Vitamin B1 (thiamine) and Clinical Depression


What is Vitamin B1?

Vitamin B1, also called thiamin or thiamine, is one of the 8 vitamins from the B Family. All B vitamins help the body convert food (carbohydrates) into fuel (glucose), which is used to produce energy. These B vitamins, often referred to as B complex vitamins, also help the body metabolize fats and protein. B complex vitamins are needed for healthy skin, hair, eyes, and liver. They also help the nervous system function properly, and are needed for good brain function.

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All B vitamins are water-soluble, meaning that the body does not store them.

Like other B complex vitamins, thiamine is sometimes called an "anti-stress" vitamin because it may strengthen the immune system and improve the body's ability to withstand stressful conditions. It is named B1 because it was the first B vitamin discovered. Isolated and characterized in the 1930s, thiamin was one of the first organic compounds to be recognized as a vitamin. Thiamin occurs in the human body as free thiamin and as various phosphorylated forms: thiamin monophosphate (TMP), thiamin triphosphate (TTP), and thiamin pyrophosphate (TPP), which is also known as thiamin diphosphate.

It’s rare to be deficient in thiamine, although alcoholics, people with Crohn' s disease, anorexia, and those undergoing kidney dialysis may be deficient. Symptoms of thiamine deficiency are fatigue, irritability, depression and abdominal discomfort. People with thiamine deficiency also have trouble digesting carbohydrates. That allows a substance called pyruvic acid to build up in their bloodstream, causing a loss of mental alertness, difficulty breathing, and heart damage, a disease known as beriberi.

Functions in the body

Thiamin diphosphate, often called thiamin pyrophosphate (TPP), is an essential cofactor, particularly in carbohydrate metabolism.

TPP is involved in the oxidative decarboxylation of acetyl CoA in mitochondria. In the Krebs cycle, TPP is the key enzyme for the decarboxylation of a-ketoglutarate to succinyl CoA. TPP is also the cofactor for transketolase, a key enzyme in the hexose monophosphate shunt.
Thiamin is found in many foodstuffs, including cereals, grains, beans, nuts, as well as pork and duck. It is often added to food (e.g. in cereals) in developed countries. The dietary requirement depends on energy intake, more being required if the diet is high in carbohydrates.

Following absorption, thiamin is found in all body tissues, the majority being in the liver. Body stores are small and signs of deficiency quickly develop with inadequate intake. There is no evidence that a high oral intake is dangerous.

Thiamin Deficiency

The most common symptoms of thiamine deficiency, or a lack of vitamin B1, include fatigue, irritability, anxiety, depression, pins and needles sensations or numbness in the legs, and constipation.

A disease called beriberi can result as a consequence of a severe deficiency. There are two main types of beriberi, which affect people in different ways. Wet beriberi can cause cardiovascular problems and is associated with symptoms such as increased heart rates, edema in the lower legs, and possible congestive heart failure. Dry beriberi is associated with nervous system ailments. Some of the symptoms are loss of feeling in the extremities, pain, tingling sensation, problems with muscle function, paralysis, and mental confusion.

The Wernicke-Korsakoff syndrome is a brain disorder also caused by a thiamin deficiency. It develops in two stages, which present different symptoms like psychosis, memory loss, vision problems and mental confusion.

In all these cases, a severe deficiency in Vitamin B1 can lead to serious health complications and even death. However, most symptoms of deficiency are reversible if the condition is detected and treated properly. In the case of chronic alcoholism that is often linked to the Wernicke-Korsakoff syndrome, the improvement of memory can be slow or incomplete.

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Sources of Vitamin B1

People can get Vitamin B1 through their diet. Thiamin is a micronutrient, meaning a nutrient needed in very small amounts, found in a variety of animal and plant foods. It is a water-soluble vitamin that it is eliminated in urine when not needed by the body. Food must therefore supply it continuously. It belongs to a group of other water-soluble vitamins that are often present together and called B-complex. Important sources of thiamin are vegetables, wholegrain products, and nuts. The best sources are yeasts and liver and pork meat. Some specific good food sources of thiamin include (per 1 cup serving or as indicated):
  • romaine lettuce (0.05 mg)
  • asparagus, boiled (0.22 mg)
  • spinach, boiled (0.17 mg)
  • tuna (0.57 mg per 4 oz-serving)
  • celery, raw (0.06 mg)
  • green peas, boiled (0.41 mg)
  • tomato (0.11 mg)
  • eggplant, cooked (0.08 mg)
  • brussels sprouts, boiled (0.17 mg per cup)
  • baked beans, canned with pork (0.6 mg)
  • cabbage, boiled (0.09 mg)
  • watermelon (0.12 mg)
  • red peppers, raw (0.06 mg per cup)
  • carrots, raw (0.12 mg)
  • summer squash, cooked (0.08 mg)
  • winter squash, baked (0.17 mg)
  • turnip greens, cooked (0.06 mg)
  • broccoli, steamed (0.09 mg)
  • green beans, boiled (0.09 mg)
  • corn, cooked (0.36 mg)
  • kale, boiled (0.07 mg per cup)
  • lentils, cooked (0.33 mg)
  • navy beans, cooked (0.37 mg)
  • lima beans, cooked (0.30 mg)
  • kidney beans, cooked (0.28 mg)
  • black beans, cooked (0.42 mg per cup)
  • oats, whole grain, cooked (0.26 mg per packet)
  • pineapple (0.14 mg)
  • oranges, each (0.11 mg)
  • cauliflower, boiled (0.05 mg)
  • split peas, cooked (0.37 mg)
  • sesame seeds (0.56 mg per 1/2 cup)
  • sunflower seeds (1.64 mg per 1/2 cup)

Multivitamins, B-complex vitamins or a Vitamin B1 dietary supplement can also ensure that people get the required daily intake of this vitamin.

The National Library of Medicine and the National Institute of Health specifies that the U.S. Recommended Daily Allowance (RDA) for adult males over 18 is 1.2 milligrams, while females over 18 need 1.1 milligrams. Pregnant women, children, and teenagers also need it but in varying amounts. The amount of thiamin found in most multivitamins or dietary supplements should be sufficient for most people.

Some doctors prescribe dosage of 50-100 mg/day to treat depression cases, but it is recommended to consult your primary physician or psychiatrist before deciding on the high-dose thiamin treatment course.

There are two forms of fat soluble thiamine readily available to try. These are known as TTFD and Benfotiamine. Fat soluble thiamine was popularized in Japan several decades ago, yet remains not so wide-used in the U.S.

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Interactions

Thiamin is known to interact with the following medications in different ways:
  • Antiacids. These medications may lower thiamin levels in the body by decreasing absorption and increasing excretion or metabolism.
  • Tetracycline. Tetracyline is an antibiotic and thiamin taken either alone or in combination with other B vitamins interferes with its absorption by the body and action in the body.
  • Antidepressants. Thiamin supplements may improve the action of antidepressants such as nortriptyline, especially in elderly patients. Other medications in this class of drugs include desimpramine and imipramine.
  • Chemotherapy drugs. Laboratory studies suggest that thiamin may prevent the activity of chemotherapy drugs, but effects are not yet understood in people. Patients undergoing chemotherapy for cancer, especially people receiving fluorouracil-contain-ing drugs, are usually advised not take large doses of vitamin B1 supplements.
  • Diuretics. Diuretics, especially furosemide, which belongs to a class of drugs called loop diuretics, may reduce the levels of thiamin in the body.
  • Digoxin. Laboratory studies also suggest that digoxin, a drug used to treat heart conditions, may lower the ability of heart cells to absorb and use thiamin, especially if digoxin is combined with furosemide.
  • Scopolamine. Thiamin may help reduce some of the side effects associated with scopolamine, a drug used to treat motion sickness.

Thiamin can also interact with food substances. Foods and beverages that may inactivate thiamin include those containing sulfites and tea, coffee and decaffeinated coffee. Consumption of betel nuts may also reduce thiamin activity due to chemical inactivation, and may lead to symptoms of thiamin deficiency. Tobacco use also decreases thiamin absorption and may lead to decreased levels in the body.

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