Nightshade vegetables belong to the family of plants with the Latin name Solanaceae.
Potatoes, tomatoes, peppers and eggplants are all common nightshade vegetables. Many are rich sources of nutrients and serve as staple foods for various cultures.
However, some think that certain groups of people may be better off eliminating nightshades. They claim that harmful substances found in these vegetables may contribute to inflammatory bowel disease and other autoimmune conditions.
This article reviews the health effects of nightshade vegetables to help you decide if these foods are good or bad for you.
What Are Nightshade Vegetables?
Nightshade vegetables are the edible parts of flowering plants that belong to the Solanaceae family.
The origin of the name “nightshades” is unclear, but could be related to their dark and mystical past. Some nightshades are rumored to have been formerly used as narcotics and hallucinogens.
The nightshade family contains over 2,000 varieties of plants, but very few of them are actually eaten as food. Some, such as belladonna, are even poisonous.
However, nightshades also include vegetables that have been the staple foods of many societies for hundreds of years.
Here is a list of some of the most commonly consumed nightshade vegetables:
- Eggplants: Also known as aubergines.
- Peppers: Including sweet, bell, chili and others.
- Potatoes: All varieties except sweet potatoes and yams.
- Tobacco: Typically dried and smoked in several forms.
- Tomatillos: A green, tomato-like veggie common in Mexican cuisine.
- Tomatoes: All varieties and tomato products.
Multiple herbs and spices are also derived from these vegetables, including cayenne pepper, crushed red pepper, chili powder and paprika. Black and white pepper are derived from peppercorns, which are not in the nightshade family.
Additionally, several condiments and other common food items contain nightshade vegetables as ingredients, such as hot sauce, ketchup, marinara sauce and salsa.
Note that although they are generally referred to as vegetables, many nightshades are botanically considered fruits, such as tomatoes, eggplants and peppers.
Summary: Nightshade vegetables belong to the Solanacaea family of plants. They include potatoes, tomatoes, eggplants and peppers.
Nightshades Are Rich Sources of Nutrients
Many health professionals encourage you to eat nightshade vegetables because of their high nutrient density.
This means they pack a lot of nutrients in a small number of calories.
- Tomatoes: Tomatoes are good sources of vitamins A and C. They also contain an antioxidant called lycopene. These nutrients may reduce markers of inflammation and lower the risk of several chronic diseases.
- Peppers: Peppers contain incredible amounts of vitamin C, which can provide many health benefits, including helping enhance iron absorption.
- Chili peppers: Chili peppers contain capsaicin, which gives the peppers their heat. Capsaicin has been found to help alleviate heartburn symptoms and may benefit weight loss efforts by helping reduce calorie intake.
- Eggplants: Eggplants are a good source of dietary fiber, providing 2.5 grams of fiber per cup. This important nutrient helps regulate bowel movements and may lower your risk of heart disease.
- Potatoes: Potatoes with the skins on contain fair amounts of potassium, vitamin B6 and manganese.
However, unlike most nightshades, potatoes are also considered a starchy vegetable. One small potato contains around 30 grams of carbs.
People with diabetes or others looking to lower their blood sugar may need to avoid eating too many potatoes.
Summary: Nightshade vegetables are nutrient-dense foods that may provide a number of health benefits through their vitamin, mineral, fiber and antioxidant content.
Nightshades May Be Harmful for Those With Autoimmune Diseases
Although nightshade vegetables are a rich source of nutrients, many people claim they are harmful and should be avoided.
The majority of these claims seem to center around a group of substances found in nightshades called alkaloids.
Alkaloids are nitrogen-containing substances typically found in the leaves and stems of nightshades. They are often very bitter and function as a natural insect repellent.
But the edible portions of these plants contain some alkaloids, too. Consequently, many people with autoimmune diseases have eliminated nightshades from their diets and believe these foods are contributing to their health problems.
Nightshades May Worsen Inflammatory Bowel Disease
Inflammatory bowel disease (IBD) is a group of autoimmune diseases characterized by inflammation of the digestive tract. Examples are Crohn’s disease and ulcerative colitis.
In people with IBD, the protective lining of the intestine doesn’t function properly and allows bacteria and other harmful substances to enter the bloodstream.
This is sometimes called increased intestinal permeability, or “leaky gut”.
When this happens, the body’s immune system attacks the harmful substances, leading to further inflammation of the gut and many adverse gastrointestinal symptoms, such as pain, diarrhea, malabsorption and others.
While research on this is limited, a few studies in animals suggest that the alkaloids in nightshades may further aggravate the intestinal lining of people with IBD.
In two separate studies of mice with IBD, the alkaloids in potatoes were found to adversely affect intestinal permeability and increase intestinal inflammation.
Additionally, two test-tube studies suggest that substances called pectins in tomatoes and capsaicin in peppers may also increase intestinal permeability.
This limited research in animals and test tubes suggests that people with IBD may benefit from eliminating or reducing nightshade intake. But research is needed in humans before more definitive recommendations can be made.
The Effects on Other Autoimmune Diseases Is Unknown
Even less is known about the effects of nightshades on other autoimmune diseases.
However, there may be some connection between increased intestinal permeability, or leaky gut, and autoimmune conditions like celiac disease, multiple sclerosis and rheumatoid arthritis.
Some experts believe that leaky gut could contribute to higher levels of inflammation all over the body that worsen disease symptoms.
Based on this belief, some have suggested that nightshades may increase intestinal permeability and aggravate the symptoms of these autoimmune conditions, as well.
Many people with these diseases have eliminated nightshades from their diets and report great improvement in symptoms, but evidence for this recommendation right now is mainly anecdotal and needs to be studied.
Summary: Some animal studies suggest that nightshades could have negative effects in people with IBD, but more research is needed in humans before definitive recommendations to eliminate nightshades can be made.
Read more at: https://authoritynutrition.com/nightshade-vegetables/