Effect of simultaneous thiamin and riboflavin deficiencies on the determination of transketolase and glutathione reductase.

Thiamin and/or riboflavin status have been assessed in rats simultaneously deprived of both vitamins and subsequently repleated with either one or the other in succession. Undernutrition in control rats was found to depress the activity of the erythrocyte enzymes (transketolase and glutathione reductase, respectively) used to assess status. On the other hand, the activity coefficients obtained by in vitro stimulation of the enzymes with their respective missing cofactors were not suppressed. Therefore the activity coefficients were superior indices of thiamin and riboflavin nutriture compared to the enzyme activities. When activity coefficients were used as the indices of vitamin status there did not appear to be interference from the simultaneous deficiency of the alternate vitamin. Apparent interference was encountered when the enzyme activity itself was used as the criteria.     

Maternal zinc, iron, folic acid, and protein nutriture and outcome of human pregnancy

Four hundred fifty women were observed during pregnancy and postpartum. Forty-three variables including 12 laboratory indices of maternal nutrient status were assessed. Of the variance in fetal weight and head circumference 9.9 and 8.1%, respectively, were predictable by polynomial stepwise regression of laboratory indices of maternal nutriture. Maternal plasma zinc levels were inversely correlated with fetal weight. The occurrence of pregnancy complications in the highest and lowest quartiles of maternal plasma zinc, albumin, iron, and folic acid were compared. Using data only from the initial blood samples for which the trimester was identified precisely (n = 394), a significant association was found between the total occurrence of fetomaternal complications and zinc and albumin levels in the lowest quartile (zinc, p less than 0.02; albumin, p less than 0.02). Low zinc or low albumin were also associated with the specific complications of fetal distress (zinc, p less than 0.002; albumin p less than 0.002). High plasma folate was also associated with the total occurrence of complications (p less than 0.008) and with fetal distress (p less than 0.002). When all data (n = 713) including repeat blood samples and data from 56 mothers in whom the trimester could not be verified precisely were evaluated, associations between other complications and lowest quartile zinc and albumin and highest quartile folate were identified. Discriminant analysis of data from the initial blood samples revealed that plasma zinc was a discriminator for fetomaternal complications only in women in the lowest quartile for plasma zinc.