As I am Japanese, I am often asked about green tea and many people are surprised when I say green tea contains caffeine.

Here are some other facts and reported benefits of green tea.

1) One cup of coffee contains 100-150mg of caffeine; a cup of green tea has only about 25mg of caffeine.

2) Green tea contains two other stimulants in addition to caffeine. These substances, theobromine and theophylline, may affect heart rate and the central nervous system in a way somewhat similar to caffeine. These substances are also found in chocolate.

3) Green tea has a natural antibiotic effect, killing bacteria in the mouth and improving the immune system to protect from cold and flu.

4) Green tea also contains Catechin which is an antioxidant that fight and may even prevent cell damage. Catechin also lowers cholesterol and blood pressure.

5) Green tea has been shown to improve blood flow and lower cholesterol.

6) Green tea promotes greater activity in the working memory area of our brains.

7) Green tea helps to block the formation of plaques that are linked to Alzheimer’s disease.

8) Green tea helps keep blood sugar stable in people with diabetes.

Below are the caffeine levels for different types of tea. All of the following caffeine levels are based on an 8-ounce serving:

• Black tea (14-61 mg)

• Green tea (24-40 mg)

• Generic iced tea, instant (26 mg)

• Arizona iced tea, lemon (11 mg)

• Lipton iced tea, lemon (5-7 mg)

How much caffeine a day?

100mg green tea (green tea cup size = half size of coffee cup) contains 20mg caffeine.

The World Health Organization recommend limiting caffeine intake to 300mg a day. More than 500mg a day may cause symptoms of addiction, trouble sleeping, sensitivity of nervous system, vomiting and stomach problems.

Even if you drink green tea regularly, you also need to take care of yourself in other ways.