Nightshades are a diverse group of foods, herbs, shrubs, and trees that have fascinated scientists, doctors, and nutritionists for centuries.
"Nightshade" is actually the common name used to describe over 2,800 species of plants, many with very different properties and constituents. However, all of the plants belong to a scientific order called Polynomials and to a scientific family called Solanaceae. They are actually more famous as drugs than as foods. The best-known nightshades when it comes to pharmacy include mandrake, tobacco, and belladonna.
Nightshade vegetables are potatoes, tomatoes, sweet and hot peppers, eggplant, tomatillos, tamarinds, pepinos, pimentos, paprika, cayenne, and tabasco sauce. The particular groups of substances in these foods are called alkaloids and can impact nerve-muscle function and digestive function in humans and may also be able to compromise joint function. Because the amount of alkaloids is very low in nightshade foods compared with other nightshade plants, health problems from nightshade foods may only occur in individuals who are especially sensitive to these alkaloid substances.
The steroid alkaloids in nightshades have been studied for their health effects in two areas. First is their ability to block the activity of an enzyme in nerve cells called cholinesterase inhibition. If the action of cholinesterase is too strong, the nervous system becomes disrupted, and muscle twitching, trembling, paralyzed breathing, or convulsions can result.
A second problem potentially related involves damage to the joints caused by inflammation and altered mineral status. Some researchers have speculated that nightshade alkaloids can contribute to the excessive loss of calcium from bone and soft tissue. For this reason, it is recommended to eliminate nightshade foods from the meal plans of all individuals with osteoarthritis, rheumatoid arthritis, and joint problems.
If you are an individual with existing joint problems, temporarily eliminate nightshade foods from your meal plan to determine if these foods contribute to your joint problems. The same recommendation would apply to individuals with existing nervous system problems.
