What Are Nightshades And Should You Avoid Them?

There is a good chance you have never heard of nightshades until now. And if you have, there is a good chance you came across it when news outlets covered the dietary pattern of New England Patriots quarterback Tom Brady.

So what are they exactly?

Nightshades are a part of the plant family Solanaceae, consisting of tomatoes, capsicums, chili peppers, goji berries, eggplant, white potatoes, paprika, among other foods. While we know these foods to be healthful components of a good diet, it has been suggested that nightshades may be harmful to certain individuals as they contain alkaloids.

"Alkaloids are nitrogen-containing substances typically found in the leaves and stems of nightshades," states Healthline. "They are often very bitter and function as a natural insect repellent."

For example, solanine is an alkaloid found in potato leaves, sprouts, and stems. But the part of the vegetable we eat is safe to consume as it contains only tiny traces of solanine.

But as mentioned earlier, some people have expressed skepticism about this. They suspect that nightshade alkaloid s trigger inflammation in their body, which can worsen health conditions like arthritis. 

Furthermore, naturally-occurring compounds known as lectins are also found in nightshades. In addition to worsening arthritis symptoms, these are also thought to be irritants for people who have a very sensitive gut. 

Brady and Gisele Bundchen are among the celebrities who avoid consuming nightshade vegetables. In his exercise and diet book The TB12 Method, Brady justifies the exclusion as a necessary step in his anti-inflammatory diet.

The obvious question may have crossed your mind by now —  what does science have to say about this?

There has not been strong evidence to support the idea that alkaloids and lectins in nightshades can actually trigger inflammation or lead to digestive problems. This study from 2010 is one of the few that found a possible link between the consumption of potato skins and intestinal inflammation in a group of mice.

Nutrition experts believe that most of us do not have to worry about nightshades. "The vast majority of people can safely enjoy nightshades and in fact, I highly recommend them," Christine Palumbo, R.D.N., an academy of nutrition and dietetics nominating committee member, told Prevention. After all, nightshades are good sources of polyphenols, vitamins, minerals, fiber, and other nutrients. 

If you suffer from conditions like arthritis or inflammatory bowel disease, you may seek guidance from a registered dietitian about whether you can reduce your intake of nightshades to see if it helps. 

It is unlikely that you will need to cut them out in a strict manner as people do, with the likes of gluten and dairy. Instead, you may simply be advised to remove the skin of potatoes, cook nightshade foods thoroughly, only avoid certain varieties, or try out the 30-day elimination diet.