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.
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.
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.
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.
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.
Sources
and Additional Information:
