4. Discussion
pernicious anemia, B12 deficiency, cognitive impairment, Deficiencies, toxicity, diarrhea, cognitive and psychomotor development
PERNICIOUS ANEMIA, IRON DEFICIENCY ANEMIA
To our knowledge, this study is the first to describe biomarkers of vitamin B12 status in children with SAM before and after outpatient treatment. Low concentrations of serum B12 alongside elevated serum tHcy and MMA were observed at admission with only 16% of children deemed to have adequate B12 status according to the 3cB12 index. Using 3cB12, 32% of children were judged to have marked to severe B12 deficiency at admission to treatment. Treatment with RUTF significantly reduced the proportion of children with marked to severe B12 deficiency, however, 9% of the children remained in this category at discharge. All non-breastfed children at discharge had adequate or moderate B12 status, and all children who still had a marked or severe B12 status deficiency at discharge (9%) were still breastfed (11% of breastfed children). Thus, while treatment of SAM, beyond correcting the anthropometric deficits, seems to be effective in improving vitamin B12 status, it appears to be insufficient to fully correct severe or marked deficiencies in some children.The serum B12 levels we observed at admission in this study were lower than those found in healthy children aged 6–30 and 6–59 months in India [Functional consequences of a low B12 status are pernicious anemia and cognitive impairment as B12 is involved in myelination of neurons. These could explain the delay in cognitive and psychomotor development reported in children suffering from SAM [Up to 67% of children still presented with some degree of deficiency in vitamin B12 at discharge from SAM treatment. This raises the question of whether RUTF could be further fortified to improve vitamin B12 status at discharge. Because vitamin B12 is water-soluble and any excess is excreted in urine, the risk of reaching toxicity with higher fortification levels is unlikely [Our study demonstrates that treatment with both standard and reduced RUTF improved the B12 biomarker profile in children with SAM. The Recommended Nutrient Intake (RNI) for vitamin B12 is 0.7–1.2 µg/d for children aged 6–59 months [Deficiencies in B12 were markedly higher in young and breastfed children, under 2 years. This was also found in previous studies [No diarrhea at admission and iron deficiency anemia at discharge were associated with lower B12 status. This is in line with previous studies among 6- to 35-month old Nepalese children [Treatment length appeared to have no impact on 3cB12. The lack of association between duration of treatment and change in B12 status would suggest low B12 status was corrected soon after treatment commenced and thereafter, the B12 biomarker concentrations stabilized over the course of the treatment period. However, with only admission and discharge blood sampling we can only speculate and are unable to investigate time to B12 repletion more thoroughly.