Most Delicious Poison: The Story of Nature's Toxins—From Spices to Vices

by Noah Whiteman

As any cat or dog owner knows, Glendinning’s findings support the fact that dogs and cats can be poisoned by many plants and fungi that pose no real problem for omnivorous humans or herbivorous pets like rabbits. For example, grapes, raisins, and tamarinds contain high levels of tartaric acid, which can cause acute kidney failure in dogs when ingested. Another well-known example is from plants in the genus Allium, including chives, garlic, leeks, onions, ramps, and shallots. Such plants are highly toxic to both cats and dogs owing to disulfides, which cause anemia, partly by reducing the activity of G6PD in a process similar to what occurs in favism. These same plants, however, are not toxic to humans, hamsters, rabbits, or horses—all omnivores or herbivores. You may be wondering how these comparisons across animals and their relationships with nature’s toxins apply to us. When we instead compare bitter thresholds and detoxification repertoires across the developmental stages of our own species, a remarkably parallel set of patterns emerges with those Glendinning found across mammal species with different diets. Before we do that, we need to briefly retrace our own evolutionary history.