Alcohol is a Drug. Is it also a Toxin or Poison?

A reader recently sent the following email:

Dear Dr. Hanson,

Regarding your article regarding alcohol as a drug
you miss a vital piece of information when you neglect to point out that the drug ethanol is a toxin [that] does indeed pass the blood brain barrier - (as do other drugs w/small enough molecules). This quality alone lifts alcohol out of the category you've invented whereby which practically anything that enters the human body one way or another is a drug. Ethanol has a particular way of impairing cognition.

I hope that you look into the facts and incorporate them into any future writing you may do on the subject.

Ms. MLD, NY


Dear Ms. MLD:

Thank you for your email noting one of the distinctions among various drugs, including ethanol.

Essential to any discussion of toxins is a fundamental axiom of pharmaceutical science: the dosage makes the toxin. This has long been recognized and, unfortunately, was not "invented" by me.

When consumed in light or moderate quantities, ethanol is not a toxin although in large enough quantities it can cause alcohol poisoning. In such cases, the dosage makes alcohol toxic. However, when consumed in moderation, alcohol is strongly associated with better health and greater longevity than is either abstaining from alcohol or abusing it.

Because, as you state, other drugs also pass through the blood brain barrier, alcohol is not unique in doing so, as you assert. Nor is alcohol unique in any "particular way of impairing cognition."

Scientific research has also demonstrated the powerful role of alcohol expectations on behavior. For example, in those societies that do not believe that alcohol disinhibits, the substance does not disinhibit.

The subject is a complex one and you obviously recognize some of this complexity. Listed here for your convenience are some additional links on the subject that you might find of interest:

Alcohol and Behavior
Alcohol and Cognition

Best regards,

David Hanson

This website is informational only, does not provide health advice, and none should be inferred.

Resources

  • Antilla, Tiia, et al. Alcohol drinking in middle age and subsequent risk of mild cognitive impairment and dementia in old age: a prospective population based study. British Medical Journal, 2004, 329, 538-539.
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  • Espeland, M., et al. Association between alcohol intake and domain-specific cognitive function in older women. Neuroepidemiology, 2006, 1(27), 1-12.
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  • Kalev-Zylinska, Maggie L. and During, Matthew J. Paradoxical facilitatory effect of low-dose alcohol consumption on memory mediated by NMDA receptors. Journal of Neuroscience, 2007, 27, 10456-10467.
  • Rodgers, B., et al. Non-linear relationships between cognitive function and alcohol consumption in young, middle-aged and older adults: The PATH Through Life Project. Addiction, 2005, 100(9), 1280-1290.
  • Zuccala, G., et al. Dose-related impact of alcohol consumption on cognitive function in advanced age: Results of a multicenter study. Alcoholism: Clinical and Experimental Research, 2001, 25, 1743-1748.

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