Thiamin (B₁)

Adequate Intake (AI)

Upper Limit (UL)

AI:

• Women:  1.1 mg
• Men:       1.2 mg

UL:  None (kidneys excrete excess)

Thiamin (B₁)

Amount body can store

Thiamin (B₁)

Primary Functions (3)

Coezyme in metabolism of:

• CHOs
• Alcohol
• Some AAs

Growth + maintenance of nerve + muscle tissues

Required for normal appetite

Thiamin (B₁)

Consequences of Deficiency

• Fatigue, weakness
• Nerve disorders, mental confusion, apathy
• Impaired growth
• Swelling
• Heart irregularity or failure

Thiamin (B₁)

Beriberi

*Caused by B₁ deficiency

Wet Beriberi:  

• Edema, heart failure
• Affects heart + circulatory system
• Assoc. w/ high CHO intake + strenuous activity

Dry Beriberi:

• Muscle wasting, muscle paralysis
• Damages nerves + muscles
• Assoc. w/ low E intake + inactivity

Cause: Thiamin deficiency (often in alcoholics)

Symptoms:

• tremors, convulsions
• mental confusion
• double vision, drooping eyelid
• amnesia, hallucinations

Thiamin

Symptoms of Overdose

None - excess excreted by kidneys

oral doses < 500 mg/d considered safe

Thiamin

Main Food Sources

Pork

Grains, grain byproducts

Brewer's yeast

Brazil nuts, pistachios, pecans

Thiamin

Needs Increase w/ increased ______ intake

Thiamin

Dietary Inhibitors

Thiaminase:  inactivates thiamin via oxidation

• Found in:
  • Raw shellfish + freshwater fish
  • Fern, betel nuts
  • Coffee, tea, berries, brussels sprouts, cabbage