How to diagnose allergy and food intolerance


26056071_smThe understanding of the effects driven by food-related inflammation on health has shaken up the old ways of interpreting many forms of disease and disorder sometimes referred to food reactions, in which an inflammatory status of low-intensity (low-grade inflammation) has been identified as the cause of the symptoms and manifestation typical of the condition.

Such new knowledge has allowed overcoming the definition of food intolerance, which for many years has distorted and diverted the attention of researchers.

The definition of a food personal profile (like the one highlighted by an IgG evaluation test) is useful to understand how to reduce inflammation, measured through BAFF and PAF indexes, and certainly not to trigger a battle against certain types of food or certain food clusters. These two cytokines (along with others, which can be examined nowadays) may represent a precise indication of the overall inflammatory levels present in the organism, and play an integral role for the diagnostic and interpretative tools on food reactivity.

Unfortunately, however, the classic mind-set, only focused on “pursuing the enemy”, has led us to look for non-existent antibodies and improbable cells for many years, forgetting what are the real needs of those suffering from generalized inflammatory consequences of their personal type of nutrition.

Beyond the evidence of IgE-mediated reactions (the classic type of acute food allergies as so far known), there exist other conditions, in which other types of antibodies (IgG) and different immune cells are involved; these lead to the accumulation of inflammatory cytokines, which become the trigger to a cascade of well-known pathological events, potentially affecting every organ and system of the body.

All this explains the profound inflammatory action that food can have on living organisms when immunological tolerance is lacking.

The classic allergy tests

The food allergy tests so far in use are essential to identify and confirm any serious IgE-mediated allergy (the only ones, for which an elimination diet may absolutely be necessary), but these tools are not able to highlight any IgE-independent cellular reaction, linked to food-related inflammation.

Sometimes, these tests are useful to integrate the current knowledge of problems related to food reactivity. Frequently, in our experience, we have observed RAST tests since young age with positive results to wheat or true grasses (gramineae, belonging to the same family of wheat for food making) in subjects later shown to be suffering from gluten sensitivity later on.

Among the classic allergy tests, we should include:

  • The Prick Test: it does not account for tardive reactions; it proves useful for the diagnosis of food and respiratory allergies.
  • The Prick by Prick test: it uses fresh aliments rather than solutions during the testing phase.
  • RAST (radioallergosorbent test): it helps confirming a suspected diagnosis, especially in cases of respiratory allergy and, to a lesser extent, of food allergies. Rarely food-related inflammation is also linked to a positive RAST result for specific aliments.
  • The Prist test: the definition of the total IgE values indicates, especially in children, a general allergic tendency, but it does not indicate to which substance.
  • The patch test: mainly used for the diagnosis of contact skin diseases.
  • A Stimulation test, that is:
    • Elimination and trigger diets (both useful for the diagnosis of either allergies or non-IgE reactions, especially if that specific diet has continued for several consecutive days);
    • The DBPCFC (Double Blind Placebo Controlled Food Challenge), which is a double-blinded load test (used in allergy diagnosis, but with some modifications also applicable to food intolerance).

Intolerance diagnosis: the non-conventional tests

Despite the latest scientific developments, which radically changed the meaning and impact of the old non-conventional tests for the identification of those conditions once called “food intolerance”, many people still carry on performing these tests, which retain only an historical value. Indeed, we have described them in a separate article on non-conventional tests.

Therefore, we find useful giving some tips on how to use profitably the available data, however these were collected.

Whatever test is used to diagnose a case of food reactivity, even more so when a non-conventional test is chosen, the results should always be interpreted by an experienced therapist, who will be responsible for the diagnosis released within along with a comprehensive evaluation of the individual and, more importantly, within the therapeutic plan tailored around the patient to lead him/her to healing and to tolerance recovery.

Unfortunately, as a result of many non-conventional tests carried out, patients have been recommended forms of diet, which are punitive at best and extremely dangerous at worst. In particular, these are all forms of diet that do not help recovering the immunological tolerance towards those foods, against which reactivity exists. Instead, it is essential to lead the patient through a sort of “weaning”, along a very detailed path, fully oriented towards healing.

At this point, I would like to stress which the real goals of the proper dietary therapy are, regardless of the test employed:

  1. to promote the recovery of tolerance towards poorly tolerated foods;
  2. to avoid dangerous types of elimination diet, which prove useful only in cases of classic allergies, that is, those mediated by high titres of IgE;
  3. to ensure the compliance to sociability and to eating-related pleasure through the implementation of a rotation diet that includes a few days of freedom.

In the current social and environmental world, it appears to be essential to promote food variety, also since the systematic repetitive intake of certain aliments (even if these are supposed to replace those ones not tolerated) easily gives rise to new forms of hypersensitivity.

Throughout the entire weaning process for those poorly tolerated foods, the reduction of reactivity must be assessed on several occasions (to determine if and how the contact with those foods may be extended), and systematically compared with clinical data.

In some cases, the old terminology “food intolerance” has also created some confusion around the inflammatory reactivity linked to milk proteins and around lactose intolerance.

It is important to remember that lactose intolerance (which is dose-dependent) is a biochemical type of intolerance, that is, it does not activate the immune system, while the reactivity to milk proteins is dose-independent and the only one that triggers inflammation.

These are two very different conditions, which happen sometimes to be found linked in the same patient.