Nightshade vegetables can cause inflammation of arthritis. A number of animal studies have shown osteoarthritis in animals that were given nightshade vegetables. Obviously this is not proof that this would affect us in the same way but it is something to consider. Nightshades also contain some nicotine and high doses of nicotine can inhibit wound healing. Hot peppers are the biggest culprit and they certainly cause us pain when we eat them. Tomatoes are also very acidic and can cause a reaction where the stomach contents are pushed back up the esophagus towards the throat with symptoms of heartburn; so anybody with Gastro Esophogal Reflux disease should limit their intake of tomatoes.

Solanine can be fatal in large doses. It is 4 times greater in the skin than in the rest of the potato. Potatoes were traditionally sold unwashed in paper sacks. This protected them from direct sunlight. Today they are washed and packed in plastic bags thus light stimulates the production of solanine. Certainly potatoes that show signs of greening or black spots should be thrown away. For some really useful and detailed information about nightshade vegetables check out Craig Sams article at http://www.trustedhands.com/content/id267.html

Now when somebody says to me that something is forbidden in macrobiotics I have to respond that nothing is absolutely forbidden. Macrobiotics is about learning what you can and cannot eat. So experiment. Try eliminating nightshade vegetables for a month or so from your diet, especially if you have health problems and see how you feel. If you feel better you probably should not eat them. If you do not see any difference eat a lot for the next week or so and see what happens. Especially note any changes in aches and pains when you exercise. Learning to recognize changes in your body when you eat different foods takes time, and many foods such as the nightshade vegetables can be eaten in small quantities with no detrimental effect. Moderation is the key here. It’s better to stay away from nightshades when you are sick and then, as you widen your diet, you can gradually incorporate them, see how you feel and make adjustments accordingly.

What about the Mediterranean diet. They eat lots of tomatoes and they're healthy. Although I don't have the definitive answer to this I do believe that our bodies are acclimatized to the culture and the foods of the part of the world that we live in. The Mediterranean diet in general is a healthy diet and it includes a wide variety of fruits and vegetables as well as healthy fats. We should also keep in mind seasonal eating. Eating tomatoes, peppers and potatoes fresh from the garden in the season that they are grown in may be fine. Unfortunately we are used to eating everything all year round; often when it is picked green and flown in from different parts of the world.

So, if you are sick or have arthritis you should probably stay away from nightshade vegetables. At the very least experiment. If you are healthy you can probably eat some nightshade vegetables without adverse affects. The key is moderation.