High serum thiamine and the sudden infant death syndrome

Serum thiamine concentrations in 233 infants dying from the sudden infant death syndrome were compared with those found in 46 infants dying from other explicable causes. The levels in the sudden infant death group ranged from 22- greater than 500 micrograms/1 (mean 144.3 micrograms/1) and in the controls less than 1.0-95 micrograms/1 (mean 26.5 micrograms/1). The difference was highly significant (p less than 0.001). Only 13 (5.6%) of the sudden infant death group had a serum thiamine concentrations below 50 micrograms/1 whereas four (8.7%) of the control infants had a level above 50 micrograms/1. Thiamine was measured in nine samples of human breast milk and was present in concentrations ranging from 55-366 micrograms/1 (mean 178 micrograms/1); manufactured milk based formulae contained up to 2160 micrograms/1. Absorption of thiamine in man is rate limited but it appears that in infants dying from the sudden death syndrome the vitamin may be freely absorbed leading to very high serum levels.