By now it is likely that you have heard about the nightshade family of vegetables. For many years I have advised clients with any issues related to inflammation - including autoimmune conditions - to avoid nightshades in a process of elimination. But what are the nightshades and do you really need to avoid them?

First it is important to distinguish nightshades from “deadly nightshade”. Deadly nightshades refer to a plant called belladonna, which was actually used as a poison in ancient times. The nightshades we are referring to in terms of diet are the commonly eaten vegetables in the same nightshade family. They are certainly not deadly, however they do contain enough toxins to cause inflammation in certain people, especially those with autoimmune disease. The nightshade vegetables I am referring to here are:

  • Tomatoes
  • Tomatillos
  • Potatoes (not including sweet potatoes)
  • Eggplants
  • Peppers (bell peppers, banana peppers, chili peppers, etc.)
  • Red pepper seasonings (paprika, chili powder, cayenne, curry, etc.)
  • Pimentos
  • Pepinos
  • Tamarillos
  • Goji berries
  • Ground Cherries (these are similar to tomatoes and have no relationship to fruit cherries)
  • Ashwagandha (an ayurvedic herb)
  • Tobacco
  • Read labels: terms like “spices” and “natural flavors” often contain the above seasonings, and “starch” often comes from potatoes.

Similar sounding foods that are NOT nightshades:

  • Sweet Potatoes
  • Peppercorns (black, white and pink)

How Are They Harmful?

These vegetables are all part of the same Solanaceae family which contain toxic compounds called alkaloids. The purpose of these toxic alkaloids is to protect the plants in nature against insects. These alkaloids poison the insect and dissolve its cell membranes. Unfortunately, alkaloids *can* have a similar effect in humans, increasing inflammation, over-activating the immune system and causing intestinal impermeability - also known as leaky gut.

If you are perfectly healthy with low inflammation in the body, and you have a balanced immune system, and a strong digestive tract, you can eat nightshade vegetables without a problem. But for anyone with a compromised immune system or digestive issues, nightshades may cause some or many of the following symptoms:

  • Joint pain
  • Stiffness upon waking, or stiffness after sitting for longs periods of time
  • Muscle pain and tension
  • Muscle tremors
  • Sensitivity to weather changes
  • Poor healing of wounds
  • Insomnia
  • Skin rashes
  • Heartburn
  • Stomach discomfort
  • Digestive difficulties
  • Headaches
  • Mood swings
  • Depression

There is only is only one way to eliminate nightshades from your diet for a minimum of 30 days. The key with an elimination diet is that you cannot cheat even once. If you do, you will not have accurate information at the end of the 30 days in order to make your determination.

Once the 30 day period is up, reintroduce the nightshades one at a time into your diet as a test. Eat them at least 3 times over a 2-day period. Then, stop again and monitor your symptoms for the next 3 days. (Basically your "test" period is 6 days after the 30 day elimination).

Did you improve during the 30 days? Did you have a negative reaction when you ate them again?  If yes, you’re nightshade-sensitive. If no, you are not. It is a fairly straightforward and simple test.

The key principle behind why elimination diets work as learning mechanisms is because when you remove a certain food or group of foods from your body you are eliminating the chronic inflammatory response. When the food is reintroduced, if you’re sensitive, you will get an acute short-term reaction. It’s a very clear communication from your body on what foods are good for you and what foods are not.

Scientifically at this point in time there are no peer-reviewed studies to support the nightshade-inflammation connection due to lack of funding for research in an area the stands to make no profit. But at the end of the day, when you test the effect that nightshades have on you as an individual you will have very powerful and convincing evidence for yourself on how to eat in a way that brings you your best health.