Biomarkers of Nutrition for Development (BOND): Vitamin B-12 Review

Abstract

This report on vitamin B-12 (B12) is part of the Biomarkers of Nutrition for Development (BOND) Project, which provides state-of-the art information and advice on the selection, use, and interpretation of biomarkers of nutrient exposure, status, and function. As with the other 5 reports in this series, which focused on iodine, folate, zinc, iron, and vitamin A, this B12 report was developed with the assistance of an expert panel (BOND B12 EP) and other experts who provided information during a consultation. The experts reviewed the existing literature in depth in order to consolidate existing relevant information on the biology of B12, including known and possible effects of insufficiency, and available and potential biomarkers of status. Unlike the situation for the other 5 nutrients reviewed during the BOND project, there has been relatively little previous attention paid to B12 status and its biomarkers, so this report is a landmark in terms of the consolidation and interpretation of the available information on B12 nutrition. Historically, most focus has been on diagnosis and treatment of clinical symptoms of B12 deficiency, which result primarily from pernicious anemia or strict vegetarianism. More recently, we have become aware of the high prevalence of B12 insufficiency in populations consuming low amounts of animal-source foods, which can be detected with ≥1 serum biomarker but presents the new challenge of identifying functional consequences that may require public health interventions.

Vitamin B12 concentrations in milk from Norwegian women during the six first months of lactation

“…The Institute of Medicine defines the Adequate Intake (AI) of B12 for infants 0-6 months to be 0.4 μg/d [15]. The concentration of human milk B12 necessary for exclusively breastfed infants to attain the daily AI (0.4 μg/d) is estimated to be 310 pmol/L assuming an average milk volume of 780 mL/d [2,3]. The milk B12 concentration in wellnourished women is in the range 150-700 pmol/L, with mean 300 pmol/L [2].…”

“…The concentration of human milk B12 necessary for exclusively breastfed infants to attain the daily AI (0.4 μg/d) is estimated to be 310 pmol/L assuming an average milk volume of 780 mL/d [2,3]. The milk B12 concentration in wellnourished women is in the range 150-700 pmol/L, with mean 300 pmol/L [2]. The estimated B12 intake of 0-6 months old fully or partially breastfed infants was calculated using historic data on age-in-months human milk consumption per day in infants [16].…”

“…Vitamin B12 (B12) is an essential micronutrient for normal growth and cognitive development in infants [1,2]. Infant B12 status depends on both sufficient transfer in utero and sufficient transfer through breast milk, both of which are strongly affected by maternal status [2][3][4]. Maternal B12 status is a strong predictor of exclusively breastfed infant B12 status, both at birth and at 6 months postpartum [5].…”

“…Maternal B12 status is a strong predictor of exclusively breastfed infant B12 status, both at birth and at 6 months postpartum [5]. In high-income countries, B12 deficiency is rare and usually observed only in exclusively breastfed infants of vegetarian mothers [2]. Milk from well-nourished women is lower in B12 (300 (range 150-700 pmol/L)) compared with infant formulas (800-1200 pmol/L) [2], and breastfed infants have lower B12 status than formula fed infants [2].…”

“…In high-income countries, B12 deficiency is rare and usually observed only in exclusively breastfed infants of vegetarian mothers [2]. Milk from well-nourished women is lower in B12 (300 (range 150-700 pmol/L)) compared with infant formulas (800-1200 pmol/L) [2], and breastfed infants have lower B12 status than formula fed infants [2]. Several studies have examined B12 status in newborns and during infancy in populations that are considered B12replete.…”