Thiamin

Studies in people

• Open question

  Gut movement speed³

  In people, eating more thiamin was linked to more frequent bowel movements, and genes changed how strong that link was.

• Open question

  Brain and nerve damage⁵

  Thiamin comes only from food, and not getting enough can lead to serious brain and nerve problems.

• Benefit

  Memory and thinking in older adults⁶

  In people over 60, eating more thiamin was linked to better scores on memory and thinking tests.

• Benefit

  Inflammation in pregnancy diabetes⁸

  In women with gestational diabetes, thiamin supplements lowered some signs of inflammation and oxidative stress.

• Open question

  Blood pressure risk¹⁰

  In Chinese adults, eating either too little or too much thiamin was linked to new high blood pressure.

• Benefit

  Uric acid levels in men¹¹

  In US adults, men who ate more thiamin tended to have lower odds of high uric acid.

• Benefit

  Stress and sleep¹²

  In people, thiamin with vitamin B2 lowered stress and sleepiness and improved sleep, but did not ease anxiety.

• Benefit

  Chronic constipation¹³

  People who ate more thiamin in their diet were less likely to report long-term constipation.

• Benefit

  Stroke risk in older adults¹⁵

  In older people, eating more thiamin was linked to a lower risk of stroke.

Animal and lab studies only

• Benefit

  Joint pain in arthritis¹⁹

  In animal studies, thiamin eased arthritis symptoms, but scientists do not yet know whether it helps people.

Study type not stated

• Benefit

  Brain function and memory¹⁷

  Thiamin helps the brain use sugar, and low levels have been tied to memory problems.

How it’s made and used

• Infant deaths from deficiency⁴

  Thiamin deficiency is common in some countries and is linked to infant deaths there.

• Long-term epilepsy risk in children⁷

  In children, severe thiamin deficiency in infancy led to epilepsy that continued years later.

• Infant deaths in South Asia⁹

  Thiamine shortage in mothers and babies in South Asia is linked to infant deaths, but testing is not routine.

• Vitamin blood levels¹⁴

  Obese people had more thiamin in their blood than healthy people, even though they ate less thiamin.

• Newborn blood levels¹⁶

  In pregnant women with gestational diabetes, 19% had low thiamin despite vitamins, and their newborns did too.

• Vitamin deficiency and heart disease¹⁸

  Thiamine deficiency may play a role in the development of cardiovascular diseases, but future studies are needed.

The signal at the top counts the findings in people and in animal and lab studies. A concern in studies of people outranks animal and lab studies, and “No concerns” needs at least one finding in people. When most findings in people point one way, the page leans that way (“Mostly”), and every finding is still shown. Findings whose study type is not stated are shown but not counted. This page is a reference, not medical advice. It describes what regulators and published research say. Talk to a doctor or dietitian about your own diet.