Thiamin status of a Melanesian population.

A semiautomated method is described which uses the Abbott ABA-100 bichromatic analyzer to measure the stimulation of erythrocyte transketolase by thiamin pyrophosphate (the thiamin pyrophosphate effect). The method was accurate with a throughput of 30 samples per hour and is suitable for the study of the thiamin status of large populations. A significant proportion (21%) of a total of 1920 individuals of a predominantly Melanesian population were found to have an elevated thiamin pyrophosphate effect (greater than 15% activation). This same proportion with an elevated thiamin pyrophosphate effect was found in an urban hospital patient group of 346 individuals. Statistical analysis indicated a significant inverse correlation between thiamin pyrophosphate effect and plasma potassium concentration (p less than 0.001). Analysis of human fecal samples for thiaminase I activity demonstrated that this enzyme was present in 23 of a total of 46 samples selected from both the Melanesian and urban hospital patient groups. Preliminary findings indicated that the thiaminase originated from a bacterial source.