The American journal of clinical nutrition
-
Nutritional rickets remains a public health problem in many countries, despite dramatic declines in the prevalence of the condition in many developed countries since the discoveries of vitamin D and the role of ultraviolet light in prevention. The disease continues to be problematic among infants in many communities, especially among infants who are exclusively breast-fed, infants and children of dark-skinned immigrants living in temperate climates, infants and their mothers in the Middle East, and infants and children in many developing countries in the tropics and subtropics, such as Nigeria, Ethiopia, Yemen, and Bangladesh. Vitamin D deficiency remains the major cause of rickets among young infants in most countries, because breast milk is low in vitamin D and its metabolites and social and religious customs and/or climatic conditions often prevent adequate ultraviolet light exposure. ⋯ In such situations, calcium supplements alone result in healing of the bone disease. Studies among Asian children and African American toddlers suggested that low dietary calcium intakes result in increased catabolism of vitamin D and the development of vitamin D deficiency and rickets. Dietary calcium deficiency and vitamin D deficiency represent 2 ends of the spectrum for the pathogenesis of nutritional rickets, with a combination of the 2 in the middle.
-
Adequate vitamin D concentrations during pregnancy are necessary to ensure appropriate maternal responses to the calcium demands of the fetus and neonatal handling of calcium. The purpose of this report is to review studies that investigated maternal and neonatal outcomes of vitamin D deficiency or supplementation during pregnancy. ⋯ Results concerning benefits for fetal growth and bone development are inconclusive. There is no evidence of a benefit of supplementation during pregnancy above amounts routinely required to prevent vitamin D deficiency.