Effects of dietary intervention on vitamin B(12) status and cognitive level of 18-month-old toddlers in high-poverty areas: a cluster-randomized controlled trial

BACKGROUND: The local diet in high-poverty areas in China is mainly vegetarian, and children may be more vulnerable to vitamin B(12) deficiency. OBJECTIVE: The aims of this study were to explore the vitamin B(12) status of toddlers living in high-poverty areas of China and to observe the effects of different complementary foods on the vitamin B(12) 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 B(12) and total homocysteine (tHcy) levels, and their neurodevelopment was evaluated. RESULTS: The median serum concentrations of vitamin B(12) and tHcy were 360.0 pg/mL and 8.2 μmol/L, respectively, in children aged 18 months. Serum vitamin B(12) 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 B(12) concentration was significantly different among the three groups (P < 0.001). The highest vitamin B(12) 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 B(12) 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 B(12) deficiency in toddlers was common due to low dietary vitamin B(12) intake. Fortified cereal and meat could help improve the vitamin B(12) 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.