Plant Cuttings

Most delicious poison: The story of nature’s toxins – from spices to vices by Noah Whiteman, 2023. Little, Brown Spark.

A few months ago I discovered what was – for me – a practically perfect plants-and-people publication. It was John Perlin’s A forest journey. Now, I think I may have found the second best ‘practically perfect P&P publication’, Noah Whiteman’s Most delicious poison [which tome is here appraised].

Why do I think Whiteman’s book is so good? As for Perlin’s, it comes down to the referencing. That straightforward – if rather effort-intensive – courtesy to one’s readers that means that sources are cited for statements of fact presented in the book. But, more of that later in this piece. First, what are the other qualities of Whiteman’s book?

Making chemistry palatable…

Most delicious poison deals principally with the chemistry of the natural world and how that has influenced human behaviour over thousands of years. More specifically it looks at how toxic chemicals found in plants affect human beings, and, through those interactions over millennia, have influenced the course of human history and development [a pretty big and bold claim, but one that the book justifies]. If the thought of a book about chemistry and human behaviour sounds dreadfully dry and dull, then you are just the sort of person who will benefit from reading Whiteman’s book. Most delicious poison is most definitely not a dry, hard-to-get-into, dusty textbook of a tome. Quite the opposite, in fact, as the author’s own words should make clear: “This book explores the fascinating and sometimes surprising ways that toxins from nature arose, have been used by us humans and other animals, and have consequently changed the world. We will follow several interrelated threads, or approaches, as we examine how these chemicals have influenced evolution and how they have penetrated each human life, for better and for worse” (p. 4).

.. and readable

Yes, Most delicious poison is academic in the sense that it’s a very impressive piece of scholarship [see more in Let’s consider the evidence…] that deals with scientific subjects, but it’s also a most readable book. Throughout, the text is written with wit and style* by a wordsmith who knows how to weave a tale that draws together many disparate strands to craft a most satisfying whole. True, some parts of the book deal with quite technical topics – e.g. the ways in which some plant-derived compounds affect the nervous system of humans (and insects…). But, such material is essential to the story that Whiteman is telling, and is explained in a comprehensible way; the intelligent lay reader – for whom the book is surely intended – will be well rewarded.

Already a chemistry-in-context connoisseur..?

If you are already interested in the intimate interaction between natural products and humanity, you will – like this reviewer – be fascinated by the tales that Whiteman tells. And, however well-read you may already consider yourself to be about this topic, you are likely to encounter material that is new to you. For instance, new to me were that: alcohol use disorder (AUD) is the clinical term used in place of alcoholism; the belief that because something is natural, it is inherently good for us is known as the ‘appeal-to-nature-fallacy’; some terpenoids found in coffee elevate ‘bad cholesterol’ levels [which contrasts with “The protective association of coffee drinking is also observed for those who drink decaffeinated coffee…” (p. 142)]; “So potent is nicotine as a neurotoxin that a disease called green tobacco sickness once ran rampant in tobacco harvester workers” (p. 155); there is a phenomenon known as ‘defensive halitosis’; “Frankincense and myrrh have long been used as mind-altering drugs” (p. 183); four of the most common psychoactive drugs derived from natural toxins are alcohol**, tobacco, cannabis, and cocaine; and a phenomenon known as the White Lotus Rebellion in 18^th Century China was part of the background to the Opium Wars.

Because of the multi-faceted nature of the interaction between plant compounds and humanity, one’s own understanding of these relationships is likely to be challenged and enriched. For instance, who knew that “The desire for new sources of spices, and for control of the flow of spices, triggered a geopolitical cataclysm that shaped the past five hundred years of human history and continues to do so today. One consequence, at least in part, is the global biodiversity and climate crisis we face” (p. 5)?

Seem familiar..?

With his evident ability to craft a multi-stranded, plant-based story, Whiteman’s writing reminds me of Stefan Mancuso’s, in such books as Tree stories, and The incredible journey of plants. We need more plant-based, scientific story-tellers of the calibre of Mancuso and Whiteman. With its subject matter, Most delicious poison touches upon topics considered elsewhere, in The ethnobotany of Eden by Robert Voeks, and David Kennedy’s Plants and the human brain. That is not to say that you don’t need to read Whiteman’s book, you do because it adds to what you may have read in those other publications (and may now be encouraged to read Voeks and Kennedy’s books…). Finally, with its interconnected mix of plants-and-people, Most delicious poison has some similarities with the content of Michael Balick & Paul Cox’s ethnobotanical textbook Plants, people, and culture, Plants that kill by Elizabeth Dauncey & Sonny Larsson, and Plants that cure by Elizabeth Dauncey & Melanie-Jayne Howes (which titles you may also be encouraged to read…).

This is a very personal book…

For all of its consideration of the bigger picture of how plant products have influenced the course of human history, Whiteman’s book is also a very personal one: “As excited as I was to weave all these threads together and tell the story of nature’s toxins, this is not what motivated me to write the book. Instead, the sudden death of my father under tragic circumstances stemming from a substance use disorder in late 2017 is what pushed me to embark on this project” (p. 5); “My attempt to grasp why he died allowed me to identify and then draw together the many ways that nature’s toxins affect the world” (p. 6). Whilst that highly-personal – and poignant – background to the book is ever-present, it doesn’t distract from Whiteman’s overall message. Rather, it adds a very important dimension about the dangers involved in over-use of natural products and their consequences for the human body. Such personal testimony is a powerful thing.

… that ranges widely through human history

But, for all of the sadness associated with the author’s own story, there is much to be positive about as Whiteman relates tales about such groups of plant-produced products as tannins, flavonoids, phenols, terpenoids, alkaloids, sterols, and cardiac glycosides. And, because those chemical names aren’t always the most familiar to people, the human dimension to those stories comes through loud and clear in their relation to consumables with which readers are much more familiar, e.g. coffee, tea, tobacco, alcohol, cannabis, latex, aspirin, and spices. In telling the stories, Whiteman ranges far and wide providing context and comprehension of the range and breadth of human history that has been influenced by nature’s chemicals***. For example, “Tracing the origins of tannins will lead us to a rather startling conclusion that bears on the evolution of land plants, the Industrial Revolution, the founding of the United States, and even the melting of the Greenland ice sheet” (p. 31).

Taking the book as a whole, the range of subjects covered – or, at least, touched upon – is impressive, and includes: history, botany, pharmacology, mammalian physiology, insect physiology, ethnobotany, taxonomy, geopolitics, ecology, evolution, geography, diet and nutrition, crop protection (e.g. the neonicotinoid problem), modern-day medical misuse (e.g. the issue of over-use of opioids), global trade and international relations, sociology, and psychology. Products from the world of plants are powerful forces in the life of humans.

Although Whiteman acknowledges that he’s not an expert in all of the subjects the book covers – he is an evolutionary biologist at the University of California and “not an anthropologist, a chemist, an ethnobotanist, a historian, or a social scientist” (p. 7) – plenty of sources are cited for those who wish to pursue the topics in more detail, from subject-specialists. And, because – one suspects – the readers are not necessarily experts in anthropology, chemistry, ethnobotany, history, and social science, there is the very real sense of accompanying Whiteman on a journey of discovery regarding the influential role played by myriad natural chemicals. There is much for all of us to discover and learn in Most delicious poison.

But, it’s not just words…

As important as are the words in the book, it’s appropriate to mention the illustrations that help to break up the text. Created by Julie Johnson, of Life Science Studios, Whiteman describes them as having a “field-notebook style” (p. 276). That description captures the essence of these black-and-white drawings – which feature chemical structures and names, and images related to their ecology or use by humans – perfectly. Although the illustrations don’t have captions, their relevance can – usually – be discerned by their positioning within the text.

Let’s consider the evidence…

A cursory flick through Most delicious poison would fill those seeking evidence-based scicomm with dismay: NO sources are cited anywhere within the text(!) BUT! We are told on page 8: “Notes, including references used throughout, and an appendix containing further information on the toxins discussed are available online, through a link included at the end of the book”. The URL – https://www.mostdeliciouspoison.com/notes.html – and/or the QR code (both on p. 278) take you to the book’s dedicated web site where you will find two invaluable sources of additional information.

One is a 4-page pdf table – the Appendix – that lists information about six “Plant-Derived Toxins Commonly Used as Stimulants” – which sextet includes: arecoline; caffeine; and cocaine. The four columns of data provide: “Plant toxin (number of daily users worldwide)”; “Common name of source (Latin name), plant family; geographical origin”; “Neurotransmitter mimicked, receptor target, or neurotransmitter enzyme inhibited”; and “Pharmaceutical or recreational drugs derived from, or modeled after, the natural product’s structure”. No sources are stated in the Appendix for the information provided in the table.

The other is a 270-page pdf file of ‘Notes’, which provides information on the sources for the factual statements made in the book: Essentially it is the book’s reference list. Knowing that resource existed raised my expectations considerably that Most delicious poison was not only a serious factual text, but also a scholarly work that was evidence-based. Full citation information is usually supplied for sources stated, as are URLs. But, do note that, occasionally, sources are stated that the reader will be unable to check and verify, e.g. source No. 5. “Whiteman, N. 2023. Personal observation”, and No. 345. “Text message to Noah Whiteman from Karin Fyhrie on January 20, 2021”.

To give some idea of how thorough is the referencing related to the book, take page 32, which contains six full paragraphs. Fully, 31 separate sources are listed in the Notes to support the facts stated in those 17 sentences. Each of those paragraphs has at least two on-line sources; the third has 12, and the last has nine. Which sounds good. But, with 9 references to support the statement “Once plants evolved on land, these compounds took on additional roles, such as discouraging consumers” perhaps it’s overkill? Maybe, but that is certainly much better than those fact-based books that supply no sources [they do exist, I’ve reviewed some of them in my time…]. Plus, not all of the sources cited may be accessible by every reader, so providing additional ones gives plenty of opportunity for those keen to read more on that topic to follow it up.

To put the number of sources into context, the main text of the book is approx. 270 pages, which is the same length as the separate list of sources. The total of numbered sources in the listing is 2,083. However, and as Whiteman acknowledges here, that is not therefore 2,083 unique sources because some are used to support several separate statements in the book (and are therefore ‘double-counted’). But, that’s still many hundreds of sources at the very least. Which degree of ‘evidencing’ elevates Most delicious poison well above the competition in the fact-based plants-and-people literature (and very close to Perlin’s A forest journey).

With sources stated that must mean all is well? Not quite. Because the numbered sources aren’t linked to in-text numbers, it’s sometimes hard to relate a particular source to a specific in-text statement. For example, in the on-line Notes listing we find “Page 130 and 131. DMT is also the principal [this is the text from the book that the source(s) relate to]. These references [10 are listed] apply to the next three paragraphs”; Pages 157 and 158, Independently, tobacco in the form of pituri. The next three paragraphs are based on the [6] references below; and page 205’s Sickle cell disease, whose [7] references apply to the next five paragraphs as well. Tying-in specific source(s) to particular statements of fact found in multiple paragraphs within the text is not therefore as clear-cut as the numerous instances of citation-inclusion might have us believe. Which is a pity, and means more work for those readers who’d like not only to cite material from the book, but also to include its source.

But, even with the hundreds of citations, there still appear some factual statements in-text that are unsourced, e.g. “Tree resins evolved long before latex did” (p. 60); “After all, animals share a nervous system that evolved in the ocean well before they colonized land” (p. 75); and “Orchids, over thirty thousand species strong, are more diverse than any other plant family” (p. 79). Although it’s not the end of the world to have to check those statements out for oneself – it may take quite a lot of ‘Googling’, but it’s probably doable – if rather irksome, especially when so many of the book’s other statements are sourced.

And – even when a source is stated – it may not always work as evidence. I offer this example. Book page 54 states: “Terpenoids are the largest chemical family made by life on earth. More than eighty thousand compounds have been identified in nature”. Great, I love a ‘stat’, and may want to use it myself one day. So, what’s the source for that number of terpenoid compounds? The Notes file gives 2 sources for that quoted piece of text. First cited is “310 [the unique number for the source]. Chen, K., & Baran, P. S. (2009). Total synthesis of eudesmane terpenes by site-selective C–H oxidations. Nature, 459(7248), 824–828. https://doi.org/10.1038/nature08043”, second is “311. Christianson, D. W. (2017). Structural and Chemical Biology of Terpenoid Cyclases. Chemical Reviews, 117(17), 11570–11648. https://doi.org/10.1021/acs.chemrev.7b00287”. Looking at Chen & Baran (2009), its Abstract tells us, “From menthol to cholesterol to Taxol, terpenes are a ubiquitous group of molecules (over 55,000***** members isolated so far) that have long provided humans with flavours, fragrances, hormones, medicines and even commercial products such as rubber¹”.

Chen & Baran (2009)’s article doesn’t give us the “more than 80,000” [yes, I checked the rest of the article’s text], nor does it appear to support the contention that “Terpenoids are the largest chemical family made by life on earth” [leading me to wonder why it was cited by Whiteman in support of those facts…]. Christianson (2017), however, gives us the evidence we seek, in the first sentence of its Abstract: “The year 2017 marks the twentieth anniversary of terpenoid cyclase structural biology: a trio of terpenoid cyclase structures reported together in 1997 were the first to set the foundation for understanding the enzymes largely responsible for the exquisite chemodiversity of more than 80000 terpenoid natural products [Mr Cuttings’ emphasis].”. Furthermore, the 1^st sentence of the article’s Introduction supports the statement that “Terpenoids are the largest chemical family”, “Terpenes, also known as terpenoids or isoprenoids, comprise the most chemically and structurally diverse family of natural products”. The lesson to be learned here appears to be that one needs to critically consider citations provided by Most delicious poison before using them to support your own statements of fact.

Finally [yes, I know this is a big section, but there’s a lot to say on this important matter], readers should be aware that the on-line listing of sources is also used as a place to introduce new information. For example, “Page 9. The eastern white pine held its own piperidine alkaloids. Piperidine is a heterocyclic amine (see Appendix) naturally produced by plants like those in the genus Piper. Piperidine was discovered in the 19th century when piperine was treated with nitric acid in the laboratory. Piperine and an isomer of piperine called chavicine are the predominant molecules that drive the peppery taste of black pepper (Piper nigrum). The piperidine ring is also used as the foundation for synthetic drugs, including fentanyl. Piperidine alkaloids are found in many species of spruce, fir, and pine, including the eastern white pine (Pinus strobus), which produces pinidine. These chemicals are also made by distantly related plants, such as poison hemlock (Conium maculatum), which produces the highly toxic piperidine alkaloid coiinne, and by pitcher plants (Sarracenia spp.), which ostensibly paralyzes the insects that fall into the pitcher. Coiinine and related alkaloids in poison hemlock may have killed Socrates. Insects also synthesize piperidine alkaloids, including fire ants (Solenopsis spp.), which produce solenopsins that are venom components, and coccinellid beetles, which produce other piperidines that are secreted in defensive glands or during reflex bleeding. Piperidine alkaloids thus play a defensive role against natural enemies of both the plants and insects that synthesize these chemicals”. All of which is interesting, and is additional to that which is stated in the book. But, none of the facts in the above are sourced. Granted, some – one, all? – of them may be covered in the references that support “Page 9. The eastern white pine held its own piperidine alkaloids”, numbers 10 to 16, but that’s not made clear, and would require considerable effort from the reader to check.

It’s because of those various deficiencies in the evidence base that I consider Most delicious poison less than a perfect plants-and-people publication. But, it’s not far off perfection, and its various shortcomings can easily be tidied-up for a subsequent version of this – otherwise – brilliant book.

Two take-home messages

First, “The main thesis of this book is that nature’s pharmacopoeia didn’t evolve for our benefit. Rather, many of the chemicals we rely on for many of our medicines and for food, drink, and recreational and spiritual practices came from organisms that produced these chemicals through evolution for the organism’s own benefit, be it protective or reproductive. Diverse groups of animals and every human culture have co‑opted these chemicals, largely from plants and fungi. In doing so, our evolutionary and cultural trajectories have changed as a species, and the fates of each of our individual lives hinge on these chemicals, for better and for worse” (p. 268).

Second, throughout the book the role of Indigenous knowledge that has led to the development of many modern-day medicines of natural origin, etc. is acknowledged and celebrated, e.g.: “For scopolamine, cocaine, and curare, Indigenous knowledge, curated over tens of thousands of years, led to modern medical breakthroughs that have improved and extended countless human lives through anesthesia. In each case, the poison is the cure” (p. 181). And, tellingly, “Knowledge of how a substance can pivot from bad to good almost always flows from Indigenous and local knowledge holders and practices” (p. 50), “those first used by Indigenous healers have yielded nearly 50 percent of all modern drugs we use today” (p. 23).

In view of the debt owed to those first medical practitioners, Whiteman bemoans the lack of compensation for those who first obtained that knowledge, e.g.: “The Indigenous peoples who discovered the power of cocaine and curare never received compensation by the pharmaceutical companies that profited from them. It is no wonder that many countries in Latin America and elsewhere in the global tropics now have biopiracy laws that strictly regulate the export of natural products” (p. 181).

It is therefore appropriate that Most delicious poison ends with a plea to protect the rights and sovereignty of Indigenous peoples to preserve biodiversity, for the benefit of all, now and for a future: “The tropics hold most of the planet’s biodiversity, and they are enormous carbon sinks as well. Although Indigenous people represent 5 percent of the global human population, 80 percent of the world’s biodiversity is found in their lands. Much of their forests, coral reefs, peatlands, savannas, and grasslands teem with life and capture an enormous fraction of global carbon dioxide. Nearly one-half (45 percent) of the intact forests of the Amazon basin are Indigenous lands, for example. That is four million square kilometers. So, whether your descendants will inhabit a planet still teeming with “endless forms most beautiful and wonderful” and one that continues to provide the air we breathe, the food we eat, and the toxins we use depends on the support and protection of Indigenous rights and sovereignty everywhere” (p. 274).

Summary

Most delicious poison by Noah Whiteman is not only a great piece of plants-and-people writing, it’s also a very good example of how to communicate scientific topics to a general audience. It’s intelligent writing for an intelligent audience, and an excellent addition to the plants-and-people literature. Very well done, Prof. Whiteman!

* A sense of Whiteman’s style may be gleaned from chapter titles such as: Forests of Phenolics and Flavonoids; Toxic, Titillating, Tumor-Killing Terpenoids; Devil’s Breath and Silent Death; and Opioid Overlords. Whiteman is quite a fan of alliterative (Tekla Bude) titles – as also seen within each chapter with sub-headings, e.g.: Rivers, rings, and reckonings; Balsams, birches, and beers; Myristicin, ma huang, and methamphetamine; and Mesopotamians, Mayans, and morphine [and he is also a fan of the Oxford comma (Jack Caulfield), which is another ‘thumbs-up’ for the book in my opinion…].

** In an absolute masterful piece of writing, Whiteman shoehorns ethanol into the section on terpenoids – and thereby justifies its inclusion in the book about plant products – because “many organisms convert ethanol to mevalonate, a precursor to terpenoids in the terpenoid pathway, so ethanol actually fits right in with terpenoids” (p. 65).

*** Some idea of the book’s scope may be gleaned from glancing through the approx. 17 pages of 2-columned Index, which goes from Aboriginal Australians, to Zygnematophyceae algae, via: alcohol use disorder (AUD [this initialism is also separately indexed]); allelopathy; Aztec people; banana slugs; blood pressure; cancer; coffee; date rape drugs; dopamine and dopamine receptors; entheogens; ethanol; fever tree (cinchona [separately indexed as cinchonas]); forest bathing (shinrin-yoku**** [also indexed separately]); GABA (gamma-aminobutyric acid); grayanotoxins; humoral theory; hyoscine; Indigenous peoples; iron gall ink; jasmonates; Jurassic Park (film); Kaldi’s Coffee; kimchi; Lysenkoism; ma huang; mescaline; narcotic effects; nutmeg; opioid receptors; Opium Wars; paclitaxel (Taxol [also indexed separately]); psilocybin; Quecha people; quinine; resveratrol; rough-skinned newts; Schultes, Richard Evans; spices; tobacco and smoking; US Board of Economic Warfare [I had no idea such an entity existed]; US Drug Enforcement Agency; vaping e-cigarettes; voltage-gated sodium channels; wasabi receptor (TRPA1 receptor [also separately indexed]); Withering, William; X, Malcolm; yams; and Zuni people.

**** Which term is succinctly defined by Whiteman: “forest bathing, or shinrin-yoku in Japanese — encountering a forest with all five senses” (p. 71).

***** Having been thwarted in obtaining evidence for ‘the more than 80,000’ in Chen & Baran (2009) I was nevertheless intrigued to know where they got their figure of 55,000 from. The reference they cited, for the sentence “From menthol to cholesterol to Taxol, terpenes are a ubiquitous group of molecules (over 55,000 members isolated so far) that have long provided humans with flavours, fragrances, hormones, medicines and even commercial products such as rubber” was Molecules That Changed the World: A Brief History of the Art and Science of Synthesis and Its Impact on Society by KC Nicolaou & Tamsyn Montagnon. However, nowhere in that book could I find mention of the figure of 55,000, although it would seem an appropriate source for confirmation of the range of flavours, fragrances, etc. provided by this group of compounds. So, where does the figure of 55,000 – cited by Chen & Baran – come from?