Abstract
Normal levels of red blood cell niacin, in a group of 86 children studied over a period of approximately 5 years, are presented. The results of these determinations are correlated with niacin intake and hematological studies. No positive correlation is found. Normal levels of plasma riboflavin, in a group of 92 children studied over a period of approximately 5 years, are presented. The results of these studies are correlated with riboflavin intake. No positive correlation is found. The results of both series of determinations are discussed in relation to theoretical considerations and in the light of other experimental findings.