Defining Psoriasis Food Triggers Using IgG Testing

The effect of diet on psoriasis is a common topic on psoriasis forums, with a great many people looking for more holistic ways of healing to complement traditional treatments.

There are some books that have been written on the subject, arguably the most popular being "Healing Psoriasis: The Natural Alternative" by Dr. John Pagano.

Defining food triggers

Dr. Pagano advocates, in conjunction with regular chiropractic adjustments and colon, cleanses, a whole foods-based approach, while also recommending cutting certain foods like red meat and nightshade vegetables (tomatoes, potatoes, eggplant, bell peppers, and certain spices; if you hang around psoriasis forums long enough, you’re bound to come across the term!).

Dr. Pagano’s dietary recommendations have been used with great success by many people, but (unsurprisingly) not everyone finds relief with his plan. There are many other online resources/success stories that espouse their own tailor-made diet plans, but there is no consensus, mirroring the reality that what works for one person doesn’t work for everyone.

Some people find great relief when cutting dairy, while others have had success only when introducing dairy products like probiotic yogurt. Can I have pasta sauce? Maybe not. Can I eat beans? Depends on who you ask. How frustrating.

Stumbling across IgG testing

Has anyone found a better way of zeroing in on which foods may be sabotaging your skin?

I’d like to throw my hat into the ring and share that yes, I did, and although I don’t talk about it very often, I’ve stayed fairly clear for the two years since my phototherapy by following the advice of an obscure blood test I stumbled across by accident: IgG, or Immunoglobulin G (in case you're wondering) antibody test.

Starting with science

But first, let’s talk about antibodies! Any opportunity to throw down some science, am I right? Antibodies are amazing proteins that your body produces to recognize foreign antigens and alert the immune system (hey team, I’ve got some viral proteins over here. Send in the troops!).

The immune system is a fascinating thing, a thousand different cells and molecules working together to keep you safe. But sometimes, just sometimes, antibodies get it wrong and react to something perfectly benign.

The antibodies responsible for classic food allergies largely belong to a specific class of proteins, called Immunoglobulin E antibodies, or IgE for short. When you go to your allergist for the skin prick allergy tests, IgG sensitizations are what they’re testing for.

What is the connection to psoriasis?

Okay, that’s nice, but what does this have to do with psoriasis? Well, IgE-mediated food allergies are well known (think peanuts, shellfish, etc.), but they’re not the only antibody that responds to your dietary choices. There’s another class of antibodies, IgG, that may play a role as well.

IgG antibodies do not usually illicit the same classic allergic response as IgE, but there is some evidence that they too can become improperly sensitized to food proteins, although medical and scientific communities are by no means in agreement on this (and terms like “food intolerance” and “food insensitivity” are still not substantiated diagnostic terms).

Regardless, food “intolerance” testing is gaining traction, and although there’s no formal scientific agreement on whether the results are medically relevant, some people are implementing the results with great success. And, as you may have guessed, I would be one of those people.

Identifying what your body is reacting to

At the height of my worst psoriasis flare to date, I stumbled across the concept of IgG testing on the internet, as something that may identify foods your body is reactive to. I was skeptical but didn’t feel I had much to lose.

I contacted a naturopath in my city, and she noted that yes, IgG testing was something that helped many of her clientele suffering from psoriasis; the unproven theory being that if you have IgG antibodies toward a specific food, then your immune system may be responding inappropriately when you eat that food (and, presto change-o, psoriasis appears!).

One finger prick later, my blood was on its way to be analyzed for IgG antibodies against a panel of 96 different foods. I received my results 3 weeks later, and they indicated that I was “highly reactive” to almost all dairy proteins, eggs, and chocolate, which were foods I knew exacerbated my symptoms… but then there was a whole host of other foods that hadn’t previously been on my radar.

Learning about my own food triggers

I came back “highly reactive” for foods like kidney beans, almonds, pineapple, banana, kiwi, garlic, and squash! Of all the psoriasis diet advice I had come across, many of these were foods I would never have considered cutting out to help my symptoms. But cut them out I did, and following the food recommendations from the IgG testing, I have managed to keep my skin under control since my phototherapy 2 years ago.

Am I completely clear? No. Because sometimes a girl just has to eat her almonds, okay? But I can say that my psoriasis is much more manageable when I follow the guidelines (in addition to reducing corn and gluten, which were not identified by the test, but which I know bring the thunder-like no one’s business).

Will this diet always work for me? Probably not, because psoriasis is crafty, but this has been one tool that helped me zero in on a skin-friendly diet which, to this day, continues to work for me.

So, where does science stand?

So where does science stand on IgG testing? Most medical professionals and researchers don’t feel there is enough data to warrant its use, and some are downright discouraging of it, feeling that it feeds into the public perception of there being food intolerances/sensitivities outside the traditional scope of food allergies.

As a scientist who lives for evidence, I tend to agree. But as someone who gets new psoriasis spots less than 24 hours after eating almonds or kiwis, I do have to wonder!