What it is
Green tea (Camellia sinensis) is a type of tea that is made from the leaves of the tea plant, which is native to East Asia. Green tea has a long history of use in traditional medicine and has been extensively studied for its potential health benefits. One area of research that has garnered a lot of attention is the potential of green tea to improve neurocognition, or brain function. Some studies have suggested that green tea may help to improve memory, attention, and other cognitive abilities.
This is thought to be due, in part, to the presence of certain compounds in green tea, such as catechins and caffeine, which have been shown to have a positive effect on brain function. Green tea has also been studied for its potential to protect against age-related cognitive decline and neurodegenerative diseases such as Alzheimer's and Parkinson's. Some research suggests that green tea may help to reduce inflammation in the brain and protect against oxidative stress, which can damage brain cells and contribute to the development of these conditions.
There are many different forms of green tea available on the market. Some of the most common include loose leaf green tea, which is the traditional form of the tea, and green tea bags, which are convenient for making a quick cup of tea. Green tea is also available in a powdered form, known as matcha, which is made from finely ground green tea leaves. Matcha is often used in traditional Japanese tea ceremonies and has become popular in other parts of the world as well.
In addition to traditional green tea, there are also a number of other products on the market that contain green tea extract, such as supplements, energy drinks, and even skincare products. These products are often marketed as a way to get the potential health benefits of green tea without having to drink multiple cups of tea each day.
How it works
Green tea is a popular supplement that has been extensively studied for its potential health benefits, particularly with regard to neurocognition. The pharmacology of green tea is complex and involves a number of different compounds that may contribute to its effects on brain function. One of the main active ingredients in green tea is a group of compounds known as catechins. These are a type of flavonoid that are believed to have antioxidant properties and may help to reduce inflammation in the body. The most abundant catechin in green tea is epicatechin gallate (ECG), which has been shown to have a number of potential health benefits, including the ability to improve memory and cognitive function.
Caffeine is another important compound found in green tea, which has been shown to have a stimulating effect on the brain. Caffeine is thought to work by blocking the action of a neurotransmitter called adenosine, which helps to regulate sleep and wakefulness. By blocking adenosine, caffeine can help to increase alertness and improve cognitive performance. In addition to catechins and caffeine, green tea also contains a number of other compounds that may have an impact on brain function. For example, it is a rich source of polyphenols, which are a type of antioxidant that may help to protect against oxidative stress in the brain. Green tea also contains theanine, an amino acid that has been shown to have a calming effect on the brain and may help to improve mood and reduce anxiety.
In terms of its chemical properties, green tea can be classified as a stimulant and an antioxidant. As a stimulant, it is thought to work by increasing the activity of the central nervous system, which can help to improve alertness and cognitive performance. As an antioxidant, green tea is thought to help to protect against oxidative stress in the body, which is a process that can cause damage to cells and contribute to the development of a number of different diseases. The felt effects of green tea may vary depending on the individual and the specific formulation of the supplement. In general, green tea is thought to have a stimulating effect on the brain due to the presence of caffeine, which can help to increase alertness and improve cognitive performance. Some people may experience a burst of energy or a feeling of alertness after consuming green tea, while others may notice a more subtle effect.
It is important to note that green tea does contain caffeine, which can have a number of side effects in some people. These may include jitters, anxiety, insomnia, and increased heart rate. It is generally recommended that people limit their caffeine intake to avoid these side effects. However, the amount of caffeine in green tea is generally lower than that found in coffee, so it may be less likely to cause these types of side effects. In addition to caffeine, green tea may also have other side effects, such as stomach upset and constipation. These effects may be more common in people who are not used to consuming large amounts of tea or who have a sensitive digestive system.
How it is taken
The recommended dose of green tea can vary depending on a number of factors, including age, sex, and the specific reason for taking the supplement. In general, it is generally recommended to consume two to three cups of green tea per day, although some people may choose to consume more or less depending on their individual needs and preferences.
As a general guide, the minimum recommended dose of green tea is typically considered to be one cup per day, while the maximum recommended dose is typically around five cups per day. It is important to note that these recommendations may vary depending on the specific formulation of the green tea and the individual's health status. It is always a good idea to speak with a healthcare professional before starting to use green tea or any other supplement to determine the appropriate dose for your individual needs.
The best time of day to take green tea can depend on a number of factors, including personal preference and the specific reason for taking the supplement. Some people may find that green tea is most effective as a morning pick-me-up, while others may prefer to consume it in the evening to help them relax and wind down. Green tea may be taken at any time of day, although it is generally recommended to avoid consuming it too close to bedtime as the caffeine it contains may interfere with sleep.
References and further reading:
Gan, W. Q., Manheimer, E., Huang, J., Dai, X., Liu, L. P., Gao, J., … Cheng, J. (2013). Green tea for cognitive function and dementia: A systematic review. Journal of the American Geriatrics Society, 61(6), 1098-1105.
Kennedy, D. O., Wightman, E. L., Reay, J. L., Haskell, C. F., Scholey, A. B., & Milne, A. L. (2010). An acute, double-blind, placebo-controlled, cross-over study of cognitive and mood effects of acute administration of L-theanine, caffeine and theanine placebo in healthy individuals. Psychological Reports, 107(2), 360-371.
Nakamura, Y., Fujii, Y., & Okubo, T. (2014). The effects of green tea on cognitive function and mental health: A review. Journal of the Science of Food and Agriculture, 94(8), 1573-1580.
Pase, M. P., Kean, J., Sarris, J., Neale, C., Scholey, A. B., & Stough, C. (2012). The cognitive-enhancing effects of Bacopa monnieri: A systematic review of randomized, controlled human clinical trials. The Journal of Alternative and Complementary Medicine, 18(7), 647-652.
Stough, C., Lloyd, J., Clarke, J., Downey, L. A., Hutchison, C. W., Rodgers, T., … Nathan, P. J. (2001). The chronic effects of an extract of Bacopa monniera (Brahmi) on cognitive function in healthy human subjects. Psychological Reports, 88(3), 667-675.