Frozen may surpass fresh when it comes to vitamins and antioxidants. In two independent studies, researchers at Leatherhead Food Research and the University of Chester have determined that frozen fruit and vegetables tend to be richer in compounds like vitamin C, polyphenols, anthocyanins, lutein, and beta-carotene.

The somewhat counterintuitive findings stem from the fact that fresh produce gradually loses nutrients as it passes through the supply chain. Although fresh apples, pears, and blueberries are marketed as “just-picked” products straight from harvest, most have spent several weeks in storage. In addition, a substantial amount of fresh fruit and vegetables will continue to degrade in the consumers’ refrigerators.

Conversely, frozen foods retain most of their antioxidants and vitamins, as they are chilled almost immediately upon harvest.

“Fast and highly organized methods of ‘harvest-to-freeze’ have evolved with the express purpose of minimizing nutrient losses,” said Brian Young, director general of the British Frozen Food Association, which provided funding for the current studies. “In contrast, ‘fresh’ food has been shown to spend up to a month in the chain of producers, wholesalers and retailers before consumers have access to store and prepare them.”

“During this time we know that product deterioration takes place – to the extent that they can have lower nutritional value than their frozen equivalent,” he added.

To measure the nutritional content of frozen produce vis-à-vis “fresh” produce, the two research teams conducted 40 different tests. The sampled products were frozen products and fresh equivalents that had been stored in a refrigerator for three days. Overall, frozen foods tended to exhibit higher levels of antioxidants and vitamins, with products like frozen carrots exceeding the “fresh” value by up to 300 percent.

Notable exceptions were fresh broccoli and spinach, which showed comparatively higher levels of certain vitamins and compounds like polyphenol.

“Unlike frozen, some fresh produce concentrations of antioxidant compounds exhibited a decrease during refrigerated storage to levels below those observed in the corresponding frozen produce,” said study author, Graham Bonwick, of the University of Chester. “The effects were most noticeable in soft fruits.”

Rachel Burch, who led the study conducted at Leatherhead Food Research, said that the results may prompt a public reevaluation of what it means to shop fresh.

“We must disregard the mistaken opinion that ‘fresh’ food is always better for us than frozen food,” she said, speaking to the Daily Mail. “These results demonstrate that frozen can be nutritionally comparable to ‘fresh’ produce.”