Vitamin B1 — Thiamine

Vitamin B1 (Thiamine or thiamin), the first B vitamin by Earl Mindell in Vitamin Bible (Warner Books, 1979) because of the support it gives to the nervous system and mental attitude. Its odor and flavor are similar to those of yeast.
Thiamine can be destroyed by the cooking process, especially by boiling or moist heat, but less by dry heat, such as baking.

Like most other B vitamins, thiamine is needed in regular supply, though after its absorption from the upper and lower small intestine, some B1 is stored in the liver, heart, and kidneys. Most excess thiamine is eliminated in the urine; some seems to be excreted in the sweat as well.

Sources: Since thiamine is lost in cooking and is depleted by use of sugar, coffee, tannin from black teas, nicotine, and alcohol, it is necessary to insure that intake of thiamine is optimal. There are a number of food sources for thiamine; however, they may not be the everyday fare for many people. Good sources of vitamin B1 include the germ and bran of wheat, rice husks (outer covering), and the outer portion of other grains. With the milling of grains and use of refined flours and white or “polished” rice, many of us are no longer getting the nourishment of thiamine that is available when we eat wholesome, unprocessed foods.

Other good sources of thiamine besides wheat germ and bran, whole wheat or enriched wheat flour, and brown rice are brewer’s yeast and blackstrap molasses. Oats and millet have modest amounts, as do many vegetables, such as spinach and cauliflower, most nuts, sunflower seeds, and legumes, such as peanuts, peas, and beans. Of the fruits, avocado is the highest in vitamin B1. Pork has a high amount of this B vitamin. Many dried fruits contain some thiamine, though the sulfur dioxide often added as a preservative seems to destroy this vitamin.

Functions: Thiamine helps a great many bodily functions, acting as the coenzyme thiamine
pyrophosphate (TPP). It has a key metabolic role in the cellular production of energy, mainly in glucose metabolism. Thiamine is also needed to metabolize ethanol, converting it to carbon dioxide and water. B1 helps in the initial steps of fatty acid and sterol production. In this way, thiamine also helps convert carbohydrate to fat for storage of potential energy.

Thiamine is important to the health of the nerves and nervous system, possibly because of its role in the synthesis of acetylcholine (via the production of acetyl CoA), an important neurotransmitter. With a lack of vitamin B1, the nerves are more sensitive to inflammation. Thiamine is linked to individual learning capacity and to growth in children. It is also important to the muscle tone of the stomach, intestines, and heart because of the function of acetylcholine at nerve synaptic junction. It is conceivable that adequate thiamine levels may help prevent the accumulation of fatty deposits in the arteries and thereby reduce the progression of atherosclerosis.

Uses: Vitamin B1 is, of course, used to treat any of the symptoms of its deficiency or its
deficiency disease beriberi (discussed below). It is used in the treatment of fatigue, irritability, low morale, and depression and to prevent air- or seasickness. It seems to help the nerves, heart, and muscular system function well. By aiding hydrochloric acid
production, thiamine may help digestion or reduce nausea, and it can remedy constipation by increasing intestinal muscle tone. Thiamine is used commonly to improve healing after dental (or, often, any) surgery.

Increased thiamine intake may be suggested for numerous mental illnesses and problems that affect the nerves. These include alcoholism and its nerve problems, multiple sclerosis, Bell’s palsy (a facial nerve paralysis), and neuritis. Treatment with thiamine, for example, has been helpful in decreasing the sensory neuropathy that accompanies diabetes and in lessening the pain of trigeminal neuralgia. Thiamine also has a mild diuretic effect and is supportive of heart function, so it is suggested in the treatment program for many cardiovascular problems.

Since thiamine is eliminated through the skin somewhat, doses of over 50-100 mg. per day may help repel insects such as flies and mosquitos from those with “sweet blood.” Other uses for increased thiamine include treatment of stress and muscle tensions, diarrhea, fever and infections, cramps, and headaches.

Deficiency and toxicity: There is no known toxicity in humans from thiamine taken orally.
People have taken hundreds of milligrams daily without any harmful effect, although some may become more stimulated than others. Thiamine injections, however, have occasionally been associated with trauma or edema.

Prolonged restriction of thiamine intake may produce a wide variety of symptoms, particularly affecting the general disposition, nervous system, gastrointestinal tract, and heart. With thiamine deficiency, as with deficiency of most any essential nutrient,
symptoms range from mild to moderate depletion disorders to the serious disease state that RDA amounts usually prevent.

Beriberi is the name given to the disease caused by thiamine deficiency. There are three basic expressions of beriberi, namely childhood, wet, and dry beriberi. Childhood beriberi stunts the growth process, and in infants high-pitched scream and rapid heartbeat are associated with the disease. Wet beriberi is the classic form with edema (swelling) in the feet and legs, spreading to the body, and associated decreased function of the heart. Dry beriberi is not accompanied by swelling but seems to be manifested by weight loss, muscle wasting, and nerve degeneration. Another thiamine deficiency disease involves degeneration of the brain and affects the general orientation, attitude, and ability to walk. This has been termed the Wernicke-Korsakoff syndrome and is usually seen in people who have been addicted to alcohol for many years.

These severe problems can and do lead to death when they are not corrected with dietary change or supplemental thiamine. Before vitamin B1 was discovered, this affected many people who ate a diet consisting mainly of polished rice. Today, deficiency of this vitamin is still quite common. Although it does not usually lead to beriberi, a number of symptoms can result from a depletion of thiamine body levels. A low-B1 diet consisting of polished rice or unenriched white flour is not often the culprit in our culture. The diet that contributes to deficiency today, especially among teenagers, is high in colas, sweets, fast foods, and many other empty-calorie foods. This diet can also lead to skin problems and symptoms of neurosis, almost like a Jekyll-and-Hyde disposition.

With a deficiency of thiamine, carbohydrate digestion and the metabolism of glucose are diminished. There is a build-up of pyruvic acid in the blood, which can lead to decreased oxygen utilization and therefore mental deficiency and even difficulty in breathing. While B1 is needed for alcohol metabolism, alcohol abuse is often associated with a poor diet and poor B1 absorption. The poor perceptions, mental states, and nerve problems that come with alcoholism may be associated with thiamine deficiency.

The first symptoms of thiamine deficiency may be fatigue, instability. These may be followed by confusion, loss of memory, depression, clumsiness, insomnia, gastrointestinal disturbances, abdominal pain, constipation, slow heart rate, and burning
chest pains. As the condition progresses, there may be problems of irregular heart rhythm, prickling sensation in the legs, loss of vibratory sensation, and the muscles may become tender and atrophy. The optic nerve may become inflamed and the vision will be affected.

Generally, with low B1 the central nervous system–the brain and nerves–does not function optimally. The gastrointestinal and cardiovascular systems are also influenced greatly. Vitamin B1 levels have been shown to be low in many elderly people, especially those that experience senility, neuroses, and schizophrenia. We might question how much of the degeneration and disease of old age may be a result of withering digestion and assimilation, leading to deficiencies of various vitamins and other necessary nutrients.

Requirements: The RDA for vitamin B1 is about 1.2 mg. per day, or 1.4 mg. during
pregnancy or lactation. Infants need more per body weight though less in total, about 0.5 mg. per day. Thiamine needs are based on many factors; given good health, we need about 0.5 mg. per 1,000 calories consumed, since B1 is required for energy metabolism. So our needs are based on body weight, calorie consumption, and the amount of vitamin B1 synthesized by intestinal bacteria, which can vary greatly from person to person.

Thiamine needs are also increased with higher stress levels, with fever or diarrhea, and during and after surgery. Those who smoke, drink alcohol, consume caffeine or tannin from coffee or tea, or who are pregnant, lactating, or taking birth control pills all need more thiamine, possibly much more than the RDA, for optimum health.

Thiamine is needed in the diet or in supplements daily. There are some stores in the heart, liver, and kidneys; however, these do not last very long. The minimum B1 intake for those who are very healthy is at least 2 mg. per day. A good insurance level of thiamine is probably 10 mg. a day, though even higher levels may be useful in some situations. When we do not eat optimally, have any abusive substance habits (especially alcohol abuse), or are under stress, increased levels of thiamine are recommended. An example is the B complex 50 products–that is, 50 mg. of B1 along with that amount of most of the other B
vitamins–suggested as a daily regimen. The upper intake levels of thiamine should not be much more than 200-300 mg. daily. Often B1, B2 (riboflavin), and B6 (pyridoxine) are formulated together in equal amounts within a B-complex supplement. When people take higher amounts of the B vitamins, many feel a difference in energy and vitality. (Note: Riboflavin taken for any length of time is best limited to 50 mg. daily.)

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Elson M. Haas MD Written by Elson M. Haas MD

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