Green Tea Nutrition Facts
Flavan-3-ols, the type of flavonoids found in green tea and other teas, provide many of the anti-aging effects of green tea. Catechins in various types of teas are the polyphenols that seem to have the most potent antioxidant effects, according to Natural Standard, the leading and most respected reviewer of herbal compounds. Specific flavan-3-ols found in green tea include monomers (catechins) called:
- and gallate derivatives.
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.
Green tea also contains many other protective compounds, including:
- linoleum acid
- methylxanthines, including caffeine, theobromine and theophylline
- many different amino acids and enzymes (proteins make up about 15 percent to 20 percent of the leaves’ dry weight)
- Carbohydrate molecules, such as cellulose, pectins, glucose, fructose and sucrose
- Small amounts of minerals and trace elements like calcium, magnesium, chromium, manganese, iron, copper and zinc
- Small amounts of chlorophyll and carotenoids
- Volatile compounds like aldehydes, alcohols, esters, lactones and hydrocarbons
Some of the benefits of green tea associated with the consumption of these compounds include reduced allergies, eye health and better vision, skin health, improved immune function, enhanced endurance, and protection from free radical damage and cancer.
1. May Reduce Your Appetite
Does green tea really burn fat, and will drinking green tea help you lose more weight? According to some research findings, consuming antioxidants found in green tea, especially catechins and the compound called EGCG, may promote metabolic health and modestly prevent weight gain. When 11 studies and articles were included in one 2009 meta-analysis that was published in the International Journal of Obesity, researchers found that “catechins or an epigallocatechin gallate (EGCG)-caffeine mixture have a small positive effect on weight loss and weight maintenance.”
Overall, EGCG’s effects remain somewhat controversial; some studies have found only modest effects on metabolism, while others have found that consuming more EGCG alone without other lifestyle changes does not do anything significant to improve body weight.
2. Helps Protect Heart Health
A great deal of evidence from randomized controlled trials suggests that consumption of flavan-3-ols and anthocyanidin antioxidants, the types found in green tea, is beneficial for metabolic and cardiovascular health. When it comes to preventing many of the risk factors for heart disease, such as having high blood pressure or cholesterol levels, some evidence shows that green tea contains 10 beta-blocking compounds, seven calcium channel blockers and 16 diuretic compounds. It also has more ACE-inhibiting properties than many other plant foods that are commonly consumed, which helps increase the amount of blood your heart pumps and lowers blood pressure.
According to a study published in the journal Chinese Medicine, many of the beneficial biological effects of flavonoids on heart health seem to be due to cell-signaling effects that lower inflammation. Not only do flavonoids have anti-inflammatory capabilities, but they’re also antithrombogenic, antidiabetic, anticancer and neuroprotective compounds.
In 2004, scientists at the University of Newcastle studied the effects of black and green tea on Alzheimer's disease. In laboratory studies, both teas prevented the breakdown of acetylcholine, the neurotransmitter strongly linked with memory. The teas also inhibited enzymes known as BuChE and beta-secretase. These enzymes are found in protein deposits found in the brain of Alzheimer’s patients.
Japanese researchers published a study on green tea and its effect on the beta-amyloid protein plaques found in Alzheimer’s disease in the April 2008 issue of the Journal of Nutritional Biochemistry. The protein plaques associated with Alzheimer’s disease increase brain cell damage and death due to oxidative stress. The researchers found that green tea catechins reduced the level of damaging free radicals in the brains of rats. The green tea rodents showed much less plaque-induced deficits in memory compared to rodents that didn’t receive green tea and those that were infused with beta-amyloid proteins.
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.