Members of the public have been warned that there is no scientifically valid test to diagnose food intolerance, and products being promoted as such should not be used.

According to the Health Products Regulatory Authority (HPRA), food intolerance tests cannot diagnose food intolerance conditions and people should not act on the results of such tests without expert advice from a doctor or registered dietitian.

Due to an increased availability of these tests in recent years, the HPRA carried out a scientific review of them in order to assess their validity. It confirmed that ‘there is no single test to diagnose food intolerance', and advised people not to rely on the results of these test kits alone, and not 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 dietician. 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," the HPRA warned.

According to the authority's CEO, Dr Lorraine Nolan, the only safe and valid way to diagnose food intolerance is to eliminate foods following clinical advice, and then reintroduce the suspected foods on a phased basis to determine if any symptoms return.

She noted that 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. She insisted that people should not rely on the results of these test kits, regardless of how they are labelled or promoted.

"Any examination relating to a person's ability to digest or tolerate foods should be made in careful consultation with a doctor or dietician. 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," Ms Nolan explained.

The HPRA's review 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 do not diagnose intolerance to a certain food type, but instead detect previous exposure to a food. While this information may be used to show foods a person has consumed in the recent past, it does not indicate intolerance.

The various tests examined as part of this review are currently available through certain nutritional, food intolerance and health centres, as well as via certain pharmacies. In light of this, the Pharmaceutical Society of Ireland, which regulates pharmacies, has informed pharmacists that they should not offer food intolerance testing services to their customers.

"The HPRA has determined that there is no single test available to diagnose food intolerance and that such tests should not be relied upon for the purpose of a diagnosis or as the basis for dietary change. In the light of this advice, we want to clearly convey this important message to pharmacists.

"In line with the statutory code of conduct for pharmacists, tests or health checks should only be performed by pharmacists, or offered in pharmacies, where there is an established clinical and scientific evidence base and where the validity, accuracy and reliability of the test can be assured," commented PSI registrar, Niall Byrne.

However, home testing kits, such as those available via the internet or post-based service, were also included.

Meanwhile, the HPRA emphasised that there is a clear distinction between food intolerance and food allergies, as the latter can be potentially life-threatening. It stressed that food intolerance tests have no role whatsoever in the diagnosis of a food allergy.

It warned 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 experience a subsequent reaction.

Anyone who has experienced an adverse effect as a result of using these tests can report this to the HPRA at devicessafety@hpra.ie.

The review was welcomed by the Irish Nutrition and Dietetic Institute, which represents registered dietitians in Ireland. It has been warning of the dangers of these tests for some time and said it hopes this review from the HPRA helps to inform the public about the importance of seeking nutrition advice only from qualified professionals.