A cup of green tea is a good way to start your day.

"It's the healthiest thing I can think of to drink," says Christopher Ocher, PhD. He is a research scientist in nutrition at the Icahn School of Medicine at Mount Sinai. "Green tea is beyond a super food."

In the past 20 years, thousands of studies have shown green tea’s benefits.

Healthy cells

Why is green tea so good for you? "It's all about the Cate chin content," says Beth Rear don, RD, a Boston nutritionist. Cate chins are antioxidants that fight and may even prevent cell damage. Green tea is not processed much before it is poured in your cup, so it is rich in Cate chins.

Healthy heart

Green tea has been shown to improve blood flow and lower cholesterol. A 2013 review of many studies
found green tea helped prevent a range of heart-related issues, from high blood pressure to congestive heart failure.

Brain health

What’s good for the heart is usually good for the brain, and your brain needs healthy blood vessels, too. In one Swiss study, MRIs revealed that people who drank green tea had greater activity in the working-memory area of their brains.  Green tea has also been shown to help block the formation of plaques that are linked to Alzheimer's disease.

Diabetes

Green tea seems to help keep blood sugar stable in people with diabetes. Because catechins lower cholesterol and blood pressure, they can protect against the damage a high-fat diet can cause, Ochner says.

Weight loss

Green tea can help increase and even change your metabolism, so you burn more calories from fat. Studies show that green tea can also help you keep weight off once you’ve lost it.

It's also a smart swap for sugary drinks. "All things being equal, if you sub 1-2 cups of green tea for one can of soda, over the next year you'd save over 50,000 calories," says Ochner. That's more than 15 pounds.

Cancer role

Studies on green tea’s impact on cancer have been mixed.  But green tea is known to aid healthy cells in all stages of growth. There are some indications green tea may help destroy cancer cells.

Less stress

Sipping tea helps you slow down and relax, Reardon says. An amino acid called theanine found in green tea can provide a calming effect.

For a healthy cuppa:

• Don't add green tea to boiling water. You'll kill helpful catechins. Better: 160-170 degree water.
• Add lemon. Vitamin C makes the healthy compounds in green tea easier to absorb. Dairy, on the other hand, makes it harder to absorb the catechins.
• Levels of the healthful compounds in green tea can vary. Rule of thumb: Pricier teas usually have more, and canned green-tea drinks have less.

Aim for at least four cups a day, two with caffeine and two without. Even more than that seems to have little health downside, other than the possible effects of caffeine, Ochner says. "There could not be a more simple way to improve your health," he says.