Breaking the Ice on Frozen Food

Convenience and price: two major incentives that make some people push their shopping trolley straight to the frozen food aisle. But if you stick to the fresh food aisles because you believe the food there is healthier, you're missing out.

Sure, that sweet-smelling, perfectly ripe peach seems a helluva lot tastier than a bag of frozen peach slices does. But looks can be deceiving. "Fresh fruit is, effectively, alive", says food scientist and professor Graham Bonwick, PhD, who has compared the nutritional quality of fresh and frozen foods. As soon as that peach was plucked from the tree, some nutrients, including vitamin C, started to break down. And the longer that fuzzy stone fruit sits on your counter, the more nutrients it could be losing.

Fruit that's flash-frozen (a process that rapidly freezes food, often with liquid nitrogen) the day it's harvested, however, enters a kind of suspended animation, which locks in the nutrients at higher concentrations.

Bonwick and his colleagues at the University of Chester in the United Kingdom conducted tests on fresh and frozen produce—including blueberries and raspberries—that they bought from supermarkets and chilled in either a fridge or freezer for three days. The amounts of vitamin C and total anthocyanins (a type of antioxidant) in the frozen berries were the same or higher than they were in the refrigerated fresh produce.

Two things to check the bag for: an organic label (to avoid downing pesticides with your vitamins and minerals) and added sugar (which you'll want to skip due to the host of health issues associated with it; plus fruit doesn't really need it).

Similar to frozen fruit, frozen vegetables are packed with good stuff. In fact, in one study, frozen broccoli had four times more of the antioxidant beta-carotene than the fresh variety did. The same was true of frozen carrots, which also scored higher for cancer-fighting polyphenols and lutein, an antioxidant that helps keep eyes healthy, than fresh carrots did.

In another study from the University of Georgia, researchers purchased produce, including broccoli, spinach, cauliflower and peas, keeping half of it fresh and freezing the rest. On the day of purchase, nutrients in both groups were similar. But five days later, the fresh veggies had lost much of their vitamin A, vitamin C and folate, all of which can contribute to a healthy immune system.

Why? Like frozen fruit, frozen vegetables are usually flash-frozen on the day they're picked, so they lose nutrients at a far slower rate than fresh veggies do. To retain those nutrients, steam or microwave them instead of boiling or sautéing them, says Lucy Jones, a dietitian in London. And like fruit, say yes to organic when you can afford it and no to added sugar (or sodium).

Bulk-buying packs of frozen meat or poultry is a cost-effective way to load up on protein. But does that protein safely survive the harsh winter of your freezer? Yes, says Jones.

"Though proteins and fats are generally relatively stable [meaning they don't easily break down], as are minerals like zinc, iron and selenium, choosing frozen over fresh meat could help you get more of all those macro- and micronutrients", says Jones. That's because the freezing-and-thawing process breaks up some of the cellular structures within the meat, which makes it easier for your body to absorb those nutrients, says Bonwick.

Shop for frozen meats with the same standards as you would shop for fresh. "Go for the same farming assurances, such as free-range, and look for the source of those meats on the label", says Jones.

Unless you live on a coast, so-called "fresh fish" can be two-weeks old or older by the time it reaches your supermarket. That doesn't mean that salmon fillet is unhealthy. But it does mean that it may have lost some of its nutrients, such as vitamins B and D, by the time it hits your plate. Frozen fish, alternatively, is usually flash-frozen almost as soon as it hits the boat deck or dock, locking in protein and heart-healthy omega-3 fatty acids. And research published in the "International Journal of Food Science" confirms that there's typically no quality difference between what your seafood counter sells and what you'll find in the frozen section.

If you're planning to make sushi or barely sear ahi tuna steaks, frozen fish could actually reduce your risk of infection because it has less exposure to parasites, says Jones. Regardless of which type of fish you buy, look for wording on the packet that says it was frozen on the boat or dock in order to get the benefits noted above.

Microwavable meals aren't what they used to be. Many companies have made huge efforts to reduce sodium and saturated fat content, says Jones.

That said, when it comes to frozen prepared foods, you need to put in a lot more work to separate the healthy from the "healthy". Review ingredients lists and look for additives that you don't recognise. "If it's a meat- or fish-based product, you want to see the fish or meat high up, if not first, in the ingredients list", says Jones. For all frozen meals, including plant-based ones, check the added sugar and sodium content (the lower the better), and aim for no more than 18 grams of total fat, per the University of South Florida. Also opt for meals with minimal ingredients, which typically means they're less processed.

The biggest takeaway: Don't judge a food by its icy exterior. Provided you do your due diligence, it's time to stop giving frozen food the cold shoulder.