These Foods Make Arthritis and Inflammation Worse

In a recent study published in the Arab Journal of Nuclear Science and Applications, scientists investigated whether or not nightshades — like potato, tomato, pepper, and eggplant — can make swollen and sore joints worse.1

Other members of the nightshade family — like potato, tomato, and pepper — contain small amounts of the alkaloid nicotine.

Their research subjects were rats that had already gone through menopause, meaning that they had low levels of circulating estrogen.

All the rats also had rheumatoid arthritis — an autoimmune condition where the immune system attacks the joints, making them inflamed and tender.


Stiff joints can be an early sign of nightshade sensitivity. If you’re avoiding nightshades, try a warming herb like wasabi instead, found in Body Ecology’s LivAmend and known to cleanse the liver.

In the study, a diet that contained large amounts of green potatoes — which are particularly rich in toxins — increased swelling and pain in the joints. The study concluded that it is essential to “eliminate or avoid the nightshade plants to alleviate the joint pain and also decrease the destruction of the tissues.”

This is not the first time that nightshades have been held responsible for joint pain.

What Are Nightshades?

Nightshades are a family of flowering plants. The botanical name for this family is Solanaceae, which may come from the Latin verb “to soothe.”

While members of the nightshade family are notoriously toxic, in small doses these toxins can soothe pain. In larger doses, these toxins overwhelm the body and attack the nervous system — leading to signs of physical distress, such as intestinal pain and arthritis.2

Common members of the nightshade family include:

  • Potato
  • Tomato
  • Eggplant
  • Chili peppers, including the spice paprika
  • Bell peppers
  • Tomatillo
  • Gooseberry
  • Goji berry, or the Chinese herb Lycium

On the initial therapeutic version of The Body Ecology Diet, we do not recommend tomatoes, eggplant, or green bell pepper. You can expand this list to include all nightshades if you find that your nervous system and your digestive system are hypersensitive.

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What Makes Nightshades Toxic

Most nightshades contain high levels of alkaloids that profoundly affect the body’s chemistry.

For example, tobacco is a member of the nightshade family, and it contains light levels of nicotine. Nicotine is a neurotoxin. Nicotine also stimulates the nervous system, making it addictive to smokers. Other members of the nightshade family — like potato, tomato, and pepper — contain small amounts of the alkaloid nicotine.

Solanine is another alkaloid toxin that you will find in leaves, fruit, and roots of nightshade plants, like potato and tomato. Signs of solanine poisoning include digestive disorders and neurological disorders, such as:

  • Diarrhea
  • Vomiting
  • Abdominal pain
  • Cramping
  • Headache
  • Dizziness
  • Hallucinations

While high amounts of solanine in the body can have a dramatic affect, small amounts are less noticeable — and solanine may only become an issue if your immune system is out of balance. Sometimes, stiff joints are the only sign of nightshade sensitivity.3,4

Potatoes naturally produce solanine, most of which is found in or just beneath the skin of the potato. Solanine is produced in response to stress as a defense mechanism — against insects and predators, when the plant or potato is damaged, or during exposure to light.5 When potatoes are exposed to light, they turn green and increase the production of solanine.

This means that green potatoes and sprouted potatoes contain more solanine and that they are poisonous. A bitter taste is also a sign of high levels of solanine. Always discard green or sprouted potatoes.

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Arthritis and Nightshades: Are You Sensitive?

The best way to figure out whether or not you are sensitive to members of the nightshade family is to remove them from your diet completely for several weeks. Then reintroduce nightshades.

We recommend being bold in your reintroduction — enjoy your Body Ecology-friendly nightshades for breakfast, lunch, and dinner. Observe how your body feels over the following 48 hours. If you find that you have more joint pain than usual, you may want to consider removing nightshades from your diet completely.

While you may miss some of your favorite dishes, there are many foods that you can use to replace nightshades, making the transition to a nightshade-free diet that much easier.

For example, black pepper and other peppercorns do not belong to the nightshade family. This means that freshly cracked pepper can heat up your dish — without heating up your joints. In fact, research has found that black pepper can relieve intestinal distress, and in Chinese medicine, black pepper is used therapeutically for this purpose.6,7

In addition to black pepper, other warming herbs include:

  • Wasabi: A hot and pungent Japanese condiment that will clear your sinuses and cleanse your liver.
  • Horseradish: A spicy root that belongs to the same botanical family as wasabi. Often used as a condiment with roast beef.
  • Ginger: Another root that is used in cuisines around the world. Many people enjoy ginger as a tea to relieve digestive discomfort and reduce morning sickness.

Eat better, feel better, and address underlying health issues. Here’s what The Body Ecology Diet is all about.

You can experiment with cauliflower as a replacement for potatoes. Cauliflower is a cruciferous vegetable that develops a velvety texture when pureed. This makes it the perfect addition to creamy, hearty soups. You can also try out our recipe for mashed cauliflower to substitute for mashed potatoes.

What To Remember Most About This Article:

A recent study linked nightshade plants with joint pain and tissue destruction in sufferers of rheumatoid arthritis. Nightshades include tomato, potato, eggplant, bell pepper, gooseberry, and tomatillo and may be toxic in large doses.

Initially, The Body Ecology Diet recommends avoiding tomato, eggplant, and green bell pepper, especially if your digestive and nervous systems are highly sensitive. Nightshades contain high levels of alkaloids that can cause symptoms like diarrhea, abdominal pain, and headaches in large amounts.

If you suspect that you’re sensitive to nightshades, start by cutting them out of your diet for several weeks. From there, reintroduce nightshades at every meal to see how your body responds within 48 hours. If joint pain flares up again, it may be time to kiss nightshades goodbye for good.

The good news is that there are a number of replacements for nightshades in your diet. For example, mashed cauliflower is a healthy, delicious twist on the old favorite of mashed potatoes, made with a cruciferous vegetable that is rich in antioxidants.


  1. Ayad, S. K. (2013). Effect of Solanine on Arthritis Symptoms in Postmenopausal Female Albino Rats. Arab Journal of Nuclear Science and Applications, 46(3), 279-285.
  2. Jain, R., Sharma, A., Gupta, S., Sarethy, I. P., & Gabrani, R. (2011). Solanum nigrum: current perspectives on therapeutic properties. Altern Med Rev, 16(1), 78-85.
  3. Friedman, M., McDonald, G. M., & Filadelfi-Keszi, M. (1997). Potato glycoalkaloids: chemistry, analysis, safety, and plant physiology. Critical Reviews in Plant Sciences, 16(1), 55-132.
  4. Robertson, P., & Roberts, P. (2003). The Solanaceae and their paradoxical effects on arthritis and other degenerative disease states. Australian Journal of Medical Herbalism, 15(4), 114.
  5. Lachman, J., Hamouz, K., Orsák, M., & Pivec, V. (2001). Potato glycoalkaloids and their significance in plant protection and human nutrition-review. Rostlinna Vyroba-UZPI, 47.
  6. Srinivasan, K. (2007). Black pepper and its pungent principle-piperine: a review of diverse physiological effects. Critical reviews in food science and nutrition, 47(8), 735-748.
  7. Huang, K. C. (2010). The pharmacology of Chinese herbs (Vol. 874). CRC press. P 164.
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