top 8 food allergens

Recently there has been a lot of media attention on the rapid increase in food allergy and everyone nowadays is gluten free, lactose free or vegan.

Unfortunately, many undertrained nutritional therapists are (deservedly) getting a bad rap for restricting people’s diets to the point that patients are becoming underweight or even worse, developing an eating disorder known as orthorexia. Much of this occurs because of incorrectly diagnosed food allergy and intolerance. The only way to diagnose food allergy or intolerance is to conduct a low reactive diet and oral food challenge. This is the Gold Standard Test

Food Allergy & Intolerance

Food Allergy & Intolerance
Brand Carahealth

Top 8 Food Allergens

  • Milk
  • Eggs
  • Peanuts
  • Tree nuts (such as almonds, cashews, walnuts)
  • Fish (such as bass, cod, flounder)
  • Shellfish (such as crab, lobster, shrimp)
  • Soy
  • Wheat

could do with eliminating certain foods whilst others may only need to rotate and reduce grains and dairy, which are the common culprits.

Currently, there is considerable confusion about the terminology used to describe adverse reactions to food. Adverse reactions to food include food allergy and food intolerance.

  • Food allergy is described as an immunological reaction involving the production of an antibody
  • Food intolerance is described as a pharmacological reaction to the compounds in foods, similar to the side effects when taking medication.

The term allergy for example, should be reserved for reactions that involve the immune system only. Some people say they are allergic to cheese because it gives them headaches. This reaction is not allergy however, but actually food intolerance to the vasoactive compounds in cheese. In reality, food allergy affects relatively few people but can be quite severe when it does.

It is important to understand that, in babies and young children in particular, the development of specific antibodies to environmental allergens such as those found in food also is a normal physiological response in which tolerance to the environment is developed and the immune system is exercised. Allergy is not a dirty word. So why is food allergy and intolerance on the rise?

The Hygiene Hypothesis Theory

The hygiene hypothesis theorises that the rise in atopic diseases such as asthma, eczema, hay fever, urticaria and allergy is because children are not getting natural exposure to events that should naturally stimulate their immune systems. This is said to be due to a number of factors including decrease in vaginal deliveries, a reduction in breastfeeding, the overuse of paracetamol to suppress fevers, the use of vaccinations that prevent natural exposure to viral illnesses, and the overuse of antibacterial products. These factors prevent the natural exposure to bacteria, viruses and, via breast milk, food antigens that stimulate the production of food antibodies, that are designed to stimulate and train our immune systems to prevent immune dysfunction.

If the immune system does not come into contact with bacteria and viruses and food antigens via breast milk, the immune system remains underdeveloped and therefore “overreacts”, resulting in not only an increased susceptibility to food allergy but also auto-immune diseases with a hyperactive immune system such as multiple sclerosis, rheumatoid arthritis, asthma, eczema etc. Being too dirty will promote disease also so the idea is to find the middle ground. If you want to reduce your child's risk of food allergy have a vaginal delivery, breastfeed until your child is at least 1, encourage natural outdoor play, avoid the overuse of antibacterials and most importantly don't vaccinate.

Leaky Gut Syndrome and Molecular Mimicry

 leaky gut process

Leaky gut syndrome, also known as increased intestinal hyperpermeability is a condition of an altered or damaged bowel lining caused by increased permeability of the gut wall resulting from toxins, poor diet, parasites, infection or medications. The leaky gut then allows substances such as toxins, microbes, undigested food, waste, or larger than normal macromolecules to leak through an abnormally permeable gut wall, initiating an immune reaction as the body makes antibodies to combat these foreign antigens and, in an immature immune system, can result in something called molecular mimicry.

Molecular mimicry results as the immature immune system cannot handle the onslaught of food antigens in the diet. According to molecular mimicry, food proteins that enter the bloodstream via a leaky gut can resemble proteins in our own body. Therefore the antibody made to combat that food protein can then attack our own cells, resulting in autoimmune disease, including Chron's disease and Ulcerative Colitis. In juvenile diabetes for example, an immature immune system cannot tell the difference between the bovine protein in milk and the cells of the pancreas, as they look so similar, so the antibodies attack both the milk protein and the pancreas resulting in early onset diabetes.

Wheat and dairy for example, are the two most common “allergic” foods. If digestive enzymes, glutase and lactase are deficient, the enzymes that break down gluten in wheat and lactose in milk respectively, the body is unable to digest the proteins in wheat and milk. As  a result of leaky gut syndrome, these undigested proteins make their way into the bloodstream as antigens (food proteins) and set up an immune overreaction which is what food allergy is.

For a full and detailed explanation on, not only the causes of the rise in food allergy and food intolerance but also the treatment, please see also The Naturopathic Causes and Treatment of the Rise in Food Allergy.

Food Allergy

The immune system normally protects the body from harmful foreign proteins by generating a response to eliminate them. An allergy is a specific form of food intolerance that involves the abnormal reaction of a person’s immune system to a substance, for example, a grain of pollen or food compound. It is important to note that this same substance would have no harmful effect in the majority of people. An immune response can involve various cell types and a variety of proteins that can trigger inflammatory responses. These foreign food substances are known as antigens. An antibody may be produced against an antigen.

The location within the body of signs and symptoms of food allergy vary in each individual, and they also vary in their timing and severity. Genetic predisposition and a susceptible immune system, notably elevated blood levels of immunoglobulin E (IgE), are the most important determinants of allergic disease. Exposure to environmental factors, including diet, is secondary to these.

Children with high blood IgE levels often suffer from asthma and hayfever and may also be allergic to one or more of the following;

Cows’ milk, wheat, soya, eggs, citrus fruit, or fish.

The prevalence is at its highest in young children, at around 5% although 80-90% of sufferers are said to “outgrow” their sensitivity by the age of three years.

The importance of breastfeeding to reduce food allergy

Breastfeeding is important to prevent food allergy as it exposes the developing immune system of a child to these food antigens so that their immune system learns to make antibodies. An antibody is a protein (an immunoglobulin) that specifically binds with the antigen to deactivate and eliminate it. The most important advice when it comes to breastfeeding is that the mother should ideally eat all the top 8 potentially allergenic foods when she is both pregnant and breastfeeding as this is how her baby becomes capable of dealing with these food proteins. Sometimes women are advised to avoid allergic foods. This is quite simply stupid advice and will lead to an increase in susceptibility to food allergy in that child.

Do children really outgrow food allergy?

Whether or not children actually outgrow allergies is controversial. From a naturopathic perspective, most do not actually outgrow them. Exposing a child to a food allergen will often result in an immediate symptom i.e. diarrhoea or skin rash. Take the food away and the symptom will disappear. However, constant exposure may not result in symptoms. This is because every time a child is exposed to an allergen the body sees this as a stress on the system. As a result of this perceived “stress”, the adrenal glands produce adrenal hormones including adrenalin, noradrenalin, cortisol and aldosterone.

High levels of adrenalin can result in hyperactivity disorders and high levels of cortisol suppress the immune system. Like corticosteroids, cortisol is also an immune suppressant. Therefore, the instant symptoms that the child previously experienced when trying a new food are no longer experienced as the immune system is suppressed. This is the mechanism whereby stress is said to suppress the immune system. As the adrenal gland can no longer keep up with the demands the secretion of adrenal hormones diminishes. This is known as “hypoadrenalism or adrenal exhaustion”.

There are many symptoms that occur with adrenal exhaustion. A good one in regard to children is dark circles under the eyes. These are known as “allergic shiners” and are an indication of adrenal exhaustion because of allergy. Long-term exposure to the food allergens can also generally deplete the body of the many nutrients required to manufacture these adrenal hormones. Particular nutrients are Zinc, magnesium, B5, B6, vitamin C and the amino acid, tyrosine.

Immediate and delayed allergy

Different forms of allergic reactions can be classified according to the mechanism of the reaction:

IgE Mediated (Immediate)

These reactions are immediate, can be severe, and are mediated by antibodies, usually IgE, interacting with mast cells. The mast cells are present below the surface of the skin and in the membranes lining the nose, respiratory tract, eyes and intestine. A substance known as histamine and other inflammatory mediators present in mast cells are released and cause symptoms such as a runny nose, asthma, dilation of blood vessels and flushing, swelling (e.g. of the lips) and difficulty in breathing.

This is known as an anaphylactic reaction and is usually localized to one or two organs of the body. Anaphylactic reactions to food vary considerably in their severity and the discomfort they cause but the majority are not life-threatening. However, the reaction can be very extreme and even fatal. Peanuts are well known for causing this type of extreme reaction. Other foods that are known occasionally to cause a severe (IgE mediated) reaction are tress nuts, eggs, milk and shellfish.

Genetic factors are considered to be of particular importance in the development of IgE mediated reactions. It has been suggested that, in these genetically susceptible infants, there is a primary immune regulatory defect, present before birth, which compromises their ability to cope with common environmental allergens that are harmless to the majority of the population. Children with IgE mediated allergy are more likely to react to a number of foods. The development in infancy of high levels of IgE to common food proteins, such as are present in eggs and cows’ milk, is often predictive of later allergy to inhalants, such as house dust and pollen.

Tests for food allergy

Food allergy can be detected by skin tests using an extract containing the appropriate antigen (allergen) or by laboratory tests (radioallergosorbent test, commonly known as RAST). These tests are also widely used in the diagnosis of an allergic disease that is not related to food. The results are likely to be positive in cases of immediate (IgE mediated) reactions to food, but general use of these tests in the diagnosis of food allergy is controversial due to the difficulties in obtaining pure food proteins for testing and frequent false-positive responses. Vega machines are also costly and unreliable and unfortunately often operated by under-qualified practitioners. There are other biological tests although, in reality, there is no such thing as a machine that tests for food allergy and my advice is if you want to burn money, just throw it on the fire.

The gold standard for food allergy testing is called an oligoantigenic diet and oral food challenge

Confirmation of the existence of an allergy can best be made by the use of an exclusion diet. This is the recommendation of top allergy specialists and the method used by all good naturopaths and nutritionists. This diet is called the oligo-antigenic diet or low reactive diet and oral food challenge. This should only be attempted under the supervision of a nutritionist or naturopath. The idea is to place the person on a restrictive diet for 2 weeks then “test” suspect foods. After the body has had a break from the food allergen it will more likely produce a stronger symptom that the person will recognise. For more information on a low reactive diet.

Non-IgE Mediated (Delayed)

These allergic reactions are delayed and are mediated by the cells of the immune system called immune complexes (antigen-antibody complexes), which continue to circulate in the bloodstream. These circulating antigen-antibody complexes can lodge in tissues creating all sorts of problems in particular, asthma, eczema and hayfever, but also can develop severe autoimmune disorders such as rheumatoid arthritis (children can get juvenile arthritis) and insulin-dependent diabetes. There is a strong relationship between the antibody for a bovine protein found in milk and the similarity of this protein to the pancreatic Islets of Langerhans for example.

Delayed reactions to food may take several hours or days to develop. Foods causing reactions of these types include cows’ milk, eggs, fish, wheat, other cereals, yeast, soya, pork, chocolate, citrus fruits, other fruit and some vegetables.

Remember, the development of specific immunoglobulin antibodies to environmental allergens encountered early in life is a normal, healthy physiological response to develop tolerance to the environment. Examples of these allergens include not only surface and airborne bacteria and viruses but also foods in particular and cows’ milk or egg. However, if there is an abnormal response and large numbers of antibodies are generated, this may cause an allergic reaction.

Cows milk allergy

The prevalence of cows’ milk allergy, for example, is estimated to be 2% in the first year of life. However, approximately 50% of infants are said to recover by one year of age and 90% by three years of age. This recovery may not be a true recovery but rather an indication that the adrenals glands have become exhausted.

Coeliac disease

Most experts agree that coeliac disease is a non-IgE mediated reaction brought about in genetically susceptible individuals by exposure to the gluten fraction of wheat and other gluten-containing grains.

Non-allergic Food Intolerance

There are various causes of food intolerance that are not due to an allergic reaction.

Enzymatic Causes

 lactose intolerance

The most common intolerance linked to the absence of an enzyme is lactose intolerance. Lactose is the sugar in milk. Before it can be absorbed and utilised by the body as fuel, lactose has to be broken down to its two component sugars, glucose and galactose. This requires the enzyme lactase. If lactase is produced in insufficient quantities, some of the lactose can pass undigested into the large intestine or the causing symptoms, such as diarrhoea. This undigested lactose can also enter the bloodstream where the immune system perceives it as an “antigen”. The body then sets up an immune reaction whereby an antibody is produced against the antigen. This can result in immune system disease as the immune system is overworked by the large presence of antigen-antibody complexes in the bloodstream. These complexes can then wreak havoc on the body by lodging in the tissues.

Inability to digest lactose is usually inherited and is most common in Asia and parts of Africa. People of Northern European descent are said to produce adequate amounts of the lactase throughout their lives. However, in areas where drinking milk after infancy is relatively uncommon, enzyme levels have become genetically programmed to start to fall after early childhood, and primary lactase deficiency among adolescents and adults is common. Having a low level of lactase production does not necessarily imply lactose intolerance. Indeed, lactose tolerance can be built up through the gradual re-introduction of lactose-containing foods in progressively increasing amounts.

In Ireland, approximately 5% of people have a lactase deficiency. However, as lactose intolerance is dose-dependent and most people still produce small to moderate quantities of lactase, only about a third of these, 1-2%, suffer any symptoms. The remainder are not likely to experience any ill effects when consuming quantities of milk and milk products typical of the Irish diet.

The main symptom of lactose intolerance is diarrhoea. However many symptoms can be attributed to lactose intolerance and this may be unbeknownst to the person such as autoimmune diseases or chronic low-grade infections in particular sinusitis, hay fever, asthma and eczema.

Pharmacological Causes of Food Intolerance

There are many food components that can produce a pharmacological effect. These effects are usually insignificant in clinical terms unless the substance is consumed in very large quantities, e.g. caffeine. The group of substances known as vasoactive amines, which includes histamine and tyramine, are normal constituents in a variety of foods such as cheese, chocolate, wine, pickled foods and citrus fruits, particularly oranges.

In addition, some foods have a histamine releasing action, e.g. egg whites, shellfish, strawberries, tomatoes and chocolate. Histamine induced symptoms are similar to those found with IgE mediated food allergy. Symptoms such as a runny nose, asthma, dilation of blood vessels and flushing, swelling (e.g. of the lips) and constriction of the bronchioles resulting in difficulty breathing. They can be distinguished by the relatively large amount of the substance needed to trigger the reaction in contrast to the minute quantity needed to trigger an allergic reaction. See also Histamine Containing and Releasing Foods.

Toxic/Irritant Substances

Some foods contain toxins or substances that can irritate the lining of the intestine. Examples of natural toxins include proteases inhibitors in grains and legumes, cyclopeptides and muscarine in mushrooms, and oxalates in spinach and rhubarb.

Adverse Reactions to Food Additives

Food additive reactions are an intolerance to artificial and natural chemicals found in packaged and processed foods.


The Sulphites

These chemicals in the form of gases cause lung irritation and may trigger asthma. They are commonly found in liquid form in cold drinks and fruit juice concentrates, but also in wine and sprayed onto foods to keep them fresh and prevent discolouration or browning. They are used to preserve smoked and processed meats, dried fruit (apricots) and salads. In the solid form, sulphites can cause urticaria when ingested. (E220 - E227) Sulphur dioxide, Sodium sulphite, Sodium bisulphite, Potassium bisulphite and Potassium metasulphite.

Benzoic acid and Parabens

Benzoates and parabens have antibacterial and anti fungal properties for prevention of food spoilage. These agents are added to pharmaceutical and food products and occur naturally in prunes, cinnamon, tea and berries. They may cause urticaria, asthma and angioedema. (E 210 - E 219) Sodium benzoate, Methylparaben, Propylparaben and Heptylparaben.


Fat and oils in food turn rancid when exposed to air. Synthetic phenolic antioxidants (BHA and BHT) prevent this spoilage from happening but can trigger asthma, rhinitis and urticaria. (E320 - 321) Butylated hydroxyanisole (BHA) and Butylated hydroxytoluene (BHT)).

Flavour enhancers

Aspartame a low-calorie sweetener can trigger urticaria (nettle rash), itchy hives and swelling of the body.

Monosodium Glutamate (MSG)

Can trigger the "Chinese Restaurant Syndrome" of headache and burning plus tightness in the chest, neck and face. (E 620 - E 635 )


Azo dyes (Tartrazine) and Non-azo dyes (erythrocine). All colourings must now be labeled. They can trigger hives, urticaria, asthma and generalized allergic reactions. (E 100 - E 180)


Nitrites Give meat a pink colour to look more attractive and found in bacon, salami and frankfurters (E 249 - E 252) Nitrates should not be permitted in foods for young children, They may cause dizziness, headaches, difficulty breathing, they are a potential carcinogen.

Emulsifiers and stabilisers

Stop oil and water components separating, as in ketchup and mayonnaise, but do not cause adverse reactions. Naturally occurring substances in food causing adverse reactions.

Vaso-active amines

Natural Histamine, Serotonin and Tyramine occur in some ripe cheeses, fish, cured sausage, red wine, chocolate and pickled foods and can cause cramping, flushing, headache and palpitations in a dose-related manner. Caffeine found in foods, medication, tea, coffee and cola drinks induces dose-dependent agitation, palpitations, nausea and tremors.


Salicylates are aspirin-like naturally occurring chemicals. Salicylates induce urticaria, asthma and nasal polyps. They are found in curry powder, paprika, dried thyme, oranges, apricots, ginger, honey, berries and fruit skins, tea and almonds. Salicylate sensitive individuals also tend to have adverse reactions to benzoates and tartrazine. Always read all packaged food labels, legislation now ensures that additives must be clearly labeled. See also Salicylate Sensitivity List.

E Numbers – all additives used within the European Community must have an E number. See also E numbers - What they mean.

Summary of food additives to avoid

  • Colourings: (E100-180) Tartrazine E102, Sunset YellowE110
  • Flavourings: (E620-635) Monosodium Glutamate E620
  • Preservatives: (E200-297)
  • Benzoates (E210-219)
  • Sulphites (E220-227)
  • Nitrates (E249-252).
  • Antioxidants (E320-321) BHA (E320) & BHT (E321)

Dietary advice to reduce food allergy and intolerance

Rotate cows milk yoghurt (it is lactose-free), soy milk, rice milk, goat milk and oat milk. Buy goat or sheep milk cheese from the local food market. Most feta in the supermarket is cows milk, some is goats, you must ask.

Wheat, rye, barley and oats contain gluten, a common culprit. Good alternatives are millet, polenta, rice, buckwheat and quinoa. All these can be used instead of pasta. There are gluten-free flours such as soy flour, potato flour and chickpea flour or gram flour. Spelt bread is a good, wheat free alternative or try rice crackers or oatcakes. There are many pasta alternatives such as rice noodles, corn noodles or buckwheat noodles.

Decrease red meat consumption as this is high in arachidonic acid which is pro-inflammatory. Increase consumption of anti-inflammatory foods such as oily fish, fruits and vegetables rich in vitamin C and bioflavonoids such as blueberries, cherries and peppers. Fresh turmeric and ginger are strong anti-inflammatories.

Avoid preservatives, flavourings and colourings and excess consumption of foods high in salicylates and vasoactive amines. Print this page out and take it shopping! The message is simple. When it comes to allergies, if you love them don’t feed them junk!

Beneficial supplements to reduce the symptoms of food allergy


Glutamine is an amino acid strongly implicated in gut repair to prevent “leaky gut”, thereby reducing the allergens getting into the bloodstream. Probiotics like acidophilus and bifidus There is loads of quality evidence to suggest that healthy bowel flora decrease risk of atopic diseases such as asthma, eczema and hay fever. Breastfeeding has a similar effect. In fact, breastfed babies develop antibodies to antigens in their mother’s milk, exercising and strengthening their immune system and naturally reducing their risk of food allergy.

Digestive enzymes

There are many enzymes involved in the breakdown of foods and a supplement can help if your digestion is impaired, however this is recommended for short-term use only.

Quercetin and Vitamin C

Both are natural anti-histamines. Quercetin is a bioflavonoid found in large amounts in apples and red onion and capers. It is a strong anti-histamine. Methione and B6 Methione and B6 are cofactors to deaminase, an enzyme involved in the breakdown of histamine. In fact, the enzyme that breaks down alcohol is the same enzyme that breaks down histamine, so reduce alcohol consumption too..

Please book a consultation This email address is being protected from spambots. You need JavaScript enabled to view it.  or consult your doctor before taking natural remedies if you are on medication or if symptoms persist.

Carina Harkin BHSc.Nat.BHSc.Hom.BHSc.Acu.

Cert IV TAE.