Study: Nightshade consumption related to loss of natural immunity
It is important when eating for optimal health to base your diet on foods from your own climate, or one that is similar to yours. Therefore, if you live in the temperate zones, eating tropical fruits and vegetables results in imbalance.
The regular consumption of tomatoes, potatoes, eggplants, and other solanaceous plants that originated in South America or other tropical regions of the world is believed to be a contributing factor in the loss of natural immunity in temperate climates and may lead to a wide range of sicknesses ranging from colds and flu to skin rashes and itches, loss of sexual vitality, polio, and others. Dr. Norman Childers, a professor of horticulture at Cook College in New Jersey who has worked with solanaceous plants all his life, reported that regular consumption of tomatoes, potatoes, and eggplants is a primary cause of arthritis. He noted that in arthritic patients symptoms of this potentially crippling disease go away usually in a period of several weeks to several months when they stop eating these foods.
Source: Norman Childers, The Nightshades and Health, N.J.: Horticulture Publications, 1977.