Should you do a food intolerance test if you have IBS or skin issues? You’ve been struggling with bloating, abdominal pain, constipation or diarrhoea for a while; you’ve been to the GP and had some tests done, only to be told there’s nothing serious going on; it’s just IBS. I hate when people are told this because, yes, IBD and coeliac disease are more serious, lifelong conditions. But IBS is still a life-altering condition – it can consume your daily life, and you’re kinda just told to get used to it. Or, you might be struggling with eczema, itchy skin, rosacea or acne, and have been told that a food intolerance must be behind the skin issues.

So because nothing so far has seemed to have helped, you’re wondering if food intolerance testing could be the answer to all your problems. Finally, a test that will highlight what foods you’re reacting to, and all you need to do is cut out the foods, and you’ll live a normal, bloat-free life, free of skin issues. But will you? Or is it too good to be true?

Let’s run through a few basics with food intolerance testing before you invest anything on tests!

Types of Food Intolerance Tests

There are a few different options when you look into food intolerance tests. There’s everything from blood tests to hair testing and then kinesiology test kits.

Let’s start with the blood tests because I think they’re the most popular.

Food intolerance blood test for IBS & skin issues

When it comes to food allergies and intolerances, there are different parts of the immune system that can get involved and cause reactions. We have 5 different types of antibodies: IgA, IgE, IgG, IgM and IgD. You can think of antibodies as different defence systems. So as an example, IgA could be the police, IgE could be the army, and IgG could be the Royal Air Force – they all help to keep us safe but work and react in different ways.

The common commercial food intolerance blood tests that you’ll see pop up on your instagram Ads or Google are looking at IgG antibodies. Now I know this gets a little scientific. But all you need to know is that you can develop IgG antibodies just by repeated exposure to a food (which is a natural and normal response) . You don’t actually have any issues with this food. In fact, elevated IgG antibodies to a food can show that your immune system has learnt to recognise and tolerate that food you’ve been eating on a regular basis.

This is where you get a false positive on food intolerance testing. The test is saying you have a problem with eggs, but it’s because you eat eggs on a daily basis, not that you actually have a problem with the food. And now you’re about to cut that food out forever, thinking it was a problem, when it wasn’t. You can also get false negatives because the test is only looking IgG reactions. IgA, IgM and IgE antibodies can all influence how your body is responding to foods.

Unfortunately, at the moment, we don’t have a great range of testing that accurately picks up food intolerances and sensitivities. If you are struggling with allergies, then skin prick testing and IgE serum testing may be a better option for you. But you’d need to speak with your doctor or an allergy specialist to determine the best course of investigation and treatment.

Hair tests for food intolerances

Hair tests are not accurate at all for food intolerance testing. So I wouldn’t recommend looking into those to get more insight into allergies or intolerances.

So, are food intolerance tests worth it if you have IBS or skin issues?

There are a few other issues with food intolerance testing for gut or skin issues. And we can split it into two scenarios that most people get with these tests.

1) You test positive for a whole load of foods

The recommendation if you react to lots of foods on a food intolerance test is to cut them all out and see how you feel. You’re looking at the list thinking, what the hell can I even eat? And now that you’ve seen this list, there’s actually a risk that your brain will now cause a reaction to these foods even if they weren’t an issue in the first place. Research has shown that if a person believes a food is bad for them, they are more likely to react to that food when they eat it (even if it’s not a problem). This is called the nocebo effect, when your negative beliefs cause you to experience physical symptoms.

A food intolerance test like this isn’t giving you any information into why you might be reacting to these foods in the first place (if you actually are). Aside from ruling out that there definitely isn’t a true allergy happening (like an itchy mouth, abdominal pain) when you eat these foods, some reasons you might experience bloating, loose stools or other gut symptoms when eating a food include:

You have issues with digestion.

If your stomach acid isn’t optimal, or you’ve got a Helicobacter pylori (H. pylori) infection, you’ll struggle with breaking food down – especially proteins. This is because H. pylori can change the pH of your stomach acid, making it more alkaline which affects how well you break things down in the stomach and interferes with hormone signalling in the gut to stimulate digestion. H. pylori also damages the mucosal lining of the stomach which can trigger inflammation. This can cause you to feel bloated, excessively full after eating even if it’s a small amount, nausea or generally losing your appetite. You may also become sensitive to certain foods due to the stomach lining being damaged and inflamed. The solution isn’t to ‘remove foods forever’ it’s to check for an infection, clear the infection and support stomach acid production, and allow the stomach lining to heal. Then you can reintroduce foods.

You have an overgrowth of bacteria.

There are certain bacteria in the gut which, when in high levels, can ferment on fibres found in a lot of healthy foods. They can produce hydrogen or methane gas, which can cause bloating, diarrhoea, constipation, abdominal pain, feeling excessively full, and of course a lot of gas and wind. And again, removing foods isn’t the long-term solution. It might offer a bit of symptom relief in the short term, but the way to get long-term relief is to clear the overgrowth of bacteria.

Your gut lining is damaged.

When you’ve got a combination of gut dysbiosis (meaning your beneficial bacteria are low, and ‘bad’ bacteria is high), poor digestion, and maybe a restricted diet due to your symptoms, you end up damaging the gut lining. Long-term use of certain pain medication and antibiotics can also impact the gut lining. This can increase reactions to food because food particles will pass through the gut wall and will trigger the immune system. Removing foods again gives you symptom relief but actually doesn’t help long term. Repairing the gut, rebalancing the gut microbiome and looking at other areas like stress is what helps long term.

You have low levels of good bacteria

And ironically, the worst thing you can do in this situation is remove foods. Because the thing that helps good bacteria grow is to have a diverse diet that includes lots of different herbs, spices, fruit, veg, even fish and meat.

2) You test positive to… nothing. Now what?

This is another scenario that can happen. And it’s what happened to me when I did a food intolerance test many moons ago when I was trying to get some relief from my chronic bloating (this was before I qualified as a nutritionist). I was full of hope that this test was finally going to give me some answers, and it came back with my only reaction being to rooibos tea. At the time, I didn’t even know what rooibos tea was, so I wasn’t drinking it. So even if I was intolerant to it, it wasn’t what was causing my IBS symptoms because I’d never had the stuff! Well, if you’re in this situation like I was, you’ve kinda spent a load of money on something and not really got any answers.

What’s the alternative to food intolerance testing for IBS and skin issues?

Shortly after doing this food intolerance test and feeling like I had no hope of ever having a normal functioning gut and clear skin, I started studying nutrition to get some more answers. And that’s when I did my first comprehensive stool test. And after all these years, this is what actually gave me answers. I’d tried the Low FODMAP diet to no relief, then paid for intolerance testing with no answers. Spending £300 on a stool test seemed a bit risky, especially when I spent £200 on a food intolerance test that didn’t help me at all. But I was willing to give it one last go to get some information. Here’s what I found:

• I had an overgrowth of bacteria and candida in my gut – these can cause constipation, bloating, diarrhoea and abdominal pain.
• I had issues with digestion – which was affecting how well I was breaking down my food and again can cause all the symptoms I’ve listed above. It can also contribute to nutrient deficiencies, which would have been slowing my acne from healing too.

So with this information, I went on a gut protocol which included supplements to help remove the bacteria and candida, support digestion and repair the gut lining. The ONLY food I removed during this time was gluten. The rest of my diet focused on adding everything back into my diet. More plants, reintroducing dairy, grains etc (all the things I was terrified of). And I can’t tell you how amazing it was to wake up for the first time with a flat stomach and see my skin healing!

How to fix your gut and skin while reintroducing foods

My advice as a nutritional therapist that works with both gut and skin issues would be this:

1. Understand that a lot of the time, it’s not the food that’s the issue. It’s the way your gut is reacting to food, and you can repair your gut.
2. It’s better to invest in a comprehensive stool test that covers markers like calprotectin, FIT (occult blood) and pancreatic elastase, alongside looking into the bacteria in your gut. We do this in 1:1 Sessions and my Gut Reset Package.
3. Use a targeted, personalised protocol to repair your gut. This depends on what you’ve found – you might need supplements, a change in diet (but not a restrictive diet) and even medications.
4. Start reintroducing foods. This is where you can trial foods you feel have been an issue (don’t do this if you have a true allergy).

Fix your gut and reintroduce foods

I want everyone to be able to have a healthy gut and healthy skin, without taking away the joy of food. You’ve already suffered by being afraid of what to order off the menu in case your gut or skin freaks out, and now you’re going to spend the rest of your life with an even more restricted diet in the hope for some relief? But please, can you ask yourself:

• Is the additional stress it creates about food even helping?
• Are all the cravings for all the foods you used to love really worth it?
• Is the isolation of not being able to go to certain restaurants or eat what you want on holiday really worth it?

You’re not just missing out on joy by avoiding all these foods; you’re missing out on nutrients too.

And look, I’m not saying that there’s no such thing as food intolerances or allergies. There is. People can have gluten sensitivities, lactose intolerance, and true allergies to everything from nuts to mustard. But my issue is that food intolerance testing isn’t accurate, and it leaves you with a long list of foods to avoid for life. If someone has an allergy or intolerance, it’s usually 1-3 things that they need to avoid, not a list of 40 foods.

I personally don’t think its worth it, and my clients don’t either. So if you’re someone who wants to start enjoying food again and be able to go out and not stress about what you’re eating, you can book an enquiry call to get started.