What are Nightshades?
Nightshades are a botanical family of plants, more technically called Solanaceae and is the name for a group of fruits and vegetables that have glycoalkaloids in them—their own natural bug repellan. Because of that rather nifty protective mechanism, they can cause inflammation in some people, exacerbating digestive and autoimmune problems. Nightshades also include spices & herbs such as paprika & cayenne. Over-consumption of these edible species can actually be poisonous to anyone, and it is possible that the low-level toxic properties of nightshade vegetables contribute to a variety of health issues over time. See the full list of Nightshades below.
How nightshades work
The built-in bug repellant in nightshades is actually a particle called glycoalkaloid. It’s great for nightshades, but not so much for the people who like to eat them.
Different nightshades have different levels of glycoalkaloids. Unripe tomatoes have a lot. “Eating them will give you an immediate stomachache,” Walker notes. But as tomatoes ripen, the amount of glycoalkaloid decreases. That’s because at that point, the plant actually wants bugs to come to it and help cross-pollinate.
In white potatoes, the skin contains the highest levels of glycoalkaloid—so simply peeling them can make a world of difference. (In case you’re wondering, no, sweet potatoes are not nightshades, and while blue and purple potatoes do have glycoalkaloids, it’s super low.) Their thicker skin protects the plant, Walker says, whereas white and red potatoes have thinner skins and need more protection.
Who they affect
Potato and eggplant nightshades don’t really bother most people—but there are some notable exceptions. “If you have inflammatory bowel syndrome, are gluten intolerant, have rheumatoid arthritis, or any form of leaky gut, I recommend you be very careful with this food group. The bug-repelling qualities of the fruits and veggies can attack an already weakened cell membrane.
They tend to effect people with autoimmune disorders more than the average person. “If you’re showing signs of joint inflammation and pain from arthritis, after consuming nightshades, I recommend doing a nightshade elimination diet for 6 weeks.
Other signs of a possible nightshade issue? If you eat them pretty regularly and are experiencing a lot of bloating, diarrhea, nausea, vomiting, or headaches, it might be worth cutting them out for a bit to see if you notice a difference.
How to cut them out
If you’re jumping on the no-nightshade train, prepare for a bit of trial-and-error. “Some people can cut out tomatoes and potatoes, but still tolerate peppers, because they have lower levels of glycoalkaloids,” Walker says. Also, she adds, nightshades have a cumulative effect, meaning there may not be one particular variety that bothers you. Instead, consuming small portions of a few different nightshades is too much for your body to tolerate on any given day.
That’s why the easiest way to find out is just to cut them altogether—at least for a little while. “I often recommend people start an elimination diet where they start by eating no nightshades, but then slowly add them back in one at a time. That way, you can see which ones your body tolerates.”
Because all nightshades are different, I recommend keeping a journal and write down how your body feels after consuming a nightshade if you’re not sure you are sensitive or not. If after you discovered you are sensitive and do the nightshade elimination for 30 days, slowly reintroduce them back in, journaling again how you feel after consumption. You can do this for each nightshade you try. You might find that simply moderating your intake is enough. Or, you might feel your best when you eliminate altogether.
Full List of Nightshades
The following are all members of the nightshade family (a couple of which you might only ever encounter while on a vacation in the tropics or in supplements):
- Bell peppers (a.k.a. sweet peppers)
- Bush tomato
- Cape gooseberry (also known as ground cherries—not to be confused with regular cherries)
- Garden huckleberry (not to be confused with regular huckleberries)
- Goji berries (a.k.a. wolfberry)
- Hot peppers (such as chili peppers, jalapenos, habaneros, chili-based spices, red pepper, cayenne)
- Pepinos (a.k.a. melon pear)
- Potatoes (but not sweet potatoes)
Please note: This is a complete list of edible nightshades, however; many of those listed include dozens of varieties. And the number of products including nightshades is enormous. In fact, if a label lists the vague ingredient “spices”, that almost always includes paprika. You might find ingredients such as sambal, shichimi, or tabasco listed and not immediately realize that those are sauces made with hot peppers.
Substitutes for Nightshades