If you’re an avid follower of the “Gundry Way”, you already know Dr. Gundry doesn’t approve of nightshade fruits and vegetables on his eating program. This is because they are high in proteins known as lectins. Along with legumes and traditional grains, these lectin-rich foods can be disastrous for your gut.
But what is a nightshade veggie and why are they so bad for your gut? Let’s dig a little deeper, shall we?
What Are Nightshades?
Nightshades are a family of plants known as Solanaceae. The family includes some pretty popular veggies like:
- Peppers (including bell, cayenne pepper, and paprika)1
It also includes the Belladonna plant (also known as deadly nightshade) – a highly poisonous plant that’s been used medicinally and cosmetically since before the Middle Ages2
Our nightshade vegetables list has all of the info.
Nightshade vegetables contain an alkaloid known as solanine, which is also a toxin but only in very high concentrations. Believe it or not, solanine poisoning has actually occurred from eating green potatoes. But while solanine isn’t going to affect you like the Belladonna, it may still cause some trouble for your digestive system.3
Why You Should Avoid Nightshades
Many health experts believe you should avoid the nightshade family altogether. Why? There are a couple of reasons.
1. The Alkaloids
We’ve already mentioned an alkaloid called solanine. But nightshades also contain the alkaloids capsaicin and nicotine (yes, nicotine — tobacco is part of the nightshade family, after all). And all of these alkaloids may have irritating effects on the body.
Solanine has been linked to aggravated joint pain and inflammation. Though no scientific studies currently support this finding, The Arthritis Foundation reports that many patients do find this to be the case.4
Nicotine is found in tobacco plants (also a nightshade family member) as well as these common nightshade vegetables. Amounts of nicotine in the veggies can range from 2-7 microgram/kg (a cigarette averages about 12 milligrams) but decrease with the fading of “green” coloring. So when a tomato ripens it does decrease in nicotine.5
You already know all about the bad side of nicotine due to the dangers of smoking, and you know it can be very addictive. But you would need to eat a LOT of nightshade vegetables to get the same amount of nicotine as a single cigarette.
The bottom line with alkaloids is: Though they may not affect everyone, some people are very sensitive to them because they can’t digest them properly.
2. The Lectins
Lectins are toxic proteins found in certain plants. They are thought to be part of a plant’s natural defense mechanism. The problem with lectins is they can bind to cells on your gut wall, damaging the gut and preventing you from properly absorbing nutrients. Lectins are found in their highest concentrations in legumes, grains, and — you guessed it — nightshades.6
Research has begun to show that – though some people are more sensitive to lectins than others – lectins are:
- Toxic, inflammatory, or both
- Resistant to your digestive enzymes
Able to cause major discomfort if consumed in high concentration
In fact, one hospital saw 10 cases of what was thought to be food poisoning but then discovered the culprit to be the abnormally high concentration of lectins in red kidney beans.7
The peels and seeds of nightshades are where the lectin content is at its heaviest
so at the very least you’ll want to make sure to peel and deseed your veggies. You can also pressure cook or ferment for the same results.
If you suffer from a leaky gut, persistent diarrhea, an irritable bowel, or any other gastrointestinal sensitivity you should definitely think about cutting lectin-rich nightshades from your diet to see if you notice any difference.
The Symptoms and Signs of Nightshade Sensitivity
Nightshade sensitivity can be very similar to a host of other conditions but generally appear as:
- Heartburn / Reflux
- Irritable Bowel
- Joint Pain and/or swelling8
Which Vegetables Should You Choose?
Cutting out nightshades need not leave you scrambling for veggie options in your diet. There’s still a great wealth of food in the vegetable family you can fill up on instead.
Tubers include sweet potatoes, yucca, and taro root. The sweet potato is particularly wonderful with health-promoting antioxidants like β‐carotene and anthocyanins — both of which have been shown to protect against certain health issues.9,10
The following leafy greens are incredibly high in nutrients (like vitamins A, C, E, and K).
- Red & green leaf lettuce
- Butter lettuce
- Seaweed/sea vegetables
They’re also more filling than you probably give them credit for because they’re packed with fiber. Leafy greens also contain carotenoid-antioxidants (which protect your cells from damage!) and high levels of iron, magnesium, potassium, folate, and calcium.11
Like leafy greens, cruciferous veggies like the ones below are also high in important carotenoid-antioxidants (like beta-carotene, lutein, and zeaxanthin) as well as vitamins C, E, and K; folate; and fiber.
- Brussels sprouts
- Collard greens
- Bok choy.12
The avocado really deserves its own category. Not because it’s really a fruit, but because it’s a first-class choice when it comes to gut-friendly veggies.
Avocados are full of healthy monounsaturated fats and soluble fiber. As well as plenty of vitamins, minerals, and antioxidants. Research has even found the avocado may also lower “bad” LDL cholesterol which is a huge contributor to cardiovascular diseases.13,14
Other Great Veggies
But there are more other great lectin-free, fiber-rich veggies like asparagus, garlic, celery, mushrooms, and onion.
Final Thoughts …
In the end, there are those who have been living with uncomfortable digestive issues for years without being able to figure out why. Yet a sensitivity to nightshade vegetables can be more common than you think.
So, if you’re someone who suffers from a gastrointestinal sensitivity, bad heartburn, or you just can’t seem to shift stubborn weight no matter what you do, it could be a good time to ditch the nightshades (AND all other lectin-drenched veggies – like grains and legumes) and see what effect that has for you.
How to Make the Best Soup with ANY Vegetable
Dr. Gundry Approved Foods (a print-friendly list)
A Simple Lectins Definition (and how they make us fat & sick)