You may have heard the buzz around nightshade plants especially in discussions around leaky gut, irritable bowel syndrome, AIP, and other elimination diets.
One site says they are terrible for you and will exacerbate inflammation. The next blog says they are great and should be eaten to enjoy their antioxidant benefits. The information out there is confusing and conflicting, so we've pulled up our sleeves, looked at the research, and decided to get to the bottom of nightshades once and for all.
We're going to cover:
- What nightshades are
- The complete list of nightshade foods you need to know about
- Whether or not beans are nightshades
- Other vegetables people mistake for nightshades
- Whether or not nightshades are healthy
- How to figure out if you should eat nightshades
- Common replacements for nightshades
WHAT ARE NIGHTSHADES?
Nightshades are the common name for the flowering plant family, Solanaceae, which consists of over two thousand types of vegetables, spices, weeds, fruits, and other flowering plants[*]. The vast majority aren't eaten by humans, but the ones that are eaten are staples in many diets around the world.
THE COMPLETE LIST OF COMMON NIGHTSHADES
There are thousands of non-edible nightshades, but here's a list of the edible nightshades you need to know about. Keep in mind that some of these categories like potatoes, peppers, and hot sauces have countless variations within themselves, so it's best to avoid them as a whole when eating nightshade-free.
Vegetables & Fruits:
- All potatoes (excluding sweet potatoes)
- All tomatoes
- All bell peppers
- Banana peppers
- All other peppers (excluding peppercorns)
- Goji berries (a.k.a. wolfberries)
- Ground cherries
Spices & Seasonings:
- Cayenne pepper
- Chili powder
- Curry powder
- Garam marsala
- Red repper
- Chipotle chili powder
- Taco seasoning mixes
- Cayenne powder
- BBQ rubs
- Chicken rubs
- Most Indian spice blends
Condiments, Sauces, & Binders:
- All hot sauces
- BBQ sauces
- Red pasta sauces
- All red and green salsas
- Guacamole that has tomatoes in it
- Pico de gallo
- Mole sauce
- Potato starch in soups, breads, crusts, etc.
Eating nightshade foods as a category includes any specific ingredient on the above list and any meal or dish made up of them. There are countless products and meals that contain these, so it's impossible to list them all.
We recommend memorizing the big categories like peppers and red spice and then use that to determine if a particular meal or dish is nightshade-free.
ARE BEANS NIGHTSHADES?
While beans are often avoided in diets that avoid nightshades (like AIP), beans are not nightshades themselves.
They do, however, contain lectins. Lectins are proteins found in both beans and nightshades. Lectins have a few links to inflammation, and researchers have studied how people with multiple sclerosis (MS) could benefit from avoiding them.
COMMON VEGETABLES MISTAKEN FOR NIGHTSHADES
Because the term is used so widely, vegetables that are not nightshades are frequently labeled as such. To set the record straight, here are vegetables that aren't nightshades:
- Peppercorns like white and black pepper are not nightshades.
- Sweet potatoes are actually yams and not a nightshade or a potato!
- Mushrooms are fungi and not nightshades.
- Onions are not nightshades either.
- Zucchini is not a nightshade.
- Cucumbers are not nightshades.
- Coffee is not a nightshade.
- Squash is not a nightshade.
- Blueberries are not nightshades.
- Okra isn’t a nightshade either.
Generally speaking, most fruits or leafy vegetables aren’t nightshades.
Now that you know how to identify nightshades, let’s get down to the nutrition.
ARE NIGHTSHADES HEALTHY FOR YOU?
The answer is usually but not always, and it depends on your existing conditions, sensitivities, and allergies.
Nightshades are often discussed in their relationship to autoimmune diseases like inflammatory bowel disease (IBD). Some nutritionists and functional wellness experts believe that eating nightshades can cause inflammation, exacerbate arthritis, and cause damage to the gut, but that is widely disputed[*].
Because potatoes and other nightshades contain solanine, which is an alkaline that is toxic in high concentrations, some nutritionists think repeated exposure to trace amounts of solanine result in inflammation. The plants carry solanine because it acts as a natural defense mechanism against predators[*].
There are also nutritionists who think that lectins (a type of protective protein) found in nightshades are always damaging to the intestines — even when soaking and other cooking methods reduce their potency.
It gets tricky because certain people do have sensitivities to the nightshade family, but their observed symptoms aren’t proven to be directly because of solanine or lectin.
WHAT ARE THE HEALTH BENEFITS OF NIGHTSHADES?
Nightshades are generally great for you! They are full of fiber, antioxidants, and other beneficial nutrients. Here are a few quick health facts about the most common nightshade foods.
Eggplant is a fantastic source of dietary fiber. Fiber helps you digest food better and reduces your risk of heart disease[*]. Eggplants are also good sources of potassium, Vitamin B, and Vitamin K.
Tomatoes are full of great vitamins and minerals like potassium, iron, and zinc. They also contain lycopene, which has been linked to a reduction in inflammation[*], and folate, which is important for tissue growth and cell function.
Potatoes like purple, white, and yellow contain fiber, Vitamin C, and Vitamin B-6. Vitamin B is important for metabolizing carbs and proteins, and Vitamin C aids in collagen production[*].
Bell peppers like red are full of nutrients, including Vitamin C, A, and Vitamin B6. Vitamin C is an antioxidant that can help boost your iron absorption, support immune function, help repair cells, and help you produce collagen for healthier bones, skin, and hair[*].
WHAT THE SCIENCE SAYS ABOUT NIGHTSHADES
The literature is often confusing and conflicting, and that's because in some ways the jury is still out. We just don't have enough tests on humans to make a sound judgment. With that in mind, here is a brief collection of what science tells us about nightshades.
Some people are allergic or sensitive to nightshades.
While having allergies or sensitivities to nightshades isn't very common, it is a legitimate issue for some people. If you think you may have an allergy, consult a doctor before testing yourself.
Some studies in mice have shown that eating nightshades like potatoes may increase intestinal permeability[*][*].
While this hasn't been tested in humans, there are studies that have widened the pores in mice intestines, and if this same effect is happening in humans, then that could contribute to IBS and chronic disease.
Intestinal permeability is linked to chronic diseases[*].
Intestinal permeability is when the wall pores in our intestines widen enough to allow toxins and other bacteria inside our blood stream. This has been linked to chronic diseases and is the foundation for unofficial diagnoses like leaky gut syndrome (LGS).
There is a lot of anecdotal evidence about reducing nightshade consumption and easing IBS symptoms, but it has yet to be definitively proven.
If you go to any forum on nightshades, you will find people talking about how much better they feel after removing nightshades from their diet. The distinction to make is whether or not those were due to genetic sensitivities and/or allergies as opposed to a natural effect that nightshades have on all people.
Nightshades are generally healthy and full of antioxidants.
In fact, the Arthritis Foundation advises you to eat nightshades and there are studies that show that the antioxidants within purple and yellow potatoes may actually help prevent cell damage and not the other way around.
Another study in 2009 found a possible link between tomatine found in tomatoes and anti-cancer benefits.
The point being, there is a lot of literature on how much nightshades can help you as opposed to hurt you.
HOW TO DETERMINE IF NIGHTSHADES ARE RIGHT FOR YOU
Figuring out if you should eat nightshades boils down to determining if you have an allergy or sensitivity. If you don't suffer from any symptoms, then they are a nutritious addition to your diet.
On the flip side, if you suffer from an autoimmune disease or suspect you have a sensitivity, then testing your reaction to nightshades is worth doing.
The best tool we have for testing sensitivities or minor allergies is through what nutritionists call an elimination diet. Elimination diets are systematic removals of food groups to determine if they are having an effect on your health. To be clear, elimination diets are not advised if you suspect you have a significant or life-threatening allergy.
Allergic symptoms to nightshades may include:
- Feeling itchy
- Rashes, hives, or other skin inflammation.
- Aches in muscles and joints
- Trouble breathing
- Excess mucus
If you suspect you have an allergy, possibly due to a reaction in your past, work with a medical professional to get an allergy test. If you think you may be sensitive, then an elimination diet is a good solution.
Nightshade sensitivity symptoms may include:
If you suspect you have a sensitivity, then perform a limited version of the elimination diet. You can do this by yourself or under the direction of a nutrition professional.
THE BASICS OF AN ELIMINATION DIET
Elimination diets are the best tool we have to determine if nightshades are good to include in our diets because it gives us information that is unique to our bodies. While it helps to have accountability in direction from a nutritionist, you can conduct this on your own time.
A basic version of an elimination diet follows this format:
- Eat normally for a week but keep track of what you eat, when you ate it, and how you felt before and after in a food journal.
- Remove all nightshades from your diet for two weeks and continue to keep track of your symptoms ' eating habits.
- Reintroduce nightshades and see if negative symptoms worsen or return.
- If you notice that you feel significantly worse upon reintroduction, then reduce your nightshade intake appropriately.
Even if you have a sensitivity, that doesn’t mean you can never eat nightshades, it just means you now have the understanding of the comfort you’re trading for the meal you have.
BEST PRACTICES WHEN COMPLETING AN ELIMINATION DIET
Elimination diets take real work and effort but are worth the time if you suspect you may be sensitive to nightshades. Here a few tips for succeeding:
- Don't plan an elimination diet when you have upcoming travel plans. It's much harder to stick to diet when traveling.
- Build your food journal into whatever existing habits you have. If you like to use a paper journal, do it in that. If you prefer digital, then use your computer. Whatever you already use is the best choice!
- Put any nightshade foods out of sight. If you know you are a sucker for salsa, don't buy it or put it out of sight. Remove any triggers that will make it harder for you to stay on track.
COMMON REPLACEMENTS FOR NIGHTSHADES
If you determine that nightshades are best avoided in your diet, here are a few common substitutes. They won't work perfectly for every recipe, but they will at least give you a good head start.
- Sweet potatoes for any potato
- Cauliflower over a side of eggplant or peppers
- Mushrooms alongside eggs instead of peppers
- Pesto on pasta and pizza instead of tomato sauce
- Guacamole instead of salsa
- Zucchini for eggplant
- Cumin for paprika and other red spices
- Turmeric for curry powder and other red spices
- Black pepper for red pepper
Sometimes you'll have to get creative, but that's part of the fun! But if you want to make your life easier, here's a quick list of our favorite AIP recipes.
THE BOTTOM LINE
There is no substantial evidence that nightshades cause inflammation, and many nightshades are actually very healthy.
That being said, having allergies or sensitivities to nightshades is possible, so the best way to test and see if nightshades are causing your symptoms are to systematically remove and reintroduce them in your diet.