Green Tea and Your Health
Green tea is a very popular drink right now because of the supposed health benefits that come from drinking it. It is available as a cold bottled beverage, in tea bags, and in supplement (powder or pill) form. Even just googling “green tea benefits” makes it seem like a superfood, with claims that it can make you smarter, help you lose weight, reduce your risk of cancer and Alzheimer’s, and prevent cavities. Some of these claims have more valid scientific evidence than others. But what exactly is green tea?
Green tea, along with all other teas, comes from the Camellia Sinensis plant. For green tea, once the leaves are picked, they are heated and then quickly dried. In order to produce other teas such as black tea, these same leaves are exposed to air and oxidized. When the dried green tea leaves are put into hot water, green tea is made. Tea originated in China, but tea manufacturing has spread to other countries in Eastern Asia.
Green tea contains about 12-40 mg of caffeine, which is slightly less caffeine that a cup of black tea, and much less than a cup of coffee. Green tea is a good source of antioxidants, which are a type of chemical that prevents processes that damage cells. Green tea also has plant “flavonoids”, which are beneficial to our health. Some animal studies have shown that these flavonoids have some protection against cancer, decrease blood sugar spikes after eating, and enhance the immune system. They may also lower LDL (AKA “bad”) cholesterol, and blood pressure, keeping our hearts healthy. Green tea can lower the mouth’s acidity therefore helping to prevent cavities (but adding a lot of honey or sugar can have the opposite effect!). A cup of green tea also includes some Vitamins A and C, and minerals Zinc and Manganese. Along with physical health, drinking tea can improve our mental health by making us feel relaxed. Matcha, finely ground green tea leaves, can provide high amounts of vitamins A, C, and E since it is so finely ground.
Another reason green tea so popular is claims that it boosts physical performance, speeds up metabolism (how quickly the body can break down food and absorb nutrients) and helps burn fat. Green tea extract is found in many supplements advertised to help “burn fat”. This information comes from various green tea studies, some of which have found that green tea can increase how many calories someone burns in one day. However the amount of calories green tea can help burn varies from study to study, which suggests that it depends on the individual rather than the green tea itself.
Because of this, many people believe drinking a lot of green tea or taking supplement pills will help them lose weight. However drinking lots of green tea is unlikely to lead to major weight loss without a diet change or exercise. Drinking green tea in place of sugar-sweetened beverages can help with weight loss though. For example, try drinking a cup of green tea without sugar instead of juice or soda to decrease the total added sugar and calories you consume in a day.
While green tea has many benefits, it is important not to drink too much or take highly concentrated supplements. One reason is that the caffeine amount, while low, could lead to sleeping problems or headaches. Additionally, the flavonoids may have an affinity for latching onto iron, which could lead to iron deficiency. Because of this, it is not recommended to have more than five cups a day.
-Nutrition student Marisa