Feeding eggs and peanuts to babies could stop them developing allergies to the foods later in life, research shows.
The study, based on data from more than 200,000 children, suggests that feeding egg to infants aged between four and six months could reduce their risk of developing an egg allergy by 40% compared with those who start eating it later in life.
It also found that feeding children peanut between the ages of four and 11 months reduced the risk of future peanut allergies by 70%.
However, the team, from Imperial College London, found no evidence that the same could be done to prevent intolerances to milk, fish, other types of nuts or wheat.
The study, which the researchers claim is the largest on the subject, analysed evidence from five studies on egg allergies in children and two on peanut allergies.
Dr Robert Boyle, leader of the research, 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 including nuts, egg, milk and wheat affect around one in 10 children in the UK, triggering symptoms such as rashes, swelling, vomiting and wheezing. And some evidence suggests that cases of food allergies are on the rise.
This new information contradicts a previous belief that parents should avoid feeding their babies foods that could trigger an allergic reaction.
Dr Boyle said: "Until now we have not been advising parents to give these foods to young babies, and have even advised parents to delay giving allergenic foods such as egg, peanut, fish and wheat to their infant."
But the advice outlined by the new study suggests a conflict with NHS guidelines, which recommend feeding babies exclusively on breast milk until they are at least six months old.
A spokesman for the UK Food Standards Agency, which commissioned the research, said: "The Government is considering these important findings as part of its review of complementary feeding for infants to ensure its advice reflects the best available evidence.
"Families should continue to follow the Government's current long-standing advice to exclusively breastfeed for around the first six months of age because of the health benefits to mothers and babies."
Experts have said that the research is still far from conclusive and further studies are needed, and Dr Boyle warns parents against introducing egg and peanuts to babies who already have any allergic condition, including eczema.
He also added that parents who feed peanut to infants must be careful to avoid choking hazards by giving it to them in the form of smooth peanut butter.
Professor Graham Roberts, an expert in paediatric allergy at the University of Southampton, commented on the study: "An element of caution is required.
"Firstly, early introduction of egg into the diet of infants only protected them from developing egg allergy in some of the studies and many infants developed allergic reactions when they were introduced to egg."
He added: "So what should parents do at the moment? If you have a baby with severe eczema or a food allergy, they should be assessed in a children's allergy clinic.
"This should include allergy testing for peanut and egg allergy. If testing is negative, the paediatrician may recommend that you introduce peanut and egg into your baby's diet."
The research was published in the Journal of the American Medical Association on Tuesday.