Developments in food allergies and eczema.
The incidence of food hypersensitivity in children is one of the most discussed topics in allergic diseases . Until recently food has been dismissed as a ‘speculative’ contributory factor to allergic conditions such as eczema and asthma but thanks to developments in research over the last five years we now know that food sensitivity is a primary cause of allergic conditions. In 2008 one of the largest cohort studies (over 900 children under the age of three years old) on allergies and food hypersensitivity, to date, was conducted Venter and colleagues on the Isle of Wight. By the age of 3 years, 5–6% of children where proven to suffer from food hypersensitivity contributing to the allergic symptoms such as eczema, colic or reflux .
But what are food allergies and what can we do to avoid them?
All food allergies involve the immune system. When a food is introduced to a food that it does not like, the immune system begins an attack to protect the body. To do this it releases specialised cells called antibodies. These hunt out the threatening invader and aim to kill it, hence their name as the ‘hunter killer cells’.
In the case of allergies, this particular antibody or ‘hunter killer’ cell is called IgE and the next time that threatening food is eaten the IgE cell will signal the release of a cocktail of natural chemicals, the ring leader being histamine.
Histamine is the chemical that causes the physical signs of a reaction such as redness, itchiness, burning, mucus secretions. This same process also happens when the invader is in a form other than food such as pollen (in the case of rhinitis or hayfever). The symptoms are usually limited to the face, throat and chest.
This reaction is instant, symptoms presenting within an hour. When the allergy is extreme, a surge of histamine is released can cause the symptoms of anaphalyxis.
However the immune system may also react in another, slyer, less detectable way, with symptoms not showing for up to 72hours. These symptoms can range from gut disturbances to skin conditions such as eczema. This is known as the non-IgE mediated response. With the time delay, you can imagine how much harder it becomes to narrow down the culprit food.
Some of the most common culprit foods for both responses are wheat/gluten, cows milk, egg, shellfish and nuts.
These bodily reactions are on the increase but why?
The prevalence of food allergies has dramatically increased over the last 20 years with hospital admissions increasing by 900%. There are a number of theories as to why this is. At the Gluten and Allergy Free conference last week, Dr Adam Fox, Consultant Paediatric Allergist at Guys and Thomas’ Hospitals and colleagues endorsed the ‘hygiene hypothesis’ as a very real factor. The hygiene hypothesis simply states that our increasingly sterile environments where kitchen surfaces are scrubbed bleached and sanitized within an inch of their lives actually reduces our exposure to bacteria which strengthen our immune system.
Genetics certainly play a central role in an individuals predisposition to atopic allergies (allergies relating to an external irritant). If you have a parent, brother or sister with an allergic disease, such as asthma, eczema or a food allergy, you are at higher risk of developing a food allergy. However, you may not develop the same food allergy as your family members. However where previous dogma suggested avoiding common allergens during pregnancy, such as peanuts, research now shows us that avoidance can in fact enhance the risk of developing food allergies. Experts now recommend the route of ‘oral tolerance’ where exposure to allergens (such as peanuts, cows milk, eggs, dairy) during pregnancy and infancy (before the end of the sixth month of the infants life) can minimize the development of allergies. Further to this, an infants exposure to gluten and wheat between four to six months sets up the best chances of avoiding a wheat or gluten allergy; this is of course unless the pregnant mother herself has an allergy to a food that she must avoid for her own health. This has now been adopted in the COT guidelines, redeveloped in 2008, on food allergies.
Infants who have suffered from eczema as a baby (before one year of age) have a 65% chance of developing other food allergies later in life. Expert thought is that the infant eczema is commonly caused by an existing food allergy to cows milk.
Gut flora is demanding increasing focus in the treatment of atopic conditions and the management of food allergies. Several studies have shown that infants in groups supplemented with probiotics were significantly less likely to develop eczema later in life. Further studies are currently running to try to determine whether this encouraging effect will continue to hold true
Developments in food allergies and eczema.
The incidence of food hypersensitivity in children is one of the most discussed topics in allergic diseases . Until recently food has been dismissed as a ‘speculative’ contributory factor to allergic conditions such as eczema and asthma but thanks to developments in research over the last five years we now know that food sensitivity is a primary cause of allergic conditions. In 2008 one of the largest cohort studies (over 900 children under the age of three years old) on allergies and food hypersensitivity, to date, was conducted Venter and colleagues on the Isle of Wight. By the age of 3 years, 5–6% of children where proven to suffer from food hypersensitivity contributing to the allergic symptoms such as eczema, colic or reflux .
But what are food allergies and what can we do to avoid them?
All food allergies involve the immune system. When a food is introduced to a food that it does not like, the immune system begins an attack to protect the body. To do this it releases specialised cells called antibodies. These hunt out the threatening invader and aim to kill it, hence their name as the ‘hunter killer cells’.
In the case of allergies, this particular antibody or ‘hunter killer’ cell is called IgE and the next time that threatening food is eaten the IgE cell will signal the release of a cocktail of natural chemicals, the ring leader being histamine.
Histamine is the chemical that causes the physical signs of a reaction such as redness, itchiness, burning, mucus secretions. This same process also happens when the invader is in a form other than food such as pollen (in the case of rhinitis or hayfever). The symptoms are usually limited to the face, throat and chest.
This reaction is instant, symptoms presenting within an hour. When the allergy is extreme, a surge of histamine is released can cause the symptoms of anaphalyxis.
However the immune system may also react in another, slyer, less detectable way, with symptoms not showing for up to 72hours. These symptoms can range from gut disturbances to skin conditions such as eczema. This is known as the non-IgE mediated response. With the time delay, you can imagine how much harder it becomes to narrow down the culprit food.
Some of the most common culprit foods for both responses are wheat/gluten, cows milk, egg, shellfish and nuts.
These bodily reactions are on the increase but why?
The prevalence of food allergies has dramatically increased over the last 20 years with hospital admissions increasing by 900%. There are a number of theories as to why this is. At the Gluten and Allergy Free conference last week, Dr Adam Fox, Consultant Paediatric Allergist at Guys and Thomas’ Hospitals and colleagues endorsed the ‘hygiene hypothesis’ as a very real factor. The hygiene hypothesis simply states that our increasingly sterile environments where kitchen surfaces are scrubbed bleached and sanitized within an inch of their lives actually reduces our exposure to bacteria which strengthen our immune system.
Genetics certainly play a central role in an individuals predisposition to atopic allergies (allergies relating to an external irritant). If you have a parent, brother or sister with an allergic disease, such as asthma, eczema or a food allergy, you are at higher risk of developing a food allergy. However, you may not develop the same food allergy as your family members. However where previous dogma suggested avoiding common allergens during pregnancy, such as peanuts, research now shows us that avoidance can in fact enhance the risk of developing food allergies. Experts now recommend the route of ‘oral tolerance’ where exposure to allergens (such as peanuts, cows milk, eggs, dairy) during pregnancy and infancy (before the end of the sixth month of the infants life) can minimize the development of allergies. Further to this, an infants exposure to gluten and wheat between four to six months sets up the best chances of avoiding a wheat or gluten allergy; this is of course unless the pregnant mother herself has an allergy to a food that she must avoid for her own health. This has now been adopted in the COT guidelines, redeveloped in 2008, on food allergies.
Infants who have suffered from eczema as a baby (before one year of age) have a 65% chance of developing other food allergies later in life. Expert thought is that the infant eczema is commonly caused by an existing food allergy to cows milk.
Gut flora is demanding increasing focus in the treatment of atopic conditions and the management of food allergies. Several studies have shown that infants in groups supplemented with probiotics were significantly less likely to develop eczema later in life. Further studies are currently running to try to determine whether this encouraging effect will continue to hold true.
Supporting the immune system and the body’s defence against allergens through a varied healthy diet is vitally important. Nutrients called antioxidants (vitamin C and E to name just two) found in nearly all fruits and vegetables are needed not only to support this mechanism but also contain a natural anti-histamine effect. Taking 500mg of vitamin C two –three times per day is recommended by many natural health practitioners for this reason.
Rates of food allergies are higher in countries that are nearer the North Pole, and a reduction in Vitamin D in the diet and from sunlight may be responsible for this increase. Currently, there is no hard evidence to either prove or disprove this theory.
Sicherer SH, Munoz-Furlong A, Sampson HA. Prevalence of peanut and tree nut allergy in the United States determined by means of a random digit dial telephone survey: a 5-year follow-up study. J Allergy Clin Immunol 2003;112:1203–1207.
Venter C et al. Prevalence and cumulative incidence of food hypersensitivity in the first 3 years of life. Allergy march 2008.
Abrahamsson, Thomas R., et al. "Probiotics in Prevention of IgE-Associated Eczema: A Double-Blind, Randomized, Placebo-Controlled Trial." Journal of Allergy and Clinical Immunology. May 2007 119(5): 1174-80. 18 Aug. 2008.
Kukkonen, Kaarina, et al. "Probiotics and Prebiotic Galacto-Oligosaccharides in the Prevention of Allergic Diseases: A Randomized, Double-Blind, Placebo-Controlled Trial." Journal of Allergy and Clinical Immunology. Jan. 2007 119(1): 192-98. 18 Aug. 2008.
Lee, Joohee, et al. "Meta-Analysis of Clinical Trials of Probiotics for Prevention and Treatment of Pediatric Atopic Dermatitis." Journal of Allergy and Clinical Immunology. Jan. 2008 121(1): 116-21.e11. 18 Aug. 2008.
