Alcohol Plus Thiamine Deficiency Spells Trouble For Brain

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NEW YORK (Reuters Health) - The complicated relationship between heavy drinking and vitamin-B1 deficiency is foggy at best. But, researchers say, seems clear that both, separately or together, can have serious effects on the brain.

In the current issue of Alcoholism: Clinical & Experimental Research, investigators report on experiments in mice showing that heavy alcohol
consumption and vitamin-B1 deficiency impair learning, memory, and muscle and
nerve function. In humans, such symptoms can arise in alcoholics whose habit
has caused a deficiency in vitamin B1, or thiamine. Some alcoholics develop
dementia, but it's unclear whether alcohol or thiamine deficiency plays the
more important role.

This new research suggests that the combined effect of alcohol and thiamine
deficiency speeds the onset of dementia in alcoholics, lead researcher Dr.
Philip Langlais of San Diego State University, told Reuters Health. Because
alcoholics often go for long periods without eating, he noted, their thiamine
stores may be particularly low.

Langlais' experiments in mice showed that alcohol consumption and thiamine
deficiency together hindered learning ability. But, contrary to his team's
expectations, the two did not act together to harm working memory the ability to, for example, look up a telephone number and remember it long enough to dial it. Instead, alcohol alone hindered working memory, and thiamine deficiency actually appeared to protect working memory from alcohol-related damage. In addition, thiamine deficiency, but not alcohol, hindered the animals' movement and coordination.

Despite the varying effects of the two conditions on different parts of the
brain, their significant combined effect on learning suggest that thiamine
supplements may protect alcoholics from dementia. According to Langlais, his experiments showed less severe impairment in brain function than some previous research; one reason, he said, may be the thiamine supplements his team gave the mice. Already, some alcoholics are treated with thiamine injections. But supplementing food or even alcoholic beverages with the vitamin may be another option.

Indeed, Langlais noted, an Australian study shows that since that country mandated that certain foods be fortified with thiamine, alcohol-related dementia has declined. Foods naturally rich in thiamine include pork, beans,leafy green vegetables, and nuts."I am continually amazed," Langlais added, "at how little we know about this issue of what causes dementia, memory problems, cognitive deficits, and brain damage in alcoholics." His team plans to next examine the effects of various thiamine doses on rats exposed to high levels of alcohol. Langlais suspects that only certain doses will be beneficial, and that very low or very high thiamine doses will worse the effects of alcohol.