Tea is the 2nd most consumed beverage in the world and there are multiple types, such as green, black, white, oolong and herbal infusions. Green tea is made by processing fresh tea leaves of the Camellia sinesis plant using heat or steam immediately after collection. This minimizes any oxidation process, which makes it unique from other types of tea. Camilla sinensis contains polyphenols and catechins. The different types of catechins in green tea are EGCG, epigallocatechin, epicatechin-3-gallate, and epicatechin, EGCG being the most prominate out of all of them. These catechins comprise 30%-40% of the dried tea leaves and are known to be powerful antioxidants. Studies have suggested that these catechins can prevent the formation of free radicals, which cause damage to your body and ultimately cell death. They have also been known to support various health functions such as being anti-inflammatory, immune regulatory, anti-cancer, cardiovascular protective, and hepatoprotective.

Green tea has shown to reduce the risk of cognitive impairment, decline and disorders. Cognitive disorders are a category of mental diseases that affect memory, language, learning, and problem solving and are caused by a complex of genetics and environmental factors. Studies showed that green tea intake could delay the progression of cognitive impairment and improve cognitive function in the elderly, and was shown to correlate with a lower prevalence of cognitive impairments in adults. The studies show that green tea is neuroprotective and reduces the oxidative stress which helps improve learning and memory deficits. Although, there was no conclusive evidence that green tea is beneficial to Alzheimer's disease.

Cardiovascular disease is the leading cause of morbidity, mortality and disability worldwide. Green tea has been shown to reduce the risk factors, such as hypertension, hyperglycemia, and hyperlipidemia. Hyperlipidemia is due to abnormalities in the metabolism of lipids in the body, which builds up as athersclerotic plaque and can cause cardiovascular disease.

Green tea has been shown to lower total cholesterol and LDL. The catechins have a direct inhibitory effect on the creation of cholesterol. The effects of green tea are similar to statins, which are a medication that help reduce cholesterol synthesis and increase the LDL receptors in the body. On average, intake of green tea showed lower total cholesterol and LDL on blood tests. There was not a significant difference in the HDL results. Tea is cardioprotective due to its inhibition of oxidation, decreasing vascular inflammation and improvement in blood lipid concentrations such as total cholesterol and LDL.