Most Delicious Poison: The Story of Nature’s Toxins, from Spices to Vice

Most Delicious Poison: The Story of Nature’s Toxins, from Spices to Vice. Noah Whiteman. New York & Boston: Little Brown Spack, 2023. 296 pp. $14.95, hardcover.

Cynthia Moe-Lobeda begins the “Invitation” at the opening of her book, Building a Moral Economy (2024): “We humans are splendidly sensuous creatures. We delight in the beauty of touch, taste, sight, sound, and smell. And we are hungry creatures. We hunger to belong. We hunger for joy, pleasure, beauty trustworthy companions. These are the holy hungers. They lead us to relish the gifts of being alive as Earth creatures in an extravagantly beautiful world—magnificent beyond imaging.” Noah Whiteman’s Most Delicious Poison explores the reality of Moe-Lobeda’s opening at a level we might not expect, at the molecular level, the level at which substances from the plant world affect our brains and other parts of our bodies.

Whiteman is an evolutionary biologist at the University of California, Berkeley. He grew up in Duluth and then moved with his family to the Sax-Zim Bog, a vast relic of the last ice age between Duluth and Hibbing. The family moved because his father took a job in a small town near the bog. With his father and brother, Whiteman had learned to love studying the plants and animals they found in their surroundings, both Duluth and the bog, but his father also suffered from alcohol use disorder (AUD), which eventually led to great anguish in his family.

Whiteman went away to college and eventually to the University of Missouri—St. Louis for a PhD in biology, focusing on tropical biology. He was inspired to study the evolutionary history of the ways plants developed the ability to produce toxins to protect themselves from herbivores, and then some herbivores evolved resistances to those toxins, and in some cases evolved the ability to use those toxins to protect themselves from predators. Humans are part of that story, and Whiteman wanted to study that history in part to better understand his father, and in particular to better understand, at a biological and neurological level, how his father had grown to develop a destructive dependency on one of those toxins, ethanol, that is produced in the natural world.

Whiteman calls the ongoing development of toxins by plants across evolutionary time, the development of resistance to toxins, and then the development of uses of toxins by animal species for their own purposes, the ongoing war of nature. Most Delicious Poison abounds in stories like russet sparrows in China learning to line their nests with leaves of wormwood (loaded with toxins) to repel parasites that would otherwise move into the nests and threaten the health of hatchlings. Humans in China do something similar each year when warm weather, wormwood leaves, and pests arrive; they hang sprigs of wormwood in their doorways to discourage pests. Chimpanzees have learned to do something similar in Tanzania. The inner pith of shoots of a plant called Vernonia produce a bitter juice that has no nutritional value for chimps, but when chimps have an intestinal nematode infection, they know to strip the leaves and bark from the Vernonia shoots and chew the pith. The juice works to help the chimps deworm themselves. This kind of self-medication is not unlike what indigenous humans throughout the world have learned to do with various plant-derived substances.

The toxins produced by plants are poisonous at high doses, but at lower does they can produce other effects, some of which humans have learned to desire or even crave. Various plant substances trigger receptors in the bodies of animals, including humans, in turn activating various bodily responses, including responses by the brain. One of those substances is ethanol, which humans and other animals have long used for various purposes, but some people, including Whiteman’s father, develop a disorder from ethanol use that they cannot control and that disrupts their family and social lives in ways that are completely debilitating. Whiteman came to understand his father’s condition at this biological level. He also has long sections of the book describing other substances derived from nature, like cocaine and opioids, that have similarly destructive effects. Some of the descriptions of the chemicals in these substances and their effects on receptors in the body are scientifically thick, and I don’t claim to have followed them all.

Whiteman explores other toxins as well that have desirable and perhaps even beneficial qualities if taken at doses sufficiently low, like caffeine in coffee and tea. And then there are the benefits of “forest bathing.” We all know that going for walks is good for us, but some scientists are studying how going for a walk in the forest can have a calming effect that walking in the city does not provide. The reason may be all the chemicals given off by trees and other plants that permeate the forest atmosphere, and then we inhale.

Most Delicious Poison ends with a section on spices, which are all derived from parts of plants that have toxins. The tastes of those spices are, at first glance, tastes that should be unpleasant, but humans have learned to desire them because of other benefits the spices offer, and those benefits are often subtle effects on the brain. Black pepper is foremost on that list. Nutmeg is another. Too much nutmeg can cause disturbing psychological episodes and even death, but a little nutmeg not only makes pumpkin pie taste better but also helps us feel better. Because spices are poisonous to other living things, humans learned that spices make good preservatives by killing bacteria. Fore example, sausage made with spices will last longer than sausage made without spice. This probably explains why peoples who live in hot climates have histories of using more spices than peoples in northern climates: food spoils quicker in hot climates than in temperate or cool climates.

These biological facts about spices have had a profound impact on human history across the last 500 years, as Whiteman explains. Trade routes had been bringing spices from south Asia and southeast Asia to Europe 2,000 years ago, but by the 15^th century, people at the far end of the trade routes, first the Portuguese and Spanish and then other Europeans, sought ocean routes around Africa and across the Atlantic Ocean so they could acquire spices without being dependent on traders of western Asia. That led to exploration and then colonization, which has had profound impacts on natural environments and indigenous peoples on every continent other than Antarctica.

Whiteman ends the book on a note of hope that our desire for the beneficial pharmaceuticals we derive from tropical environments will motivate us to implement measures to preserve those places so that we can continue to learn and benefit from the plants that thrive there and from the people who have learned to make beneficial uses of those plants.

Fredric L. Quivik