Thiamin (vitamin B1) helps your body turn food into energy and keeps nerves, muscles and the heart working normally. Deficiency is rare in the US, but it can be serious in some groups.
Here is what the NIH says about daily needs, food sources and who should be careful.
Daily thiamin requirement
Average daily recommended amount (mg):
- Children 1 to 3 years: 0.5 mg
- Children 4 to 8 years: 0.6 mg
- Children 9 to 13 years: 0.9 mg
- Teen boys 14 to 18: 1.2 mg, teen girls: 1.0 mg
- Adult men: 1.2 mg, adult women: 1.1 mg
- Pregnant or breastfeeding women: 1.4 mg
The NIH states that thiamin has not been shown to cause harm, and no upper limit is listed.
Best food sources of thiamin
Good sources include:
- Whole grains and fortified bread, cereal, pasta and rice
- Pork, other meat and fish
- Legumes such as black beans and soybeans
- Seeds and nuts
Thiamin deficiency and beriberi
Low thiamin can cause weight and appetite loss, confusion, memory loss, muscle weakness and heart problems. Severe deficiency is called beriberi, with tingling or numbness in hands and feet, muscle loss and poor reflexes. In people with alcohol dependence it can lead to Wernicke-Korsakoff syndrome.
Higher risk: people with alcohol dependence, older adults, people with HIV/AIDS, people with diabetes and those who have had bariatric surgery.
Medicines and supplements
Furosemide (Lasix) and fluorouracil can lower thiamin levels, so tell your doctor if you use them long term. Supplements come in multivitamins, B-complex and thiamin-only products, commonly as thiamin mononitrate or thiamin hydrochloride.
Frequently Asked Questions
How much thiamin do adults need per day?
Adult men need 1.2 mg and adult women 1.1 mg per day. Pregnant and breastfeeding women need 1.4 mg.
Which foods are rich in thiamin?
Whole grains, fortified cereals, pork, fish, legumes, nuts and seeds.
What is beriberi?
Beriberi is the severe form of thiamin deficiency, causing tingling, numbness, muscle loss and poor reflexes.
Who is at risk of low thiamin?
People with alcohol dependence, older adults, people with HIV/AIDS or diabetes, and those who had bariatric surgery.
Can too much thiamin be harmful?
The NIH states thiamin has not been shown to cause harm, but take supplements only as advised.
Related reading: Vitamin B2 (riboflavin) daily needs | Niacin (vitamin B3) daily needs | Vitamin B12 deficiency symptoms
Sources
Medical disclaimer: this article is for general information and does not replace advice from a qualified doctor. Do not start, stop or change any supplement or medicine without medical advice.
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