Nightshade Plants – Toxicity and Sensitivity

Do you often suffer from a leaky gut or joint pain after a heavy supper containing all sorts of food items like a salad with cherry tomatoes, a stew containing eggplant, red habanero sauce, and a cupful of mashed potatoes? If your answer is yes, then you most probably have an undiagnosed sensitivity to the Nightshade family of plants. However, you must consult your physician first before taking any medications based on something you read on the internet.

Nightshade family ranges from supposedly harmless vegetables like potatoes, tomatoes, and eggplants to poisonous plants like belladonna, datura, and henbane.


You will understandably stay away from toxic varieties, but there is a problem when apparently safe items cause harm to your body in the form of inflammatory bowel disorder, allergies, heartburn, and joint pains.

Read further to find out about the mechanism of action and symptoms of ingesting alkaloids and other toxins present in these plants.

An introduction to the nightshade family

Nightshade plants belong to the Solanaceae family which is spread over 98 genera and over 2000 species of flowering plants, vegetables, herbs, shrubs, trees, and even poisons.

From your everyday veggies like potatoes and tomatoes to the deadly Atropa belladonna, Solanaceae plant family is diverse. The only thing that binds all the plants is high levels of vitamin D (calcitriol) and alkaloids.

The various side effects of these plants are a consequence of high amounts of alkaloids (solanine, nicotine, atropine, etc.) present.

Although species of the Nightshade family are seen all around the world (except Antarctica), North and South Americas have the maximum diversity.

Some plants belonging to different families are also called nightshades like Enchanter’s nightshade and Malabar nightshade. (1)

List of nightshade plants and their items

Currently, over 2000 varieties of Nightshade plants, herbs, and poisons are known to us; out of which only a small fraction is seen routinely in our recipes.

It’s better to be safe than sorry when it comes to our health, and hence, you would want to go through a list of plants of the nightshade family so that you’ll know what you’re up against.

  • Potatoes
  • Tomatoes
  • Aubergine (eggplant)
  • Capsicum
  • Okra
  • Tomatillos
  • Sorrel
  • Gooseberries
  • Ground cherries
  • Tobacco
  • Pepino melons
  • Paprika
  • Cayenne pepper

Blueberries, huckleberries, and goji berries, although belonging to a different family, contain similar alkaloids and allergens. So, if you’re sensitive to nightshade plants, beware of these seemingly innocent berries as well.

Nightshade plants are conspicuously found in all our regularly used items like baking powder, adhesives, and pills as mentioned below –

  • Homeopathic medicines containing Atropa belladonna extracts
  • Sleeping pills with atropine and scopolamine
  • Over the counter pills with potato starch as the filler
  • Baking powders containing potato starch
  • Edible flowers like petunia, day jasmine, and chalice vine
  • Vodka (it’s made by fermenting potatoes)
  • Adhesives used in envelope have small amounts of potato starch (Don’t lick the sides!)

Toxins and alkaloids in nightshade plants

Many plants produce some chemicals like alkaloids and lectins which act as their own ‘bug spray’ against many harmful pests and insects.

Edible plants of the Nightshade family like tomato, potato, red peppers, and aubergines contain minimal amounts of these toxins in their stems and leaves (which we generally don’t eat).

Such small quantities don’t have any detrimental effects on our body; however, immunocompromised people and persons with an autoimmune disease need to keep a little distance from these plants.

On the other hand, poisonous varieties like Atropa belladonna contain a high concentration of the same chemicals. The mechanism of action and health problems associated with these toxins are mentioned below –


Solanine is a glycoalkaloid, i.e., a sugar moiety is attached to it, found in the green parts of potato plant like leaves and stems.

When we ingest this glycoalkaloid, the juices in our digestive system separate the sugar molecule to produce solanidine which is then stored in our liver.

Under normal circumstances, it doesn’t create any significant symptoms, but in times of stress, like a chronic debilitating disease, pregnancy or starvation, solanidine is released from the liver and casts its dark magic on our unsuspecting body. (2)

Similar to solanine present in potatoes, the green parts of tomato plants contain tomatine. While eating these vegetables, we need to steer clear of their green parts like – green sprouts on potato and unripe, green tomatoes.

Solanidine irritates the digestive tract and inhibits an essential enzyme in our nervous system, acetylcholinesterase. Inhibition of this enzyme increases the amount of the neurotransmitter acetylcholine in synapses which leads to various side effects.

Solanine poisoning is a rare phenomenon which presents with nausea, abdominal pain, diarrhea, CNS depression, and even death in severe conditions. (3)


Capsaicin is the reason that the red-hot salsa sauce you had that day brought tears to your eyes and numbed your mouth. Red peppers contain varying amounts of capsaicin depending on the species of plants.

Ghost pepper and habanero contain a significant amount of this spicy component while jalapeno which is a bit milder has a lesser quantity of capsaicin.

Capsaicin irritates the free nerve endings present in our tongue which produce a neurotransmitter called Substance P, and hence, the so-called spicy taste sensation develops.

You must understand that capsaicin doesn’t really have any effect on our taste buds and it only stimulates the pain receptors.

After some time, these pain receptors become desensitized which produces the numbness that you feel after four to five mouthfuls of that hot salsa sauce. (4)

Studies have shown that topical application of capsaicin four days a week reduces the intensity of joint pain in patients of osteoarthritis without any significant side effects. (5)


Nicotine chewing and cigarette smoking, as all of you have heard a million times, produces irreversible detrimental effects on our body and mind.

However, few people know that all the vegetables of the Nightshade family are harbingers of this prohibited compound. (6) There’s no doubt that potato chips and French fries are rapid mood lifters and now you got an explanation for that!

Nicotine stimulates acetylcholine receptors in the brain which in turn triggers the reward center in our mind which produces a sense of well-being and happiness. (7)

This is the reason why smokers find it difficult to stop cigarette smoking despite being aware of all its hazards.


We all are aware of allergies to specific food items like peanuts, milk, and soy. Lectins in peanuts are responsible for the production of hypersensitivity reactions in susceptible individuals.

Similarly, some kinds of lectin compounds present in Nightshade vegetables lead to inflammatory conditions like leaky gut and cramps, especially in the presence of underlying conditions like inflammatory bowel diseases.

Problems with nightshade consumption

1. Food allergy

Although your lips and tongue don’t swell and become red every time you gorge on a cupful of mashed potato, there are chances that you may be sensitive to the alkaloids present in other vegetables of the same family.

Unlike peanut or soy allergy, it’s difficult to pinpoint the source of allergy when nightshade vegetables are involved.

If you suffer from sensitivity reactions (similar to gluten sensitivity) like leaky gut, heartburn, nerve sensitivity, and joint pain after eating any of the nightshade plants mentioned above, you might want to put a stop to consumption of these food items.

So, look out for these symptoms the next time you enjoy nachos with habanero sauce.

2. Inflammatory bowel disease

Glycoalkaloids present in potato skin and its green sprouts react with cholesterol in the membrane of cells lining the gut hence, disrupt the integrity of your gut wall.

This produces intense inflammation and autoimmune reactions to the food particles coming in contact with the damaged parts.

Therefore, alkaloids in nightshade vegetables induce inflammatory bowel disorders and also perpetuate an already existing problem. (8)

A laboratory study published in the Journal of Inflammatory Bowel Diseases showed that regular potato consumption even in normal amounts has adverse effects on our gut wall integrity and aggravates underlying inflammatory bowel diseases (ulcerative colitis and Crohn’s disease). (9)

3. Heartburn

Capsaicin present in red peppers and capsicum irritates the nerve endings present in the wall of the esophagus (food pipe) which reduces the tone of the sphincter at its end, and hence, contents of the stomach find a freeway into the vulnerable food pipe.

This produces complications like acid reflux and heartburn. (10) Even if you’re not sensitive to capsaicin, it’s always smart to minimize its intake as it causes more harm than good.

4. Joint pain

Osteoarthritis is one of the most debilitating conditions as its most common symptom is constant joint pain which hinders our movement and everyday work.

Although there’s no direct evidence linking consumption of nightshade vegetables and osteoarthritis, there are a few cases of hypersensitivity to these vegetables which have joint pain and movement difficulties as prominent symptoms. (11)

5. Aggravation of autoimmune conditions

Various autoimmune conditions like ulcerative colitis (inflammatory bowel disease), rheumatoid arthritis, etc. are deteriorated when some allergens in the nightshade vegetables exacerbate your already hyperactive immune system.

An autoimmune protocol diet (AIP) has come into existence for susceptible individuals because existing diet regimens like paleo diet contain many potential allergens like nuts, seeds, dairy products, and our very own nightshade vegetables.


Substitutes for nightshade plants

You can shield yourself from all the troubles that come with gorging on vegetables from the Nightshade family by substituting them with other food items that are similar in taste if not in nutrient content.

  • Sweet potatoes and yams
  • Celery
  • Cauliflower
  • Mushrooms
  • Radishes
  • Fresh fruits like oranges, blueberries, grapes, and melon
  • Spices like black and white pepper

Points to take home on nightshade plants

Nightshade sensitivity, although seldom heard of, is a genuine problem and can be life-threatening if appropriate measures are not taken in time.

Some species like belladonna, datura, and henbane have obvious toxic effects on our body while other everyday vegetables like potatoes, tomatoes, and peppers create a problem only in susceptible individuals.

Despite the long list of problems, Nightshade plants have a silver lining owing to the use of nicotine in Parkinson’s diseases and capsaicin in pain relief. (12)

All you need to do is keep your warning bells on a high alert while consuming or using products made from Nightshade plants.


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