they recommend drinking no more than one cup daily, and not serving it to children.

If not taken with sugar, the alkaline nature of green tea helps reduce the blood glucose level. Moreover, the antioxidant and astringent qualities of green tea ensure good health and better functioning of the pancreas. Improving the function of the pancreas means a more efficient and regulated secretion of insulin and the subsequent improvement in decomposing and absorbing of sugar. This increase in effective functions can help prevent the onset of diabetes.
A well-known compound found in green tea is called EGCG (which stands for epigallocatechin-3-gallate). EGCG is associated with enhanced metabolic activities that may prevent weight gain or assist with weight maintenance. Some of the ways that EGCG seems to work is by boosting thermogenesis (the body producing heat by using energy) and suppressing appetite, although not every study has found evidence that these effects are substantial.

Rooibos tea is anti-inflammatory in nature, which means that it reduces blood pressure and scavenges free radicals like other antioxidants. Quercetin, another powerful antioxidant found in rooibos tea, has been linked to preventing a wide variety of heart conditions. It promotes an increase in HDL cholesterol (good cholesterol) and inhibits the LDL cholesterol (bad cholesterol) from binding to the walls of arteries and blood vessels.