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The first vitamin identified, vitamin B1 or thiamine, helped to force medical researchers to adopt a new way of looking at health and nutrition. In the 1870s and 1880s, researchers determined that polished rice was somehow responsible for causing beriberi, a condition suffered by many peasants, sailors, and others. The prevailing medical model channeled research into looking for bacteria or other disease-causing agents in the rice. It wasn’t until the early years of the new century that most researchers finally accepted the truth: whole rice and other nutritious foods contain compounds (named vitamins in 1911) that actively prevent diseases like beriberi.

Why is it essential? Vitamin B₁ is crucial for the metabolism of carbohydrates, fat, and protein and the normal functioning of the nervous system. It is involved in glucose metabolism, digestive processes, and the formation of the neurotransmitter acetylcholine. Vitamin B₁ also plays a crucial role in the formation of adenosine triphosphate (ATP), the body’s principal energy-carrying compound.

Benefits and uses: Among the conditions that vitamin B₁ may help to prevent or treat are glaucoma, canker sores, and fibromyalgia. Thiamine can promote rapid healing of minor injuries and help keep skin supple. Vitamin B1 is necessary for a healthful pregnancy and postpartum recovery. Its beneficial effect on nerve cells makes it a useful adjunct treatment for such conditions as learning disabilities and memory loss in the elderly and victims of Alzheimer’s disease.

Daily requirement: The new RDI ranges from 1.1 to 1.5 mg per day for adults.

Deficiency risk factors: A B₁ deficiency is most commonly found in alcoholics, the elderly, people with malabsorption conditions, and those eating a very poor diet. Taking high amounts of other B vitamins may increase the need for B₁, as might excessive consumption of coffee and use of birth control pills. Symptoms of a deficiency may include fatigue, depression, visual problems such as dry eyes or double vision, nervous system ailments, and eventually Wernicke-Korsakoff syndrome, a potentially fatal brain disease.

Optimal intake: An optimal daily dosage is 25 to 50 mg. One study reports that the healthiest people eat at least 9 mg per day.¹

Food sources: Among the most common sources of vitamin B₁ are vegetables, whole grains, nuts, seeds, beans, fish, meat, and legumes. Brewer’s yeast is rich in thiamine.

Recent findings: A study done on 120 young adult females found that those given 50 mg B₁ each day for two months experienced an improvement in thiamine status that was associated with reports of being "more clearheaded, composed, and energetic." The influence was noted even in subjects with adequate thiamine status at the start of the study.² For select patients who are at highest risk of developing Wernicke encephalopathy, the first stage in the acute thiamine deficiency condition Wernicke-Korsakoff syndrome, taking the vitamin by infusion is much more effective than oral supplements, researchers report.³ A cross-sectional survey of elderly Japanese found that a much higher percentage (33 percent) of subjects were assessed to have poor B₁ status than were poor in either vitamin A (1 percent) or vitamin C (4 percent). One factor was thought to be a preference for polished rice as a staple food.⁴

Safety: Like the other B vitamins, thiamine is basically nontoxic even in very high doses.

Types of products: Almost all vitamin B₁ supplements are 100 mg, though others provide as much as 500 mg. Thiamin is a common ingredient in multinutrient formulas.

References

1. Cheraskin, E., et al., "The ‘ideal’ daily vitamin B₁ intake," J Oral Med (1978), 33:77–79
2. Benton, D., et al., "Thiamine supplementation mood and cognitive functioning," Psychopharmacology (1997), 129(1):66–71
3. Hahn, J.S., et al. "Wernicke encephalopathy and beriberi during total parenteral nutrition attributable to multivitamin infusion shortage," Pediatrics (1998), 101(1):E10
4. Yamagami, M., et al., "[Vitamin A, B1, and C status of elderly living alone]," Nippon Koshu Eisei Zasshi (1998), 45(3):213–24