Thiamin (thiamine), vitamin B1
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| Thiamin,
vitamin B1 |
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Thiamin (also spelled "thiamine") is a water-soluble B-complex
vitamin, previously known as vitamin B1 or aneurine. Thiamin was isolated and
characterized in the 1920s, and thus was one of the first organic compounds to
be recognized as a vitamin.
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Thiamin is involved in numerous body functions, including: nervous system and
muscle functioning; flow of electrolytes in and out of nerve and muscle cells
(through ion channels); multiple enzyme processes (via the coenzyme thiamin
pyrophosphate); carbohydrate metabolism; and production of hydrochloric acid
(which is necessary for proper digestion). Because there is very little
thiamin stored in the body, depletion can occur as quickly as within 14 days.
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Severe chronic thiamin deficiency (beriberi) can result in potentially serious
complications involving the nervous system/brain, muscles, heart, and
gastrointestinal system.
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Dietary sources of thiamin include beef, Brewer's yeast, legumes (beans,
lentils), milk, nuts, oats, oranges, pork, rice, seeds, wheat, whole grain
cereals, and yeast. In industrialized countries, foods made with white rice or
white flour are often fortified with thiamin (because most of the naturally
occurring thiamin is lost during the refinement process).
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Aneurine HCL, aneurine mononitrate, antiberiberi factor, antiberiberi vitamin,
antineuritic factor, antineuritic vitamin, anurine, B complex vitamin, beta-hydroxy-ethylthiazolium
chloride, thiamin chloride, thiamin diphosphate, thiamin HCL, thiamin
hydrochloride, thiamin monophosphate (TMP), thiamin nitrate, thiamin, thiamin
pyrophosphate (TPP), thiamin triphosphate (TTP), thiamine chloride, thiaminium
chloride HCL, thiaminium chloride hydrochloride.
These uses have been tested in humans or animals. Safety
and effectiveness have not always been proven. Some of these conditions are
potentially serious, and should be evaluated by a qualified healthcare provider.
| Uses based on scientific evidence |
Grade* |
| Metabolic disorders (Subacute necrotizing
encephalopathy, Maple syrup urine disease, Pyruvate carboxylase
deficiency, Hyperalaninemia)
Taking thiamin by mouth helps to temporarily correct some complications
of metabolic disorders associated with genetic diseases including
subacute necrotizing encephalopathy (SNE, Leigh's disease), maple syrup
urine disease (branched-chain aminoacidopathy), and lactic acidosis
associated with pyruvate carboxylase deficiency and hyperalaninemia.
Long-term management should be under strict medical supervision.
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A |
| Thiamin deficiency (Beriberi, Wernicke's
encephalopathy, Korsakoff's psychosis, Wernicke-Korsakoff syndrome)
Humans are dependent on dietary intake to fulfill their thiamin
requirements. Because there is very little thiamin stored in the body,
depletion can occur as quickly as within 14 days. Severe chronic thiamin
deficiency can result in potentially serious complications involving the
nervous system/brain, muscles, heart, and gastrointestinal system.
Patients with thiamin deficiency or related conditions should receive
supplemental thiamin under medical supervision.
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A |
| Acute alcohol withdrawal
Patients with chronic alcoholism or experiencing alcohol withdrawal are
at risk of thiamin deficiency and its associated complications, and
should be administered thiamin.
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B |
| Total parenteral nutrition (TPN)
Thiamin should be added to TPN formulations for patients who are unable
to receive thiamin through other sources (such as a multivitamin) for
more than seven days.
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B |
| Alzheimer's disease
Because thiamin deficiency can result in a form of dementia (Wernicke-Korsakoff
syndrome), its relationship to Alzheimer's disease and other forms of
dementia has been investigated. Whether thiamin supplementation is of
benefit in Alzheimer's disease remains controversial. Further evidence
is necessary before a firm conclusion can be reached.
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C |
| Athletic performance
There is inconclusive scientific evidence in this area.
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C |
| Cancer
Thiamin deficiency has been observed in some cancer patients, possibly
due to increased metabolic needs. It is not clear if lowered levels of
thiamin in such patients may actually be adaptive (beneficial).
Currently, it remains unclear if thiamin supplementation plays a role in
the management of any particular type(s) of cancer.
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C |
| Cataract prevention
Preliminary evidence suggests that high dietary thiamin intake may be
associated with a decreased risk of cataracts. Further evidence is
necessary before a firm conclusion can be reached.
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| Coma/hypothermia of unknown origin
Administration of thiamin is often recommended in patients with coma or
hypothermia of unknown origin, due to the possible diagnosis of
Wernicke's encephalopathy.
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| Crohn's disease
Decreased serum thiamine levels have been reported in patients with
Crohn's disease. It is not clear if routine thiamin supplementation is
beneficial in such patients generally.
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C |
| Didmoad (Wolfram) syndrome
Didmoad (Wolfram) syndrome is a rare autosomal recessive inherited
disease that results in diabetes mellitus, optic atrophy, diabetes
insipidus, sensorineural deafness, and occasionally megaloblastic
anemia. The defect is believed to cause a decrease in the enzyme that
converts thiamin to its active form. Management, including thiamin
supplementation, should be under strict medical supervision.
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| Heart failure (cardiomyopathy)
Chronic severe thiamin deficiency can cause heart failure (wet
beriberi), a condition that merits thiamin supplementation. It is not
clear that thiamin supplementation is beneficial in patients with heart
failure due to other causes. However, it is reasonable for patients with
heart failure to take a daily multivitamin including thiamin, because
some of these individuals may be thiamin deficient.Diuretics may lower
thiamin levels. Since diuretics are commonly administered to patients
with heart failure, patients taking diuretics are at an increased risk
of thiamin deficiency. This area remains controversial, and further
evidence is necessary before a firm conclusion can be reached.
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C |
| Pyruvate dehydrogenase deficiency (PDH)
There is preliminary evidence of clinical improvements in children with
PDH following thiamin administration. Further evidence is necessary
before a firm conclusion can be reached.
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C |
| Subclinical thiamin deficiency in the elderly
While typically asymptomatic, the elderly have been found to have lower
thiamin concentrations than younger people. There is limited evidence
that thiamin supplementation may be beneficial in individuals with
persistently low thiamin blood levels. Further study is necessary before
a firm conclusion can be formed in this area.
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| Fractures (hip)
Preliminary evidence shows that supplemental thiamin is not beneficial
for hip fractures.
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*Key to grades
A: Strong scientific evidence for this use;
B: Good scientific evidence for this use;
C: Unclear scientific evidence for this use;
D: Fair scientific evidence against this use;
F: Strong scientific evidence against this use.
Grading rationale
Uses based on tradition or theory
The below uses are based on tradition or scientific theories. They often
have not been thoroughly tested in humans, and safety and effectiveness have
not always been proven. Some of these conditions are potentially serious, and
should be evaluated by a qualified healthcare provider.
Age-related lens opacification, Bell's palsy, canker sores, chronic diarrhea,
circulation enhancement, depression, diabetes, diabetic nephropathy,
dysmenorrheal (painful menstruation), epilepsy, erectile dysfunction,
fibromyalgia, gastrointestinal disorders, HIV support, high blood pressure,
insect repellant, learning, low back pain, memory enhancement, myelodysplasia,
optic neuropathy, multiple sclerosis, poor appetite, protection from
radiation-induced genetic changes, tissue healing after surgery, ulcerative
colitis.
The below doses are based on scientific research,
publications, traditional use, or expert opinion. Many herbs and supplements
have not been thoroughly tested, and safety and effectiveness may not be proven.
Brands may be made differently, with variable ingredients, even within the same
brand. The below doses may not apply to all products. You should read product
labels, and discuss doses with a qualified healthcare provider before starting
therapy.
Adults (18 years and older):
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The U.S. Recommended Daily Allowance (RDA) for adults ages 19 years and older
is 1.2 milligrams daily for males and 1.1 milligrams daily for females, taken
by mouth. The RDA for pregnant or breastfeeding women of any age is 1.4
milligrams daily, taken by mouth. As a dietary supplement in adults, 1-2
milligrams daily is sometimes used. Thiamin is also used to treat thiamin
deficiency, metabolic/genetic enzyme deficiency disorders, neuropathy, and
Wernicke's encephalopathy (prevention/treatment) under medical supervision.
Children (younger than 18 years):
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The Adequate Intake (AI) for infants ages 0-6 months is 0.2 milligram; for
infants 7-12 months the AI is 0.3 milligram; for children 1-3 years the U.S.
Recommended Daily Allowance (RDA) is 0.5 milligram; for children 4-8 years the
RDA is 0.6 milligram; for children ages 9-13 years the RDA is 0.9 milligram;
for males ages 14-18 years the RDA is 1.2 milligram; for females ages 14-18
years the RDA is 1 milligram, taken by mouth. The RDA for pregnant or
breastfeeding women of any age is 1.4 milligrams daily, taken by mouth.
Thiamin is also used to treat thiamin deficiency/beriberi under medical
supervision.
The U.S. Food and Drug Administration does not strictly
regulate herbs and supplements. There is no guarantee of strength, purity or
safety of products, and effects may vary. You should always read product labels.
If you have a medical condition, or are taking other drugs, herbs, or
supplements, you should speak with a qualified healthcare provider before
starting a new therapy. Consult a healthcare provider immediately if you
experience side effects.
Allergies:
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Rare hypersensitivity/allergic reactions have occurred with thiamin
supplementation. A small number of life-threatening anaphylactic reactions
have been observed with large parenteral (intravenous, intramuscular,
subcutaneous) doses of thiamin, generally after multiple doses.
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Skin irritation, burning, or itching may rarely occur at injection sites.
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Contact dermatitis may occur with occupational exposure, and may cause
sensitization and lead to dermatitis-type reactions after subsequent oral or
injected administrations.
Side Effects and Warnings:
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Thiamin is generally considered safe and relatively nontoxic, even at high
doses. No clear tolerable upper level (UL) of intake has been established.
Dermatitis or more serious hypersensitivity reactions occur rarely.
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Large doses may cause drowsiness or muscle relaxation.
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Injections of thiamin may cause burning. Reactions can often be avoided by
slow administration into larger veins.
Pregnancy and Breastfeeding:
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U.S. Food and Drug Administration Pregnancy Category: C.
Most herbs and supplements have not been thoroughly
tested for interactions with other herbs, supplements, drugs, or foods. The
interactions listed below are based on reports in scientific publications,
laboratory experiments, or traditional use. You should always read product
labels. If you have a medical condition, or are taking other drugs, herbs, or
supplements, you should speak with a qualified healthcare provider before
starting a new therapy.
Interactions with Drugs:
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Reduced levels of thiamin in blood and cerebrospinal fluid have been reported
in individuals taking phenytoin (Dilantin®) for extended periods of time.
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Antacids may lower thiamin levels in the body by decreasing absorption and
increasing excretion or metabolism.
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Barbiturates may lower thiamin levels in the body by decreasing absorption and
increasing excretion or metabolism.
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Loop diuretics, particularly furosemide (Lasix®), have been associated with
decreased thiamin levels in the body by increasing urinary excretion (and
possibly by decreasing absorption and increasing metabolism). Examples of
other loop diuretics include bumetanide (Bumex®), ethacrynic acid (Edecrine®),
and torsemide (Demadex®). Theoretically, this effect may also occur with
other types of diuretics, including thiazide diuretics such as chlorothiazide
(Diuril®), chlorthalidone (Hygroton®, Thalidone®), hydrochlorothiazide (HCTZ,
Esidrix®, HydroDIURIL®, Ortec®, Microzide®), indapamide (Lozol®), and
metolazone (Zaroxolyn®); or potassium-sparing diuretics such as amiloride (Midamor®),
spironolactone (Aldactone®), and triamterene (Dyrenium®). Effects may be
most pronounced with larger doses taken over extended periods of time.
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Tobacco use decreases thiamin absorption and may lead to decreased levels in
the body.
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Effects of neuromuscular blocking agents (NMBAs) may be enhanced with
concomitant (simultaneous) use of thiamin.
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Some antibiotics destroy gastrointestinal flora (normal bacteria in the gut),
which manufacture some B vitamins. In theory, this may decrease the amount of
thiamin available to humans, although the majority of thiamin is obtained
through the diet (not via bacterial production).
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Oral contraceptives (birth control pills/OCPS) may decrease levels of some B
vitamins, vitamin C, and zinc in the body.
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People receiving fluorouracil-containing chemotherapy regimens may be at risk
for developing symptoms and signs of thiamin deficiency.
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In theory, metformin may reduce thiamine activity, and based on animal
research, taking thiamin and metformin together may contribute to the risk of
lactic acidosis.
Interactions with Herbs and Dietary Supplements:
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Consumption of betel nuts ( Areca catechu L.) may reduce
thiamine activity due to chemical inactivation, and may lead to symptoms and
signs of thiamin deficiency.
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Horsetail ( Equisetum arvense L.) contains a thiaminase-like
compound that can destroy thiamine in the stomach, and theoretically causes
symptomatic thiamine deficiency. Horsetail products are available without this
property, and for example, the Canadian government requires that horsetail
products be certified free of thiaminase activity.
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In theory, diuretic herbs may decrease thiamin levels in the body by
increasing urinary excretion.