Why supplement?
Supports bones and calcium absorption
Vitamin D helps the intestine absorb calcium and maintains bone mineralization. D3 (cholecalciferol) is a common supplement form. People with little sun or indoor lives are more often discussed for supplementation. Convert the label from mcg or IU. Put the use on calcium absorption and bone nutrition, and read status with 25(OH)D.
Maintains muscle function
Enough vitamin D helps maintain muscle function and balance-related performance, and also appears in immune-regulation nutrition discussion. Supplements more often choose D3 with a fat-containing meal. Read daily mcg/IU. Put the use on muscle and bone nutrition, not on self-chosen megadoses.
How to take it
IU–mcg conversion: 1 mcg vitamin D = 40 IU.
How oftenUse the recommended daily intake; the usual adult upper limit is 100 mcg (4,000 IU)/day unless a doctor advises otherwise.
What to watch
Cautions
People with kidney disease, parathyroid disease, high blood calcium, or who take calcium-containing medicines should ask a doctor first.
Do not self-treat vitamin D deficiency with high doses; adjust using blood tests.
· Long-term excess may cause nausea, thirst, or constipation
· Toxicity can cause high blood calcium, kidney injury, and heart-rhythm problems.
Long-term dependenceNot addictive; fat-soluble vitamins can accumulate with long-term excess.