Nightshades: Are Your Favorite Foods Your Worst Enemies?

Nightshades: Are Your Favorite Foods Your Worst Enemies?

Tomatoes are part of the nightshade family. The fruit was once considered poisonous by many Europeans.

Some of your favorite foods may be causing you pain.  Even worse, they may be contributing to a host of diseases and disorders, from arthritis and heart disease to cancer and Alzheimer’s.

The foods in question are part of an ancient and diverse family of edible, ornamental and medicinal plants known as nightshades.  Formally known as Solonaceae, each member of the nightshade family has very different characteristics and uses.

Tomatoes and potatoes are nightshades – and everyday staples of diets around the world. Tobacco, another nightshade, has a long and controversial history. Belladonna and mandrake are also deadly, but have valuable medicinal potential.  Morning glory, butterfly flower, and petunias offer beauty.  And like a witty-tongued relative, peppers of all kinds put a zing in cuisine, with paprika and cayenne making foods spicy and colorful.

All 3,000 plus species of nightshade plants contain the alkaloid solanine. It’s the edible side of the nightshade family that causes controversy, due to the effects solanine may have on the human body.

History of Nightshades

Nightshade plants have such distinct effects on people that they are part of both historical and popular literature.  Mandrakes are specifically named in the Old Testament, in Genesis and the Song of Soloman. They’re also included in four of Shakespeare’s plays, and have a role in the magic potions of Harry Potter in The Chamber of Secrets. The Romans used them to poison enemies, and many believe this is how they earned their name; once consumed certain nightshades brought death, the “shade of night.”

Eggplants have high levels of alkaloids. Some arthritis sufferers believe eating eggplant increases their pain.

Of course, not all nightshades are deadly.  Tomatoes, potatoes and peppers are everyday foods for millions of people.  From marinara and ketchup, to mashed potatoes and French fries, nightshade vegetables are not just comfort foods. They’re important economically, serving as agricultural crops that provide jobs, income, and food.

The plants themselves have a very practical reason for producing the alkaloid solanine.  Acting as a natural pesticide, the alkaloids in nightshade plants protect them from insects and herbivores looking for a good meal.  Ranchers and farmers have long known that jimson weed and stink weed — both members of the nightshade family — cause illness and even death in their livestock. Pastures are routinely kept free of these weeds so their animals don’t eat them.

Nightshades and Human Health

The question is, if nightshades have this effect on animals, what affect might they have on people?

Some who suffer from arthritis say their symptoms disappear when they abstain from eating tomatoes, potatoes and eggplant.  Books, foundations, and websites offer testimonies declaring that nightshade vegetables trigger pain and are responsible for other ailments.  Many personally claim that eliminating these foods brings relief and healing.

In the 1950’s Norman F. Childers, PhD, wrote an account of his experience with nightshades.

“Around my early 50’s I began to experience achy, hurting knee and ankle joints and wondered if the problem was being caused by potato and eggplant, so I stopped eating them. The problem disappeared. Secretaries on the Rutgers campus began avoiding these foods and tobacco. Their pains also disappeared,” Childers noted.

Fascinated with his findings and convinced that nightshade vegetables were to blame for a wide array of health problems, Childers wrote books and eventually established The Arthritis Nightshades Research Foundation.  He lived a healthy, vital life well into his 90’s.

Personal testimony aside, no firm scientific evidence exists that nightshade foods affect the nervous system or the joints. In fact, researchers recently found that nightshade vegetables can actually benefit those who suffer from some health problems.

A study in the Journal of Nutrition demonstrated that both yellow and purple potatoes reduced blood markers for inflammation in healthy men. Another study by the Johnston County Osteoarthritis Project in North Carolina, published in the journal Public Health Nutrition, found that people with the highest serum levels of lutein, the antioxidant in tomatoes, were 70 percent less likely to have Osteoarthritis.

While individuals, foundations, and medical establishments disagree about whether or not nightshades cause pain and disease, the answer may lie somewhere in between fact and personal testimony.  While all nightshade vegetables contain alkaloids, some contain more alkaloids than others.  Some arthritis sufferers say that after eating one of their favorite meals — eggplant parmesan — they suffer from increased pain.

Alkaloid content can be reduced by cooking nightshades vegetables; 40 to 50 percent of the alkaloid in tomatoes and potatoes is lost upon cooking.

Just as some people are more highly sensitive to allergens, such as pollen, ragweed or shellfish, certain people may be highly sensitive to alkaloids.  They may notice that eating specific nightshade vegetables triggers pain and avoiding them altogether alleviates pain.  However, those who have mild sensitivities may be able to eat these vegetables with no trouble at all. 

Yellow and purple potatoes have high levels of antioxidants. A study found they may also reduce inflammation.

It’s a fact that diet plays a significant role in health, disease prevention, and healing.  Many studies have shown that a Mediterranean diet – which includes fish, poultry, beans, vegetables, and olive oil – helps alleviate pain and gives people an overall sense of well-being. Other studies have shown that vegetarians live longer and healthier lives.

So where do nightshades fit in? Although they’ve been a part of our diet for thousands of years, the cookbook is still open on nightshades and how they affect our health.

Authored by: Loralee Erickson