Conclusions of a WHO Technical Consultation on Folate and Vitamin B₁₂ Deficiencies

Abstract

Folate and vitamin B 12 deficiencies occur primarily as a result of insufficient dietary intake or, especially in the case of vitamin B 12 deficiency in the elderly, poor absorption. Folate is present in high concentrations in legumes, leafy green vegetables, and some fruits, so lower intakes can be expected where the staple diet consists of unfortified wheat, maize, or rice, and when the intake of legumes and folate-rich vegetables and fruits is low. This situation can occur in both wealthy and poorer countries. Animal-source foods are the only natural source of vitamin B 12 , so deficiency is prevalent when intake of these foods is low due to their high cost, lack of availability, or cultural or religious beliefs. Deficiency is certainly more prevalent in strict vegetarians, but lacto-ovo vegetarians are also at higher risk for inadequate intakes. If the mother is folate-depleted during lactation, breastmilk concentrations of the vitamin are maintained while the mother becomes more depleted. In contrast, vitamin B 12 concentrations in breastmilk can be markedly lower in vitamin B 12depleted women. The impact of gene polymorphisms on folate and vitamin B 12 status and requirements in a population will vary depending on the underlying prevalence in that population. Although not well understood, gene polymorphisms almost certainly affect the risk of adverse pregnancy outcomes. Folic acid and vitamin B 12 in synthetic form are absorbed at about twice the efficiency as the food forms, especially in lower doses.

Safety and benefits of interventions to increase folate status in malaria‐endemic areas

“…The public health importance of the impact of applying these cut‐off values is not fully understood (De Benoist, 2008). Elevated concentrations of circulating homocysteine were once considered as a functional indicator of folate deficiency because of their association with cardiovascular disease, but the causality of this association is now highly doubtful (Miller et al , 2010; Clarke et al , 2012).…”

Micronutrient intake and status in Central and Eastern Europe compared with other European countries, results from the EURRECA network

“…3. Regarding nutritional status, data gathered should include information on mean or median status using best practice biomarkers defined in the context of EURRECA: Hb, serum/plasma ferritin or serum/plasma transferrin receptor for Fe; erythrocyte (red cell) folate, serum/plasma folate or serum/plasma homocysteine for folate; serum/plasma total B 12 , serum/plasma methylmalonic acid or serum/plasma holotranscobalamin for vitamin B 12 ; serum/plasma Zn for Zn; and urinary iodine (24 h or spot), serum or dried whole blood spot thyroglobulin or serum thyroid-stimulating hormone for iodine (20)(21)(22)(23)(24)(25)(26)(27) .…”

The Role of Nutrition in Children's Neurocognitive Development, From Pregnancy Through Childhood

“…However, it can occur in both developing and developed countries especially in older people, in those with absorption problems and in vegetarians (De Benoist, 2008). Folate fortification of bread products has been made mandatory in Australia and in many other countries, which has reduced this deficiency significantly (Brown et al, 2011).…”