Thiamine

Vitamin B1 concentration in a typical healthy human body is approximately 30 mg of vitamine B1 in all forms with about 40-50% of this being in the muscles. Normal human blood contains about 90 ng/mL(1).

Vitamin B1 occurs in the human body as free thiamine and as thiamine monophosphate, thiamine triphosphate, and thiamine pyrophosphate. Beriberi is the disease resulting from severe thiamine deficiency; inadequate consumption of thiamine is the main cause of thiamine deficiency in underdeveloped countries. Alcoholism is the primary cause of thiamine deficiency in industrialized countries. Conditions resulting in an increased need for thiamine include strenuous physical exertion, fever, pregnancy, breast-feeding, and adolescent growth. Certain plants contain anti-thiamine factors which react with thiamine to form an oxidized, inactive product. Consuming large amounts of tea and coffee (including decaffeinated) have been associated with thiamine depletion in humans. Habitual consumption of raw freshwater fish, raw shellfish and ferns increase the risk of thiamine deficiency(1).

... High dietary levels of thiamine hydrochloride have been reported to depress the metabolism of zoxazolamine and aminopyrine in rats without significantly altering the oxidative metabolism of hexobarbitone. /Thiamine hydrochloride/

In rats treated with PCB, vitamin B1 levels in blood, liver, and sciatic nerve decreased, transketolase activity decreased, and pyrophosphate effect increased. In DDT-treated rats, vitamin B1 levels decreased in blood, brain, and liver, as did transketolase activity, while pyrophosphate effect increased.

Although the clinical importance is unknown, thiamine reportedly may enhance the effect of neuromuscular blocking agents.

... Alcohol inhibits absorption of thiamine.

For more Interactions (Complete) data for Vitamin B1 (9 total), please visit the HSDB record page.

Dietary Sources of Vitamin B1(1). [Table#839]

Whole grain cereals, legumes such as beans and lentils, nuts, lean pork and yeast are rich sources of vitamin B1(1). [Table#840]

Asthma - Reversible bronchoconstriction (narrowing of bronchioles) initiated by the inhalation of irritating or allergenic agents.

Thiamine supplementation is reported to be well-tolerated and safe to use. A retrospective study on the adverse effects of thiamine supplementation among more than 300,000 patients found no serious side effects. However, some commonly reported adverse effects include nausea, urticaria, lethargy, ataxia, and impaired gut motility.

Vitamin B1 concentration range of 18.2 to 212.1 ug/L was reported in breast milk samples from Manila in a 1962 study of apparently healthy mothers. In another study, the mean vitamin B1 content of breast milk in women from India, Thailand, and the US was 153, 93-149, and 142 ug/L, respectively(1).

The human body excretes excess thiamine in the urine. No toxicity from high thiamine intake from food or supplements is evident. Food and Nutrition Board (FNB) concluded that excessive thiamine consumption might cause adverse effects despite a lack of solid evidence of toxicity. According to the Institute of Medicine, no established upper limit for thiamine intake that causes toxicity is reported in the literature.

It is thought that the mechanism of action of thiamine on endothelial cells is related to a reduction in intracellular protein glycation by redirecting the glycolytic flux. Thiamine is mainly the transport form of the vitamin, while the active forms are phosphorylated thiamine derivatives. There are five known natural thiamine phosphate derivatives: thiamine monophosphate (ThMP), thiamine diphosphate (ThDP), also sometimes called thiamine pyrophosphate (TPP), thiamine triphosphate (ThTP), and the recently discovered adenosine thiamine triphosphate (AThTP), and adenosine thiamine diphosphate. Each derivative has unique functions, however, most are involved as coenzymes.

Vitamin B1 is found in all plants and animals; however, most organisms contain only low concentrations(1,2). It is found intracellularly in microorganisms, in plants (although unevenly distributed), and in tissue of animals, with the highest amounts occurring in the heart, kidney, liver, and brain(1). In plants, vitamin B1 occurs predominantly as free thiamine and in animals it occurs almost entirely in phophorylated forms, mainly thiamine pyrophosphate(2). It is biosynthesized by microorganisms and plants. Dietary sources include whole grains, meat products, vegetables, milk, legumes and fruit. Vitamin B1 is also present in rice husks and yeast(3).

/SIGNS AND SYMPTOMS/ Adverse reactions with thiamine are rare, but hypersensitivity reactions have occurred, mainly after parenteral doses. These reactions have ranged in severity from very mild to, very rarely, fatal anaphylactic shock ... The UK Committee on Safety of Medicines had received, between 1970 and July, 1988, 90 reports of adverse reactions associated with the use of an injection containing high doses of vitamins B and C. The most frequent reactions were anaphylaxis (41 cases, including 2 fatalities), dyspnea or bronchospasm (13 cases), and rash or flushing (22 cases); 78 of the reactions occurred during, or shortly after, intravenous injection and the other 12 after intramuscular injection.

/SIGNS AND SYMPTOMS/ Serious hypersensitivity/anaphylactic reactions can occur, especially after repeated administration. Deaths have resulted from IV or IM administration of thiamine.

/SIGNS AND SYMPTOMS/ Anaphylaxis. There have been occasional reports of serious and even fatal responses to the parenteral administration of thiamin. The clinical characteristics have strongly suggested an anaphylactic reaction. Symptoms associated with thiamin-induced anaphylaxis include anxiety, pruritus, respiratory distress, nausea, abdominal pain, and shock, sometimes progressing to death.

/SIGNS AND SYMPTOMS/ Allergic Sensitivity and Pruritus. One case of pruritus after an intake of 500 mg/day of thiamin intramuscularly /was reported/. Another study, which involved intravenous administration of 100 mg of thiamin hydrochloride to 989 patients, reported a burning effect at the injection site in 11 patients and pruritus in 1 patient. No reports of pruritus after thiamin ingestion were found.

For more Human Toxicity Excerpts (Complete) data for Vitamin B1 (13 total), please visit the HSDB record page.

An essential vitamin for carbohydrate metabolism and nerve function; Found in whole grains, meats, vegetables, milk, legumes, fruit, rice husks, and yeast; [Merck Index] Used as a nutritional supplement and flavoring agent for foods; [FDA] Used as a medicine, nutrient, in enriched flours, and other foods; [HSDB]

Prevention and treatment of vitamin B1 deficiency

Medicine, nutrition, enriched flours. Isolated usually as the chloride ... Available as thiamine hydrochloride and thiamine mononitrate

Reported uses

THERAPEUTIC CATEGORY: Vitamin (enzyme cofactor)

For more Uses (Complete) data for Vitamin B1 (6 total), please visit the HSDB record page.

(1972) 1.34 X 10+7 g

(1975) 5.78 X 10+6 g

(1984) 3.36 X 10+7 g

(1972) 1.09 X 10+8 g

(1975) 1.60 X 10+8 g (Vitamin B1)

(1984) 2.80X10+8 g /Vitamin B1, Thiamine hydrochloride or Thiamine Mononitrate, synthetic/

(1972) Probably > 4.54 x 10+5 grams

(1975) Probably > 4.54 x 10+5 grams

(1986) No data

... /A method for the chemical synthesis of thiamine/ constructs the thiazole ring on a preformed pyrimidine intermediate. Thiamine manufacturers generally follow this approach. Some use malonitrile as the starting material for construction of the 4-amino-5-aminomethyl-2-methylpyrimidine ring (also called Grewe diamine). Others start with acrylonitrile but all proceed via the key Grewe diamine intermediate through to thiothiamine.

... /A method for the chemical synthesis of thiamine consists of separate syntheses of 4-amino-5-bromomethyl-2-methylpyrimidine hydrobromide and of the thiazole moiety or its acetate. Condensation of the two intermediate heterocycles gives thiamine bromide hydrobromide which is converted to thiamine chloride hydrochloride by treatment with silver chloride in methanol or with an ion-exchange resin.

Reaction of 5-(beta-hydroxyethyl)-4-methylthiazole with 2-methyl-4-amino-5-bromomethylpyrimidine, hydrogen bromide salt, followed by neutralization and reaction with hydrochloric acid

Thiazolium, 3-[(4-amino-2-methyl-5-pyrimidinyl)methyl]-5-(2-hydroxyethyl)-4-methyl-, chloride (1:1): ACTIVE

Most of the thiamine commercialy available is synthetic

Biosynthesized by microorganisms and plants. Dietary sources include whole grains, meat products, vegetables, milk, legumes and fruit. Also present in rice husks and yeast.