Vitamin B1

Thiamine (vitamin B1) is a water-soluble B vitamin. People get most of the thiamine they need from food, but some thiamine is made by the body. Good sources of thiamine include grain cereals, legumes, nuts, meat, and yeast.

Thiamine

Thiamine is readily available in many foods, including beef, beans, lentils, milk, nuts, oats, oranges, wheat, whole-grain cereals, and yeast. As a supplement, thiamine is usually taken by mouth and is often taken together with other B vitamins. It is available in tablet, capsule, powder, or liquid form. In some cases, thiamine may also be given intramuscularly (injected into a muscle).

Table 1 lists the usual dose and the recommended dietary allowance for thiamine for different age groups.

Table 1. Usual daily dose and RDA for thiamine for different age groups

Your health care provider may have recommended using this product in other ways. Contact a health care provider if you have questions.

Thiamine is used to:

• help the body use carbohydrates, fats, and proteins for energy
• help with normal growth
• maintain good health
• prevent thiamine deficiency when taken at or above the recommended daily dose

People have also used thiamine for:

• cataracts
• diabetic nephropathy (damage to the kidney due to diabetes)
• diabetic neuropathy (damage to nerves due to diabetes)
• heart disease
• menstrual pain

People who have or are at risk for thiamine deficiency (i.e., low levels of thiamine) may benefit from using supplements. Many conditions can significantly lower thiamine levels, including:

• alcoholism - over time, thiamine deficiency can cause Wernicke-Korsakoff syndrome (WKS), a condition that affects memory and problem-solving skills
• cirrhosis (a condition caused by liver damage, often because of alcoholism)
• people who are on dialysis for kidney failure
• people taking diuretics (medications that increase urine output)

Thiamine supplementation has been shown to be effective in treating thiamine deficiency and Wernicke-Korsakoff syndrome (WKS). There is not enough evidence to support thiamine supplementation for other uses.

Your health care provider may have recommended this product for other conditions. Contact a health care provider if you have questions.

Thiamine taken by mouth is safe for most adults when used in the recommended daily amount. Rarely, people may have an allergic reaction to taking thiamine supplements by mouth (i.e., skin swelling, redness, itchiness). If you have an allergic reaction, stop taking the supplement and contact a health care provider.

Taking thiamine injections can cause feelings of warmth, tingling, itching, pain, rash, nausea, weakness, tightening of the throat, sweating, and, in some cases, death.

Thiamine appears to be safe for use during pregnancy and while breast-feeding when it is used in the recommended daily amount.

Coffee and tea appear to prevent thiamine from being used properly in the body. For people that get enough thiamine in their diet, this is not usually a problem. People that drink large amounts of coffee or tea and do not get enough thiamine in their diet may be at risk for thiamine deficiency.

Eating large amounts of raw freshwater fish or shellfish may cause thiamine deficiency. Thiamine levels are not affected by cooked fish.

Before taking any new medications, including natural health products, speak to your physician, pharmacist, or other health care provider. Tell your health care provider about any natural health products you may be taking.

1. Health Canada. Natural Health Products Ingredients Database. Multi-Vitamin/Mineral Supplements Monograph. Available from: https://webprod.hc-sc.gc.ca/nhpid-bdipsn/atReq.do?atid=multi_vitmin_suppl&lang=eng.
2. Natural Medicines Comprehensive Database. Thiamine.
3. National Center for Complementary and Alternative Medicine. MedlinePlus. Thiamine (Vitamin B1). Available from: http://www.nlm.nih.gov/medlineplus/druginfo/natural/965.html