Thiamin (B1)

Function

Thiamin helps to process carbohydrates, fats, and proteins. Specifically, it is needed to make adenosine triphosphate, or ATP, the body’s main energy-carrying molecule. Thiamin is also necessary for memory and other brain functions.

Recommended Intake

Thiamin Deficiency

Thiamin deficiencies are rare in the United States because thiamin is added to refined grains. However, deficiencies do sometimes occur. Symptoms of thiamin deficiency include:

• Fatigue
• Weak muscles
• Muscle ache
• Insomnia
• Dizziness
• Low blood pressure
• Numbness and tingling in arms and legs
• Nausea and vomiting
• Anorexia
• Constipation
• Depression or mood swings

Thiamin deficiency was more common before thiamin was added to refined grains. This deficiency can lead to beriberi, a disease that affects the cardiovascular and nervous system.

Thiamin Toxicity

There have been no adverse effects reported with taking too much dietary thiamin—the body excretes any excess amount that is consumed. In rare instances, coughing, hives, itching swelling, and breathing difficulties have occurred from thiamin injections given by doctors.

Major Food Sources

Thiamin is mostly found in whole-grain and enriched grain products like bread, pasta, rice, and fortified cereals. These foods are enriched with thiamin because the vitamin is often lost during the refining process. Pork, liver, and other organ meats are naturally high in thiamin. This table lists good food sources of thiamin.

Health Implications

Populations at Risk for Thiamin Deficiency

The following populations may be at risk for thiamin deficiency and may require a supplement:

• Chronic alcoholics
• People being treated with hemodialysis or peritoneal dialysis
• People with malabsorption syndromes
• People with congestive heart failure , Crohn’s disease , anorexia , folate deficiency, and multiple sclerosis
• People taking loop diuretics like furosemide (Lasix)
• Cancer patients on chemotherapy

Beriberi

A severe thiamin deficiency, though rare in the United States, can cause the disease beriberi. Beriberi can damage the heart and the nervous system. Symptoms include fatigue, diarrhea, weight loss, memory loss, and heart failure. This condition is still seen in alcoholics, in people who’s ability to absorb thiamin is impaired, and in developing countries where foods are not fortified. Treating beriberi with vitamin B1 cures most cases, though severe deficiency can cause irreversible damage.

Korsakoff’s Syndrome

A deficiency of thiamin can cause Korsakoff's syndrome, which mainly affects short-term memory. Symptoms of Korsakoff’s syndrome include difficulty with walking and balance, paralysis of some of the eye muscles, confusion, and drowsiness. It is often caused by alcoholism and also occurs with forms of brain damage such as tumors, head injuries, and strokes. Treatment of Korsakoff’s syndrome involves intravenous thiamin and oral thiamin supplements over many months. If alcoholism is the cause, that also needs to be treated.

Congestive Heart Failure

In people with congestive heart failure (CHF), the heart's ability to pump weakens, and fluid begins to accumulate in the lungs and legs. Loop diuretics are often prescribed to treat CHF; however, these drugs can deplete the body of thiamin. Since thiamin is required for normal heart function, this can cause problems. Thiamin supplements appear to help.

Conditions That May Increase Need for Thiamin

While thiamin deficiency in a healthy person is uncommon, there are conditions that can increase the need for thiamin, making a deficiency possible. If you have any of the following conditions, talk with your doctor about your thiamin needs:

• Alcoholism
• Burns
• Fever (continuing)
• Illness (continuing)
• Intestinal disease
• Diet high in simple carbohydrates
• Total parenteral nutrition
• Eating disorders
• Severe infection
• Dialysis
• Cancer
• Major depression
• Pregnancy and breastfeeding
• AIDS
• Prolonged diuretic use
• Surgical removal of the stomach

Tips for Increasing Your Thiamin Intake:

To help increase your intake of thiamin:

• Add sun-dried tomatoes, French beans, or yellow corn to your favorite chili recipe.
• Make a fruit salad with mandarin oranges, pineapple, raisins, orange juice, watermelon, and your other favorite fruits.
• Slice an avocado. Add a little balsamic vinegar and pepper, and scoop out for a snack. Or, mash the avocado and mix with chopped tomatoes and red onions for a refreshing salsa.
• Bake a potato. Poke holes in the potato and cook at 350° F for 45-60 minutes (or microwave for 6-8 minutes).
• Try Cajun catfish. Coat a catfish fillet with a little olive oil and sprinkle with flour, pepper, and Cajun seasoning. Broil or bake the catfish at 400° F until golden brown and fish flakes when tested with a fork (approximately 10-15 minutes).
• Spread lox on a bagel. Start with light cream cheese on a bagel. Then add lox (smoked salmon), lettuce, red onion, and capers.