Are nightshade vegetables actually bad for you?

Nightshades — potatoes, eggplants, bell peppers and tomatoes — are unfairly vilified all over the internet.

Andy De Santis, RD 3 minute read August 13, 2021

Nightshade vegetables — eggplants, tomatoes, potatoes and bell peppers — get a bad rap. GETTY

Nightshades have been getting a bad rap recently. Here’s what you actually need to know about the vilified vegetables.

What are nightshade vegetables?
Nightshades, scientifically referred to as Solanaceae, are a diverse family of flowering plants, both edible and non-edible. For most of us, the most relevant nightshades are the commonly available edible varieties such as tomatoes, potatoes, eggplants and bell peppers.

From the perspective of a dietitian, these particular foods are characterized by their rich content of fibre, potassium and unique antioxidant compounds that offer additional benefits to our health.

Tomatoes, for example, are uniquely rich in the compound lycopene, which may offer some protection against prostate cancer, while bell peppers are among vegetables richest in Vitamin C.

So where does it all go wrong?
Well, it depends who you ask. In some parts of the online “health” world, the nightshade family of vegetables have been vilified as being inflammatory or even toxic foods.

Where does all this stem from? Quite literally, the stems.

Nightshade foods contain varying levels of compounds known as alkaloids, which tend to concentrate in the leaves and stems, and can indeed be problematic if eaten in excess — they’re the reason overgrown or sprouting potatoes generally should not be consumed.

There are, however, only negligible amounts of these compounds in the actual edible components of nightshade foods. That’s why the majority of otherwise healthy people aren’t rushed to the hospital after eating a tomato salad.

Some nightshade detractors say that while not acutely toxic, the consumption of tomatoes, bell peppers, eggplant and potatoes could ultimately contribute to bodily inflammation. But as this Harvard School of Public Health article aptly states, that’s an “unfounded myth”: there is no scientific evidence to support these claims.

Are there exceptions to the rule?
In some rare cases, yes. A very, very small number of people could be allergic to nightshades. Statistics aren’t widely available, but doctors say nightshade allergies are infrequent.

Survey data also suggests that 1 in 2 people with either psoriasis or atopic dermatitis report nightshades as potential symptom triggers. So if someone with those conditions wants to avoid nightshade foods, that’s reasonable enough.

The reality, though, is that the evidence relating to the potential negative effects of eating nightshade vegetable is mostly anecdotal and not particularly convincing as it relates to an otherwise healthy person. There aren’t high-quality studies to demonstrate that, all other thing being equal, omitting these four foods is a net positive for human health.

In fact, nightshade vegetables are good for most of us: they contain potassium that lowers blood pressure, and their soluble fibre and plant sterols lower cholesterol. Unlike the alarmist anti-nightshade talk online, we actually have a great deal of evidence backing up those claims. And those benefits are notable, because high blood pressure and high cholesterol are two of the primary causes for pharmaceutical prescriptions in Canadians.

So while you can certainly omit nightshade vegetables if you so choose, I don’t recommend you do, unless you have a truly compelling reason.

Andy De Santis is a registered dietitian and author who has operated a private practice in Toronto since 2015. He spends his free time eating, writing and talking about kale @AndyThaRD. He can be reached at