Both green and black tea come from the same plant, a shrub native to Asia called Camellia sinesis. The tender young leaves become either green, oolong, or black tea through the subsequent drying and processing. Green tea comes from young leaves that are cured through gentle heat drying. Black tea may contain older, larger leaves, often cured through more intense heat. The difference in leaf age as well as in curing processes creates the delicate flavor and green color of green tea or the robust, slightly bitter taste of black tea.
No matter which tea you prefer, both black tea and green tea confer many health benefits. Tea is rich in antioxidants, elements that scavenge or neutralize free radicals. Free radicals are molecules with unpaired electrons. They seek an electron to complete a pair, which usually results in 'stealing' an electron from another source. This can damage a cell's DNA, causing damage that's replicated every time a cell divides. Certain substances called antioxidants prevent free radical damage. Tea is rich in antioxidants, but so are many fruits and vegetables.
According to the Tea Association of the United States, both green and black tea confers many health benefits. Mostly, teas lower the risks of:
Heart attack and heart disease
Green Tea Has More Vitamin C Than Black Tea
It's absolutely true that green tea has more vitamin C than black tea. According to Amazing Green Tea, green tea contains 436 mg of vitamin C while a comparable cup of black tea contains 239 mg of vitamin C. While you'll have to drink five cups of the stuff, you can indeed get about as much vitamin C from green tea as from a lemon. Green tea also contains magnesium and manganese, as well as some B vitamins.
There are more abundant sources of vitamin C, however. If obtaining vitamin C is your primary reason for drinking green tea, you'd be better off eating more fruits and vegetables. If your goal is to increase your intake of antioxidants for health, green tea is a better choice than black tea.