Vitamin D3 is a fat-soluble vitamin and is regarded as a hormone precursor that acts on calcium and phosphorus metabolism.
Vitamin D3 is closely related to sunlight, so it is also called "sunshine vitamin". Vitamin D3 is mainly synthesized by the human body itself. The skin of the human body contains a type of cholesterol, which becomes vitamin D3 after exposure to sunlight. Therefore, if the child can fully receive direct sunlight on the skin for more than 4 to 6 hours, the vitamin D3 synthesized by itself can basically meet the needs.
What are the physiological functions of vitamin D3?
1. Improve the body's absorption of calcium and phosphorus, so that the levels of plasma calcium and plasma phosphorus reach saturation;
2. Promote growth and bone calcification, and promote healthy teeth;
3. Increase the absorption of phosphorus through the intestinal wall and increase the reabsorption of phosphorus through the renal tubules;
4. Maintain normal levels of citrate in the blood;
5. Prevent the loss of amino acids through the kidneys.