DEAR DOCTOR K: I'm trying to eat more fruits and vegetables, but I don't have time to go to the grocery store every week. So I stock up on frozen produce. Am I missing out on any nutritional benefits by eating frozen instead of fresh?
DEAR READER: For taste, variety and quality of nutrients, recently picked local produce is the way to go. But if fresh produce is inconvenient or beyond your budget, frozen fruits and vegetables provide plenty of nutrition.
Fresh fruits and vegetables are indeed more nutritious, but the difference between fresh and frozen produce may not be as stark as you think. Researchers at the University of California-Davis found that:
-- Fresh and frozen produce are similar in terms of carbohydrate, protein, fibre and mineral content.
-- Fresh produce can lose half of its vitamins and beneficial plant-derived chemicals during storage or cooking.
-- More water-soluble vitamins such as C are lost during the frozen packaging process than fat-soluble vitamins such as A and E.
Another point to consider is that not all produce sold as "fresh" really is fresh. Glance down the supermarket produce aisle, and you'll see wilted lettuce and peppers with soft spots on them.
If you're looking for truly fresh produce, your best bet is to go to a farm stand or local farmers market. True, some farm stands sell fruit that is not picked-this-morning fresh. But if the produce is labelled as locally grown, it probably is fresh. If you ask a farm stand clerk if the produce was picked today, you will usually get an honest answer. As my wife would be the first to tell you, I'm not a "foodie". I'm more of a gourmand than a gourmet. So I asked a colleague for some advice.
Dr Michelle Hauser is a certified chef, nutrition educator and a clinical fellow in medicine at Harvard Medical School. She explains that grocery store produce may be picked unripe so it can be stored for months. Then it may be artificially speed-ripened on its way to the grocery shelf. As a result, it may be less nutritious than naturally matured fruits and vegetables.
Produce destined for the freezer aisle is picked when ripe. It may be briefly cooked in hot water and then frozen in or near the fields. This helps to preserve its nutritional value.
So the bottom line for me is: Don't worry too much about whether your produce is fresh or frozen.
If stocking up on frozen fruits and vegetables helps you get your five-to-nine daily servings, stick with it.
But if you pass a farmers market, make a quick stop for some fresh peaches or apples. Your taste buds will thank you.
Dr Anthony L. Komaroff is a physician and professor at Harvard Medical School.
