Tomatoes, a staple in everyone’s pantry, and potatoes, a cult favorite, along with eggplants and peppers, belong to the nightshade family of vegetables. However, what’s a delicious ingredient for many can be a source of discomfort for some. Experiencing symptoms like redness, itching, or digestive issues after a meal featuring these foods might point to a lesser-known but significant condition: a nightshade allergy. This comprehensive article covers everything you need to know about nightshade allergies, from the underlying causes and risk factors to the intricate genetics and effective management strategies.
Did You Know?
Genetic changes are the most common cause of food and other allergies. Using your existing DNA raw data file, you can find out which food, environmental, and drug allergies you’re susceptible to. Learn more.
What Is Nightshade Allergy?
Nightshades are part of the Solanaceae family, consisting of 3000 flowering plants. Although some of these plants are beneficial, some can be dangerous if consumed.
For instance, belladonna, a deadly nightshade, increases heart rate and blood pressure.
Tobacco is a nightshade plant used to make cigarettes.
Yet, many nightshades, such as tomatoes, eggplants, potatoes, and bell peppers, are staple foods in various cuisines across the globe.
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 eating nightshades.
This condition is called nightshade allergy, intolerance, or sensitivity.
Nightshades possess certain chemical compounds that may be harmful to some people.
These chemicals, called phytochemicals, help plants fight against certain foreign substances.
A phytochemical called lectin may trigger an immune reaction if undigested, resulting in autoimmunity.
Are Nightshade Allergies Genetic?
Genetic variants can be the root cause of the development of a nightshade allergy.
Mutations in the BCHE gene are associated with nightshade allergy.
The BCHE gene provides instructions for making butyrylcholinesterase (BChE). This cholinergic system enzyme plays a significant role in digestion, blood pressure, heart rate regulation, and spinal cord function.
BChE is a bio-scavenger, 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
Low levels of BChE in the body due to mutations may not be sufficient to fight against glycoalkaloids (BChE inhibitors) in nightshades.
Eventually, a nightshade allergy can develop.
Genetic Factors
Research studies suggest the involvement of specific genes in nightshade allergy.
While nightshade allergies aren’t caused by a specific gene, a group of variations in certain genes can have a cumulative effect and increase the risk of allergic reactions.
For example, the BCHE gene plays a role in inactivating the alkaloids present in the nightshade plants.
Any variation in this gene that causes lower levels of poor functioning of the BChE enzyme may result in alkaloid build-up in the body, increasing the risk of a nightshade allergy.
Other Causes Of Nightshade Allergies
Nightshade allergies are unusual, so you should also consider more common allergens, such as dairy, nuts, seafood, soy, and gluten. Additionally, two factors contribute to nightshade allergies.
High Concentrations Of Alkaloids
Nightshade allergy is mainly caused by the toxic alkaloids in them that defend the plant against molds, pests, and other pathogens.
People develop allergies to alkaloids, which trigger the immune system.
It releases immunoglobulin E (IgE) antibodies to tackle the allergen by releasing histamine into the blood.
This results in nightshade allergy symptoms.
High concentrations of alkaloids like solanine, nicotine, and capsaicin can cause gut irritation and joint inflammation.
Autoimmune Or Gastrointestinal Conditions
People with autoimmune disorders have a weakened immune system.
Weaker immune systems do not respond appropriately to the alkaloids in nightshades, allowing allergies to run rampant.
Rheumatoid arthritis, celiac disease, and inflammatory bowel disease (IBD) are some prevalent autoimmune disorders.
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Who’s At Risk For Developing A Nightshade Allergy?
You are more likely to develop nightshade allergy if you have certain risk factors:
- A family history of nightshade allergy
- An existing autoimmune condition
- Irritable Bowel Syndrome (IBS)
- An immature digestive system, as seen in children under 12 years old
- Other food intolerances
- Asthma
Nightshade Allergy Symptoms
Nightshade allergy is more severe than nightshade intolerance.
While intolerance causes loose stools, bloating, and nausea, which are uncomfortable rather than deadly, allergies can lead to severe symptoms like potentially fatal anaphylaxis.
Initial symptoms can take up to 72 hours to appear, and they can look like:
- Itchy or red skin due to urticaria (hives)
- Wheezing or breathing issues
- Joint and muscle aches
- Brain fog or dizziness
- Excessive mucus secretion
- Sore throat
- Migraines
- Fatigue
- Gas or heartburn
Diagnosing and Treating a Nightshade Allergy
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 deleting foods containing the allergen. As instructed by your doctor, keep a food log to track your symptoms and any possible triggers.
Drugs to prevent allergic reactions when exposed may also be part of the treatment approach. Typical prescription drugs include:
- Antihistamines: They work against histamines, which trigger the allergic reaction. Clarinex, Allegra and Zyrtec are some common antihistamines.
- Decongestants: They aid in narrowing blood arteries to allow mucus to drain. Doctors generally prescribe Nasal sprays and Sudafed.
- Anticholinergic nasal sprays: These inhibit nasal secretions. Atrovent Nasal is an anticholinergic spray.
- Steroid nasal sprays: They reduce swelling but take a few days to work. Nasonex and Flonase are some effective steroid nasal sprays.
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 the allergens. Here are some easy swaps to common nightshade foods:
| Allergens | Alternatives |
| Tomato sauce | Pesto or Alfredo sauce |
| Tomatoes, | Beetroots, carrots, or grapes |
| Blueberries | Raspberries, strawberries or cranberries |
| Eggplants | Mushrooms |
| Bell peppers | Carrots, onions, celery, or zucchini |
| White potatoes | Sweet potato, radish, or cauliflower |
| Paprika, cayenne, chili flakes | Basil, oregano, black/white pepper |
Frequently Asked Questions
Are Onions Nightshades?
While onions aren’t part of the nightshade family, it’s best to stay away from them if you have IBS since they can exacerbate the symptoms.
Is Pepper A Nightshade?
Interestingly, black and white peppers come from a different family of plants, not from the nightshade family. They’re safe to consume if you have a nightshade allergy or intolerance.
Is Chocolate A Nightshade?
Though chocolate isn’t a nightshade, it does contain some alkaloids. Fortunately, these are easier to digest than the alkaloids in nightshades, so they shouldn’t cause an allergic reaction.
Summary: Everything You Need To Know About Nightshade Allergies
- The Nightshade family includes many commonly used vegetables like tomatoes, potatoes, chilies, eggplants, and bell peppers.
- Nightshade vegetables contain an alkaloid chemical that protects them 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.
