Skip to main content
The Globe and Mail
Support Quality Journalism
The Globe and Mail
First Access to Latest
Investment News
Collection of curated
e-books and guides
Inform your decisions via
Globe Investor Tools
per week
for first 24 weeks

Enjoy unlimited digital access
Enjoy Unlimited Digital Access
Get full access to
Just $1.99 per week for the first 24 weeks
Just $1.99 per week for the first 24 weeks
var select={root:".js-sub-pencil",control:".js-sub-pencil-control",open:"o-sub-pencil--open",closed:"o-sub-pencil--closed"},dom={},allowExpand=!0;function pencilInit(o){var e=arguments.length>1&&void 0!==arguments[1]&&arguments[1];select.root=o,dom.root=document.querySelector(select.root),dom.root&&(dom.control=document.querySelector(select.control),dom.control.addEventListener("click",onToggleClicked),setPanelState(e),window.addEventListener("scroll",onWindowScroll),dom.root.removeAttribute("hidden"))}function isPanelOpen(){return dom.root.classList.contains(}function setPanelState(o){dom.root.classList[o?"add":"remove"](,dom.root.classList[o?"remove":"add"](select.closed),dom.control.setAttribute("aria-expanded",o)}function onToggleClicked(){var l=!isPanelOpen();setPanelState(l)}function onWindowScroll(){window.requestAnimationFrame(function() {var l=isPanelOpen(),n=0===(document.body.scrollTop||document.documentElement.scrollTop);n||l||!allowExpand?n&&l&&(allowExpand=!0,setPanelState(!1)):(allowExpand=!1,setPanelState(!0))});}pencilInit(".js-sub-pencil",!1); // via darwin-bg var slideIndex = 0; carousel(); function carousel() { var i; var x = document.getElementsByClassName("subs_valueprop"); for (i = 0; i < x.length; i++) { x[i].style.display = "none"; } slideIndex++; if (slideIndex> x.length) { slideIndex = 1; } x[slideIndex - 1].style.display = "block"; setTimeout(carousel, 2500); }

Q: I’ve heard that I shouldn’t eat nightshade vegetables to keep my rheumatoid arthritis from flaring up. Which ones are considered nightshades? Will avoiding them help?

Nightshade vegetables have long gotten a bad rap for aggravating chronic health problems, including arthritis. It’s said that eating these foods can cause joint swelling, pain and stiffness.

Nightshade vegetables (and fruits) belong to the Solanaceae plant family which contains roughly 2,700 species, most of them inedible. The edible ones include bell peppers, chili peppers, eggplant, tomatoes, tomatillos and potatoes.

Story continues below advertisement

But before you discard these nutritious foods from your diet, here’s what you need to know.

Seven water-packed foods to increase hydration

The best locally grown foods from coast to coast to coast

Five underrated vegetables to add to your diet

Do nightshades inflame?

The concern with nightshades revolves around alkaloids, naturally-occurring compounds in the leaves and stems that act as natural insect repellents. Alkaloids include solanine (found in potatoes, especially ones that have turned green), capsaicin (the chemical that gives chili peppers their heat) and nicotine.

The theory goes that alkaloids in nightshade vegetables promote inflammation and worsen symptoms in people with autoimmune inflammatory disorders such as rheumatoid arthritis, psoriasis and inflammatory bowel disease (e.g., ulcerative colitis, Crohn’s disease).

Yet, there is no scientific evidence to prove, or even strongly suggest, that eating nightshade vegetables has a direct impact on arthritis symptoms. The research is lacking.

The idea that nightshades inflame joints comes from surveys of people who have arthritis and patient testimonials.

What’s more, the amount of alkaloids in edible nightshades is very low to begin with. (The exception is green potatoes; when exposed to light, potatoes produce solanine as well as the green pigment chlorophyll.)

As well, cooking further reduces the alkaloid content of nightshade vegetables.

Story continues below advertisement

Still, it is possible that some people are affected by nightshades. Studies in mice, while limited, have suggested a link between alkaloids and inflammation.

In mice with inflammatory bowel disease, alkaloids were found to increase intestinal permeability, or leaky gut, as well as inflammation. Increased intestinal permeability means that bacteria could seep through the intestinal lining and enter the bloodstream, triggering inflammation.

How to know if you’re sensitive

If you think that eating nightshade vegetables exacerbates your arthritis symptoms, eliminate them from your diet for four weeks. Keep a diary to track your food intake along with changes in the frequency and severity of symptoms.

After one month, add these foods back to your diet. If doing so increases your symptoms, you may be sensitive to nightshades. Consider other factors, too, which can make rheumatoid arthritis worse such as stress and fatigue.

Anti-inflammatory nutrients in nightshades

Nightshade vegetables are excellent sources of nutrients that help to dampen inflammation in the body, including fibre, vitamin C and beta-carotene. If you decide to avoid nightshades, replace them with other foods that supply these nutrients.

Sweet bell peppers, for example, are outstanding sources of vitamin C. Others include strawberries, kiwifruit, cantaloupe, citrus fruit, Brussels sprouts, broccoli, cabbage and cauliflower.

Story continues below advertisement

Switch white potatoes for sweet potatoes, butternut squash or carrots, vegetables high in fibre and beta-carotene. Leafy greens such as spinach, kale, Swiss chard and dandelion greens are also excellent sources of beta-carotene.

And, similar to white potatoes, these vegetables deliver plenty of potassium, a mineral that helps to regulate blood pressure, nerve impulses and muscle contractions.

Eggplant is loaded with anthocyanins, a potent anti-inflammatory phytochemical. You’ll also find anthocyanins in blueberries, blackberries, strawberries, red grapes and beets.

Tomatoes, rich in vitamin C, are one of the top food sources of lycopene, a phytochemical with strong antioxidant and anti-inflammatory properties. Pink grapefruit and watermelon supply decent amounts, too.

Instead of tomato sauce, toss pasta with pesto sauce made with basil or parsley, herbs packed with anti-inflammatory compounds.

Diet advice for arthritis

There is no definitive anti-arthritis diet, but research suggests that an overall anti-inflammatory diet can help to ease symptoms. It has also been shown to reduce the risk of developing rheumatoid arthritis in the first place.

Story continues below advertisement

Eat oily fish such as salmon, trout and sardines, rich in anti-inflammatory omega-3 fats, at least twice a week. Consider taking a fish-oil supplement if you don’t like fish.

Emphasize anti-inflammatory monounsaturated fats in your diet, such as extra virgin olive oil, avocado, almonds, almond butter, peanuts, peanut butter and pecans.

Eat more meals based around beans, lentils, tofu and edamame, to help reduce red meat intake and increase fibre intake.

Include fibre-rich whole grains in your daily diet. Oats, freekeh, quinoa, brown rice, de-hulled barley, spelt berries, wheat berries and 100-per-cent whole grain pastas are good choices.

Eat a variety of colourful vegetables and fruits to consume a wide range of anti-inflammatory nutrients and phytochemicals.

Flavour your meals with anti-inflammatory herbs and spices such as rosemary, mint, ginger and turmeric.

Story continues below advertisement

Leslie Beck, a Toronto-based private practice dietitian, is director of food and nutrition at Medcan.

Live your best. We have a daily Life & Arts newsletter, providing you with our latest stories on health, travel, food and culture. Sign up today.

Follow related topics

Report an error Editorial code of conduct
Due to technical reasons, we have temporarily removed commenting from our articles. We hope to have this fixed soon. Thank you for your patience. If you are looking to give feedback on our new site, please send it along to If you want to write a letter to the editor, please forward to

Welcome to The Globe and Mail’s comment community. This is a space where subscribers can engage with each other and Globe staff. Non-subscribers can read and sort comments but will not be able to engage with them in any way. Click here to subscribe.

If you would like to write a letter to the editor, please forward it to Readers can also interact with The Globe on Facebook and Twitter .

Welcome to The Globe and Mail’s comment community. This is a space where subscribers can engage with each other and Globe staff. Non-subscribers can read and sort comments but will not be able to engage with them in any way. Click here to subscribe.

If you would like to write a letter to the editor, please forward it to Readers can also interact with The Globe on Facebook and Twitter .

Welcome to The Globe and Mail’s comment community. This is a space where subscribers can engage with each other and Globe staff.

We aim to create a safe and valuable space for discussion and debate. That means:

  • Treat others as you wish to be treated
  • Criticize ideas, not people
  • Stay on topic
  • Avoid the use of toxic and offensive language
  • Flag bad behaviour

Comments that violate our community guidelines will be removed.

Read our community guidelines here

Discussion loading ...

To view this site properly, enable cookies in your browser. Read our privacy policy to learn more.
How to enable cookies