Food Protein Allergy Versus Food Chemical Intolerance
Definition
| Food Protein Allergy | Food Chemical Intolerance |
|---|---|
| An immune reaction to a protein involving an antibody response. This happens when the immune system sees a foreign protein as a threat, as it would view a pathogen during an infection. | A non-immune, pharmacological reaction to food flavour/colour/preservative chemicals caused by an inability to metabolise and neutralise the chemical. Flavour/colour/preservative chemicals can produce an allergy-like effect by a variety of different methods, including leukotriene production and histamine degranulation. |
Composition
| Food Protein Allergy | Food Chemical Intolerance |
|---|---|
| Reactions occur to apparently healthy whole foods. | Reactions occur to artificial chemicals and to apparently healthy whole foods. |
| Reactions are thought to occur to stereotypically neolithic foods like dairy and grains, but in fact occur to both neolithic and palaeolithic foods. | Reactions can occur to modern processed foods, and are sometimes mistakenly thought to occur to stereotypically palaeolithic foods, but in fact occur to both neolithic and palaeolithic foods. |
| Usually only one or two specific foods are involved at most, and wider ranging reactions are limited to genus. | A large range of foods are involved, are not limited by genus but to common chemical components within the foods. |
| Common allergens include cow's milk, eggs, soy, peanuts (legumes), tree nuts, fish and shellfish and wheat. | Common reactive chemicals include sulphites, MSG, aspartame, tartrazine and sunset yellow, azo dyes, artificial and natural colourings and flavourings, artificial antioxidants, benzoates, many other additives, salicylates (aspirin compounds) and biogenic amines (biologically active neurotransmitters or pseudo-neurotransmitters). |
Prevalence
| Food Protein Allergy | Food Chemical Intolerance |
|---|---|
| Usually affects small children whose immune systems are underdeveloped. Though many children "grow out of" allergies, they may last for life. | Children are more vulnerable because they are smaller and reactions are dose related. Women of child bearing age are vulnerable because of the influence of female hormones. The elderly are vulnerable because ageing livers and kidneys are less able to excrete chemicals from the body. |
| Less than 1% of adults and less than 8% of children under three years old are affected by classical IgE food allergies, though an unknown number may have non-IgE allergies mediated by the digestive system's immune system. | According to research by the RPAH, food intolerance is extremely common. The prevalence is unknown and varies depending on the chemical. Sulphite intolerance affects around 70% of asthmatics (around 7% of the population). Salicylate intolerance affects around 20% of asthmatics (around 2% of the population). Food intolerance is not limited to asthmatics but occurs in relation to many other disorders. |
| Common allergens vary the world over according to frequency in the diet and the timing of their introduction into the diet of babies and children; rice and buckwheat allergy are common problems in Japan, lentil allergy is a common problem in the Mediterranean. Allergenicity is more common in industrialised countries. This implies possible chemical, nutritional, or lifestyle factors are involved. One theory called the "hygiene hypothesis" regards the immune system as incorrectly primed by lack of exposure to pathogens. However, children with food intolerances are more likely to develop allergies, implying that particular food chemicals may prime the immune system for allergies. | Common reactive chemicals are the same the world over; however, food intolerance is thought to be more common in industrialised countries. Western diets are typically very high in food flavour chemicals compared to other more traditional diets. Food intolerance syndromes sometimes develop after a period of emotional trauma or physical ill health, but are often present from birth. |
Symptoms
| Food Protein Allergy | Food Chemical Intolerance |
|---|---|
| Symptoms are usually easy to spot unless they are non-IgE delayed reactions. | Symptoms are variable and wide-ranging. Individuals do not necessarily react the same way to the same food chemical. Individuals may react differently to the same food chemical over the course of a lifetime. |
| IgE symptoms usually include: itching of the lips, mouth and throat, watering eyes, sneezing and contact rashes in and around the mouth. They may include digestive disorders and can cause vomiting and diarrhoea, hives, eczema, or bowel disorders. Allergic reactions do not affect the nervous system. Non-IgE reactions can be delayed and can mimic the symptoms of an infection. | Symptoms can include many of the symptoms of allergic reactions, such as skin rashes, hives and urticaria. They can also cause headaches, asthma, eczema, frequent colds, flu and ear infections, arthritic joint pain, muscle pain, stomach aches, colic, bloating, IBS, GERD, and affect the nervous system and brain, causing aggression, defiance, ADD, ADHD, autism, PMT, depression, irritability, anxiety, panic attacks, forgetfulness, restlessness, fatigue, brain fog, concentration problems, hypoglycaemia, and many other symptoms. |
| Possible danger of anaphylactic shock. | Possible danger of anaphylactic shock, but via inducing an immune-mediated allergy. Possible danger of Reye's syndrome. |
Diagnosis
| Food Protein Allergy | Food Chemical Intolerance |
|---|---|
| Family doctors are very familiar with this condition. | Family doctors are often unfamiliar with this condition and may be skeptical about its existence. |
| Diagnosis is common. Allergies are often over-diagnosed in relation to unexplained food reactions. Treatment is straightforward. | Outside Australia diagnosis is rare and often misunderstood and misdiagnosed as idiosyncratic food allergy. Outside of Australia, food intolerance is rarely treated correctly, even when diagnosed. |
| Easy to identify and associate with a specific food. Allergy blood testing is not usually necessary but can be helpful to provide final confirmation. | Difficult to identify and associate with foods, no pattern may be apparent until after the foods have been excluded for some time. Chronic consumption of reactive chemicals leads to the presence of a chronic condition which often appears to be unconnected to food. |
| Fast reaction occurring within seconds or minutes of consumption of an allergen. | Reaction times vary and can be delayed, they can begin within a few minutes, to a few hours, to a few days of repeated consumption, and can last anywhere between a few hours, days, a week, or even up to a month. |
| Reactions are specific and short-lived. | Reactions are cumulative and dose related. |
| Can be identified easily with skin patch testing and laboratory blood tests for IgE allergies. Non-IgE allergies are harder to identify and usually require elimination and challenge testing. | Can only be identified through a comprehensive elimination diet over the course of 4-6 weeks. |
Treatment
| Food Protein Allergy | Food Chemical Intolerance |
|---|---|
| Biological mechanisms are reasonably well understood. | Biological mechanisms are less well understood and quite complex. |
| Through strict avoidance of the foods involved. | Through strict avoidance of the foods involved. |
| Desensitisation through strict avoidance or through build-up exposures reports mixed results, working in some cases and not in others. | Desensitisation through strict avoidance reports mixed results, working in some cases and not in others. Desensitisation through build-up exposures usually does not work, but when it does work it must be maintained by constant exposure or reactions will reoccur. |
| Children often "grow out of" mild allergic reactions. Allergies can cease with 3-6 months avoidance of the foods involved, but may be permanent, especially when reactions are severe. | Avoidance for at least six months followed by gentle reintroduction increases tolerance in some, for others chemical intolerance may be permanent. |
| Antihistamines can help with reactions. | Antihistamines can help with some reactions but can also be problematic in themselves. Bicarbonate or calcium carbonate can help with reactions. |