Nightshades, Inflammation & PCOS - PCOS Diva
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Nightshades, Inflammation & PCOS

By Amy Medling, founder of PCOS Diva

You may have heard about celebrities and professional athletes who avoid nightshades. Have you ever wondered why?

As it turns out, nightshades may aggravate inflammation, leaky gut and autoimmune diseases. Since women with PCOS are prone to these things, should you avoid nightshades too?

It depends upon your sensitivity to them. For many people, nightshades are not a problem. Those with a sensitivity should proceed with caution. Here’s the scoop:

What is a nightshade?

Nightshades are a group of about 2,500 plants (including fruits). Some people have a sensitivity to them, and when consumed may cause diarrhea, gas, bloating, nausea, heartburn, painful joints, irritable bowel disorders, headaches, gastrointestinal issues, heartburn, and depression.

Nightshades include:

  • tomatoes
  • potatoes
  • eggplant
  • goji berries, garden huckleberries, some types of blueberries and gooseberries
  • peppers (all varieties such as bell pepper, wax pepper, green & red peppers, chili peppers, cayenne, paprika, etc.- anything that contains “pepper” in the name)
  • tomatillos

What makes nightshades problematic?

Nightshades contain glycoalkaloids (the plants’ natural defence against insects, animals, and fungi which act as a form of active pesticide/fungicide) and alkaloids. Both of these produce irritations in your GI system and can worsen leaky gut (for a complete explanation of leaky gut, read “Leaky Gut and PCOS”). The result can seriously impact your immune system and hormone balance, and stimulate systemic inflammation.

The worst offender is the potato. A hallmark of many westerners’ diets, potatoes have been shown in lab rats to increase permeability of the colon, which allows undigested proteins and toxins in to the blood stream (leaky gut). The study showed that the higher the glycoalkaloid level, the more intense the inflammatory response. Glycoalkaoids remain stable in potatoes which have been boiled, frozen or dehydrated and the more you consume, the more the inflammation response ramps up in your body.

How can you avoid nightshades’ effects?

If you are sensitive to nightshades, avoid them. If you are unsure, consider a 30-day elimination diet and see if you experience a change in your inflammation levels. Watch out for potato starch as a filler or thickener in products (including medications and baking powders).

To be on the safe-side, avoid green tomatoes and potatoes or potatoes that are sprouting. Peel your potatoes and cook all nightshades (though this will minimally reduce the effects).

The potential benefits of nightshades are far outweighed by the increased inflammation they cause for those sensitive to them. Women with PCOS should be particularly aware of their effect since inflammation is the root of our symptoms. Consider eliminating nightshades and monitor your results. You might be surprised!


Amy Medling, author of Healing PCOS and certified health coach, specializes in working with women with Polycystic Ovary Syndrome (PCOS), who are frustrated and have lost all hope when the only solution their doctors offer is to lose weight, take a pill, and live with their symptoms. In response, Amy founded PCOS Diva and developed a proven protocol of supplements, diet, and lifestyle programs that offer women tools to help gain control of their PCOS and regain their fertility, femininity, health, and happiness.  



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