08/01/2016 10:58 AM AEDT | Updated 15/07/2016 12:51 PM AEST

What Are Nightshades And Why Doesn't Gisele Eat Them?

Michael Stewart via Getty Images
NEW YORK, NY - MAY 06: Tom Brady (L) and Gisele Bundchen attend the Costume Institute Gala for the 'PUNK: Chaos to Couture' exhibition at the Metropolitan Museum of Art on May 6, 2013 in New York City. (Photo by Michael Stewart/Getty Images)

It's pretty safe to assume that supermodel Gisele Bundchen's diet doesn't feature McDonalds and donuts on the daily, but her private chef Allen Campbell has revealed exactly what the highest paid model in the world does and doesn't eat.

As she and her husband Tom Brady's personal chef, Campbell is in charge of planning the couple's meals. He spoke to to explain how he selects ingredients -- and which ones he avoids.

Eighty percent of what the couple eat is vegetables, which isn't surprising -- but what might shock some is what is on the banned list.

"[The pair] doesn’t eat nightshades, because they’re not anti-inflammatory. So no tomatoes, peppers, mushrooms, or eggplants. Tomatoes trickle in every now and then, but just maybe once a month. I’m very cautious about tomatoes. They cause inflammation," said Campbell.

Also known as 'solanaceae', edible plants in the nightshade family include white potatoes (though no other colours), paprika, eggplants, tomatoes, capsicums and chillis. There is a huge variety of non-edible nightshades which are toxic to humans. Nightshades contain substances called alkaloids, which can cause inflammation and stress on the body in some people.

While there is no evidence that nightshades are dangerous to healthy people, some people with arthritis or autoimmune disease choose to avoid or limit their intake of these fruit and vegetables. This is largely based on anecdotal evidence.

"Despite the lack of evidence, many people feel that they have adverse effects from consuming this group of plants," Dietitian Laura Ryan told The Huffington Post Australia.

"Symptoms reported can range from diarrhoea, gas, bloating, nausea, painful joints, headaches and depression to name a few. Unfortunately there is no reliable evidence to indicate nightshades are the cause of these reactions."

"It is also worth noting that some of these foods contain large amount of naturally occurring food chemicals (e.g. salicylates, amines, MSG) which may actually be the cause of adverse reactions, not the nightshade component as such. Traditionally people have removed all members of the nightshade family from their diet if they felt this was the cause of their reaction.

"My advice would be that if you are experiencing any adverse reactions to foods that you should seek the advice of an accredited practising dietitian specialising in food allergies and intolerances that can help you work through your diet and identify potential food intolerances in a safe and appropriate manner," Ryan said.

While we don't know the exact reason why Campbell eliminates nightshades from Brady and Bundchen's diet, its likely that he is just being cautious.

Sorry, mushrooms, you are not on the menu.