Nightshade Plants According to Natural News, there are over 2,800 species of nightshade plants. Nightshades that may cause or exacerbate arthritis belong to the Solanaceae family and include vegetables and fruits such as potatoes, tomatoes, sweet peppers, hot peppers, eggplant, cherries, ground cherries and garden huckleberry. Sweet potatoes, yams, black pepper, white pepper and avocados are among the nightshade foods with no apparent effect on arthritis. According to George Mateljan's website, The World's Healthiest Foods, although they belong to the same plant order as nightshades, they belong to different plant families. Why They May Cause Harm Nightshade plants contain alkaloids; the lowest concentration is in nightshades consumed as foods (fruits and vegetables), with higher levels found in other nightshade plants. Most people can eat nightshade vegetables without experiencing problems, and cooking reduces their already low alkaloid content. This contributes to the assumption that the harmful effects experienced by people who consume these foods stem from alkaloid sensitivity and not an allergic reaction to alkaloids, as stated on Tahoma Clinic's website in the article, "Degenerative Arthritis," by Jonathan V. Wright, M.D. Alkaloids and Arthritis Alkaloids are nitrogen compounds. Some alkaloids are known poisons, while others have medicinal uses--for example, nicotine, quinine, cocaine, and morphine. According to George Mateljan, researchers theorize that the steroid alkaloids found in nightshades leech calcium from bones and cause joint inflammation. This leads to the recommendation that people suffering from arthritis, gout and other degenerative joint diseases eliminate nightshades from their diets to determine if there is a causal relationship between these food items and their illnesses. Research According to the University of Washington website, "Diet and Arthritis," July 6, 2006, no positive proof exists that certain foods cause or worsen arthritis. They acknowledge that, although information linking nightshade plants to arthritis is available, the relationship remains unproven. In his article, "Degenerative Arthritis," Jonathan V. Wright, M.D., states that laboratory testing cannot verify the association between nightshades and arthritis because the problem stems from sensitivity to alkaloids and not an allergic reaction. Dr. Wright also states that it can take 3 to 4 months before you feel the benefits of eliminating nightshades from your diet. Conclusion Do not experiment with your diet without consulting your health care provider. Eliminating foods normally consumed causes depletion of needed vitamins and minerals and the possible onset of associated health problems. Based upon your current health status, your doctor will advise you of any negative effects that may result from eliminating nightshade foods from your meals.