B-1 deficiency causes serious health woes
What is beriberi? This might sound like the response to a "Jeopardy!" query from the category Ancient Diseases. However, this nutrient-deficiency disease still exists in various parts of the world, including developed countries, where it is linked to alcoholism and diabetes. The nutrient is vitamin B-1, also called thiamin.
Question: How does thiamin deficiency affect the body?
Answer: Beriberi literally means, "I can't, I can't." Since the nervous system, the heart and the intestines are harmed, someone with a B-1 deficiency feels weak. They don't feel like eating. They have memory problems, feel confused and irritated, and lose muscle control and sense of touch. Even control of muscles in the eyes can be affected. Consequently, someone with beriberi can't physically or mentally do what they want to do.
Q: How are alcoholics affected by thiamin deficiency?
A: The condition of beriberi in alcoholism is now called Wernicke-Korsakoff syndrome. Excessive alcohol consumption decreases the amount of thiamin absorbed from food, and it also increases the amount of the vitamin lost from the body. Add to this the usual poor-quality diet of many alcoholics, and the symptoms of beriberi can develop quickly. This is the likely cause of the erratic eye movements, staggering gait and deranged mental functions seen in serious alcoholism.
Q: What is the relationship between thiamin and diabetes?
A: Researches have reported that people with type 1 and type 2 diabetes commonly have low levels of thiamin in their blood. A recent British study found that diabetics lost three to four times as much thiamin in their urine each day as nondiabetics.
Because thiamin deficiency could be causing some of the complications of diabetes, ongoing studies are exploring the effects of thiamin supplementation of diabetics. It remains to be seen exactly how much thiamin is needed by people with diabetes and if increased intake is beneficial.
Q: What foods are good sources of vitamin B-1?
A: Recommended intake for a normal healthy adult is 1.2 to 1.5 milligrams per day. Many fortified breakfast cereals meet daily needs with one serving. Three ounces of lean pork or extra-lean ham provide about one milligram, and a cup of most beans or four ounces of salmon each provide about a third of a milligram. In the U.S., most white flour is enriched with B-1, so a slice of white bread has about a tenth of a milligram.
Due to thiamin's low toxicity, no upper limit was set for vitamin B-1 by the Institute of Medicine in the United States. Experts in the United Kingdom established 100 milligrams per day as an upper "guidance level" for adults.
Alan Titchenal, Ph.D., C.N.S. and Joannie Dobbs, Ph.D., C.N.S. are nutritionists in the Department of Human Nutrition, Food and Animal Sciences, College of Tropical Agriculture and Human Resources, University of Hawaii-Manoa. Dr. Dobbs also works with University Health Services.