Vegetables like tomatoes, eggplants, or bell peppers belong to the nightshade family and are staples in many people's diets.
However, for those with a nightshade allergy, one or more vegetables in this family can cause unpleasant reactions.
Genetic Changes Are The Most Common Causes of Food and Other Allergies. Learn More
What Is Nightshade Allergy?
Nightshades are foods that belong to the Solanaceae family.
It consists of almost 3,000 species of flowering plants.
Nightshades can either be beneficial or harmful.
The belladonna, a deadly nightshade, causes increased heart rate and blood pressure. Tobacco is a nightshade plant used to make cigarettes.
Many nightshades are the staple food in various cuisines across the globe.
Some edible nightshades are:
- Bell peppers
- Garden huckleberries
- Goji berries
- Ground cherries
Nightshades are rich in potassium, iron, fiber, vitamin C, and antioxidants such as anthocyanins and lycopene.
They are beneficial for heart health and cancer prevention.
However, some people exhibit adverse effects after consuming nightshades.
This condition is called nightshade allergy. It is also known as nightshade intolerance or nightshade sensitivity.
Nightshades possess certain chemical compounds that may be harmful to some people.
These chemicals, called phytochemicals, help plants fight against certain foreign substances.
They include Alkaloids, Saponins, Lectins, etc.
Alkaloids are naturally occurring compounds highly found in tubers.
Saponins are steroids or triterpenoid glycosides which retard nutrient intake and affect digestion.
Lectins are proteins that bind to carbohydrates and block digestion.
According to a study, undigested lectins trigger an immunological reaction, causing autoimmunity.
Causes of Nightshade Allergy
A few factors are responsible for causing nightshade allergy. They are:
High Concentrations Of Alkaloids
Nightshade allergy is mainly because of the alkaloids in them.
They play a defensive role against pathogens like molds and pests to protect the plant.
People develop allergies to alkaloids (toxic substances to the body) which trigger the immune system.
It releases immunoglobulin E (IgE) antibodies to defend the allergy-causing food (the allergen).
IgE antibodies send some chemicals called histamine into your bloodstream.
These chemicals cause nightshade allergy symptoms.
High concentrations of alkaloids worsen the symptoms of nightshade allergies.
Autoimmune Or Gastrointestinal Conditions
People with autoimmune disorders are immune compromised.
Their weak immune system does not work against the toxic substances in nightshades, leading to the cause of nightshade allergy.
Numerous autoimmune conditions have a leaky gut as their underlying cause.
Rheumatoid arthritis, celiac disease, and inflammatory bowel disease (IBD) are some prevalent autoimmune disorders.
Alkaloids in nightshades can aggravate gut irritation and exacerbate inflammation.
Solanine, Nicotine, and Capsaicin are some alkaloids found in nightshades.
Solanine is a glycoalkaloid that can cause joint inflammation and stress in the body.
According to reports, eating green potatoes can cause solanine toxicity.
Capsaicin in bell peppers can irritate the gastrointestinal tract and result in various digestive problems.
Genetic variants play a vital role in causing nightshade allergy.
The BCHE gene is responsible for developing the condition.
The BCHE gene regulates numerous functions in your body that can be activated or deactivated by factors such as stress, nutrition, and infection.
Any changes to the BCHE gene functioning can increase nightshade allergy risk.
Nightshade Allergy Symptoms
Nightshade allergy is more severe than nightshade intolerance.
Nightshade intolerance causes loose stools, bloating, and nausea, which are uncomfortable rather than deadly.
Nightshade allergies can lead to severe symptoms like potentially fatal anaphylaxis. Initial symptoms can take up to 72 hours to appear:
- Skin rashes like urticaria (hives)
- Itchiness and redness in the skin
- Wheezing or breathing issues
- Joint and muscle aches
- Brain fog or dizziness
- Excessive mucus secretion
- Sore throat
- Severe headaches (migraines)
- Gas or heartburn
Is Nightshade Allergy Genetic?
Genetic variants (changes) can be the root cause of developing a nightshade allergy.
Mutations in the BCHE gene are associated with nightshade allergy.
The BCHE gene provides instructions for making butyrylcholinesterase (BChE ), a cholinergic system enzyme.
The cholinergic system is a part of the autonomic nervous system.
It plays a significant role in digestion, blood pressure, heart rate regulation, and spinal cord function.
BChE plays a vital role in the autonomic nervous system and is recognized as a bio-scavenger, defending the body against toxins or poisons.
BChE is essential for
- Inactivating toxic phytochemicals in nightshades
- Regaining consciousness from specific types of anesthesia
- Controlling the over-reactive immune system
- Defending against nerve chemicals, snake toxins, and other AChE inhibitors
Changes in the BCHE gene can cause abnormalities in the production and function of the BChE enzyme.
Low levels of BChE in the body may not be sufficient to fight against glycoalkaloids (BChE inhibitors) present in nightshades.
This can lead to nightshade allergy.
Who’s At Risk For Developing Nightshade Allergy?
You are more likely to develop nightshade allergy if you have a few common risk factors:
- Family history of nightshade allergy
- Living with an autoimmune disorder
- Diagnosed with irritable bowel syndromes
- Children below 12: Their digestive systems are yet to mature and are less likely to absorb food components that trigger allergies.
- Other food intolerances
- Asthma: This frequently raises the intensity of symptoms as well as the likelihood of developing an allergy
Nightshade Allergy: Diagnosis and Treatment
Nightshade allergies are unusual, so you should also consider allergens that are more frequently encountered, such as dairy, nuts, seafood, soy, and gluten.
Similar to other allergies, a doctor can identify a nightshade allergy by performing some diagnostic tests, including:
Blood test (RAST or ELISA): A doctor collects blood samples and checks for the presence of IgE antibodies linked to particular allergens.
Skin prick test: A doctor pricks the skin with a needle to test for suspected allergens and monitors for a reaction.
A standard food allergy treatment involves the deletion of foods containing the allergen. Keep a food log to track your symptoms and any possible triggers, as instructed by your doctor.
Drugs to prevent allergic reactions when exposed may also be part of the treatment approach. Typical prescription drugs consist of:
Antihistamines: They work against histamines, which trigger the allergic reaction and cause symptoms like hives and sneezing.
Commonly used antihistamines are Clarinex (desloratadine), Allegra, and Zyrtec (cetirizine).
Decongestants: They aid in narrowing blood arteries to allow mucus to drain.
Afrin nasal spray (oxymetazoline), Sudafed PE (phenylephrine), and Sudafed (pseudoephedrine) are some known decongestants.
Anticholinergic nasal sprays: These inhibit nasal secretions.
E.g., Atrovent Nasal (ipratropium)
Steroid nasal sprays: They reduce swelling but take a few days to work.
E.g., Nasonex (mometasone) and Flonase Allergy Relief (fluticasone propionate)
EpiPens: Epinephrine injections stop anaphylaxis, a severe allergic reaction that can be fatal.
Substitutes for Nightshade
The simplest method to prevent food allergy symptoms is to avoid triggering food. Here are some easy swaps to common nightshade foods:
- Use olive oil, pesto, and Alfredo sauce instead of tomato sauce.
- Replace beetroots, carrots, and grapes with tomatoes.
- Try raspberries, strawberries, cranberries, or cherries instead of blueberries and goji berries.
- Replace mushrooms (shitake or portobello) with eggplants.
- Replace carrots, Swiss chard, zucchini, onion, or celery with bell peppers.
- Replace sweet potatoes, radishes, cauliflower, squash, turnips, or parsnips with white potatoes.
- Add black pepper, white pepper, cumin, basil, oregano, turmeric, or parsley instead of paprika, cayenne, chili powder, or red pepper flakes.
- The Nightshade family includes many commonly used vegetables like tomatoes, potatoes, chilies, eggplants, and bell peppers.
- Nightshade vegetables contain an alkaloid chemical that they use to protect against foreign substances.
- While most people can tolerate alkaloids, some develop an allergic reaction.
- One of the most common causes of nightshade allergy is changes or variations in the BCHE gene that produces the BChE enzyme, which is crucial for breaking down alkaloids.
- Nightshade allergy can be diagnosed through typical allergy diagnostic tests and treated with antihistamines and EpiPens.