Nightshades refer to a group of flowering plants that belong to the species Solanaceae. While many plants that belong to this family are not edible or even extremely toxic, some common edible nightshades include tomatoes, eggplants, peppers (sweet bell peppers, cayenne and chili peppers), potatoes and goji berries… They are packed with nutrients and are staple foods of many cultures. But now some health experts say that people with autoimmune diseases (including inflammation in the gut) should avoid these vegetables (some “experts” even suggests everyone should eliminate all nightshades completely). Some people swear by eliminating these veggies helps relief their joint pain. Heck, if even fresh veggies are not healthy, are there still anything healthy anymore?! What the heck can I eat?!
The Deadly Nightshade… War Weapons, Augustus and Shakespeare?
I always love interesting food stories with a little bit of history and “folk science” – the deadly nightshade Belladonna contains an extremely concentrated level of alkaloid based toxins that can cause delirium and hallucinations, making them a perfect choice of poison that Romans used to contaminate their enemies’ food reserve as a “biological weapon“. Rumor has it that the Roman empress Livia Drusilla used the juice of Belladonna berries to murder her husband, the emperor Augustus. Interestingly, it’s also believed to make up the potion that Juliet took to fake her own death and reach a catatonic state in the final plot of Shakespeare’s Romeo and Juliet.
Lectins and Alkaloids – Plants’ Natural Defence Mechanism
If you’ve read Dr. Steven Gundry‘s revolutionary book The Plant Paradox, you’ve probably come across the term “lectins” and “alkaloids” and how plants use these self-produced “bug spray” as a defence mechanism to protect them from harm by pests, mold and animals – us humans are no exception. It’s understandable that the concentration of lectins and alkaloids reduces as the plants mature – as they ripened, the plants do want animals to eat them in order to help them spread the seeds and reproduce. With a compromised immune system, our body cannot fight off these toxins efficiently. Because of their negative effects on health, these phytonutrient are often labelled as “anti-nutrient”. You can find more resources on nightshades and lectins in the reference section.
So What Should We Do with Nightshades?
To counter the poisonous affect of plants’ “natural pesticides”, Gundry recommends that we
- Eat seasonal fruits that are fully ripened naturally – now as we live in a global economy where fruits are available throughout all seasons and across the world, fruits are often picked when they’re unripe so that they can withstand the time spent in transportation and shelving in the supply chain. In short, choose to buy local and seasonal produce – but wait, I love my avocados from South America??
- Removing the stems, seeds and skins of nightshades and cooking them can help reduce the amount of lectins and alkaloids significantly. (But by removing the skins you’re also missing out on the fibre and many good nutrients in them!)
- Start a lectin-free diet and eliminate nightshades, which I don’t agree with.
Okay, I get that plants need to protect themselves from their predators just like animals do, but I’m still struggling with the idea that all those seemingly healthy food can be bad for you. And if nightshades have these natural pesticides, don’t other veggies and fruits have similar substances to protect themselves too (perhaps at a lower level or in less toxic format)? Aren’t tomatoes, eggplants and bell peppers all used in the widely advocated Mediterranean Diet? That’s a lot to take in…
I have to say I found Gundry’s book quite entertaining and informative, and a lot of the stuff that he said make sense to me and have sound scientific proof. There’re also lots of anecdotal evidence that eliminating nightshades and other lectin/alkaloid-rich foods help reduce inflammation for some people and I believe in most of those success stories. But eliminating all these lectin-rich food would also mean missing out on all their associated health benefits – the powerful antioxidant lycopene and vitamin C in tomatoes, the high fibre, minerals and antioxidants in eggplants, the resistant starch you can find after cooking and cooling potatoes which help manage blood sugar and satiety, the heart-health promoting capsaisin in chili peppers, not to mention the anti-aging and energy-boosting properties of the increasingly popular “superfood” goji berries (it’s actually also good for eye health in Chinese Medicine, which is a property of goji berries that’s often overlooked in the western health world). It’s definitely a big trade off.
I understand the scientific background of both sides of the argument, and I don’t think we should be scared by nightshades and belittle their values. If you find out by trial and error that these fruits and veggies really do cause you discomfort, then you could try and reduce the amount and perhaps find alternatives that have similar nutrients that you’re looking for in the short term.
For me, I do find eating tomatoes and eggplants upset my stomach (along with many other stuff so I can’t single them out), cooking them and reducing the intake seem to help a bit, but I also value the many health benefits that they bring to the table so I don’t completely eliminate them.
I very much agree with Dr. Will Cole‘s perspective on nightshades:
While nightshades contain alkaloids which can trigger inflammation in some people, it’s not so much the foods fault as much as it is the person’s gut and immune system that are compromised and imbalanced. For these people, I would recommend focusing on other healing foods and functional medicine protocols to heal the gut and balance the immune system so they can tolerate these nightshades, and benefit from their healthy properties.
Here’re few youtube videos that I think are neutral and helpful in explaining the pros and cons of nightshades and whether you should eat them.
- What Are Nightshades (and why you should avoid them) https://gundrymd.com/nightshades/
- All About Nightshades https://paleoleap.com/nightshades/
- Are Nightshades Bad For You https://www.healthline.com/nutrition/nightshade-vegetables
- Healthy People Don’t Need to Avoid Nightshade Vegetables https://www.vice.com/en_us/article/nexedg/are-nightshades-bad-inflammation
- Shakespeare Lives in Science; Poisons, Potions and Drugs. https://www.shakespearelives.org/poisons-potions/
- The Plant Paradox by Steven Gundry (even though I don’t completely agree with his lectin-free diet, I do recommend this book, interesting read and mind-blowing!)