Vitamin B1 (Thiamine): Energy for Nerves, Body, and Mind

If you sometimes feel unable to concentrate or lack motivation, even though you get enough sleep and eat well, it could be due to a vitamin B1 deficiency. This micronutrient is essential for your energy supply and nerve function. Thiamine, as vitamin B1 is also known, was the first B vitamin to be discovered—and remains one of the most important to this day.

In this article (the first of eight on individual B vitamins), you’ll learn how thiamine works in the body, how to recognize a deficiency—and why this vitamin deserves special attention in cases of chronic fatigue, stress, diabetes, or alcohol consumption.

What Is Vitamin B1 and Why Do We Need It?¹ ² ³

Vitamin B1 (thiamine) is a water-soluble vitamin that our bodies cannot produce on their own. It must be regularly obtained through food. The most important role of thiamine is to convert carbohydrates into energy—particularly for organs with high energy demands such as the brain, heart, and nerves.

In the body, thiamine is quickly converted into thiamine pyrophosphate (TPP), a coenzyme form that plays a role in converting glucose to ATP—thus participating in key steps of energy production.

Other Functions of Thiamine Include:

·       conduction of nerve impulses

·       muscle contraction (especially cardiac muscle)

·       glucose metabolism in the brain

Signs of a Vitamin B1 Deficiency⁴

A mild thiamine deficiency can manifest as difficulty concentrating, irritability, loss of appetite, or fatigue. Additional possible symptoms include:

·       numbness or tingling in hands and feet

·       muscle weakness, possibly unsteady gait

·       rapid heartbeat or heart weakness

·       nerve damage (peripheral neuropathies)

·       memory problems, possibly confusion.

If the deficiency becomes chronic, it can lead to serious neurological and muscular consequences. In severe cases, Korsakoff syndrome or Wernicke encephalopathy can develop—neurological emergencies that occur especially in cases of alcohol dependence.

Vitamin B1 – Uses for Illnesses and Ailments

Based on the described effects of deficiency symptoms, several conditions and ailments can be treated successfully with B1, including:

·       fatigue, tiredness, and chronic fatigue syndrome

·       loss of appetite (in case of deficiency)

·       memory disorders (in deficiency states/Korsakoff syndrome, preventively)

·       heart failure (due to diuretic-induced deficiency)

·       hyperemesis gravidarum (pregnancy-related deficiency)

·       alcohol-related deficiency (also preventive before glucose administration)

·       dialysis-related deficiency

·       bariatric surgery (e.g., after gastric bypass)

·       fibromyalgia

·       Wernicke encephalopathy

·       diabetic neuropathy

High-dose benfotiamine, a fat-soluble precursor of B1, is used in clinical practice, e.g., in diabetes treatment, as it is absorbed better into nerve tissue than water-soluble thiamine (Volvert et al., 2008; Loew, 1996).

Vitamin B1 – Who Needs How Much?⁵

According to the German Nutrition Society (DGE), the daily requirement for adults is about 1.0–1.3 mg, but it can increase. Pregnant women, e.g., have a slightly higher need.

People at Higher Risk of Deficiency

·       individuals with alcohol dependency (impaired absorption, increased demand)

·       people with chronic intestinal diseases (e.g., Crohn’s disease)

·       diabetics (due to increased oxidative stress)

·       pregnant and breastfeeding women

·       competitive athletes

·       people with unbalanced diets (e.g., fast food, white flour products)

·       B1 can also be lost through high coffee consumption or heat during cooking.

Vitamin B1 – Food Sources and Supplementation Advice⁶ ⁷

Significant amounts of thiamine are found mainly in plant-based foods.

Whole grain products:

·       rolled oats (whole grain): approx. 0.45 mg/100 g

·       brown rice (uncooked): approx. 0.40 mg/100 g

Legumes:

·       lentils (dried): approx. 0.87 mg/100 g

·       white beans (dried): approx. 0.50 mg/100 g

Seeds:

·       sunflower seeds: approx. 1.90 mg/100 g

·       sesame seeds (unhulled): approx. 0.80 mg/100 g

White flour, polished rice, and heavily processed foods contain hardly any thiamine – this can lead to a supply gap. Such a gap can be filled with supplements.

When purchasing supplements, look for active or bioavailable forms like benfotiamine or thiamine HCl and take them in the morning with a meal.

Combining thiamine with other B vitamins is beneficial (→ blog post on the B-vitamin complex). High doses (> 50 mg/day) should only be taken in consultation with medical professionals.

FAQ – Frequently Asked Questions About Vitamin B1

1. Can the body store vitamin B1?

Only to a very limited extent: vitamin B1 is mainly stored in the liver, heart, kidneys, and muscles—about 30 mg in total. However, it is water-soluble and excreted through the kidneys.

2. How does alcohol affect vitamin B1 metabolism?

It inhibits absorption in the intestine, accelerates breakdown in the liver, and increases urinary excretion. Chronic alcohol abuse is one of the most common causes of clinically relevant B1 deficiency.

3. Are there interactions with medications?

Yes, certain medications such as diuretics (e.g., furosemide), antacids, fluorouracil, or oral contraceptives can impair B1 absorption or metabolism. Long-term use of antibiotics can also affect vitamin B1 status by altering gut flora.

4. Is it possible to overdose?

No toxic effects are known with oral intake, as excess vitamin B1 is excreted in the urine. It is considered very well tolerated, even at high doses. Only in rare cases have allergic reactions been reported with intravenous administration. 

5. What symptoms of vitamin B1 deficiency can occur in children?

In infants, deficiency may manifest as apathy, vomiting, rapid heartbeat, hoarseness, refusal to drink, and failure to thrive. In severe cases, "infantile beriberi" can occur, which is an acutely life-threatening form of deficiency.

Vitamin B1 – A Small Molecule with a Big Impact!

Thiamine is a key vitamin for mental clarity, physical performance, and stable nerves. Especially in stressful times or with certain health conditions, the need can increase significantly. Those who understand the value of this vitamin are investing in the foundation of their energy.

For more in-depth information, feel free to read our other blog posts—including those on B vitamins—and visit our online shop. There you will also find the volumes of our Codex Humanus and the series Medizinskandale, which also cover B vitamins.

Sources:

     ¹ ⁶https://ods.od.nih.gov/factsheets/Thiamin-HealthProfessional/

     ² ⁷https://health.clevelandclinic.org/b-vitamin-benefit

     ³https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-b/

 ⁴https://www.merckmanuals.com/professional/nutritional-disorders/vitamin-deficiency-dependency-and-toxicity/thiamin-deficiency

·       Loew, D. (1996): “Pharmacokinetics of thiamine derivatives especially of benfotiamine”, Int. J. Clin. Pharmacol. Ter.

·       Volvert, M.-L. et al. (2008): “Benfotiamine, a synthetic S-acyl thiamine derivative, has different mechanisms of action and a different pharmacological profile than lipid-soluble thiamine disulfide derivatives.” BMC Pharmacol.