Myth or Fact: Are Frozen Vegetables Less Nutritious Than Fresh in Winter?

What the study measured

Researchers from the University of Georgia and Montclair State University spent two years comparing eight common foods: broccoli, cauliflower, corn, green beans, green peas, spinach, blueberries and strawberries. They measured vitamin C, beta-carotene (which the body converts into vitamin A) and folate, and published their findings in the Journal of Food Composition and Analysis (Li et al.).

They tested three versions of each food: fresh, frozen, and "fresh-stored", meaning kept in the fridge for five days to mimic how most of us actually eat fresh produce. In the majority of comparisons there were no significant differences in vitamin content. Where there were, frozen outperformed fresh-stored more often than the other way round. The authors concluded that their results do not support the common belief that fresh food is significantly more nutritious than frozen (Montclair State University).

The likely reason is timing. Vegetables for freezing are usually processed soon after harvest. Fresh produce spends time in transport, on shelves and then in your fridge before it reaches the plate.

Building a winter plate

• Buy in season where you can. Cabbage, kale, leeks, Brussels sprouts, winter squash and roots such as carrots, parsnips and beetroot keep well and are at their best now.
• Use the freezer for the rest. Peas, spinach, green beans, broccoli and berries are reliable all winter.
• Make the most of citrus. Oranges, mandarins and grapefruit are winter fruit and good sources of vitamin C.
• Read the label. Plain frozen vegetables are the goal. Some mixes come with added salt, butter or sauces.
• Cook gently. Vitamin C is sensitive to heat and dissolves in water, so steaming, microwaving or a quick stir-fry usually keep more of it than long boiling.

Three easy winter dishes

Green pea and mint soup

Soften a chopped onion in olive oil, add 500 g frozen peas and 750 ml vegetable stock, simmer for 5 minutes, then blend with a handful of fresh mint. Season and finish with a spoon of yoghurt.

Roasted roots with spinach and lemon

Roast chunks of carrot, parsnip and red onion with olive oil at 200°C for about 35 minutes. Fold in a few handfuls of thawed, squeezed frozen spinach for the last 5 minutes, then add lemon juice and black pepper.

Winter berry porridge

Cook oats as usual and stir in a handful of frozen blueberries for the last minute. Top with sliced mandarin and a few chopped nuts.

The bottom line

Frozen vegetables aren't a compromise. Combine the best of the season with a well-stocked freezer and your winter plate can be just as nutritious as a summer one.

Sources

1. Li, L. et al., "Selected nutrient analyses of fresh, fresh-stored, and frozen fruits and vegetables", Journal of Food Composition and Analysis (2017)
2. Montclair State University, publication record and abstract