The recognition of food sensitivity was first recorded by Hippocrates, who observed that milk could cause gastric upset and skin redness and itching. In 200 A.D. Galen described a case of allergy to goat's milk and in1679 Willis observed that the ingestion of wine could precipitate asthma.
Allergies Today
The incidence of food and environmental allergies and the number of atopic individuals has increased dramatically in recent times. Hypersensitivities involving bronchial symptoms and asthma, for example, have nearly doubled in the last decade. It is estimated that atopic dermatitis alone now affects between 10-15% of the population at some time during their lives, and that this condition is often directly provoked by foods. Adverse reactions to food are now reported in about 25% of younger children.
Some physicians even claim that food allergies are a leading cause of most undiagnosed symptoms. Why has the incidence of allergy risen so dramatically?
Food products most frequently incriminated in allergic reactions are often hidden as ingredients in commercial foods. Many modern foods, as well as medicinal drugs such as penicillin, also contain preservatives, stabilizers, artificial colorings, and flavourings. Some scientists believe that increased chemical pollution in our air, water, and food is to blame for our increasing reactions to foods. Foods can easily become contaminated by the use of insecticides in farming.
Other possible reasons for increased food hypersensitivity include: earlier weaning and earlier introduction of solid foods to infants; genetic manipulation of plants, resulting in food components which cross-react with normal tissues; and less diversity in the average diet —leading to repeated exposure to food substances and the subsequent development of hypersensitivities.
Probably all of these and more have contributed to the increased frequency and severity of allergic symptoms.
Cause and Development
It is well-documented that food allergy is an expression of an inherited genetic predisposition. Hence, allergic histories can often be found in both parents and siblings. One study discovered that when both parents are allergic, 67% of the children are also allergic.
When only one parent is allergic, 33% are allergic. Inadequate digestion of food products due to hypochlorhydria and/or pancreatic enzyme deficiency is also thought to be a significant cause of food allergies. When proteins are not digested to amino acids, dipeptides, or short chain polypeptides, they retain their antigenic properties. These antigenic molecules may then be absorbed through a “leakygut” and exposed to the immune system, creating a state of chronic immune hypersensitivity.
Allergy Symptoms
Food and environmental allergies have been linked to a wide range of medical conditions affecting virtually every part of the body.They have been shown to cause migraines, eczema,thrombophlebitis, arthritis, colitis, enuresis, earinfections, gall bladder disease, childhood hyperactivity,hypotension, urticaria, asthma,glaucoma, and many other pathological conditions.
Any of the symptoms shown in the table should make the clinician suspect possible food allergies. Gastrointestinal dysfunctions such as peptic ulcer,dyspepsia, gastroduodenitis, and hiatal hernia may promote some of these adverse reactions to food.
IgE vs. IgG Mediated Reactions - TWO types of food allergy
Classical skin testing for allergies such as skin-scratch testing only measures IgE-mediated reactions. Assessment of relative IgG antibody levels to a multitude of foods using sensitive Enzyme-Linked Immunosorbent Assay (ELISA) technology identifies those foods against which the patient is producing antibodies. Measuring both relative IgE and IgG antibody levels provides an invaluable starting point for dietary intervention.
The key differences between IgE and IgG allergies/sensitivities are:
IgE-Mediated Allergies IgG-Mediated Allergies • Immediate onset (within minutes) • Delayed onset (4-72 hours) • Circulating half-life of 1-2 days • Circulating half-life of 21 days • Permanent allergies (life-long) • Temporary allergies • Stimulates histamine release • Stimulates histamine release • Includes foods, inhalants & moulds and activates complement • Includes foods, herbs & spices
I am able to help you determine which allergy you have and help you decide on which test to have. Contact me on Max@Max-Tomlinson.com
Role of IgE and IgG- the really heavy science stuff!!
IgEantibodies are believed to trigger allergic reactions when they crosslink on the surface of gastrointestinal mast cells, stimulating the release and productionof chemical mediators such as histamine, proteoglycans, and leukotrienes. These potent reactors instigate a barrage of effects on surrounding intestinal tissue and, by inducing intestinal permeability, may also allow passage of food antigens into the bloodstream. When this happens, other organs in the body then become targets for the allergic reaction; further involvement with other celltypes in the body may result in the creation of a chronic, perpetual immune response.
Since most severe,immediate allergy symptoms are IgE-mediated, many doctors have limited their testing to this class of immunoglobulins. Certainly, an abundance of medical literature supports using the IgE assay as a means of diagnosing Type Iallergic reactions.
There is also considerable evidence,however, underscoring the significance of IgG as a marker in allergy testing aswell. In fact, it is estimated that IgG and IgG complex mediators are involved in 80% of all food allergy reactions.Repeated exposure to anantigen can eventually produce allergy-like responses, or hypersensitivities.These reactions are usually delayed, with symptoms that may not surface until hours, or even days, after the initial exposure.
One study found that nearly 60% of patients with food intolerance exhibited late (delayed), rather than early or immediate reactions to provoking foods. Although IgE may be involved, it is theorised that these delayed reactions are primarily mediated by IgG. Specific IgE has a half-life in circulation of one to two days, and a half-life on the mast cell of about 14 days. IgG, on the other hand, appears to have a circulating half-life of 21 days, with a residual time on the mast cells that can last as long as 2-3 months. Thus an IgG assay is an essential tool for diagnosing the possible causes of delayed, non-anaphylactic responses, the so-called “hidden” allergies, which cannot be detected with conventional IgE tests such as radioallergosorbent test (RAST) or skin testing.
Numerous studies indicate a role for IgG in non-IgE, mast-cell mediated diseases as well as various food allergies. IgG can induce basophil degranulation,triggering the release of histamine and other potent chemical mediators upon exposure to specific antigens—a common mechanism of allergic reactions. In one study,individuals with hypersensitivity to shrimp were determined by double-blind,placebo controlled challenges. Shrimp-specific IgE and IgG, but not IgM andIgA, were significantly higher in the group with shrimp hypersensitivity as compared to controls. Another group of researchers verified that children with atopic eczema showed much higher levels of IgG antibodies tocasein and ovalbumin subclasses than did controls.
Getting Help
The natural therapies team at the Fulham medical centre are experts at dealing with allergies. We can help you decide what to test and how to interpret your results. We have helped many people overcome this condition. Book inon 020 73856001 or email Max to set up a phone or internet consultation. Max@Max-Tomlinson.com
