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Food Allergy – The Explosion - What can we do?One in five individuals in Australia have at least one allergy, which places Australia with one of the highest prevalence's of allergy amongst the developed world (1). If the present trend continues it is estimated that there will be a 70% increase in the number of Australians with allergies by 2050, which correlates to 7.7 million people (1). The high and ever increasing prevalence of food allergy and atopic disease has researchers identifying genetic predisposition as a risk factor, where in children with neither parent having an allergy, a child will have a 20% chance of having one allergy disorder (2). If one parent has an allergy disorder the risk increases to ≈ 40%. If both parents have allergy disorders then the risk increases to 60 - 70%. In addition to genetics some studies reveal the importance of the impact of environmental influences (2). Researches from the John Hopkins Children Centre believe there is a trend toward more severe and more persistent allergies (3). However it should be noted that the severity of allergy presentation in a family history is not a good predictive guide as to how sensitive a child may be (4). In many cases when the presentation of allergy or food intolerance in the parent is only mild the possibility of allergy or food intolerance being related to a child’s symptoms can be overlooked (4). The allergen pathway commences before the child is born, with allergens crossing the placenta, programming the immune system down the allergy pathway (4). This impact commences about halfway through the pregnancy, which is the time a mother could start focusing on minimising allergen exposure via modifying the maternal diet and minimising environmental factors (4). The modification of the maternal diet encompasses a varied diet based on the Australian Dietary Guidelines (4). It discourages bingeing on any food in the second half of the pregnancy and during breastfeeding (4). There should be the total avoidance of egg, seed, peanut and nut (from the household) (4). There are precautions to take with respect to milk and dairy foods, and also fish and other sea foods, and a minimisation of one’s intake of soybeans and other legumes (4). With respect to meats, allergies can occur, with pork allergy tending to be more likely to occur when eaten with fat (4). It is recommended that lean meats are consumed. Wheat, oats, barley and buckwheat can all cause allergy and tend to only cause symptoms in highly allergic infants (4). In relation to vegetables, potato allergy is commonly seen in the highly allergic child, however in general there is no reason to modify vegetable intake during pregnancy (4). This may, however, be necessary during breastfeeding as some infants may react to tomato and spicy foods (5). Of the fruits the avoidance of the citrus family is recommended, with the reactions occurring to fruit often being related to a food intolerance rather than an allergy (5). Kiwifruit is the most allergenic fruit with the possibility of allergy development in the highly sensitive child (4). The environmental measures include the total avoidance of cigarette smoke, ensuring houses are well ventilated, particularly kitchens where there are gas cook tops, and taking dust mite allergen precautions and pet precautions, particularly with respect to cats, rabbits, guineas pigs and mice (4). There should be total latex avoidance, in particular powdered latex products that cause the allergy to develop (4). The allergen pathway highlights the possibility of the presentation of allergy related symptoms early in life, with researchers identifying that 2.2 – 5.5% of infants have food hypersensitivity during the first year of life (5). In the presentation of allergy in children we usually find that they are allergic to two or three different foods, with the most common being peanut, egg, milk, other nuts, sea foods and sesame. Wheat, soy and rice can also cause allergies (5). We should also consider the possibility of food intolerances. There is often confusion about the difference between allergy and intolerance and the terms are sometimes used in place of one another. There is a difference between food allergy and intolerance both in the types of foods and the way they affect individuals. Food intolerance or sensitivity to certain foods is defined as the inability to properly process and fully digest certain foods, leading to chronic symptoms. A food intolerance does not involve the immune system though rather involves the stimulation of nerve endings in tissues by a chemical component which may be naturally occurring, an additive, or a combination (6). Symptoms of food intolerance are extensive and variable. They can be very similar to those of an allergic response. Symptoms of allergic reaction are usually sudden, while an intolerance response may sometimes occur straight after ingesting a problem food or have a delayed response. Symptoms may take 12-24 hours to develop. The severity of symptoms can also depend on the quantity of the problem food ingested. They may not occur until a threshold amount is ingested. A child that continually screams when being breast fed, has unsettled sleep patterns, wakes moaning with writhing, has loose stools, is colicky, has eczema, nappy rash or reflux, or displays irritable, impulsive or overactive behaviour should prompt us to consider the possibility of food allergy/food intolerance. The initial investigation of a possible food allergy/food intolerance can be undertaken by an experienced dietitian, while awaiting an appointment with an allergist. Once identified then an appropriate management plan can be established. Continual guidance and support are key factors in the management of these conditions through what can be a challenging time for children and their families. See also Food Allergy vs. Food Intolerance References1. Australasian Society of Clinical Immunology and Allergy, November 2007, ‘Economic Impact of Allergies’. |
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