What role does the skin play in proper calcium absorption from the digestive tract?
1 Answer
Skin is the main source of vitamin D. Vitamin D helps in calcium absorption from the digestive tract.
Explanation:
The UV light from the sun initiates a chemical reaction in our skin. This reaction produces vitamin D3 (also known as cholecalciferol) from 7- dehydrocholesterol.
About 20% vitamin D comes from the dietary source. But the vast majority (80%) is produced in the skin.
Vitamin D3 produced in the skin is hydroxylated two times (first in the liver then in the kidney) and produce 1,25-Dihydroxyvitamin D3 (1,25 Dihydroxycholecalciferol). This is the active form of vitamin D.
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The activated vitamin D has the following functions :
 Among these functions, calcium homeostasis is an important one. Active vitamin D increases the absorption of calcium and phosphate from the intestine, thus maintaining the homeostasis of calcium.
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So, skin plays an important role in proper absorption of calcium from the intestine, by producing vitamin D.
