There are four fat-soluble vitamins that do not dissolve in water, and green tea contains three of them: vitamins A, E, and K.
These components remain in the tea leaves even after steeping in hot water, so to ingest them, one must consume the tea leaves themselves.
Vitamin A
Several types of vitamin A show health benefits in the body, such as retinol and retinoic acid, among others.
The absorption mechanism into the body includes direct absorption of retinol from the small intestine and absorption of beta-carotene and other substances in the small intestine as precursors to retinol, which is then synthesized within cells. Some of the retinol is converted into retinoic acid.
The functions of vitamin A are as follows:
Retinol
- Normalizes vision by forming the pigment (rhodopsin)
- Maintains the health of the eyes and skin mucous membranes and strengthens resistance
Retinoic Acid
- Promotes growth
- Prevents keratinization of epithelial cells
- Prevents and suppresses cancer
Vitamin E
Once ingested, it is absorbed from the small intestine, transported to the liver through the lymphatic system, and carried to various tissues by transport proteins.
Vitamin E has antioxidant effects and helps maintain immune function. Its specific benefits include:
- Preventing arteriosclerosis
- Maintaining the function of white blood cells
- Maintaining reproductive function
- Vitamin E is known to enhance the effects of vitamins A and C. Its antioxidant function is enhanced by vitamin C, which also prevents the oxidation of vitamin A.
Vitamin K
There are two types of vitamin K: K1 (phylloquinone) and K2 (menaquinone), with K1 being especially abundant in green tea.
Once ingested, it is absorbed from the small intestine, transported to the liver through the lymphatic system, and stored there.
Vitamin K has the effect of clotting blood to stop bleeding during injuries. Additionally, it has preventive effects against osteoporosis and arteriosclerosis.