Early Life Nutrition and Allergy (Module 1)
Maternal diet, weaning practices and infant feeding may affect the patterns and prevalence of food allergies. However, we lack the evidence on which to base guidelines regarding the introduction of allergenic foods. Key questions we want to answer are:
- Which is the better strategy: to introduce allergenic foods early in life or delay their introduction?
- What is the optimal timing of introduction of allergenic foods into the diet?
- What are the optimal quantities of allergenic food to be consumed (frequency and amount) to promote the induction of tolerance?
- Which is the better policy: exclusive breast feeding during the first six months of life or early introduction of complementary feeding (including allergenic foods) in combination with breast feeding in the first six months of life?
Early life nutrition and allergy
A follow-up of the EuroPrevall birth cohort, with its data on maternal diet and infant feeding practices, offers the opportunity to investigate whether there is a link between dietary factors and allergy outcomes later in life. It will also provide data from an unselected pan-European population regarding patterns and prevalence of food allergies, which would support the updating of lists of foods for which labelling is mandatory.
A follow-up assessment at school age (when most of the participants will be between six and ten years old) will allow the life course of food allergies, including the development of respiratory and skin allergies, to be described and linked into one cohesive data set.
Dietary interventions for allergy prevention
Randomised controlled trials (RCTs) are underway in Europe to discover whether dietary strategies early in life can prevent allergies developing later on in childhood. These studies will contribute to providing an evidence base on early life nutrition and its role in oral tolerance induction.
However, the different outcome measures and study designs make it difficult to integrate the results. We will link them together to build a consolidated evidence base to define whether intervention with early introduction of food reduces sensitisation to egg and peanut.
Intervention studies contributing to iFAAM
- EAT (Enquiring About Tolerance): An RCT of 1302 children, drawn from the general population, who are exclusively breastfed until three months of age then introduced sequentially to cows’ milk, egg, fish, wheat, sesame and peanut or, exclusively breastfed until around six months of age (not clear if these children are then introduced in a controlled way after six months). The outcome measure is an IgE-mediated allergy to any of the six foods between one and three years of age, as defined by food challenge.
- LEAP (Learning About Peanut Allergy): An RCT of 640 infants with a high risk of eczema and/or egg allergy who either consume or avoid peanut at four to eleven months of age. The prevalence of peanut allergy is then defined at five years of age along with sensitisation to food and inhaled allergens, rhino-conjunctivitis and asthma.
- PEAAD (Preventing Peanut Allergy in Atopic Dermatitis): Non-randomised, self-allocated controlled trial of 460 children (five to thirty months of age) with atopic dermatitis who receive either a peanut snack three times a week or, a peanut free diet. Outcome measures are IgE-mediated peanut allergy after one year of consumption or avoidance and the prevalence and severity of eczema.
- HEAP (Hens Egg Allergy Prevention): Randomized placebo controlled trial of 800 children recruited at birth and randomized into a ‘hen’s egg feeding’ or ‘avoidance’ group starting at four to six months of age, children receive egg or placebo three times a week. Sensitization to egg (primary outcome) and egg allergy (secondary outcome) are determined at age one.
There are also three studies ongoing in Australia, all of which are randomised placebo controlled trials focused on egg:
- STAR (Solids Timings for Allergy Research) Perth, 226 high risk infants,
- BEAT (Beating Egg Allergy) Sydney, 300 infants of intermediate risk of developing allergy; and,
- STEP (Starting Time for Egg Protein) project (1512 infants), which links centres in Adelaide and Perth with one in Umea, Sweden.
These studies represent significant investment and will contribute to providing an evidence base on early life nutrition and its role in oral tolerance induction. However, the different outcome measures and study designs make it difficult to integrate the results.