Food allergies and intolerances
Do you know the difference between food allergies and food intolerances or sensitivities?
What is a food allergy?
The body’s immune system is responsible for identifying invaders – such as bacteria and viruses – and triggering a response to fight the infection. With IgE-mediated food allergies, the body sees the protein in some foods as a dangerous invader and attempts to get rid of it. To do this, the immune system produces antibodies called immunoglobulin E (IgE). This triggers the release of histamine into the blood. Histamine is responsible for causing the allergic reaction in the body. For some people, the reaction may be mild, but for others even a tiny amount of the allergen can cause a serious reaction. When a food allergy leads to anaphylaxis, where the chest closes and the patient becomes unable to breathe, it may be fatal.
Symptoms: * hives (skin) * tingling/itching in the mouth * swollen tongue * coughing * difficulty breathing * wheezing * vomiting * stomach pain * swelling throat * drop in blood pressure (causing dizziness/fainting) *
Common food allergies
- Cow’s milk
- Peanuts
- Tree nuts
- Shellfish
- Eggs
- Fish
- Soya
- Wheat (not gluten)
Diagnosis and treatment
Your doctor will order a blood test in order to determine or confirm what you are allergic to. This test is called an allergen specific immunoglobulin E (IgE) blood test. Each allergen causes a specific type of IgE antibody and these can be identified in the blood. A number of allergens can be tested, among them, specific foods, bee stings, animal dander, house dust, mould spores, or even drugs like penicillin and many others allergens. Your doctor can also order an IgE level test which determines the level of immunoglobulin in your blood. An allergy skin test can also give conclusive results.
Based on your results, the doctor may include antihistamines, cortisone (inflammation) and a bronchodilator for asthma symptoms in your treatment plan. You will also be advised to take extra care not to eat the allergy food. This means that you will have to read food package labels – carefully checking the ingredient list for foods that you are allergic to.
Food allergies can be life threatening and even if you have never had a severe reaction before, you may in the future. Your doctor may prescribe an epinephrine pen for you to keep with you in case you accidently ingest the allergy food, or in the case of other allergens, like bee stings.
What is food intolerance or sensitivity?
Reactions to food that do not produce the immediate immune responses described above are called food intolerances or immunoglobulin G (IgG) mediated allergies. These are usually common foods that most people are able to eat without a reaction. In the sensitive individual, ingestion of the food causes the production of IgG antibodies (also a reaction to a protein found in the food) which builds up in the body over time, causing inflammation. Symptoms may develop quite soon after you have eaten the offending food or the reaction may only occur several days later. Not everyone experiences the same reactions.
Sensitivities may be caused by chemicals or additives in food like preservatives, sulphites or colourants or a lack of specific enzymes needed to break down a certain food (like lactose intolerance). Some people with food intolerances can eat the foods in small quantities with no ill effects, but others can become very ill when just a small amount of the allergy food is eaten.
Symptoms: * heart burn * nausea * reflux * vomiting * stomach cramps * headaches * migraines * gas * bloating * neurological symptoms (brain fog) * mood changes * IBS symptoms * chronic rhinitis * fibromyalgia *
Common intolerances
- Cow’s milk (proteins casein and whey)
- Lactose (sugar in milk)
- Egg – white and yellow
- Gluten (non-celiac gluten sensitivity)
- Various ground and tree nuts
- Soya
This is by no means an exhaustive list and many people are surprised to find other common foods on the red list after an IgG allergy test. These include bananas, peas, celery and various types of fish.
Celiac disease is an autoimmune disease, occurring in 1 in 100 genetically predisposed people. Gluten found in wheat, barley and rye causes extensive damage to the small intestines of celiacs. The body attacks the lining of the small intestine, causing damage to the villi which are responsible for nutrient absorption. This causes severe diarrhoea and malnutrition due to the mal-absorption of nutrients, as well as possible anaemia and an increased risk for lymphoma. Undiagnosed, celiac disease can lead to long term health complications. A blood test followed by a biopsy (endoscopy) of the small intestine will confirm the diagnosis.
Diagnosis and treatment IgG food allergy tests are available at some pharmacy clinics, testing anything from 50 right up to 200 different foods. The Cambridge Nutritional Sciences (CNS) FoodPrint test can be done through Synexa Life Sciences in Cape Town. A homeopath, naturopath or dietician can help you make sense of your test results. You will be advised to eliminate all foods found on the red and yellow list, and only eat foods from the green list for a number of months. Depending on your results, you should be able to bring back foods gradually over a period of time.
Resources
- Web MD, www.webmd.com
- Mayo Clinic, www.mayoclinic.com
- Cam Nutri, www.camnutri.com
- Health Line, www.healthline.com
- Kid’s Health, www.kidshealth.org