Michelle Obama

Walgreen, Walmart and Supervalu have pledged to help First Lady Michelle Obama bring fresh produce to 'food deserts' in the US.

Supervalu figures suggest more than 23 million people – including six million children – live in USDA-designated food deserts, where it is difficult to access fresh produce and meats in grocery stores.

The three chains have all committed to opening new stores in these areas.

Walmart said it would open 275-300 new sites by 2016, while Supervalu will add another 250 outlets to its chain and Walgreen plans to introduce 1,000 'food oasis' stores.