Table 2 Constituents in tea and their functions on the body

Potassium

140–300

1000–3400

Maintain body fluid balance

Magnesium

1.5–5

310–420

Maintain normal glucose metabolism

Manganese

3.8–8

2–5

Maintain the activity of enzymes related to reproduction and bone

Fluorine

1.5–5

1.5–4

Prevent dental decay

Calcium

3–4

800

Contribute to bone growth

Sodium

2–8

2000

Maintain body fluid balance

Sulfur

5–8

Contribute to circulating metabolism

Iron

0.6–1

15–20

Related to hematopoiese

Copper

0.5–0.6

2

Participate in the action of enzymes

Silicon

0.2–0.5

20–50

Improve bone development

Zine

0.2–0.4

15

Improve growth and development

Selenium

Trace

0.05–0.25

Enhance immune function

Nickel

0.05–0.28

0.3

Maintain normal metabolism

Aluminum

0.4–1

 < 40

Not necessary

Lead

Minimal amount

 < 0.03

Not necessary

Polyphenols

3461–3644 (green tea)

Antioxidant, antibacteria, antivira, anticancer, lowering blood lipid [131]

1290–2176 (black tea)

Tea pigment

200–1000 (black tea)

Antioxidant, lowering blood lipid [132]

Flavonoid

276–375

Antioxidant, anticancer [133]

Tannins

354–591 [129]

Combating oxidative stress, antipathogenic microorganism [134]

Caffeine

200–400

Stimulating the brain and the heart, diuresis

Polysaccharid

10–50

Regulating immune function, lowering blood glucose [135]

Cellulose [130]

1000–2000

25,000

Helps digestion, reduces blood lipids, and inhibits lipid peroxidation [136]

Chlorophyll

60–120

Very little

Antioxidant, anticancer [137]

Carotene

0.7–2 (green tea)

1000 U

Preventing blindness and cataract, anticancer

Vitamin B

0.8–1.3

1.5–2

Benefit for the skin and nerves

Vitamin C

5–30

50–100

Anti-scurvy, increase immune function

Vitamin E

2–8

10

Anti-oxidant/aging, balance lipid metabolism