Paediatricians and allergologists have put together guidelines with recommendations from studies demonstrating that the risk for hay fever, atopic dermatitis and allergic asthma can be lowered. It is therefore absolutely possible for (soon-to-be) parents to take measures to protect their children from allergies. This is especially important for at-risk children with a parent or a sibling who already suffers from hay fever, atopic dermatitis or asthma. Adults can also lower their allergy risk by adopting certain lifestyle changes.
Children born via C-section appear to have an increased risk of allergy (nearly one in three babies are currently delivered via C-section in Germany). During a natural birth, the baby comes into contact with various microorganisms in the birth canal. This is believed to train the newborn immune system and reduce the susceptibility to allergies. If a C-section is not medically necessary, the increased risk of allergies should be taken into consideration when making the decision about this childbirth method.
Breastfeeding helps infants build up their own protection against allergies. They should therefore be exclusively breastfed during the first four months. (The German National Breastfeeding Commission (Nationale Stillkommission) recommends that babies continue breastfeeding after the introduction of solid foods at the beginning of the fifth month of life in order to maintain the many inherent health benefits.)
If breastfeeding is not possible, at-risk children should be given hydrolysed formula. Soya milk is not recommended as a replacement for breast milk.
Baby food should also be as varied as possible. Several years ago, it was recommended that allergenic foods be avoided as long as possible. This view has changed in the meantime. Eggs, wheat, fish, etc. should be included in the diet during the first year of life; avoiding these foods does not appear to reduce the risk of allergies. Fish (without bones) in particular should be included the baby’s diet, since studies show that it can protect against allergies.
Both the quality and the amount of food are factors in allergy prevention. Being overweight increases the likelihood of developing asthma, in addition to other health risks. This applies to children as well as adults.
Women should eat a varied and balanced diet during pregnancy and while breastfeeding. Earlier recommendations to avoid fish, nuts or other allergenic foods are no longer followed. On the contrary, there is some evidence that fish consumption by the mother reduces the risk of allergy in the child.
Pets such as birds, cats and dogs normally have no influence on the development of allergies. However, it is not recommended for at-risk children to keep a cat in the home. Studies show that this can increase the risk in predisposed children of developing atopic dermatitis. If there is already a cat in the home of an at-risk child, an allergy specialist should be consulted as to whether the cat should be removed. On the other hand, having a dog in the home is not associated with an increased risk of allergy.
Passive smoking increases the risk of allergy in children. If smoking occurs in the home, the likelihood increases that the child will develop asthma. Children can be sensitised to allergens as early as in the womb; a smoke-free environment should therefore be ensured from pregnancy onward. Smoking also increases the risk of asthma in adults.
Mould spores can trigger allergies. Mould flourishes in damp places with poor air circulation. It is therefore recommended to air out rooms regularly by opening the windows, and to remove damp spots as well as any existing mould stains.
The level of indoor air pollution should be kept as low as possible. Formaldehyde and volatile organic compounds are believed to increase the risk of allergies, especially asthma. These substances are emitted from new furniture in the home or when repainting the walls. Motor vehicle exhaust may also influence the development of allergies. The proximity of one’s (living) environment to streets with heavy traffic is associated with an increased risk of allergy, especially asthma.
The authors of the guidelines have come to the conclusion that vaccinations do not increase the risk of allergy. They therefore recommend that children (including at-risk children) receive the vaccinations according to the schedule developed by the Standing Committee on Vaccination (STIKO) in Germany.
In addition to these influencing factors, other means of protection are still being investigated. For example, there is some evidence that children who grow up on farms, attend day care under the age of two, or have several older siblings are better protected from allergies. These conditions presumably strengthen the immune system in early childhood.
Probiotics (supplements containing viable microorganisms such as lactic acid bacteria) are also believed to strengthen the immune system. There are some indications that probiotics can prevent atopic dermatitis. However, the studies were inconsistent in terms of the bacterial strains and the amounts of bacteria, which made it impossible to provide any recommendations. Prebiotics also demonstrated a protective effect against atopic dermatitis in individual studies. These indigestible substances promote the growth of good bacteria in the gut and can be found in certain vegetables, such as onions, salsify and chicory. But there is also not enough research on prebiotics to make any recommendations in terms of allergy prevention.
The same applies to other foods that have been found to have protective effects, such as those in the Mediterranean diet (plant-based foods, olive oil, a moderate amount of animal products), omega-3 fatty acids (sources include fatty fish such as salmon, mackerel, herring, or rapeseed and flaxseed oil) and the fatty acids in dairy fat. More research is required on these dietary substances before any specific recommendations can be made.
Prof. Dr. med. Dr. h.c. T. Zuberbier
Last changes made: July 2016
Schäfer T et al. S3-Leitlinie Allergieprävention – Update 2014. Deutsche Gesellschaft für Allergologie und klinische Immunologie e.V. (DGAKI), Deutsche Gesellschaft für Kinder- und Jugendmedizin e.V. (DGKJ), 2014. Leitlinie gültig bis Juli 2019.