The Buzz: Nightshades

What’s the buzz?

Nightshades are vegetables with a shady reputation that some say you should avoid.

What does the science say?

Just when you thought everyone agreed that vegetables are good for you, many online “health experts” have put nightshade vegetables on their “do not eat” list. And when celebrities like now retired quarterback Tom Brady (who has been seen by many as the picture of good health) nix them from their diet, it may leave you questioning if you should avoid them too.

First of all, what the heck are nightshades, anyway? And how did they get such a shady reputation? The word nightshades is just a name for a category of plants, some of which are edible, like eggplant, tomatoes, white and purple potatoes, artichokes, and peppers, while others such as tobacco and certain flowers are not. There is a belief that a compound called alkaloids (solanine in particular) found in nightshades may cause or exacerbate inflammation, particularly for certain health conditions like arthritis. It’s thought that people with inflammatory conditions may feel some symptom relief when they remove nightshade vegetables from their diet. While studies in mice suggest that the glycoalkaloids found in nightshades aggravate intestinal inflammation, there has yet to be any solid research that nightshades cause inflammation in relation to human diseases. In addition, you may see information on anti-inflammatory diets circling the internet that exclude nightshades, but there have been no studies that have demonstrated that this eating pattern actually lowers inflammation markers in people. Most of the concern around nightshades comes from anecdotal evidence from individuals with autoimmune disorders who report individual cases of symptom relief after removing these vegetables.  (One small study that is often cited by online articles includes tobacco along with the nightshade vegetables on the list of items removed from the participants’ diet to see if their arthritis symptoms improved. Because tobacco is known to directly cause inflammation, it should have been controlled for, but was not, so results are not too useful.)

Although it’s possible to have a sensitivity to solanine (or something else in these vegetables) or feel symptom relief when removing nightshades from your diet, it is highly unlikely that they cause inflammation in most people. In fact, many of the nightshade vegetables are known for their anti-inflammatory properties and health-promoting nutrients. One study event showed that white and purple potatoes (both nightshade vegetables) reduced inflammation in arthritis patients. Nightshade vegetables like tomatoes, peppers, eggplant, and peppers (just to name a few) provide vitamins A, B6, C, and K, as well as potassium, fiber, and many antioxidants including lycopene and lutein — all of which can help reduce inflammation and provide many other health benefits.

What’s the takeaway?

There is little reason to remove a long list of health-promoting vegetables from your diet. In fact, adding a greater variety of colorful vegetables to your diet will only improve your health and possibly help reduce inflammation. If you think you may have a sensitivity to nightshades or other foods, working with a registered dietitian can help you identify any food sensitivities and determine the best plan for you.


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