Are edible nightshades toxic or poisonous? If so, in what quantities?
When you think of a ‘ nightshade’, the image of a deadly nightshade plant or a pretty flower probably comes to mind. In reality, nightshades are part of a vast family of varied plants (the Solanaceae family). Quite a few types of nightshade are highly toxic – but lots aren’t. Had you realised that potatoes, tomatoes, chili peppers (to use the US spelling) and even the tobacco plant are types of nightshade? Which gives you something to think about next time you squeeze ketchup on your fries. The chemicals that make nightshades poisonous are called alkaloids. These harmful chemicals help to protect the plants from anything that wants to eat them; it’s the reason hot peppers are so fiery – they contain the spicy alkaloid, capsaicin. While the heat from eating a chili pepper may deter other mammals, humans can’t seem to get enough (see this previous answer to find out why). And while eating lots of hot peppers isn’t fatal, it can certainly make you sick. ( Technically it is possible to die from chili pepper overdose but you have to try very hard – Ed) Some nightshade plants are deadly, such as belladonna ( deadly nightshade) and the jimson weed. Never eat these. They contain tropane, another much more toxic alkaloid. Side-effects are nasty: hallucinations, coma, and death. A few leaves or berries are enough to kill an adult human. Children and animals are especially at risk since the berries look edible and taste sweet. Oddly, tropane can also save lives when given in controlled doses as atropine, a drug that can treat an irregular heartbeat. Potatoes and tomatoes are the most popular edible nightshades. They do contact a harmful alkaloid called solanine, which when ingested in large quantities can cause vomiting, diarrhoea and hallucinations. We can get away with eating tomatoes and potatoes because solanine levels are low in the edible parts of these plants. Toxic levels of solanine are found only in the leaves, stems, and unripe fruit. Therefore, eating ripe tomatoes is fine, so you should feel free to eat as much tomato sauce and mashed potatoes as you want. But if anyone offers you tomato leaf tea, don’t drink it. Oh, and avoid the green potatoes.
List of edible nightshades:
Tomato Tomatillo Naranjilla Eggplant (aubergine) Potato Pepper (includes hot and sweet varieties as well as spices like paprika, chili powder, cayenne, and Tabasco) Pimento Gogi berry (wolfberry) Tamarillo Cape gooseberry/ground cherry Pepino Garden huckleberry