These days many moms are plagued by the question of vitamin D supplementation, wondering if they should take it or not, and worrying that their babies will be poisoned. I hope this article, can solve the confusion of moms. Why supplement vitamin D? Infants and young children grow and develop rapidly, and the rapid growth of bones requires more calcium to be deposited in the bone. Vitamin D promotes the absorption of calcium and phosphorus from the small intestine, so that calcium can be deposited from the blood into the fast-growing bones and make the bones hard. Therefore, calcium deficiency in infants and young children is caused by vitamin D deficiency. Calcium deficiency is the “fruit” and vitamin D deficiency is the “cause” of calcium deficiency. Infants and young children’s body calcium deficiency, first manifested in the skull soft, fontanel large, pressure skull have ping-pong feeling. Later, the appearance of the chest bones is abnormal, such as the sternum protrudes like a chicken breast, the lower edge of the two ribs turned out. If the bones of the lower limbs are soft, standing and weight-bearing will cause “O”-shaped legs or “X”-shaped legs. In addition to skeletal changes, early manifestations of night sweating, occipital baldness occipital baldness, sleep is not stable and easy to startle and so on. These symptoms are called vitamin D deficiency rickets. Where does vitamin D come from? 1, appropriate sun exposure This is the most effective, convenient and economical method. Often let the baby in the outdoor activities. In spring and fall, you can let the baby directly under the sun, and in summer under the shade of trees, so that the baby’s skin is often exposed to ultraviolet rays. Ultraviolet irradiation, can promote the skin storage of 7-dehydrocholesterol, photochemically transformed into vitamin D3. sunlight irradiation, can make the skin storage of vitamin D3 spare, will not make the vitamin D overdose. 2, oral vitamin D food in addition to the liver of marine fish contain a certain amount of vitamin D, dairy (including human milk and cow’s milk), egg yolks and meat in the content are very small, grains, vegetables and fruits are almost no, infants and young children every day from the natural food intake of vitamin D can not meet their developmental needs, the need for oral vitamin D to be supplemented. How much vitamin D should I take? Normal-born children need to take vitamin D supplementation of 400 units/day, usually from half a month to one month after birth, and continue to take it until the age of 2-3 years. Preterm infants should be given 800-1000 units of vitamin D/day right after birth, and then 400 units/day until 2-3 years of age after 3 months of corrective age. What should I pay attention to when taking vitamin D? 1, in addition to vitamin D preparations, formula milk also contains a certain amount of vitamin D. Formula-fed babies need to be supplemented according to the amount of vitamin D contained in the formula milk. 2, babies can be poisoned if they take too much vitamin D. 400 units is a daily maintenance amount, not a therapeutic amount. If the baby has rickets, the dosage must be increased under the guidance of the doctor to give appropriate treatment. 3, breastfeeding mother supplementation of vitamin D is not desirable, even if the mother supplementation of 2000 international units of vitamin D per day, can be through the breast milk to the baby’s vitamin D is also very little, if the supplementation is too much, up to 4,000 international units, will cause the mother poisoning.