The "Bad" Food That Gastroenterologists Say Is Exceptionally Beneficial for Gut Health

Nightshades are a group of plants, and everyone from Tom Brady to TikTok health influencers has spoken out against them, claiming that they cause inflammation and may aggravate or contribute to autoimmune diseases like psoriasis and inflammatory bowel disease. But are nightshades actually a bad guy in the kitchen? The details are below.

First of All, What Are Nightshades?

The formal name for this family of plants is Solanaceae, and it includes roughly 2,300 distinct plant species, including nightshades. According to Kenneth Brown, M.D., a gastroenterologist in Plano, Texas, and the presenter of the Gut Check Project podcast, they received their moniker because many types bloom at night.

Common nightshade plants include:

• Tomatoes
• Tomatillos
• Potatoes
• Eggplant
• Peppers
• Pepper-based spices (including paprika, chili powder, cayenne powder, red pepper)
• Pimentos
• Goji berries
• Ground cherries
• Huckleberries
• Ashwagandha
• Tobacco

According to a study published in Processes, this family is special because the plants create poisonous substances called glycoalkaloids as part of a cunning evolutionary strategy, as we highlighted in our guide to nightshades. These substances serve as the plant's "armor" to protect it from various illnesses as well as insects and animals that are attracted to it. At specific stages of the ripening process, solanine is the most noticeable glycoalkaloid present in tomatoes, potatoes, eggplant, and other edible nightshades.

Why Do Nightshades Occasionally Get a Bad Reputation?

According to William W. Li, M.D., an internal medicine specialist in Boston and author of Eat to Beat Disease: The New Science of How Your Body Can Heal Itself, most members of a large family are absolutely respectable, but a few rotten apples can damage the reputation of the entire clan.

For instance, solanine might result in digestive symptoms including nausea, vomiting, or a stomach ache. However, this illness is highly uncommon and typically only manifests itself after consuming a large quantity of young, green potatoes or really old potatoes with sprouts. (Therefore, the word "rare" is stressed.) Potatoes grow more chlorophyll or sprouting extensions when exposed to UV radiation; these are two indications that their solanine levels are too high to be problematic.

Other nightshades, such as tomatoes, potatoes, eggplants, and peppers, include alkaloids or lectins, a kind of protein that binds to carbohydrates and can irritate the digestive system in certain people. Brown notes that the levels are often too low to have an impact on the majority of people.

According to Akil Palanisamy, M.D., an integrative medicine physician in San Francisco and the author of The T.I.G.E.R. Protocol: An Integrative, 5-Step Program to Treat and Heal Your Autoimmunity, practically everyone can prevent potential adverse effects by simply boiling the meals that contain these chemicals.

Therefore, eggplants and other nightshades aren't thought to be harmful unless you're one of the extremely rare individuals who has an allergy to them. "As with all foods—not just nightshades—if your body responds negatively, it's best to avoid eating them," Li explains.

Speak to your doctor if you have any concerns about nightshades, or attempt an elimination diet under the direction of a nutritionist while keeping a symptom diary. You'll gradually reintroduce different meals after removing them, noting any changes in your symptoms.

"There has unfortunately been a widespread misunderstanding about nightshades being toxic and dangerous to eat," Li adds. However, a vast array of scientific and clinical investigations on the impact of these foods on health have largely demonstrated that they are good for it. They really have a lot of naturally occurring bioactive substances that boost immunity, reduce inflammation, help with gastrointestinal health, and enhance circulation.

Why Nightshades Are Among the Best Foods for Gut Health

Nearly all nightshades include a serving of fiber, which feeds your healthy gut flora and aids in digestion, in addition to providing a variety of vitamins, minerals, and antioxidants for relatively little calories.

When you step back and consider tomatoes, peppers, and eggplants, you're really describing a Mediterranean-style diet, which is known to be among the healthiest eating habits, if not the healthiest, according to Will Bulsiewicz, M.D., a gastroenterologist with a practice in Charleston, South Carolina, and the author of The Fiber Fueled Cookbook.

According to Brown, consuming a range of fruits and vegetables—including nightshades—can help to improve the gut bacteria. A May 2018 study that was published in the journal ASM Journals found that those who eat 30 or more plant kinds (including spices) each day had better microbiomes than those who consume 10 or fewer plant types per week.

Additionally, a varied diet rich in vegetables makes less place for foods that are bad for the stomach, such red meat, artificial sugars, and alcohol. You'll also benefit from a variety of fibers and nutrients that support the growth of your good gut flora by consuming a variety of fruits, vegetables, herbs, and spices.

"Your gut is healthier the more diversified your microbiome is. Reduced inflammation and a lower risk of chronic conditions like heart disease and type 2 diabetes result from this. According to Li, it can also encourage quicker healing, a more efficient metabolism, and even improved moods.

The Healthiest Nightshades for Your Gut

Although no studies have directly compared the microbiome advantages of nightshades, Li claims that the following fruits and vegetables are standouts because of the advantageous vitamins, minerals, and other bioactive substances that they contain. Eat up!

Peppers

Because they contain less potentially irritating substances and are high in fiber and vitamins, including vitamin C, peppers are typically well tolerated, according to Brown.

Tomatoes

This fruit is also high in fiber and antioxidants like lycopene, which can support gut health, Brown says. In addition, thanks to the vitamins (such as C) and minerals, "intake of tomatoes is associated with lower risk of heart disease, reduced risk of prostate cancer and improved bone health as well," Palanisamy adds.

Huckleberries, Ground Cherries and Tomatillos

These fruits are packed with antioxidants, fiber and vitamins, says Brown, which means they're beneficial for gut health and overall well-being.

Cooked and Chilled Potatoes

All potatoes include vitamins, fiber, and potassium, but leftover potatoes (those that have been cooked and cooled) get extra credit from Palanisamy since they contain a lot more resistant starch than fresh potatoes. "The process of cooling cooked potatoes for about 12 hours causes the formation of this resistant starch, which is an excellent prebiotic that feeds and supports the gut microbiome," according to him. "Potatoes are pretty unique among plants in terms of being able to synthesize this resistant starch." (Resistant starch can also be found in green bananas, black beans, pinto beans, barley, and pumpernickel bread.)

Eggplants

Li points out that because eggplants are a high source of prebiotic nutrients including fiber, carotenoids, and polyphenols, all of which support and nourish good gut flora, this vegetable has been demonstrated to increase the variety of the microbiome.

We heartily suggest these 18 juicy tomato recipes, our 27 best summertime eggplant recipes, 22 low-calorie potato side dishes, and this paprika spice combination you'll want to sprinkle on pretty much everything if you're feeling inspired to chow down on nightshades.

The Bottom Line

The great majority of people may profit from the enormous nutritional advantages that this plant family offers, including enhanced gut health, however certain people may need to limit or avoid nightshades. And they should unquestionably be a component of a diet that is balanced, according to Brown. The Mediterranean diet, which includes a lot of nightshades, has also been proven to be among the healthiest diets in the world, not just for improved gut health but also for a healthier, longer life, says Palanisamy.