Effects of dietary intervention on vitamin B12 status and cognitive level of 18-month-old toddlers in high-poverty areas: a cluster-randomized controlled trial

Abstract

Background: The local diet in high-poverty areas in China is mainly vegetarian, and children may be more vulnerable to vitamin B₁₂ deficiency.

Objective: The aims of this study were to explore the vitamin B₁₂ status of toddlers living in high-poverty areas of China and to observe the effects of different complementary foods on the vitamin B₁₂ status and cognitive level of these toddlers.

Methods: The study was nested within a cluster-randomized controlled trial implemented in 60 administrative villages (clusters) of Xichou County in which infants aged 6 months old were randomized to receive 50 g/d of pork (meat group), an equi-caloric fortified cereal supplement (fortified cereal group) or local cereal supplement (local cereal group) for one year. At 18 months, a subsample of the 180 toddlers (60 from each group) was randomly tested for serum vitamin B₁₂ and total homocysteine (tHcy) levels, and their neurodevelopment was evaluated.

Results: The median serum concentrations of vitamin B₁₂ and tHcy were 360.0 pg/mL and 8.2 μmol/L, respectively, in children aged 18 months. Serum vitamin B₁₂ concentrations less than 300 pg/mL were found in 62 (34.4%) children, and concentrations less than 200 pg/mL were found in 30 (16.7%) children. The median vitamin B₁₂ concentration was significantly different among the three groups (P < 0.001). The highest vitamin B₁₂ level was demonstrated in the fortified cereal group (509.5 pg/mL), followed by the meat group (338.0 pg/mL) and the local cereal group (241.0 pg/mL). Vitamin B₁₂ concentration was positively correlated with the cognitive score (P < 0.001) and the fine motor score (P = 0.023) of the Bayley Scales of Infant Development, 3rd Edition (BSID III) screening test. Compared to the local cereal group, children in the meat group had higher cognitive scores (P < 0.05).

Conclusion: In poor rural areas of China, vitamin B₁₂ deficiency in toddlers was common due to low dietary vitamin B₁₂ intake. Fortified cereal and meat could help improve the vitamin B₁₂ status of children and might improve their cognitive levels.

Trial registration: The larger trial in which this study was nested was registered at clinical trials.gov as NCT00726102 . It was registered on July 31, 2008.

Keywords: Complementary food; Deficiency; Neurodevelopment; Toddler; Vitamin B12.