What are Nightshades?

Disclaimer: I am not an expert, just someone trying to make life easier for the ones she loves. If you suspect you have food allergies, talk to your doctor.

What are Nightshades? 

Nightshades are plants that, while they may seem unrelated, are actually all part of the family Solanaceae, consisting mainly of ‘New World’ plants.

Potatoes, tomatoes, peppers, tobacco, and eggplant are the most common offenders. It is believed that the irritant in Nightshades is an alkaloid called solanine.

Like all food allergies, if you are not actually intolerant or allergic to nightshades, and you find that cutting them out makes no improvement to your symptoms, it is safe to resume eating them. They have many health benefits, and these particular nightshade plants are not toxic to most people.

What foods should I avoid?

The main offenders are any type of potatoes, peppers (red, yellow, green, paprika, chilli, any and all spicy peppers), and tomatoes, with the notable exception of peppercorns (black and white), and sweet potatoes or yams. An extensive list can be found here and another one here.

If solanine is the main irritant for you, other foods that contain solanine (but are not nightshades) are: apples, blueberries, strawberries, huckleberries, goji berries, okra, cherries, artichokes. I do include these ingredients in many of my recipes, as they only contain trace amounts. Someone who is very very sensitive (like Mr. Nomato) may have issues with them, but not everyone who is allergic to nightshades will.

In my experience, the biggest culprits are processed foods, especially the less obvious ones. I end up making most of my food from scratch because of this. These are my personal red flags:

“Food Starch”, “Vegetable Starch”, “Potato Starch”, or “Modified Vegetable Starch” – these are very often from potatoes if they don’t explicitly say corn starch.
Examples: broths, bread, pre-shredded cheeses.

“Natural and/or Artificial Flavour and/or Colour” – you’ll have to use your own discretion on this one since it’s on almost every label. Chances are if it’s savoury and red, yellow or orange in colour, they use paprika.
Examples: mayonnaise, orange cheese or mustard all contain paprika, while those donuts are probably safe.

“Spices” – spices don’t necessarily mean ‘spicy’, but sometimes you can’t take the risk. If you contact the company, they will be able to tell you whether they contain nightshades or not.
Examples: a pre-packaged bag of sweet potato fries. So close!

Vague Ingredients – anything where they try to include a combination of foods under a broad banner word.
Example, ‘vegetable broth’ on your bag of pre-cooked chicken. Unless it states what is exactly in the broth, it’s best not to risk it.


How do I know if I have a nightshade intolerance?

The best way to really find out any unknown food allergy is to do an elimination diet in consultation with your doctor. It is also very helpful to keep a careful food diary even before you go to see your doctor, and write down what you eat and when you are sick.

The traditional elimination diet does not leave nightshades out of your starting point, encouraging you to eat things like potatoes, so just be aware that if you are ill in that first week and suspect nightshades, this could be why.

If you believe you may have a nightshade intolerance, it is recommended that you cut them out for about 30 days and see if you notice a difference (for us it was immediately noticeable). Nightshades tend to hide in many foods, so make sure you are very strict about reading labels.

Some of the most common symptoms include:
Irritable Bowel Syndrome
Can contribute to, or worsen, leaky gut
Arthritis pain or stiffness
Migraine headaches
Intestinal distress and cramping
Depression or mood swings

Sometimes Nightshade Allergies are found in conjunction with other allergies, so if cutting them out alleviates some, but does not explain, all of your symptoms, chances are you have an allergy to something else as well.

Is there any scientific evidence to support nightshade allergies?

There are still few studies about nightshade intolerance. As soon as I heard about it, I hit the net, and let me tell you there’s not much out there in the way of solid science. Most of the ‘research’ is purely anecdotal or too unproven for me, and next to no studies have been done to test exactly what is going on. Anecdotally, in our house, Mr. Nomato noticed an almost immediate improvement once we removed them from his diet.

So here is my vow to you. I will continue to research, and any credible, peer-reviewed, publicly available science articles I find will be posted here.

1) An Apparent Relation of Nightshades (Solanaceae) to Arthritis by Dr. Norman F. Childers, Ph.D., and M.S. Margoles, M.D.

 2) Potato glycoalkaloids adversely affect intestinal permeability and aggravate inflammatory bowel disease by Patel, B. et al. 

3) Potato tuber proteins efficiently inhibit human faecal proteolytic activity: implications for treatment of peri-anal dermatitis by Ruseler-van Embden, JG. et al. 


Where can I find more information about nightshade allergies?

This is a list of some of my favourite websites and resources. I will be adding more as I find them.

Diagnosis: Diet 
A blog run by a doctor who studies the effects of nutrition on health

The Arthritis Nightshades Research Foundation 
A website dedicated to the work of Dr. Norman F. Childers and the connection between nightshades and arthritis. His research can be found here.

Jane’s Healthy Kitchen 
A Paleo Diet blog that is a gold mine for nightshade free recipes. This links directly to the nightshade portion.

Nightshade Free Survival Guide 
A Paleo Diet blog that discusses how Nightshades affect those with autoimmune disease.


Where can I find more information for allergies in general?

Your doctor should always be the first step in any allergy related questions! That being said, here are some helpful links!

Healthline’s Best Allergy Food Blogs of 2015
The best allergy-centric blogs according to Healthline