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Deficiency/Cognition/Heart

Vitamin B1 (Thiamine)

Essential B vitamin that helps turn carbohydrates into energy and mainly benefits adults with low intake or deficiency risk.

Vitamin B1 (Thiamine)
68
score
B
evidence
Safe
risk

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Quick Take

Worth it if your intake is low or risk is elevated; otherwise it is mostly a cheap insurance nutrient.

Thiamine is an essential water-soluble B vitamin found in pork, legumes, whole grains, seeds, and fortified cereals. In the body it becomes thiamine pyrophosphate, a cofactor needed to use glucose for ATP and support nerve function. Best-supported uses are correcting deficiency, preventing beriberi or Wernicke syndromes in at-risk people, and improving neurologic symptoms caused by low status. It is most useful for adults with low food intake, frequent alcohol use, highly refined diets, or diuretic-related losses.

Potential benefits

01
Corrects thiamine deficiency
02
Prevents beriberi/Wernicke
03
Improves deficiency neuro symptoms
04
May improve heart failure function
05
May improve mental clarity
06
May lower microalbuminuria

Protocol

Amount
10-50 mg
Frequency
Once daily
When
Any time of day — consistency matters more than timing; take with food if it causes stomach upset.

Onset Time

Days to 2 weeks for clear deficiency symptoms; 4-8 weeks for lab repletion

Who Should Consider

Adults with frequent alcohol use
People eating very refined or low-variety diets
Older adults with low appetite
People using loop diuretics
People after bariatric surgery
Adults with confirmed low thiamine status

Food Sources

  • Pork loin (~0.8-1.0 mg per 100 g)
  • Fortified breakfast cereal (~0.5-1.5 mg per serving)
  • Black beans (~0.4 mg per cooked cup)
  • Sunflower seeds (~0.4 mg per 30 g)
  • Trout (~0.3 mg per 100 g)
  • Brown rice (~0.2 mg per cooked cup)

How It Works

Thiamine is converted to thiamine diphosphate, a coenzyme for pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase, and transketolase. Low thiamine reduces ATP production from carbohydrate and especially stresses nerve and cardiac tissue, which have high energy demands.

Updated 5/19/2026

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