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No scientifically valid test to diagnose food intolerance

HPRA advises those concerned about a potential intolerance to seek advice from a health professional

The Health Products Regulatory Authority (HPRA) today states that products being promoted as food intolerance tests cannot diagnose food intolerance conditions and advises people not to act on the results of these tests without expert advice from a doctor or registered dietitian. The HPRA has undertaken a review of these products on the market to examine their validity due to an increased availability in recent years and can confirm that there is no single test to diagnose food intolerance. It is advising people not to rely on the results of these test kits alone to detect a condition or to remove certain food groups from their diet. If anyone is suffering from gastrointestinal issues or believes they could be intolerant of a certain type of food they should consult a doctor or dietitian. Attempting to self-diagnose a suspected food intolerance using a test kit alone could potentially result in a delay in identifying and treating other medical conditions.

According to Dr Lorraine Nolan, Chief Executive, HPRA, there is no scientifically valid test to detect food intolerance and that the only valid and safe way to diagnose food intolerance is to eliminate foods following clinical advice and then reintroduce a suspected food on a phased basis to determine if symptoms return.

“Food intolerance is a term that has emerged to describe various unpleasant conditions such as indigestion and bloating that can occur after eating certain foods. People should not rely on the results of these test kits on their own regardless of how they are labelled and promoted. Any examination relating to a person’s ability to digest or ‘tolerate’ foods should be made in careful consultation with a doctor or dietitian. It should not be based on these tests alone as to do so could lead to a misdiagnosis or the removal of important nutrients in the diet. Removing a range of foods from your diet without expert advice on how this should be managed can result in nutritional deficiencies among vulnerable populations and impaired growth in children which can have important long-term health consequences."

The HPRA’s scientific review of medical devices commonly referred to as food intolerance tests included the most commonly used test kits in Ireland such as immunoglobulin G (IgG) tests which are based on a blood sample. It found that these tests will not diagnose intolerance to a certain food type but rather will detect previous exposure to a food. While this information may be used to help determine the types of food which a particular person has eaten in the recent past, it does not indicate intolerance. The various tests examined as part of the HPRA’s review are available through certain nutritional, food intolerance and health centres and via certain pharmacies. It also reviewed test kits that people can use in their own home such as those available via the internet and those offering a postal based service.

The HPRA has consulted widely on this issue with a number of stakeholders including the Pharmaceutical Society of Ireland, the Irish Pharmacy Union, the Irish Food Allergy Network, and other experts. It has also today published an update to its existing guidance on this issue (Information Notice: IN2018-01) which is available to members of the public who may have questions or concerns about food intolerance testing. Individuals who have experienced an adverse effect as a result of using these tests can report this to the HPRA at This email address is being protected from spambots. You need JavaScript enabled to view it. .

The HPRA wishes to emphasise that there is a clear distinction between food intolerance and food allergies as the latter can be potentially life-threatening. It stresses that food intolerance tests have no role in the diagnosis of a food allergy. The HPRA warns that a negative food intolerance test result does not mean that someone is not allergic to that food. Confusing a negative food intolerance test result with a food allergy could pose serious risks if a person then goes on to consume that food type and to have a subsequent reaction.

The HPRA is the competent authority for the regulation of medical devices and monitors their safety and effectiveness once on the market. It does not approve or certify medical devices for sale in Ireland.

Gluten Introduction and The Risk of Coeliac Disease

Background: The European Society for Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) recommended in 2008, based on observational data, to avoid both early (less than 4 months) and late (7 or more months) introduction of gluten and to introduce gluten while the infant is still being breastfed. New evidence prompted ESPGHAN to revise these recommendations.

Objective: To provide updated recommendations regarding gluten introduction in infants and the risk of developing coeliac disease (CD) during childhood.

SUMMARY: The risk of inducing CD through a gluten-containing diet exclusively applies to persons carrying at least one of the CD risk alleles. Since genetic risk alleles are generally not known in an infant at the time of solid food introduction, the following recommendations apply to all infants, although they are derived from studying families with first-degree relatives with CD. Although breastfeeding should be promoted for its other well-established health benefits, neither any breastfeeding nor breastfeeding during gluten introduction has been shown to reduce the risk of CD. Gluten may be introduced into the infant's diet anytime between 4-12 completed months of age. In children at high risk for CD, earlier introduction of gluten (4 vs. 6 mo or 6 vs. 12 mo) is associated with earlier development of CD autoimmunity (defined as positive serology) and CD, but the cumulative incidence of each in later childhood is similar. Based on observational data pointing to the association between the amount of gluten intake and risk of CD, consumption of large quantities of gluten should be avoided during the first weeks after gluten introduction and during infancy. However, the optimal amounts of gluten to be introduced at weaning have not been established.

(C) 2016 by European Society for Pediatric Gastroenterology, Hepatology, and Nutrition and North American Society for Pediatric Gastroenterology,

 

Read the referenced Article on Journal of Pediatric Gastroenterology & Nutrition

Major allergy attacks with collapse and swelling [called anaphylaxis]

Sudden severe allergy can be deadly. The body may react so violently to a foreign substance that huge amounts of histamine are released. Histamine is a normal chemical of the body. It is stored in various parts of the body, especially in the skin and the wet linings of the airways and bowel. In other words, it’s stored in the border zone between the body and the outside world. If the body is allergic to something which crosses the border, then it tries to expel it by releasing massive amounts of histamine. Unfortunately, this does more harm than good. The histamine allows blood vessels to open up. The blood literally falls to our feet, our brain is starved of blood, and we might faint or collapse. The open vessels cause red blotchy skin, and fluid also rushes out of the vessels, causing swelling. Now if the swelling occurs in our big toe, it’s unsightly and you might not get your shoe on, but that’s about it. If the swelling occurs in your throat, you might choke, and that’s serious. The histamine also causes incredible itch.

This whole process in called anaphylaxis. It can happen within seconds of exposure. What are the causes? Well, there are literally thousands of things that have caused anaphylaxis. Some people react in this way to foods, and the commonest foods on record that cause this problem (thankfully in only a small number of people) are peanuts, other nuts, fish, shellfish, milk (usually in babies), egg, and seeds such as sesame. There are many others. There are people who react violently to certain fruits or vegetables, or to vitamins or herbal drugs, or to food additives. The other major cause of anaphylaxis is severe drug allergy. The commonest are antibiotics (such as penicillin) or certain pain killers and anti-inflammatories. Substances which are eaten, drunk, injected (including insect stings), applied to the skin, or breathed in, can cause major allergy in susceptible people. These substances must be avoided by these people, and they often have to carry adrenaline (called epinephrine in the USA) to self-inject if necessary. The trade name for this product in Australia is EPIPEN or ANAPEN and it is available under the PBS in Australia for anaphylaxis. If you have had such a reaction, speak to your doctor. Assessment is required. And if you know of someone who describes such an allergy, take them seriously!

IgG blood testing for delayed food allergies?

Q. A family member had a blood test called IgG to check for any delayed allergies. It showed milk and eggs to be a severe, but delayed allergy (no skin reaction). Is there a blood test that can check if she has a delayed allergy to other birds’ eggs (i.e. turkey, duck, quail, etc.) and other animals’ milk (i.e. goat milk, sheep milk, or maybe unpasteurized raw cow milk, etc.)?

 

 

A. In IgG testing, the blood is tested for IgG antibodies instead of being tested for IgE antibodies (the antibodies associated with food allergies). IgG is a “memory antibody”.
When you have a blood test to query response to an immunization, this is also IgG testing. A common example is a “Rubella titer”.
In the context of food, IgG signifies memory through exposure to a food. Because a normal immune system should make IgG antibodies to foreign proteins (to include foods), a positive IgG test to a food is a sign of a normal immune system, and suggests tolerance or “memory” of the food rather than food allergy. Therefore, IgG testing is not recommended for evaluation of food allergies.
If the patient has previously eaten the food (milks, eggs), he or she would likely have IgG to the food.

 

 

Q. My son was diagnosed with peanut allergy by screening blood testing when he was 18 months old (done for a family history of food allergy in first cousins) but he never had a major reaction to peanut before the diagnosis, and nothing has happened since. He is now 5 years old. He has had cookies that were made in a facility where peanuts are present, without any reaction. He recently had a negative skin test for peanut and his last blood test level was 2.3. I was told that my son should continue to avoid peanuts. However, I recently read about a new kind of blood test for peanut allergy, and I am wondering if this test could be helpful for my son?

 

 

A. Peanut allergy seems to be on the rise in the US over the past decade. While there are some promising treatments being researched, the current standard of care is complete avoidance of peanut. Because this restriction can have such a major impact on everyone involved, it is very important that you receive an accurate diagnosis. Peanut allergy affects most areas of a person s life, from the home setting, to play dates, to school, to dining out and beyond.The most important factor in making an accurate diagnosis of peanut allergy is the actual history of the type of reaction that occurred upon consuming a peanut. Specific IgE blood tests (like ImmunoCAP, a common test) and skin prick tests are used in combination with the clinical history to make a diagnosis. In some cases an allergist-supervised oral food challenge is recommended, and this is, in fact, considered the gold standard for accurate diagnosis of allergy to peanut. (This same approach is applied to any possible IgE-mediated food allergy, not just to peanut.)One problem that allergists face is that some people do not have a clear-cut history of reaction to peanut. Situations that allergists see frequently include:In these cases, allergists will typically perform a skin prick test to gain more information. If the skin test is negative, a specific IgE blood test such as ImmunoCAP test can be ordered to gain more information. If the test comes back negative (meaning complete absence of peanut-specific IgE or a very low positive result with no history of anaphylaxis or other serious reaction), an allergist will often proceed to an oral food challenge in the office to confirm the test results,However, if the first blood test comes back positive, yet the clinical history is vague or indicates a mild reaction history, a new test, called the peanut "component test", can be ordered to gain more information in this situation. This component test - the one you are asking about - can determine which specific peanut proteins are triggering the positive test results. It is important to note that there are many smaller protein fragments that make up a whole peanut. Thus, when a person reacts to peanut, he or she may be responding to one or more different protein fragments in the peanut. Determining which of these protein pieces are causing the reaction is important, as some (scientific names Ara h 1 , Ara h 2 , and Ara h 3 ) carry more risk than others. Thus, if these specific tests are negative, there is less risk, and if positive, there is more risk. This will help guide whether an oral food challenge would still be okay (despite the positive initial peanut blood test).Given your son s unclear history of reaction to peanut, we would recommend that you speak to your allergist about the peanut component test and a possible oral food challenge depending on the results of the test. The information gained from the test will be helpful to you, either way!

See the original questions and answers here at the American College of Allergy, Asthma & Immunology

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