Abrams Steven A
Department of Pediatrics, Dell Medical School at the University of Texas, Austin, Texas, USA,
Ann Nutr Metab. 2020;76 Suppl 2:6-14. doi: 10.1159/000508421. Epub 2020 Nov 24.
Vitamin D is necessary for the active (transcellular) absorption of calcium and for skeletal health. Inadequate vitamin D in infants leads to increased risks of poor bone mineralization and ultimately rickets. Rickets is uncommon in full-term infants with a much higher risk in very premature infants. However, the primary cause of rickets in premature infants is a deficiency of calcium and phosphorus, not vitamin D. Available research, as well as most guidelines, recommend an intake of 400 IU daily of vitamin D as adequate for bone health in preterm and full-term infants. Higher doses have not been consistently shown to have specific clinical benefits for healthy infants. There are no strong data to support either routine testing of serum 25-hydroxyvitamin D or targeting high serum 25-hydroxyvitamin D levels (e.g., 30 ng/mL) in healthy preterm or full-term infants. Vitamin D is commonly provided to infants via drops for breastfed babies or via infant formula, although alternative dosing approaches exist for breastfed infants, which some families may prefer. These include the use of drops placed on the mother's breast, dissolvable doses, and high maternal doses (approximately 6,400 IU daily). Infant formula contains vitamin D, and most infants will reach an intake from formula of about 400 IU daily within the first 2 months of life if they are consuming routine cow milk-based formula. Although vitamin D toxicity is very uncommon, caution should be used to avoid extremely concentrated high doses found in some commercially available drops. Infants with liver or kidney disease may need special attention to vitamin D intake and status. Further research is needed to define the role of vitamin D in non-bone health outcomes of infants and to identify methods to enhance compliance with current recommendations for vitamin D intake in infants.
维生素D对于钙的主动（跨细胞）吸收和骨骼健康是必需的。婴儿体内维生素D不足会增加骨矿化不良的风险，并最终导致佝偻病。佝偻病在足月儿中并不常见，在极早产儿中风险要高得多。然而，早产儿佝偻病的主要原因是钙和磷缺乏，而非维生素D缺乏。现有研究以及大多数指南都建议，早产和足月婴儿每日摄入400国际单位的维生素D就足以维持骨骼健康。更高剂量并未始终显示对健康婴儿有特定的临床益处。没有有力数据支持对健康的早产或足月婴儿进行血清25-羟维生素D的常规检测或设定高血清25-羟维生素D水平（如30纳克/毫升）的目标。维生素D通常通过给母乳喂养婴儿滴服或通过婴儿配方奶粉提供给婴儿，不过对于母乳喂养婴儿存在其他给药方法，一些家庭可能会更喜欢。这些方法包括将滴剂滴在母亲乳房上、可溶解剂量以及母亲高剂量（约每日6400国际单位）。婴儿配方奶粉含有维生素D，如果食用常规的以牛奶为基础的配方奶粉，大多数婴儿在出生后的头两个月内将从配方奶粉中获得约每日400国际单位的摄入量。尽管维生素D中毒非常罕见，但应谨慎避免使用一些市售滴剂中发现的极高浓度高剂量。患有肝脏或肾脏疾病的婴儿可能需要特别关注维生素D的摄入量和状况。需要进一步研究来确定维生素D在婴儿非骨骼健康结局中的作用，并确定提高婴儿对当前维生素D摄入建议依从性的方法。
