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It is estimated that approximately 15% of children born in the Western countries are currently affected by one or other type of hypersensitivity to foods, i.e. food allergies. In South Africa this problem is also assuming alarming proportions/ numbers. Even more frequent are cases of food intolerance.

Food allergies and Food intolerances
Food allergies are defined as reproducible reactions/symptoms occurring after ingestion of a specific food (food additive, such as monosodium glutamate, an artificial food colourant, tartrazine), for which immunological reactions are proven. 

The widespread allergy to egg white, nuts, fish or strawberries can be manifested as an inflammatory reaction every time an offending food (allergen) is consumed. In these cases a special type of antibody (IgE) is produced and the affected individuals may develop various disorders of the gastrointestinal tract, skin problems such as urticaria or chronic dermatitis, or respiratory problems manifested as rhinitis or asthma.

Food intolerances, on the other hand, are gastrointestinal tract reactions (e.g. diarrhoea, cramps) to a particular food, not based on an immunological reaction.

The following explanations have been proposed:

  • Genetic predisposition
  • Dietary factors
  • Incorrectly functioning intestinal mucosa barrier (hyper-permeability of the child’s gastrointestinal tract)
  • Inflammation of the intestinal lining
  • A delay in the development or the lack of maturation of the common mucosal immune system
  • A strong bias in newborn infants towards the antibodybased immunity

Probiotic bacteria and allergies
The role of probiotic organisms in the prevention of the development of food allergies and in alleviating these disorders has been extensively investigated over the last few years in a number of clinical trials. The outcome of these trials clearly established the beneficial role played by probiotic microorganisms in these disorders. The mechanisms through which probiotics can exert their influence are of dual nature.

The best-known example is lactose intolerance, caused by too low levels of an enzyme that splits lactose into smaller molecules. Both can be overcome, at least theoretically, either by placing the patient on an exclusion diet, eliminating the allergy-inducing food, or by inducing oral tolerance (the generation of active immunological suppression) towards the offending substance.

Both approaches, apart from the difficulties associated with the identification of foods responsible for the allergic reactions, are likewise difficult to implement, particularly among children, and frequently are not successful.

Causes of these disorders
Opinions on the origin and causes of these disorders are highly controversial and there are no easy and unambiguous answers. They can directly alter the allergen itself or can affect the response of the host in a number of ways.
By enzymatic action probiotics can split the molecule of the allergen into smaller molecules (e.g. proteins can be digested to peptides and amino acids) and/or they can change the structure of the molecule and thus alter the immunogenicity of the offensive compound.  The action of probiotics on the host organism is much more complex and focuses primarily on:

  • maintaining the integrity and functionality of the intestinal mucosa;
  • the maturation of the human immune system; and
  • enhancement and/or control of the functions of a child’s immune system.

Dietary factors
As far as dietary factors are concerned, dietary antioxidants such as omega-3 as well as omega-6 fatty acids appear to be the most important in the prevention of allergies. They can be administered easily in the form of flaxseed oil capsules.

Mothers, whose children suffer from any form of allergies, should consult an experienced dietician.

Dr Ela Johannsen
(MSc Microbiology, Lodz, Poland, PhD Microbiolology, Rhodes University, Grahamstown)
E-mail address: This e-mail address is being protected from spambots. You need JavaScript enabled to view it
References provided on request.