Food sensitivity could be caused by increased permeability of the small intestine (as called leaky gut syndrome). When the permeability of the intestine is increased, food components can pass through the intestinal wall more frequently and enter the bloodstream 1. When this happens, IgG antibodies against non-pathogenic antigens from food are produced during the body’s antibody-mediated reaction (humoral response) and the combination of an antibody and its antigen (immune complexes) are formed 2.
A food sensitivity is a generalized reaction to food that may be accompanied by elevated levels of food-specific IgG class antibodies 3 4. Unlike a true food allergy, the symptoms of a food sensitivity can be delayed for a few days following consumption of the trigger meal. Due to delayed reaction periods and ambiguous symptoms that mimic common ailments, people with food sensitivities can go a lifetime without realizing they have one. Bloating 6 7 4 8, inflammatory5, headaches, and diarrhea are some of the symptoms that could indicate a food sensitivity 9.
A food allergy is an immunological reaction that happens shortly after ingesting a specific food. Even a small amount of the allergy-causing food might cause symptoms such as bloating, hives, and enlarged airways10.
Two elements of your immune system are involved in food allergies. One is immunoglobulin E (IgE), an antibody-like protein that travels through the bloodstream. Mast cells, on the other hand, are found in all bodily tissues, but particularly in the nose, throat, lungs, skin, and digestive tract10 11.
When IgE is functioning properly, it detects triggers, such as parasites or other potentially hazardous substances, and instructs the body to produce histamine. Coughing, wheezing, and hives are all indications of histamine 10.
However, IgE can also react to normal proteins, causing your body to respond to one or more specific dietary proteins. When you eat something, the protein gets digested and absorbed into your system. The IgE is released and binds to the mast cell surface. Because of IgE, the food will trigger symptoms all across the body12.
IgG vs IgE
IgE is a protein that is produced in reaction to a foreign material entering the body. IgG allergies are typically food sensitivities that are milder and stay longer than ordinary IgE allergies 13.
Food allergies caused by IgE happen immediately or within a short time after consuming the food, but food sensitivity (IgG) takes some time, from weeks to months or years, to show up 14.
Clinical significance of Food Sensitivity
Some studies have shown that there is a link between specific diseases and food sensitivity (IgG). High levels of IgG antibodies against various foods or food additives are frequently present. For example, high IgG antibodies have been found in patients with headaches/migraines, arthritis, irritable colon (irritable bowel syndrome), inflammatory bowel illnesses, asthma, and a variety of other ailments 15 9. Additional examples of food sensitivity associated with secondary diseases are described below:
Rheumatoid Arthritis (RA): The importance of antibody-initiated inflammation in the development of RA is shown by the genetic linkage between epitope specific autoantibody responses and the generation of inflammation dependent and independent alterations in cartilage by pathogenic autoantibodies 16 17.
Irritable colon: Patients with irritable bowel syndrome were treated with an elimination diet in several studies. A large percentage of patients reported a significant improvement in their symptoms, with some even reporting a subjective full recovery6 18 19.
Headaches and migraines: A research even from the 1935s found that after following an elimination diet, 66 percent of 127 migraine patients were free of symptoms 20. Other more recent research has replicated these findings, demonstrating that an elimination diet based on IgG levels has a considerable impact on the frequency of migraine attacks 21 22 23 24.
Inflammatory bowel illnesses: In a retrospective study, Cai and colleagues (2014) discovered that patients with inflammatory bowel disease have a high incidence of IgG antibodies against certain foods, which can be used to design an elimination diet 25. Similar findings were found in subsequent research26 5 27 .
Food sensitivity testing
For this test, a package called “myfoodprofile” is available, which includes test strips coated with 54 different foods.
The myfoodprofile kit, a semi-quantitative, is used to determine human antibodies of immunoglobulin class G (IgG) against dietary antigens in serum, EDTA, heparin, or citrate plasma in a semiquantitative in vitro manner. IgG antibodies can generate circulating antibody/antigen complexes with dietary antigens, which can adhere to vascular walls and cause immune complex-induced disorders or worsen existing inflammatory diseases (food sensitivity).
In the first reaction stage, the test strips are moistened and then incubated with the patient sample. Specific IgG antibodies will attach to the antigenic components on the strip if the samples contain them. A second incubation with an enzyme-labeled anti-human IgG (enzyme conjugate) catalyzing a color response is used to detect the bound antibodies.
A food sensitivity (also known as delayed IgG food allergy) is an immune response to food. The immunological response is triggered by an increase in small intestine permeability, which permits food components to leak through the intestinal wall and into the bloodstream. Diet-related hyperacidity of the gut flora, medication, infections, preservatives, alcohol/nicotine, stress, and other variables can all contribute to permeability (also known as leaky gut syndrome).
The immune system recognizes these antigenic structures as alien and begins producing specialized anti-bodies of the IgG class (sensitization). This immunological response, which usually happens after a set amount of time (a few hours to days after eating the meal), causes an inflammatory reaction that can become chronic. Chronic inflammation can occur anywhere in the body, not just in the gastrointestinal tract. Diarrhea, constipation, bloating, nausea, upset stomach, irritable colon, migraine, asthma, joint diseases, lack of focus, skin disorders, and weight problems (overweight/underweight) are the most common symptoms. An elimination diet (exclusion diet) for a specified amount of time is usually prescribed to ease symptoms. The patient’s diet is restricted to foods with (high) IgG antibody concentrations. To limit or prevent permeability of the intestinal wall to food antigens, treatment approaches that improve gut flora can be considered.
It is impossible to tell whether a patient’s symptoms are caused by antibodies to specific meals based just on IgG detection. The test findings (myfoodprofile) can only be used as a starting point for a short-term diet adjustment. Then, and only then, can possible illness connections be discovered. Exclusion diets involving the avoidance of foods with high IgG titers have been shown to reduce symptoms in a variety of conditions in multiple trials.
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