Thiamine, or Vitamin B1, is essential for metabolizing carbohydrates and producing energy. The vitamin helps the body convert food into energy, and aids the function of the heart and cardiovascular system and the brain and nervous system. It is water-soluble. Thiamine (vitamin B-1) helps the body cells convert carbohydrates into energy. It is also essential for the functioning of the heart, muscles, and nervous system.

Food Sources

Thiamine is found in fortified breads, cereals, pasta, whole grains (especially wheat germ), lean meats (especially pork), fish, dried beans, peas, and soybeans. Dairy products, fruits, and vegetables are not very high in thiamine, but when consumed in large amounts, they become a significant source.

Side Effects

A deficiency of thiamine can cause weakness, fatigue, psychosis, and nerve damage. Thiamine deficiency in the U.S. is most often seen in alcoholics, because heavy drinking limits the ability of the body to absorb this vitamin from foods. Since few alcoholics consume higher than normal amounts of thiamine to make up for the difference, they become deficient and may develop the disease called beriberi.

In severe deficiency, brain damage can occur. One type is called Korsakoff syndrome (confusion and loss of short-term memory); the other is Wernicke's disease (eye disturbances, unsteady gait, and confusion). Either or both of these conditions can occur in the same person.

There is no known toxicity associated with thiamine.

1. Wilkinson TJ, Hanger HC, Elmslie J, George PM, Sainsbury R. The Response to Treatment of Subclinical Thiamine Deficiency in the Elderly. Am J Clin Nutr. 1997 Oct;66(4):925-8.

The significance of subclinical thiamine deficiency in the elderly was determined by assessing response to thiamine supplementation in a randomized double-blind, placebo-controlled trial. Thirty-five of 222 people aged > or = 65 y had two concentrations of erythrocyte thiamine pyrophosphate (TPP) < 140 nmol/L 3 mo apart and 41 other people had the first, but not the second, TPP concentration below this value. Both groups were randomly assigned in a double-blind trial to oral thiamine (10 mg/d) or a placebo.

All subjects randomly assigned to receive thiamine showed increases in TPP concentrations compared with control subjects. Only the subjects with persistently low TPP concentrations showed subjective benefits from treatment with improvements in quality of life (measured on a visual analogue scale; P = 0.02) and decreases in systolic blood pressure (P = 0.05) and weight (P < 0.01) when compared with subjects given placebo. There was a trend toward benefits in sleep and energy (P = 0.07). We conclude that a low TPP concentration on two occasions is a better predictor of response to treatment than an isolated measurement. Quality of life was enhanced by providing thiamine supplements. Blood pressure and weight were lower after thiamine supplementation.

2. Middle-aged Binge Drinkers Risk Dementia.

Middle-aged adults who binge drink may face a heightened risk of dementia later in life, a new study suggests. Researchers found even among adults who usually drank moderately, those who occasionally binged were more likely than their peers to develop dementia over the next 25 years. Overall, middle-aged adults who binged at least once a month - downing, for instance, five bottles of beer or a bottle of wine in one sitting - had a three times greater risk of developing dementia, including Alzheimer's disease.

Chronic heavy drinking has been linked to dementia risk in past studies, and alcoholism can sometimes lead to dementia due to toxic effects on brain cells or to deficiency in the B vitamin thiamine. Periodic binge drinking may contribute to dementia by directly killing off brain cells or possibly by raising the odds of falls and head injuries, which can predispose a person to dementia.

The findings were published in the medical journal Epidemiology. The study included 554 Finnish adults who provided information on their health and lifestyle, including drinking habits, in 1975, when they were 40 years of age or older. Twenty-five years later, they took a standard test of mental functioning used to diagnose dementia. Kaprio's team found those who reported binge drinking at least once a month in 1975 were at greater risk of dementia later in life - even if they drank only lightly to moderately between binges.

In a follow-up to the original survey, conducted in 1981, the researchers also asked respondents whether they had ever imbibed to the point of passing out. Those who said they had done so at least twice were 10 times more likely than their peers to be diagnosed with dementia later in life. Studies have found binge drinking to be common among college students and other young adults, and research suggests short term problems with memory and attention are among the consequences.

Coupled with the current findings on middle-aged adults, Kaprio said, this raises the possibility that binge drinking at a young age may also contribute to dementia later on. He also noted, however, the brain's "plasticity" may allow it to better recover from alcohol damage inflicted in young adulthood.

3. Alzheimer's disease, Linus Pauling Institute

Because thiamin deficiency can result in a form of dementia (Wernicke-Korsakoff syndrome), its relationship to Alzheimer's disease and other forms of dementia have been investigated. Several investigators found evidence of decreased activity of the thiamin pyrophosphate-dependent enzymes, a-ketoglutarate dehydrogenase and transketolase, in the brains of patients who died of Alzheimer's disease. Such findings are consistent with evidence of reduced glucose metabolism found on PET scans of the brains of Alzheimer's disease patients. The finding of decreased brain levels of thiamin pyrophophosphate (TPP) in the presence of normal levels of free thiamin and thiamin monophosphate (TMP) suggests that the decreased enzyme activity is not likely to be the result of thiamin deficiency, but rather of impaired synthesis of TPP.

Presently, there is only slight evidence that thiamin supplements are of benefit in Alzheimer's disease. A double blind placebo-controlled study of 15 patients (10 completed the study) reported no beneficial effect of 3 grams of thiamin/day on cognitive decline over a 12-month period. A preliminary report from another study claimed a mild benefit of 3 to 8 grams of thiamin/day in dementia of Alzheimer's type in 1993, but no additional data from that study are available. A mild beneficial effect in patients with Alzheimer's disease was reported after 12 weeks of treatment with 100 milligrams/day of a thiamin derivative (thiamin tetrahydrofurfuryl disulfide), but this study was not placebo-controlled. A recent systematic review of randomized, double blind, placebo-controlled trials of thiamin in patients with dementia of Alzheimer's type found no evidence that thiamin was a useful treatment for the symptoms of Alzheimer's disease.

4. Congestive heart failure (CHF), Linus Pauling Institute

Severe thiamin deficiency (wet beriberi) can lead to impaired cardiac function and ultimately congestive heart failure (CHF). Although cardiac manifestations of beriberi are rarely encountered in industrialized countries, CHF due to other causes is common, especially in the elderly. Diuretics used in the treatment of CHF, notably furosemide (Lasix), have been found to increase thiamin excretion, potentially leading to marginal thiamin deficiency. A number of studies have examined thiamin nutritional status in CHF patients and most found a fairly low incidence of thiamin deficiency, as measured by assays of transketolase activity. As in the general population, older CHF patients were found to be at higher risk of thiamin deficiency.

An important measure of cardiac function in CHF is the left ventricular ejection fraction (LVEF), which can be assessed by echocardiography. In a randomized double-blind study of 30 CHF patients, all of whom had been taking furosemide for at least 3 months, intravenous (IV) thiamin therapy (200 mg/day) for 7 days resulted in an improved LVEF compared to IV placebo. When all 30 of the CHF patients in that study subsequently received 6 weeks of oral thiamin therapy (200 mg/day) the average LVEF improved by 22%. This finding may be significant because improvements in LVEF have been associated with improved survival in CHF patients. Conclusions that can be drawn from the studies published to date are limited due to small sample sizes, lack of randomization in some studies, and a need for more precise assays of thiamin nutritional status. Presently, the role of thiamin supplementation in maintaining cardiac function in CHF patients remains controversial.

5. Cancer, Linus Pauling Institute

Thiamin deficiency has been observed in some cancer patients with rapidly growing tumors. Recent research in cell culture and animal models indicates that rapidly dividing cancer cells have a high requirement for thiamin. All rapidly dividing cells require nucleic acids at an increased rate, but some cancer cells appear to rely heavily on the TPP-dependent enzyme, transketolase, to provide the ribose-5-phosphate necessary for nucleic acid synthesis. Thiamin supplementation in cancer patients is common to prevent thiamin deficiency, but some investigators caution that too much thiamin may fuel the growth of some malignant tumors. These investigators suggest that thiamin supplementation be reserved for those cancer patients that are actually thiamin deficient. Presently, there is no evidence available from studies in humans to support or refute this theory. However, it would be prudent for individuals with cancer who are considering thiamin supplementation to discuss this issue with the clinician managing their cancer therapy.

6. University Researchers Make Diabetes Breakthrough.

Researchers at the University Essex have found that high doses of vitamin B1 (thiamine) could lower cholesterol in diabetes patients and help prevent heart disease.

The results of the research project, led by Professor Paul J Thornalley of the Department of Biological Sciences, suggest that diabetics should avoid even mild thiamine deficiency and that thiamine supplements could significantly decrease the risk of heart disease and kidney failure.

Diabetes increases the risk of heart disease two to three fold in men and three to five fold in women. The increased risk is linked to high levels of cholesterol and lipids in the blood. Previous studies have shown that the use of drugs, such as statins, can lower the risk of heart disease in diabetics by between 20 and 40 per cent. However, Professor Thornalley's Disease Mechanisms and Therapeutics Research Group are confident that high doses of thiamine can also help to reverse the increases in blood cholesterol and lipid levels.

Professor Thornalley explained: "There will of course be clinical trials to investigate further the findings we have made using an experimental model of diabetes. However, given the continuing toll of heart disease in diabetic patients, and the emerging benefits of thiamine therapy for diabetics suffering from kidney disease - as reported by our research group last year - I would strongly suggest that those with diabetes are given thiamine supplements."

7. B1 Lack May Spur Anorexia Nervosa.

Vitamin B1 (thiamin) deficiency can result in depression, mood swings, and loss of appetite -- symptoms typical of anorexia nervosa. Researchers from the University of Leicester in England analyzed nutrient levels in 37 people treated for anorexia and compared them with 50 healthy subjects. Thirty-eight percent of the patients with anorexia were deficient in vitamin B1, 19 percent severely so, while no one among the healthy subjects was deficient. Low vitamin B1 levels were not related to fasting, vomiting, or drinking alcohol, which suggests that some anorexics have a larger metabolic requirement for vitamin B1.

8. Winston AP, et al. Prevalence of Thiamin Deficiency in Anorexia Nervosa. Int J Eating Dis 2000 (Dec); 28 (4): 451-445.

Objective: Deficiency of thiamin (vitamin B1) causes a range of neuropsychiatric symptoms that resemble those reported in patients with anorexia nervosa (AN) but the prevalence of thiamin deficiency in AN has not been reliably established. This study was designed to investigate the prevalence of thiamin deficiency in AN.

Method: Thirty-seven patients attending a specialist eating disorders unit and meeting all or some of the DSM-IV criteria for AN were compared with 50 blood donor controls. All subjects underwent measurement of erythrocyte transketolase activation following the addition of thiamin pyrophosphate, the standard biochemical test for thiamin deficiency. Deficiency was defined as a result more than 2 SD above the mean of the control population.

Results: Fourteen patients (38%) had results in the deficient range; 7 (19%) met the most stringent published criterion for deficiency. Deficiency was not related to duration of eating restraint, frequency of vomiting, or alcohol consumption.

Discussion: Thiamin deficiency may account for some of the neuropsychiatric symptoms of AN and routine screening or supplementation may be indicated.

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