Comparable Performance Characteristics of Plasma Thiamine and Erythrocyte Thiamine Diphosphate in Response to Thiamine Fortification in Rural Cambodian Women

Abstract

Background: Traditionally, vitamin B₁ status is assessed by a functional test measuring erythrocyte transketolase (ETK) activity or direct measurement of erythrocyte thiamine diphosphate (eThDP) concentration. However, such analyses are logistically challenging, and do not allow assessment of vitamin B₁ status in plasma/serum samples stored in biobanks. Using a multiplex assay, we evaluated plasma concentrations of thiamine and thiamine monophosphate (TMP), as alternative, convenient measures of vitamin B₁ status. Methods: We investigated the relationships between the established biomarker eThDP and plasma concentrations of thiamine and TMP, and compared the response of these thiamine forms to thiamine fortification using samples from 196 healthy Cambodian women (aged 18-45 years.). eThDP was measured by high performance liquid chromatography with fluorescence detection (HPLC-FLD) and plasma thiamine and TMP by high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). Results: Plasma thiamine and TMP correlated significantly with eThDP at baseline and study-end (p < 0.05). Among the fortification groups, the strongest response was observed for plasma thiamine (increased by 266%), while increases in plasma TMP (60%) and eThDP (53%) were comparable. Conclusions: Plasma thiamine and TMP correlated positively with eThDP, and all thiamine forms responded significantly to thiamine intervention. Measuring plasma concentrations of thiamine forms is advantageous due to convenient sample handling and capacity to develop low volume, high-throughput, multiplex assays.

Keywords: direct biomarkers; erythrocyte thiamine diphosphate; plasma; thiamine (vitamin B1); thiamine monophospahte.

Figure 1

Changes in thiamine forms among individuals randomized to receive placebo (control), low (low concentration (2 g/L)), or high (high concentration (8 g/L)) thiamine-fortified fish sauce. eThDP, plasma thiamine, plasma TMP, and plasma total thiamine responses expressed as change (post-intervention—baseline). Solid horizontal lines indicate median change, the box represents the interquartile range (IQR), the whiskers represent 1.5 times the IQR, and circles indicate outliers. eThDP, erythrocyte thiamine diphosphate; TMP, thiamine monophosphate. Between group differences indicated by, * p ≤ 0.01.