|Vitamin B1 (thiamin) is essential for the body to be able to use carbohydrate as an energy source as well as for metabolising amino acids. Vitamin B1 is essential for the health of the brain, nerves and cardiovascular system. Vitamin B1 is needed by the body to process carbohydrates, fats, and proteins. Vitamin B1 is also required to form ATP. Nerve cells require vitamin B1 to
function as well. Vitamin B1 deficiency is usually connected to alcoholism, malabsorption diseases, and poor diet. Thiamine is a coenzyme for the decarboxylation of pyruvate and the oxidation of alpha keto-glutamic acid. Lipoic acid which is formed in the liver is also required for the reactions. Patients with liver disease may show signs of B1 deficiency. The minimum amount of thiamin needed by the body can increase because of increased physiological or metabolic demands arising from pregnancy and lactation, heavy physical exertion, illnesses like cancer, liver diseases, hyperthyroidism, and surgery.
Thiamin deficiency occurs as a result of many factors, including crash dieting, alcohol abuse, liver disfunction, kidney dialysis, and sustained periods of IV nutrients. Also at risk are those who consume a lot of sweets, soft drinks, and highly processed foods. Vitamin B1 deficiency is common among alcoholics, as chronic alcohol consumption decreases the amount of Vitamin B1 absorbed by the body. Alcohol not only blocks thiamin assimilation but injures the small intestine, making nutrient absorption in general very difficult. Similarily, tea, coffee (both caffeinate and decaffeinated), and the chewing of betelnuts or tea leaves deplete thiamine, as do some medications and cigarette smoke. Vitamin B1 deficiency also occurs quite commonly in parts of Asia where the main food source is polished rice, as removal of the rice husk greatly reduces the vitamin B1 content of this grain. Thiamin deficiency is observed in individuals who have low thiamin intake and a diet rich in polished rice, especially if their diet also consists of anti-thiamin factors such as tea, coffee, raw fermented fish, and betel nuts.
A lack of sufficient thiamine in the diet can cause loss of appetite, poor digestion, chronic constipation, loss of weight, mental depression, nervous exhaustion, and insomnia. It can lead to muscular weakness, leg cramps, slow heartbeat, irritability, defective hydrochloric acid production in the stomach and consequent digestive disorders. In case of insufficient supply of thiamine in the body, the heart muscles become lazy and fatigued, and the auricles or the upper chambers of the heart lose their strength and gradually enlarge. This may lead tto a condition known as hypertrophy of the heart. Prolonged gross deficiency can cause beriberi, neuritis, and oedema. Lack of vitamin B1, can slow down circulation to the scalp to the extent that hair may fall and new hair may grow very slowly. Deficiency of thiamine can be induced by excessive use of alcohol, dietary sugar, and processed and refined foods.
There are two major manifestations of thiamine deficiency: cardiovascular disease (wet beriberi) and nervous system disease ("dry beriberi" and Wernicke-Korsakoff syndrome). Both types are most often caused by excessive alcohol consumption. Severe thiamin deficiency, known as beriberi, is common among those who rely on staples of white flour and white rice. There are two forms of beriberi: wet beriberi, which affects the heart and blood vessels, and dry beriberi, which affects the nervous system. Wet beriberi causes shortness of breath, heart palpitations, oedema (fluid build up in the tissues), changes in the electrical activity of the heart and heart failure. Symptoms of dry beriberi include pain, tingling, or loss of sensation in hands and feet (peripheral neuropathy), muscle wasting with loss of function or paralysis of the lower extremities, and potential brain damage and death. Beriberi can also occur in breast-fed infants when the mother has an inadequate intake of thiamine. It can also affect infants fed unusual formulas with inadequate thiamine supplements. Others at risk for beriberi include patients undergoing dialysis, patients receiving high doses of diuretics, and people in developing countries with limited diets who consume milled rice.
A thiamin deficiency also produces Warnicke-Korsakoff syndrome, sometimes called cerebral beriberi, a disorder of the central nervous system. Wet beriberi is characterized by swelling, increased heart rate, lung congestion, and enlarged heart related to congestive heart failure. As a result, beriberi now occurs primarily in patients who abuse alcohol, because drinking heavily can lead to malnutrition and poor absorption and storage of thiamine. This is the cause of Wernicke-Korsakoff syndrome, which is alcohol-related brain damage affecting language and thinking. Alcoholism is the major cause of thiamin deficiency in Wernicke-Korsakoff syndrome or cerebral beriberi. Wernicke-Korsakoff syndrome is characterized by abnormal ocular motor signs, ataxia and derangement of mental functions. The ocular motor signs include paresis of abduction which is accompanied by horizontal diplopia, strabismus and nystagmus. Derangement of mental functions include a global-confusional apathetic state and amnesia.