The effect of vitamin B12-supplementation on actigraphy measured sleep pattern; a randomized control trial

Vitamin B12 deficiency is common worldwide and has been associated with poor sleep. The effect of vitamin B12 supplementation on sleep in infants is not known. To measure the effect of daily supplementation of vitamin B12 for one year on sleep in infants at risk of deficiency. This was an individually randomized double-blind placebo-controlled trial in 600 infants in low-to middle-income neighborhoods in Bhaktapur, Nepal of daily supplementation of vitamin B12 for one year. Infants were included if they were 6–11 month year-old and with a length-for-age less than one z-score. Sleep was a predefined, secondary outcome, and was measured by actigraphy including sleep duration at night and total sleep duration (day and night), sleep onset latency (SOL), and wake after sleep onset (WASO). The effect of vitamin B12 on sleep was additionally assessed in predefined subgroups defined by stunting, underweight, vitamin B12 status, low birthweight, anemia and exclusive breastfeeding for 3 months. There was no effect of vitamin B12 supplementation on sleep duration at night, total sleep duration, or WASO. There was a small significant negative effect for SOL. None of the included subgroup analyses revealed effect modification on any of the sleep outcomes. Overall, vitamin B12 supplementation did not have an effect on sleep in infants or for high-risk subgroups, with the exception of a small negative effect for SOL. The present study does not support vitamin B12 supplementation to improve sleep in infants. clinicaltrials.gov: NCT02272842. U1111-1161-5187.