Is Vitamin D a double-edged sword?
For most people, vitamin D taken orally or in moderate doses intravenously is safe unless overdose is used.
However, long-term daily use of more than 4,000 units (IU) of vitamin D may be unsafe and increase the risk of hypercalcemia. However, short-term treatment of vitamin D deficiency requires a higher intake, which can improve health when consumed under the guidance and supervision of medical personnel.
Vitamin D has two different systems for the body.
①Calcium system: for calcium and bones.
② Non-calcium system: including the immune system, prostate, other glands, skin, intestines, brain, muscles, etc.
Calcium System – Vitamin D Pathway
Primary sources of vitamin D include: sunlight, food, and supplements.
The pathway for the conversion of calcium system vitamin D: through liver → kidneys → cells → bones and skeletal system.
After entering the human body, vitamin D first reaches the liver and binds to a protein.
Why is it necessary to bind to protein? Because it can stay in the blood longer after binding. The half-life of vitamins not bound to proteins is 24 hours.
To extend its half-life to three to four weeks, it is bound to protein. This allows vitamin D to be stored in the blood and then released by the kidneys when needed. This vitamin D can then enter cells and eventually enter the bones.
• Non-calcium system – Vitamin D pathway
The non-calcium system is the vitamin D system that controls all other functions and is separate from the calcium system. In other words, the non-calcium system does not pass through organs such as the liver and kidneys, but directly enters the non-calcium system to exert its effects (directly enters the immune system, prostate, other glands, skin, intestines, brain, muscles, etc.).
In the blood, vitamin D attached to protein hardly enters the non-calcium system, and only a very small amount of D enters.
If you have liver damage, are pregnant, have cancer, or are infected with a virus, the protein binds more tightly to vitamin D, and more vitamin D is needed to be released.
This is why only trace amounts of vitamin D enter the non-calcium system from the blood.
Dr. Berg shared that most vitamin D research has been done on calcium systems, requiring 600 to 800 IU daily, or a serum vitamin D level of 25-30 ng/mL. He said this amount may be sufficient for bone health, but not enough for vitamin D's other functions.
However, from a preventive perspective, supplementing vitamin D to an adequate level still plays a very important role in reducing the occurrence of bone diseases and fractures. Therefore, high-risk groups should pay special attention and undergo screening. When there is a deficiency or deficiency, they should start taking vitamin D supplements or treatment to the normal range to improve their health.
(Chang Foundation e-Newsletter 2020JUL)