What Are Nightshades? How Alkaloids Affect Your Health

Hot peppers have an infamous family…

The nightshade family is flowering plants also known by their Latin name Solanaceae. There are more than 2,000 plants in this family, including hot peppers and sweet peppers. Most of these nightshades are not eaten as food and are in fact, poisonous. The long list of nightshade fruits and vegetables, though, also includes many fruit and vegetable kitchen staples including chili peppers, sweet peppers, tomatoes, potatoes, eggplants, tomatillos, and goji berries.  Nightshade plants all have certain distinctive traits in common including the shape of their flowers. They also contain compounds that may have negative effects on your health (but also many positive health benefits as well).

Nightshade alkaloids

One of the characteristics of nightshade plants is their alkaloid content. There are several alkaloids that show up in these plants. Capsaicin is the alkaloid that gives chili peppers their heat but it is just one of several that show up in this family of plants. Others include nicotine and tropane as well as the most problematic of all: solanine.

About solanine

Solanine is the alkaloid compound found in nightshades like chili peppers that is responsible for most of their negative health effects. Nightshade plants use this alkaloid to protect themselves from insects that might try to eat them. Solanine acts as a kind of poison but is concentrated in the leaves and stems. If you are not eating the leaves and stems of pepper and potato plants, you probably do not have to worry about any health effects from consuming solanine.

Are nightshades bad for you? Probably not

As noted above, nightshade plants have a reputation for toxicity. The reputation comes from the fact that some members of the Solanaceae family — such as the belladonna plant — are potentially lethal to humans. In recent years, there have been many people who claim to have experienced all kinds of health problems from nightshade consumption. Supposed issues include inflammation as well as nausea and other gastrointestinal issues.

There is little evidence to back up any of the negative claims made about nightshades. In other words, most people should be able to eat hot peppers and other typically sold fruits and vegetables of this family without encountering any of the symptoms.

Who should avoid nightshades?

While these fruits and vegetables are generally safe, there are people who may want to avoid them. Certain conditions can cause nightshade sensitivity, and eliminating nightshades from your diet then becomes critical. For example, some people who are suffering from autoimmune diseases such as rheumatoid arthritis may have difficulties dealing with the solanine content of chili peppers and other nightshade fruits and vegetables. Note that not everyone who has an autoimmune disease will have a negative reaction, just those who are sensitive to solanine.

As with any food, it is important to weigh the benefits against the drawbacks. Nightshades are generally nutritious. In the case of chili peppers, they are full of vitamins and antioxidants. These are nutrients that can be beneficial for people with autoimmune diseases. In other words, you are not necessarily forbidden from eating foods containing hot peppers just because you have an autoimmune disease.

If you eat nightshade fruits and vegetables regularly and suffer from an inflammatory disease, you may want to try removing them — including all chili pepper products — from your diet for a short period. Two weeks should be long enough. If your symptoms lessen in severity over the two-week span, you may have a nightshade sensitivity.

UPDATE NOTICE: This post was updated on September 5, 2019 to include new content.
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how much of the stem of a pepper would you have to eat to experience bad effects? if you cut a small bit off the top of a pepper and it got in to the vegetable mix would you notice it? or does it take larger amounts?


Thank you for the article. I am one of the lucky ones to have a nightshade sensitivity. But as they say “The dose makes the poison”. I can eat eggplants or peppers once a week in small amounts, generally without problems. But eating them for 2-3 consecutive days produces inflammation and indigestion that could last a month or even longer. So I have to be very careful. I have no problem with small amounts of potatoes and tomatoes. Paprika is the worst, though.


Thank you, very helpful!!