18: Thiamine (Chapter 20a)
- Page ID
- 117130
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)Thiamine (vitamin B1), the first vitamin discovered and synthesized, plays a critical role in energy metabolism, neurological functioning, and early cognitive development. Thiamine deficiency disorders range broadly in presentation and severity, but beriberi can be fatal. Despite its long history, and the well-established adverse outcomes of deficiency, thiamine lacks both a standardized biomarker and interpretative criteria. The most common biomarker currently in use is blood thiamine diphosphate (ThDP), likely due to the growing availability of high performance liquid chromatography equipment and ease of standardization; however the lack of clinically meaningful cut-offs limits the practical use of ThDP. Although the functional biomarker of erythrocyte transketolase activity coefficient (ETKac) is still run in a few labs and has a well-established cut-off for deficiency, the limitations of working with washed erythrocytes and the fact that this assay is not readily available in most clinical settings hinders its use. At the individual level, use of a therapeutic thiamine challenge remains the clear course of action given the safety of thiamine, as compared to known severe adverse outcomes of untreated thiamine deficiency. At the population level, challenges still exist; however, the growing interest and method development for thiamine assessments via dried blood spots is an exciting prospect. Use of dried blood spots could ease sample collection, processing, storage, and shipment costs, widening the possibility of field-friendly assessments, for example, integrated into population-level surveys in beriberi-endemic regions. Such thiamine assessments would help enormously with properly estimating the global burden of thiamine deficiency, and triggering appropriate action for public health interventions in necessary areas.
- 18.1: Thiamine (20a.1)
- This page discusses thiamine (vitamin B1), its role in metabolism and cognitive health, and the impacts of its deficiency, including serious conditions like Wernicke-Korsakoff syndrome. It highlights vulnerable groups, such as chronic alcoholics, and emphasizes the importance of thiamine-rich foods versus the lower levels found in processed grains. Historical and ongoing fortification efforts in several countries are noted, along with the effects of cooking on thiamine levels.
- 18.2: Biochemical indices of thiamine status (20a.2)
- This page outlines the ongoing debate surrounding the assessment of thiamine status, emphasizing two primary biochemical markers: thiamine diphosphate (ThDP) and erythrocyte transketolase activity coefficient (ETKac). It highlights challenges in establishing reliable cut-offs for deficiency, as the effectiveness of ThDP can be inconsistent in populations with low intake.
- 18.3: Conclusions (20a.3)
- This page discusses the challenges of thiamine deficiency diagnosis, highlighting the absence of standardized biomarkers and criteria. Blood ThDP is commonly used but lacks meaningful cut-offs. ETKac presents established deficiency cut-offs but is less accessible. A therapeutic thiamine challenge is advised for safety, and dried blood spots are promising for population assessments.