You’ve probably heard of gluten intolerance and know it has something to do with wheat in the diet. Restaurants and supermarkets all cater for the gluten-free population now, but how do you know if you need to avoid gluten? In this blog, I’m going to help you make an informed decision on whether you need a gluten intolerance test and how to make sure that you’re not avoiding foods unnecessarily.
What is a gluten intolerance test?
A gluten intolerance test identifies IgG-mediated antibodies in your blood produced by your immune system if you have an intolerance to gluten. A finger-prick sample provides enough blood for the antibodies to be identified.
What are the symptoms of a gluten intolerance?
The symptoms of a gluten intolerance will vary from one person to another and may include some of the following issues:
- Digestive: bloating, abdominal pain, diarrhoea, abdominal pain, nausea, reflux, constipation, blood in stools, anal fissures, flatulence
- Skin: skin rash, dermatitis
- Neurological: headaches, brain fog, sensory symptoms
- Mental health: depression, hallucinations, mood swings, anxiety
- Other: fatigue, numbness, joint/muscle pain, interstitial cystitis
Is a gluten intolerance the only cause of not tolerating gluten?
It’s important to note that gluten intolerance linked with raised IgG antibodies to gluten is not the only cause of not tolerating gluten. Coeliac disease is an autoimmune disease which requires specific testing for tissue transglutaminase antibodies that are not included in a standard food intolerance test. The symptoms of coeliac disease are generally very quick to appear and, in some individuals, will appear while still eating the food. They can be caused by exposure to the tiniest amount of gluten – even one toast crumb would be too much gluten if someone has coeliac disease!
The symptoms of coeliac disease may be similar to gluten intolerance in some cases and may include the following:
- Digestive: diarrhoea, stomach pain/discomfort, bloating, flatulence, indigestion, constipation, nausea, vomiting, lactose intolerance
- Skin: dermatitis herpetiformis (blistering, itchy rash)
- Neurological: peripheral neuropathy, ataxia (affecting balance, coordination, speech), brain fog
- Mental health: depression, anxiety
- Other: unintentional weight loss, failure to thrive (in children), fatigue (from malnutrition), infertility
A gluten allergy is another possible cause of not tolerating gluten. This would be identified using an IgE antibody test with raised IgE-mediated antibodies to gluten in the results. Gluten allergy can present with symptoms such as:
- Digestive: nausea, vomiting, diarrhoea, constipation, abdominal pain
- Skin: itchy skin, hives, eczema, redness of skin, angioedema (swelling of part of body e.g. eyes), skin rashes
- Respiratory: sneezing, nasal congestion, coughing, wheezing, shortness of breath
- Anaphylaxis: difficulty breathing, swelling of the throat and a constricted airway drop in blood pressure, rapid pulse, dizziness or loss of consciousness.
Other possible reasons for not tolerating gluten may include gastritis and gastrointestinal inflammation, histamine intolerance, inflammatory bowel disease, and other autoimmune diseases other than coeliac disease.
How do I know if my symptoms are from a gluten intolerance allergy or coeliac disease?
Keeping a food diary will allow you to track the relationship between consuming food and experiencing symptoms – this can be as simple as meals/symptoms noted in a paper diary or as complex as a colour-coordinated spreadsheet. If you are experiencing symptoms instantly while eating or shortly after eating, you may want to explore gluten allergy and coeliac disease, as well as a gluten intolerance test.
If you are monitoring your symptoms and notice unexplained weight loss, extreme fatigue, breathlessness, or any symptoms of anaphylaxis (difficulty breathing, swollen throat/airway, drop in BP, rapid pulse, dizziness, loss of consciousness), you should contact your doctor immediately to discuss your symptoms.
What else should I test, as well as gluten intolerance?
Even if your symptoms look like a gluten intolerance test, it would be wise to rule out coeliac disease and gluten allergy at the same time. Not everyone who has coeliac disease or a gluten allergy will also have a gluten intolerance with raised IgG antibodies to gluten in their blood.
Can I change my diet and avoid gluten before testing?
An accurate gluten intolerance test requires you to eat gluten in the days/weeks leading up to your blood test. This also applies to coeliac disease and gluten allergy testing. If you are not eating the foods, the antibodies will not be in your blood sample.
If your symptoms are severe, speak to your doctor or a nutritional therapist before making any changes to your diet.
My gluten intolerance test was negative – does that mean I don’t have a gluten intolerance?
If your gluten intolerance test has returned with negative results, first check that you were eating gluten in the days leading up to your blood test. If you weren’t, then it’s possible you have a false negative. Speak to your health professional about reintroducing the gluten and retesting.
If you haven’t already, we would also suggest that you test for coeliac disease and gluten allergy. You may also want to ask your doctor to test you for helicobacter pylori (a stool test), and there are private stool tests available through nutritional therapists that can look for dysbiosis (bacterial imbalance) of the gut. SIBO (small intestinal bacterial overgrowth) is also worth ruling out, especially if you are experiencing issues with all carbohydrates or have noticed improvements when following a low FODMAP diet.
I don’t like needles – how else can I test for gluten intolerance?
You can rule out gluten as a cause of your symptoms with an elimination diet – we would always recommend that you do this under the guidance of a nutritional therapist. An elimination diet allows us to review how your body reacts to gluten when it is reintroduced and confirms whether gluten is tolerated or not. However, an elimination diet does not allow us to differentiate between coeliac disease, gluten allergy, or gluten intolerance.
Summary
When deciding whether to get a gluten intolerance test, the best advice is not to self-diagnose without reading all of the above first, and to get as much tested (intolerance, allergy, coeliac etc) before you make any changes your diet.
A negative gluten intolerance test does not always mean that you tolerate gluten. You could still have a gluten allergy, coeliac disease or another autoimmune disease, gastritis or gastrointestinal inflammation, helicobacter pylori, SIBO, histamine intolerance, and more.
If you suspect gluten may be underlying your symptoms, seek help from your doctor or a nutritional therapist who can help you access the gluten intolerance test and any other testing that you need.
