Timing of first solid food tied to child diabetes risk

When babies already at increased risk for type 1 diabetes had their first solid foods before four months of age or after six months, their chances of developing the disorder at least doubled, according to a new study.

Four to six months is the recommended age window for all kids to start on solid foods, but the new results suggest timing could be even more important for babies at high risk for type 1 diabetes (T1D) because of genetic susceptibility.

The results weren't totally surprising, according to senior author Jill Norris, since type 1 diabetes is a lifelong disease in which the immune system attacks the cells that make insulin and previous research has found that the development of certain immune cells is related to the introduction of solid foods.

"We did not choose this window out of the blue," said Norris, who studies chronic diseases like diabetes at the University of Colorado, Denver.

But this was the first study to examine how many kids were actually diagnosed with diabetes.

"We think the clearest message for parents is to wait to introduce any solid foods until after the 4 month birthday," Norris told Reuters Health in an email. "And when baby is ready, solid foods should be introduced by 6 months of age or soon thereafter, preferably while the mother is still breast-feeding the baby."

Norris and her coauthors followed 1,835 children at high risk for type 1 diabetes - based on genetic testing done at birth or family history - until they were eight years old. Fifty-three children were diagnosed with the disease.

Infants first given solid food before they were four months old were almost two times as likely to develop the disease as those given solid food during the ideal age window. Kids who got solid food after they were six months old were three times as likely to be diagnosed with the disease.

There are many other risk factors at play for these kids, for example, when there were complications during vaginal birth, the children were also about twice as likely to develop the disease, regardless of when solid food was introduced.

Of the 53 kids who did get diabetes, 28 had been given solid food before four months of age, and seven hadn't tried solid food until after six months, according to results in JAMA Pediatrics.

"We hypothesize that at a very young age, an infant's gut and immune systems may not be ready for the new food, triggering a cascade of reactions that lead to autoimmune diseases, like T1D, in susceptible children," Norris said.

Although the study stratified results by food types, there is not yet enough evidence to recommend which foods are best to introduce when, she said. But she did stress the importance of continuing to breastfeed while transitioning to solid food, since this study and others suggest that breast milk has a protective effect.