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Are Nightshades the Culprit of Your Arthritis Flare-up?

We all know at least one person who suffers from Rheumatoid Arthritis (RA)- a debilitating disease that causes pain, fatigue, stiffness, and joint damage. If the inflammation progresses, RA can also affect other organs such as the lungs, heart, skin, and eyes. At least one out of every 100 Canadians live with RA, and because there is no known cure (or at least I have not received the good news from my rheumatologist), it’s not surprising that many fad diets promise a quick fix for those who suffer. One of these diet trends is to eliminate nightshade vegetables.

Nightshade plants are a part of the Solanaceae family. They got their name because these plants prefer to grow in the shade. Nightshade plants include commonly consumed fruits, vegetables, and spices such as:

· Cayenne

· Paprika

· Eggplants

· Peppers

· Potatoes

· Tomatoes

Should you fight or flight from nightshades?

Nightshade vegetables naturally produce alkaloids- an organic compound made up of carbon, hydrogen and nitrogen. Solanine is a type of alkaloid that is found in nightshade vegetables, particularly potatoes. It can be toxic if eaten in large amounts but not too worry, solanine is mostly found in the green parts of a plant such as the leaves and stems. The big concern is with eating “green” potatoes. Greening happens when a potato is exposed to light during growth, causing solanine levels to rise, which produces a bitter taste. This is what you need to look out for!

Capsaicin is an alkaloid found in cayenne and paprika, common spices in the Solanaceae family. It is a chilli pepper extract that helps to relieve pain. A study found that dietary capsaicin actually reduced the inflammatory responses in people with obesity, meaning that it has potential usefulness in managing inflammation in inflammatory and autoimmune arthritis.

There is limited research on the effects of solanine and inflammation. Although, two separate studies were conducted on mice to better understand this relationship. One study showed that solanine causes inflammation and the other proved it decreases inflammation.

Nonetheless, more research is needed to decide to cut out nightshade vegetables from your diet. Having a balanced diet that incorporates plant-based protein and fibre is the best route to go in terms of reducing inflammation!

Can nightshades be part of an anti-inflammatory diet?

When you eliminate nightshades from your diet, you are missing out on essential antioxidants with anti-inflammatory components.

Here are a few ideas to incorporate nightshades into your diet, particularly using pantry staples:

Eggplants are rich in fibre. They have a low glycemic index and conta

in the antioxidant, anthocyanin, which reduces inflammation.

Peppers are a good source of vitamin C and lycopene, which are antioxidant that provides anti-inflammatory effects

Potatoes are readily available in Canada and contain high amounts of vitamin C and potassium. Potassium had shown to have anti-inflammatory properties that could reduce pain caused by arthritis. Potatoes are also an important source of vitamin B6, folate and fibre. When potatoes are cooked, cooled, and reheated, the amount of resistant starch increases, which is beneficial for the gut microbiome to help reduce inflammation.

Recipe source:

Tomatoes are high in the antioxidant, lycopene as well as vitamins A and C, which can decrease inflammation. In a recent study, where a concentrated emulsion of lycopene was given to animals with rheumatoid arthritis, potential benefits in reducing inflammation were shown. Although, the bioavailability of consuming foods that have lycopene is between 10 to 30%, its absorption increases when the vegetables are cooked, particularly in tomatoes. Sofrito is a tomato-based sauce, which usually contains olive oil, onions, and garlic. Sofrito is part of the Mediterranean Diet and it has shown anti-inflammatory effects. You can serve sofrito as a side sauce, mix it in rice with beans and put it on top of tacos, fish, or chicken.

Bottom line:

It's important to listen to your body. If you feel that you get a flare-up after consuming nightshades, try to eliminate or reduce the consumption of nightshades for two weeks. Then, introduce one vegetable or spice at a time every couple of days. Keep a journal and write down any new symptoms. Also, think about other external stressors in your life such as changes in weather, physical and mental stress, poor sleep, or high disease activity. Are nightshades the culprit of your arthritis attack?

Disclaimer: All the advice shared here is general information. Consult your Health Care Provider or Registered Dietitian for personalized health information. Compiled April 2020. Revised Aug 2021.

Special thanks to Emily Malfara, a 4th-year nutrition student at Ryerson University who did the research for this post.

Have you applied to the Let's Get Real Anti-inflammatory Nutrition & Lifestyle Program? I would love to hear from you. Let's thrive together!


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