Robert Sullivan at the NY Times:
What doesn’t kill you might make you stronger. When it comes to nature’s toxins, they might even save your life (or at least blunt the sting of its finality). The distinction, as the evolutionary biologist Noah Whiteman explores in “Most Delicious Poison,” is all in the dosage.
Take alcohol. Ethanol is likely born of plants’ evolutionary search for protection. Long before the first happy hour, yeast’s alcohol-making evolved as a means for the fungi residing in rotting fruit to survive oxygen deprivation. Ethanol thwarts most microbes; but yeast thrives, burning energy from sugar in oxygen’s absence. The same ethanol that might jump-start a party can, through addiction, mean the destruction of the liver — not to mention lives. Alcohol’s paradox, Whiteman writes, is tied to ethanol’s ability to mimic (or possibly bind to) gamma-aminobutyric acid — that is, the neurotransmitter our brains use to soften the nervous system’s activity.
more here.