Allergies are very common and are on the rise. When I was a kid allergies were almost nonexistent. Now in Australia and New Zealand, allergies affect around one in three people at some time in their lives. In the UK, it is estimated that up to 50% of children are diagnosed with an allergic condition. More than 17 million Europeans have a food allergy, and hospital admissions for severe reactions in children have risen seven-fold over the past decade, according to the European Academy of Allergy and Clinical Immunology (EAACI) and it is estimated that up to 15 million Americans have food allergies.
Researchers are trying to discover why food allergies are on the rise in developed countries worldwide, and to learn more about the impact of the disease in developing nations. Before we get to that, how do we define an allergy?
Allergy occurs when a person’s immune system reacts to substances in the environment that are harmless for most people. These substances are known as allergens and are found in house dust mites, pet hair, pollen, insects, moulds, foods and some medicines. When the allergen enters the body it triggers an antibody response. The antibodies attach themselves to special cells, called mast cells. When the allergen comes into contact with the antibodies, the mast cells respond by releasing certain substances, one of which is called histamine. When the release of histamine is due to an allergen, the resulting swelling and inflammation is extremely irritating, uncomfortable and could also cause death.
Areas most effected are the:
– nose and/or eyes producing symptoms such as hay fever, rhinitis and conjunctivitis;
– skin producing symptoms such as eczema or hives; and
-lungs triggering asthma.
Allergy symptoms typically appear within minutes to two hours after you have been exposed to the allergen. Allergies may be confused with food intolerances, which are characterised by slow-onset symptoms. The reactions to intolerance can occur between 8 and 72 hours after consumption of the intolerant food or additive, so are more difficult to pinpoint than food allergies. Lactose intolerance usually produces symptoms, which are more delayed, and gradual and may include bloating, abdominal cramps, flatulence, altered bowel movements and lethargy.
Researchers have suggested that a number of factors might cause someone to become allergic:
1. Genetics
If your mum and dad have allergies than you have a higher chance of developing an allergy. This increased tendency to develop allergies because of genes is known as atopy. Changes in genes take many hundreds of years to cause consequences in disease. So atopy/genetic tendency alone cannot account for the current increase in allergy seen over the past few decades. Current research is investigating how genes can be ‘turned on or off’ by environmental factors.
2. Environmental factors
Our environment today is very different from 50, 60, 70 or 80 years ago. Epigenetics, the study of changes in organisms caused by modification of gene expression has been considered as a potential mechanism involved in the development of allergic diseases. The exposure to environmental factors during early childhood may induce a long-lasting altered genetic state influencing the development of asthma or atopic dermatitis and food allergy. Progresses have been made linking environmental pollution, environmental tobacco smoke and diet exposure with atopy through epigenetic mechanisms. One hypothesis for which there are accumulating data, is that the increase in allergy mirrors our declining exposure to bacteria and other micro-organisms in our environment. This has led to the Hygiene Hypothesis.
3. The Hygiene Hypothesis
This hypothesis suggests that the immune system needs to come into contact with a variety of micro-organisms and bacteria while it is developing at the infant stage, in order that it responds appropriately later in life. Even more important is how a baby is birthed. Concurrent with the trend of increasing caesarian deliveries, there has been an epidemic of both autoimmune diseases such as type 1 diabetes, Crohn’s disease, and multiple sclerosis and allergic diseases, such as asthma, allergic rhinitis, and atopic dermatitis. Most current literature suggests that the gastrointestinal tract of a normal foetus is sterile. During a vaginal birth and rapidly thereafter, bacteria from the mother and the surrounding environment colonises the infant’s gut. Intestinal bacteria are key in promoting the early development of the gut’s mucosal immune system, both in terms of its physical components and function.
We also now live in an environment where we use cleaners and personal care products containing anti-microbial agents. Food preparation is more hygienic than ever and we swim in chlorinated pools (chlorine is natural antibiotic). Inadequate exposure to environmental micro-organisms may therefore result in the immune system of atopic children developing a tendency towards allergy. Some research shows that children who have regular contact with farm animals have a lower incidence of allergy.
Other researchers suggest the use of vaccines and increase use of antibiotics has defeated many infections that previously killed large numbers of the population however, the immune system does not have a chance to produce a strong immune response against infectious agents. This may be one of the factors why many people’s immune systems are now reacting to allergens.
4. Changes in the foods we eat
Our diets tend to include more poorly sourced food and processed, packaged foods and less fresh foods. Source of our food means how food is grown- in natural nutritious soil or soil that is fortified artificially with chemical fertilisers and/or food that is grown from GM seeds and highly sprayed with pesticides such as Glyphosate. Glyphosate has been shown to cause gut dysbiosis and destroys the small intestinal villi causing malabsorption of nutrients. Processing destroys valuable nutrients. Vitamin D, omega-3 fatty acids or antioxidant deficiencies may contribute to the development of allergies.
5. Changes in how we are exposed to food allergens
Common allergens are found in many processed or packaged foods, added as an ingredient or used in manufacturing. An example is what is found in the wax of fruit. There are two types of proteins used in the wax industry, soy and casein. Casein is found in milk. Soy and casein are common allergens. Cosmetic and personal care products also contain common allergens whether they are natural or chemically based. Common allergens such as wheat protein, milk, and certain essential oils are found in hair shampoo and conditioners.
In next week’s post I review how we can reduce our exposure to allergens, reduce the severity of allergic symptoms, alleviate symptoms naturally and ultimately prevent allergies from reoccurring.