Parents want to give the best and most nutritious food for their babies, especially when it comes to their first solid meal. Now a new study says that the timing of when a baby starts solids is more important than the food they are given.

Babies who are first exposed to solid food before the age of 4 months or at age 6 months or older are significantly more likely to develop type 1 diabetes mellitus, the study published online in JAMA Pediatrics on Monday. A few weeks or months off appears to make a huge difference and researchers found the right time to first introduce solids is between 4-5 months of age.

In their study of 1835 children with an increased genetic risk of the disease, 53 went on to develop type 1 diabetes.

"The increased risk for type 1 diabetes mellitus found with early (less than 4 months) and late (equal or greater than 6 months) introduction of solid foods appears to be driven by late first exposure to rice/oat and early first exposure to wheat/barley and fruit," the study says.

The researchers selected these ages according to the current US guidelines which recommend children to be given their first solids between 4-6 months of age.

Introducing solid foods in general too soon or too late was associated with a greater risk of developing type 1 diabetes after adjustment for human leukocyte antigen genotype, having a first-degree relative with the disease, maternal education, and type of delivery.

Meanwhile, early exposure to fruit, excluding fruit juice, was associated with a greater risk (HR 2.23, 95% CI 1.14-4.39), although the relationship became non-significant after accounting for other food exposures.

"The risk predicted by early exposure to solid foods might suggest a mechanism involving an abnormal immune response to solid food antigens in an immature gut immune system in susceptible individuals," the authors wrote. "As the increased risk is not limited to a specific food, it is possible many solids, including cereals and fruits, contain a common component that triggers an immature response."

"Additionally, the increased risk predicted by late exposure to solid foods may be related to the cessation of breastfeeding before solid foods are introduced, resulting in a loss of the protective effects of breast milk at the introduction of foreign food antigens," they wrote.

Although breastfeeding duration was not related to diabetes risk in the current study, breastfeeding at the time of the first exposure to wheat or barley was associated with a lower risk of developing the disease (HR 0.47, 95% CI 0.26-0.86), "suggesting that breast milk may protect against an abnormal immune response to new antigens in an immature gut," according to Norris and colleagues.