Question
The blood calcium and vitamin D test results for my baby on September 27th were low. A community doctor advises supplementing with high-dose vitamin D3, but I am worried about the potential harm of over-supplementation to the baby’s growth and development.
Answer
Generally, a blood 25-hydroxyvitamin D concentration greater than 30 ng/ml indicates sufficient vitamin D levels, with an ideal range of 30-50 ng/ml. Vitamin D2 and D3 have similar effects in the body; D2 is usually obtained from plant-based foods, while D3 comes from animal-based foods and is synthesized by the skin. There is no need to worry too much about the difference between the two; just pay attention to the total amount (25-OH-D). Additionally, if calcium intake from diet is sufficient (for example, dairy products have high calcium content), there is no need for long-term additional calcium supplementation. A preventive daily intake of 400U of vitamin D is sufficient.