I have heard rumours for decades that nightshades may be bad for my psoriasis. I have always been willing to experiment with different foods, including those that may help my skin or excluding those that may aggravate it. Somehow I never did experiment with nightshades, possibly because the stories that I heard were just rumours and never backed up by personal experience from any of my friends who had the same health problems.
Most people have either never heard the word nightshade or have heard it but don't have any idea what it means. Nightshades are not the dinky little eye covers that long distance airlines give to their passengers on overnight flights. Nightshades are plants that fall into a group of 2800 different species in the scientific order Polemoniales. They include some fruits and vegetables that one never thinks could be related in any way, yet they all have some common characteristics. Primarily, they are all related to the tobacco family and all contain varying amounts of nicotine and other alkaloids.
Maybe you don't smoke because you know that nicotine is very bad for your health. Yet you are almost certainly unknowingly consuming nicotine every day in what you eat because of nightshades.
As for the other alkaloids, these are components of nightshades that vary widely in content in these plants but are the reason why all nightshades are considered to be drugs. Alkaloids can have bad effects on nerve-muscle function as well as the digestive system and joints of all animals that consume them. The amount of alkaloids in food are very small, so most humans are not affected. However, people who are sensitive to alkaloids may have very bad effects. Autoimmune diseases are generally rooted in the digestive system, so any food that can deteriorate the digestive system is likely to cause problems.
So, what vegetables are we taking about here, as nightshades? The most common ones are all types of tomatoes, potatoes (normal and sweet varieties), eggplant and all varieties of peppers, from sweet to chili and cayenne species. I have found over the years that tomatoes give me bad reactions with both psoriasis and arthritis but I have still eaten them because of the good effects of lycopene. One of my favourite dishes is an Afrikaner dish that I have cooked regularly in winter. It is a red meat, tomato and potato stew over rice. I always showed a deterioration the following day or two but this stuff is so good that I lived with the after-effects of a well-loved meal. Red meat plus two nightshades over rice, that is a big mix of bad ingredients for someone with psoriatic arthritis. In future I will keep that for the occasional treat instead of cooking it weekly in winter.
At my weekly surf club meetings many chili peppers are consumed by my friends. I have tried them a couple of times and found that the following day or two my skin breaks out a bit. I had read somewhere that some people consider them to be good for arthritis, so I tried two one evening just to see if they affected my arthritis. They did and not for the better, so I decided to leave them out of my diet.
Lets go back to the bad stuff in nightshades. The alkaloids can block the signals that go back and forth between the nervous system and the muscles. The nervous system is the network via which the brain controls the whole body, so blocked or intermittent signals can cause big problems. These include muscle twitching, trembling, paralyzed breathing and convulsions. They also cause inflammation in the joints and arthritis problems are the result of inflammation.
Follow this link to an excellent article on nightshades and their effects on arthritis.
It is only about 3 weeks since I stopped eating nightshades, so I am still testing the results. Last week I did a surfing/sailing/camping trip for 4 days. I slept on an uncomfortable folding bed and abused my body with long hours of surfing and sailing (3 hours of surfing and 4 hours of dinghy sailing in one day alone). I had not the slightest hint of arthritis pain in those 4 days. Consider that I am no spring chicken, I turned 64 last month.
As I have said elsewhere on this blog, I follow many strategies to help my psoriasis and arthritis. Overall they work. Some will be helping more than others but it can be difficult to sort the good from the really good. Leaving nightshades out of my diet is looking very promising to become one of the best decisions to improve my health and well-being.