Nightshades are a diverse group of foods, herbs, shrubs, and trees.

Most of the health research on nightshades has focused on a special group of substances found in all nightshades called alkaloids. 

Effect of steroid alkaloids on joint health

A second type of problem potentially related to the potato alkaloids involves damage to the joints caused by inflammation and altered mineral status. Whether alkaloids can contribute to joint damage of this kind is not clear from current levels of research. Some researchers have speculated that nightshade alkaloids can contribute to excessive loss of calcium from bone and excessive depositing of calcium in soft tissue. For this reason, these researchers have recommended elimination of nightshade foods from the meal plans of all individuals with osteoarthritis, rheumatoid arthritis, or other joint problems like gout.

Potatoes, tomatoes, sweet and hot peppers, Aubergine,  pimentos, paprika, and cayenne peppers, goji berries, shellac wax are classified as nightshade foods. A particular group of substances in these foods, called alkaloids, can impact nerve-muscle function and digestive function in animals and humans, and may also be able to compromise joint function. Because the amount of alkaloids is very low in nightshade foods when compared with other nightshade plants, health problems from nightshade foods may only occur in individuals who are especially sensitive to these alkaloid substances. Since cooking only lowers alkaloid content of nightshade foods by about 40-50%, highly sensitive individuals may want to avoid this category of food altogether, while non-sensitive individuals may be able to eat these foods, especially in cooked form, without problem. Green and sprouted spots on potatoes usually reflect high alkaloid content, even though the green itself involves the presence of chlorophyll, not alkaloids. For this reason, sprouted areas should always be thoroughly removed before potato cooking, or the potatoes should be discarded altogether.

NOT Nightshades:
Black Pepper
White Pepper
Green Peppercorns (not bell pepper)

Nightshade family

Potatoes
Tomatoes
Sweet Peppers
Hot peppers
Aubergine
Pimentos
Paprika
Cayenne Pepper
Goji berries
Shellac wax

You can have : Black Peeper, Green pepper and white pepper.

Avoid foods and fluids you are allergic or intolerant to.