If you’ve spent any amount of time here on Mark’s Daily Apple, you know we love our vegetables. Plant foods are powerhouses of nutrients and antioxidant action. They’re the backbone of a solid Primal diet, and the main event in my signature Big Ass Salad. But the issue of nightshades has come up quite a bit over the years. Nightshade vegetables, which are vegetables that belong to the Solanaceae family of plants, include a long list of veggies and spices: eggplant, potatoes, peppers, tomatoes, tomatillos, pimentos, paprika, cayenne pepper, hot sauce, etc. (Black pepper isn’t a part of this list.)
I do eat a lot of these foods, but they’re not for everyone. In this article, we’ll dig into why some people simply can’t do nightshades, and how to tell whether you should eat them or not.
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What Are Nightshades?
Nightshade vegetables are the vegetables that grow from plants in the Solanaceae family, which Solanaceae family includes thousands of plants. Only a handful are used for food.
Some of the more common nightshade foods include:
- Peppers – hot, bell, sweet, etc.
- Cape gooseberry, or ground cherry
- Goji berry
- White potato (sweet potatoes don’t count)
This is not an exhaustive list, so if you have a nightshade allergy or intolerance, consult a dietician for a comprehensive list of foods to avoid. Nicotine is a non-food consumable that is included in the nightshade category.
Nightshade Vegetables vs. Deadly Nightshade
Aren’t nightshades those plants (many with alluring little berries) our camp counselors told us never ever to go near? Let’s clear that up first.
The answer is: quite possibly. The kinds of nightshade plants growing wild in the woods can be highly toxic. Some can kill you if you ingest them. Others have psychotropic properties. Simply put, deadly nightshade is poisonous.
Inherent in this power is pharmaceutical potential. Nightshades contain alkaloids, which are chemical substances that have one or more circular structures containing nitrogen, and cause a substantial change in humans. Some natural healers may use very tiny amounts of specific nightshades therapeutically for a range of ails. Because they’re highly toxic, this is not a time for self-experimentation. You could make yourself sick, cause permanent damage to your body, or even die if you use them incorrectly. Always work with a qualified practitioner.
Why Are Nightshades Bad?
Nightshades aren’t bad for everyone. Nightshades contain alkaloids, which are harmful to some humans and innocuous to others. Whether they bother you or not depends on your epigenetics , or how nightshades interact with your genes. People who have problems with nightshades sometimes do not produce the enzymes  that break them down.
Nightshade allergy or Intolerance
You can be either allergic to nightshades or intolerant to them, each of which come with different symptoms.
Nightshade Allergy Symptoms
Nightshade allergy symptoms look like the symptoms of allergies  to other foods and substances:
- Skin rashes or flare ups
- Aches and pains
Nightshade Intolerance Symptoms
The symptoms of nightshade intolerance are usually digestive in nature, including:
- Abdominal discomfort
- Indigestion, or heartburn
- GERD 
But what does this mean for the tomato salad I always serve for summer barbecues? Should I give up eggplant parmigiana? No peppers or hot sauce? I thought spicy food was good for me!
Before you raid your kitchen and gardens, let’s stop and take a closer look here.
First off, nightshade foods contain a tiny fraction of the alkaloid levels found in other toxic nightshade plants. If nightshades presented a significant health threat to humans, we would’ve stopped eating them a long time ago or died off from the inability to learn from our neighbor’s experience. Even when nightshade foods are common ingredients in specific ethnic diets (peppers in parts of Latin America or tomatoes in Italy, to give some basic examples), the population as a whole in those parts doesn’t seem to suffer ill effects.
Are Nightshades Bad for You? Answer: It Depends
So, what gives? Are nightshade vegetables evil, or are they okay to eat? Our simple answer: eat them and enjoy them in moderation if you don’t feel any ill effects. Most experts accept that some people are much more sensitive to them than others. Nightshades, in those with this sensitivity, have been associated with symptoms like stomach discomfort, digestive difficulties, joint pain , and muscle tremors.
Sometimes, medical professionals will advise those with certain conditions like GERD, gout, or arthritis to avoid nightshades and see if it alleviates symptoms.
If you don’t have these conditions but are concerned, it’s a good idea to take a full 2-4 weeks off from nightshade foods and see if you feel any differently. Some of us have mild enough reactions that we may not feel the difference until we set our own “control” scenario for comparison.
Finally, if sensitivity doesn’t seem to be a problem, but you’d like to take some reasonable precautions, know that cooking nightshade foods can break down a portion of the alkaloids in nightshades. Yet another reason to avoid potatoes: sprouted potatoes and potatoes turning green have higher levels of alkaloids than they have while fresh.
The bottom line: humans are built to eat a widely varied diet. As much as we love our tomatoes, eggplants, and peppers, we wouldn’t recommend making them the sole or primary vegetables in your diet. Variety offers the best in nutrient-rich and low-risk nourishment, and it keeps things interesting.
What are your thoughts on nightshades? Do you choose to embrace or avoid them? What influences your decision?