“Cassava is a woody shrub native to South America. For people living in drought-prone tropical regions, it is a godsend: delicious, calorie-dense, and highly productive. The indigenous peoples of the Americas who first cultivated cassava are reliant on it and have developed an arduous, days-long process of preparation that involves scraping, grating, washing, and boiling the plant before it is eaten.
At the beginning of the 17th century, the Portuguese introduced cassava to the Old World. But they did not import the ancient methods of processing, assuming that indigenous people were wasting their time.
We do not always know why we do the things we do. This applies as much to indigenous peoples as to modern westerners. The first cultivators of cassava could not explain why the scraping, grating, washing, and boiling process was necessary, because they did not know – could not know – that every step of the process is essential in order to reduce the cyanide content in the plant. If even one step is skipped, chronic cyanide poisoning is the result. And the really devilish thing about cassava poisoning is that the buildup of cyanide in the body is so gradual that it is almost impossible to identify cassava as the culprit.”