Vitamin B12 deficiency

**Definition:** Vegetarianism and poverty-imposed near-vegetarianism are the most common causes of nutritional cobalamin insufficiency worldwide in all age groups. In such populations, low maternal cobalamin status is associated with adverse pregnancy outcomes (preterm birth, intrauterine growth retardation, early recurrent miscarriage), neural tube defects, reduced neurocognitive performance in children, accelerated bone turnover, and low bone mineral density with fractures. Insufficient cobalamin intake is also seen in breast-fed infants of mothers with pernicious anaemia.

**Inclusions:** - cobalamin deficiency - cyanocobalamin deficiency