Current pediatrics states that newborns need routine daily preventive vitamin D supplementation from 15 days to 2 weeks of age; vitamin A can be supplemented intermittently, given in high doses once every 4-6 months, and vitamin AD is a combination of vitamin A plus vitamin D. Vitamin D deficiency can lead to disorders of calcium and phosphorus metabolism, causing calcium malabsorption resulting in rickets; the classic manifestations of vitamin A deficiency are hyperkeratosis of the skin, dry eyes and night blindness. Parents can choose vitamin D and vitamin AD for their children in this way. 1. 400-600 IU of vitamin D daily, and 1 high-dose supplement of vitamin A every 4-6 months, 1 time 50,000-200,000 IU. 2. You can also choose to supplement 1,500 IU of vitamin A and 400 IU of vitamin D daily, that is, 1 vitamin AD oil daily.