Feeding egg and peanut for babies between the ages of four and six months may reduce their risk of developing an allergy to the foods, finds a new study.
The study, which was commissioned by the UK Food Standards Agency, also found feeding children peanut, between the ages of four and eleven months, may reduce risk of developing peanut allergy.
Dr Robert Boyle, lead author of the research from the Department of Medicine at Imperial, said: "This new analysis pools all existing data, and suggests introducing egg and peanut at an early age may prevent the development of egg and peanut allergy, the two most common childhood food allergies.
Allergies to foods, such as nuts, egg, milk or wheat, affect around one in 20 children in the UK. They are caused by the immune system malfunctioning and over-reacting to these harmless foods. This triggers symptoms such as rashes, swelling, vomiting and wheezing.
"The number of children diagnosed with food allergies is thought to be on the rise", added Dr Vanessa Garcia-Larsen, a co-author on the study from the National Heart and Lung Institute at Imperial. "There are indications that food allergies in children have become much more common over the last 30 years.
She added that the reasons behind this rise are still unclear - doctors may be better at recognising food allergy, or there may be environmental factors involved.
In the new study, called a meta-analysis, the team initially analysed 16,289 research papers on allergies and other immune system problems. Out of these, 146 were used for data analysis of when to feed babies allergenic foods such as egg, peanut, wheat and fish.
The results showed that children who started eating egg between the ages of four and six months had a 40 percent reduced risk of egg allergy compared to children who tried egg later in life.
Children who ate peanut between the ages of four and eleven months had a 70 percent reduced peanut allergy risk compared to children who ate the food at a later stage.
Dr Boyle cautioned against introducing egg and peanut to a baby who already has a food allergy, or has another allergic condition such as eczema. "If your child falls into these categories, talk to your GP before introducing these foods."
He also noted that whole nuts should not be given to babies or toddlers due to the choking hazard. "Whole nuts should be avoided in young children - if you decide to feed peanut to your baby, give it as smooth peanut butter."
The team also analysed whether introducing peanut, egg, milk, fish or wheat early into a baby's diet affected their risk of autoimmune diseases such as coeliac disease and found no effect.