Smart Supplement Series

Thiamine (Vitamin B1)

Gut Microbiome - Human Health Connectivity

Thiamine riboswitches are the most abundant regulators of gene expression in human gut microbiome communities to help maintain gut, brain and human health.

My last blog focused on introducing riboswitches, molecular switches in the genes of bugs regulating the expression and function of biological pathways to maintain gut health.  The next few blogs will focus on introducing science supporting the role of key micronutrients that directly influence gene expression and function in the microbiome.  These micronutrients are wide spread in the gut microbial communities, supplementation can help improve fitness of the gut microbiome diversity and contribute significantly to improve and maintain overall health.

We begin this journey by understanding the importance of thiamine (vitamin b1) in directly impacting microbiome biology and human biology.   Thiamine was the first vitamin ever discovered (hence the B1), yet it does not receive the same attention and use as some of the other nutrients.  Its impact on multiple body systems including the entire microbiome communicty makes it indispensable for optimal health and wellbeing. This blog explores the multifaceted relationship between thiamine and human health, from basic functions to clinical applications and emerging research.

What is Thiamine?

Thiamine, commonly referred to as vitamin B1 is a water-soluble vitamin found in a wide variety of foods such as whole grains, legumes, nuts, and seeds. It plays a central role in converting carbohydrates into energy, making it essential for cellular metabolism. While thiamine is most known for its importance in energy production, it also has a significant impact on the gut microbiome.

Why is Thiamine Important?

In Humans

Thiamine functions as a cofactor (to help) several key enzymes involved in energy metabolism.  The active form of thiamine is known as “thiamine pyrophosphate” or (TPP).  It participates in:

Direct impact on enzymes involved in the conversion of carbohydrates (sugars) into into energy by the mitochondria.  TPP is the coenzyme:

• For the decarboxylation of the pyruvate dehydrogenase complex (converting pyruvate to acetyl-CoA to enter Kreb’s (TCA) Cycle in the mitochondria for energy production)

• alpha-ketoglutarate dehydrogenase – a key enzyme regulator the metabolic flux in the Kreb’s Cycle

• Amino acid metabolism (branched chain alpha-keto acid dehydrogenase

It is also a key regulator of enzyme activities within the carbohydrate metabolism pathways involved in NADPH production, nucleic acid synthesis and maintenance of cellular glutathione.  Thus, thiamine is a critical player in the enablement of efficient energy production and health of virtually every cell in the body.  This makes thiamine particularly important for the health of organs with high metabolic demands including the brain, heart, kidneys, liver and muscles.

In Microbiome

Thiamine (its active form TPP) acts as a “switch” of turning genes “on” or “off” within the microbiome.   In fact, the “TPP Riboswitch” is one of the most widely distributed switches in the microbiome kingdom, responsible for controlling a significant proportion of gene expression.  This critical (and significant) role of thiamine in directly influencing gene expression and metabolic regulation in the microbiome is greatly underappreciated.  Depending on the thiamine concentrations present in the gut environment, the presence of TPP riboswitch influences which bacterial species can thrive, potentially leading to changes in overall microbiome composition.

In gut microbiota, one of the major functions of the TPP riboswitch is to regulate the expression of genes responsible for bacterial synthesis of thiamine (e.g. ThiC, ThiE, ThiF, ThiS for biosynthesis; thiBPQ and TT operon for transport and others).  Bacterial phyla such as Bacteroidetes and Fusobacteria have the capabilities to synthesize thiamine pyrophosphate (TPP).  In fact, gut bacteria like Bacteroides fragilis, Prevotella and Clostridium can produce thiamine ins sufficient quantities contributing to the human host supply of thiamine.  In contrast, certain bacteria such as Ruminococcaceae require external thiamine for growth (they get this from surrounding bacteria or from external supplementation).

Thiamine is therefore a critical micronutrient supplement playing a major role in the growth and maintenance of healthy microbiomes directly and indirectly.  In fact, research has shown that individuals with conditions like small intestinal bacterial overgrowth (SIBO) and brain fog, often experience thiamine depletion that can be treated with supplementation.

Thiamine – Gut – Brain Axis

An extension of the direct influence of gut microbiome on brain function is the critical role of thiamine impact on health of the gut flora and brain functions.  Thiamine serves as a vital link in the gut-brain axis, influencing both gastrointestinal health and cognitive functions.  Thiamine deficiency can impair gut function, lead to neurological problems and disrupt the balance between the digestive system and brain health.

Factors Affecting Thiamine Status

Thiamine deficiency can results from various factors including alcohol consumption, high sugar intake, certain cooking methods, stress, illness and some medications.

Dietary Sources of Thiamine

These include whole grains (specially fortified with vitamin b1), legumes (lentils), seeds (sunflower, flax), nuts (macadamia), nutritional yeast and fish (trout, tuna).

Supplemental Approaches

• Thiamine Hydrochloride: The standard form

• Benfotiamine: A fat-soluble derivative with better absorption characteristics

• Thiamine Tetrahydrofurfuryl Disulfide (TTFD): Lipid soluble form with unique properties

• Probiotic strains known to positively interact with thiamine metabolism

• Prebiotic fibers that selectively feed beneficial, thiamine-producing bacteria

Summary Conclusion

The relationship between thiamine and human health exemplifies how a seemingly simple nutrient can have profound and far-reaching effects. From its fundamental role in energy metabolism to its specific functions in neurological, cardiovascular, and metabolic health, thiamine deserves greater attention in both clinical and public health contexts.

As research continues to unveil new aspects of thiamine's functions, the importance of maintaining optimal status becomes increasingly clear. Whether through thoughtful dietary choices or strategic supplementation when indicated, supporting thiamine sufficiency represents a foundational approach to human health—one that impacts virtually every cell and system in the body.

By recognizing thiamine not just as a nutrient to prevent deficiency diseases but as an essential factor in optimal health and disease resilience, we gain a more complete understanding of nutrition's fundamental role in human wellbeing.

As always, it is important to talk to your health care provider before making any decision on dietary changes and supplementation.

Information for taking action, next steps

• What Dose Should Be Used (Source: MedlinePlus)

  • As a dietary supplement in adults, 1-2 mg of thiamine per day is commonly used. The daily recommended dietary allowances (RDAs) of thiamine are: Infants 0-6 months, 0.2 mg; infants 7-12 months, 0.3 mg; children 1-3 years, 0.5 mg; children 4-8 years, 0.6 mg; boys 9-13 years, 0.9 mg; men 14 years and older, 1.2 mg; girls 9-13 years, 0.9 mg; women 14-18 years, 1 mg; women over 18 years, 1.1 mg; pregnant women, 1.4 mg; and breast-feeding women, 1.5 mg.

  • BY MOUTH:

    • For thiamine deficiency: The usual dose of thiamine is 5-30 mg daily in either a single dose or divided doses for one month. The typical dose for severe deficiency can be up to 300 mg per day.

    • For reducing the risk of getting cataracts: A daily dietary intake of approximately 10 mg of thiamine has been used.

    • For kidney damage in people with diabetes (diabetic nephropathy): 100 mg of thiamine three times daily for 3 months has been used.

    • For menstrual cramps (dysmenorrhea): 100 mg of thiamine, alone or along with 500 mg of fish oil, has been used daily for up to 90 days.

  • Clinical Trials in humans have evaluated the use of dosage ranging from 200 mg/day to 800mg/day to test for effectiveness for various clinical conditions (references below).

  • It is important to talk to your health care provider before making any decision on dietary changes and supplementation.

Buy Quality Supplements

• Nature Made

• Swanson