红茶和绿茶哪个更健康?
Tea is beloved by people all over the world. Both green and black tea are made from the leaves of the Camellia sinensis plant. The key difference between the two is that black tea is fermented and green tea is not. To make black tea, the leaves are first rolled and then exposed to air to trigger the fermentation process. This reaction causes the leaves to turn dark brown and allows the flavors to heighten and intensify. On the other hand, green tea is pan-fried to prevent fermentation and thus is much lighter in color than black tea. While green and black tea differ, they may provide some of the same health benefits. Both green and black tea are rich in a group of protective antioxidants called polyphenols. Even more specifically, they both contain flavonoids, a subgroup of polyphenols. The flavonoids in both green and black tea are thought to protect your heart. And green and black tea both contain caffeine, a known stimulant. Green tea contains less caffeine than black tea — about 35 mg of caffeine per 8-oz (230-ml) cup for green tea, compared to 39–109 mg for the same serving of black tea. Caffeine stimulates your nervous system by blocking the inhibitory neurotransmitter adenosine. It also aids the release of mood-enhancing neurotransmitters such as dopamine and serotonin. Now the difference. Green tea contains EGCG, an antioxidant which in test-tube and animal studies has been shown to fight cancer and bacterial cells and protect both your brain and liver. But black tea contains beneficial theaflavins. Theaflavins are a group of polyphenols that are unique to black tea. Theaflavins are unique to black tea. Through their antioxidant effects, they may improve blood vessel function and support fat loss. So green and black tea have similar health benefits, including for your heart and brain. Their antioxidant profiles differ, but while green tea may have more powerful antioxidants, scientific evidence does not strongly favor one tea over the other. |