Writing in the Journal of the American Medical Association (JAMA), scientists from Stanford University report that, despite a lot of literature being available about food allergies, “high-quality studies are few”.
“Prime needs for advancement of the field are uniformity in the criteria for what constitutes a food allergy and a set of evidence-based guidelines on which to make this diagnosis,” wrote the authors, led by Jennifer Schneider Chafen.
An estimated four per cent of adults and eight per cent of children in the 380m EU population suffer from food allergies, according to the European Federation of Allergy and Airways Diseases Patients' Associations.
The most common food allergen ingredients and their derivatives are cereals containing gluten, fish, crustaceans, egg, peanut, soybeans, milk and dairy products including lactose, nuts, celery, mustard, sesame seed, and sulphites.
“However, currently licensed treatments target only the symptoms of reactions and anaphylaxis [severe allergic reaction], not the allergies themselves,” wrote the authors.
Furthermore, they note that evidence as to whether the incidence of food allergies is increasing is lacking.
Such findings are based on an analysis of 72 studies on allergies to foods including cow's milk, eggs, peanut, tree nut, fish, and shellfish.
For many people, the best approach is to avoid the food altogether, as evidenced by the boom in the ‘free-from’ food market, which been enjoying sales growth of over 300 per cent in the UK since 2000, according to market analyst Mintel.
The literature only provides one example of the efficacy of such elimination diets. “Many authorities would consider randomised controlled trials of elimination diets for serious life-threatening food allergy reactions unnecessary and unethical; however, it should be recognized that such studies are generally lacking for other potential food allergic conditions,” wrote the researchers.
Looking towards the potential solutions, Schneider Chafen and her co-workers note that probiotics in conjunction with breastfeeding or hypoallergenic formula appear to help prevent food allergy, however science is also lacking of their independent effects.
The immunotherapy approach is “promising”, said the researchers, “but data are insufficient to recommend use”.
“This systematic review of food allergies found that the evidence on the prevalence, diagnosis, management, and prevention of food allergies is voluminous, diffuse, and critically limited by the lack of uniformity for the diagnosis of a food allergy, severely limiting conclusions about best practices for management and prevention,” wrote the authors.
Hope
Dr. Ronald van Ree from the University of Amsterdam told the BA Festival of Science in England in 2006 that food allergies could be consigned to the history books within a decade if the combination of biotechnology and vaccines work as planned.
Dr van Ree noted that a clever combination of biotechnology (hypo-allergenic recombinant allergens) and vaccine-development (novel adjuvants based on anti-inflammatory molecules from pathogens) could provide new tools to treat food allergy.
Source: JAMA
2010, Volume 303, Number 1, Pages 1848-1856
“Diagnosing and Managing Common Food Allergies: A Systematic Review”
Authros: J.J. Schneider Chafen, S.J. Newberry, M.A. Riedl, D.M. Bravata, M. Maglione, M.J. Suttorp, V. Sundaram, N.M. Paige, A. Towfigh, B.J. Hulley, P.G. Shekelle