A study has found white bread may increase the risk of cancer.

Scientists from the University of Texas found foods with a high glycemic index – such as white bread, bagels and corn flakes, were linked to higher incidence of cancer. Specifically lung cancer.

The authors say glycemic index is a measure of the quality of dietary carbohydrates. It is defined by how quickly blood sugar levels are raised after a meal.

The theory is, a high-GI diet triggers higher levels of blood glucose and insulin.

This will increase levels of a type of hormone called Insulin-Like Growth Factors (IGFs).

It’s the elevated IGFs that have been linked with a higher risk of lung cancer.

Lead study author Dr Stephanie Melkonian, of the University of Texas MD Anderson Cancer Center, said: “We observed a 49 per cent increased risk of lung cancer among subjects with the highest daily GI compared to those with the lowest daily GI.”