You know the mantra: Eat more fruits and vegetables.
But I'm often asked whether there's more nutritional value when they're cooked or raw. Fresh or frozen? How about canned?
The answer varies, and it depends on many factors. And, considering the big picture, it also may not matter very much.
Even before they're picked, the same varieties of fruits and vegetables can differ in their nutritional makeup depending upon where they are grown -- the quality of the soil and other growing conditions.
Whether or not they're picked at the peak of ripeness, time in transit from field to store, and the length of time the foods sits on the shelf before you buy and eat it also makes a difference.
Foods that have less-than-optimal growing and handling conditions can lose nutritional value before you even make the decision about eating them raw or cooked.
To complicate things even further, cooking or processing can have different effects on different nutrients in the same foods.
For example, some research suggests that when carrots are cooked, the body has access to more of their health-supporting carotenoids, beneficial chemicals that give carrots their orange color.
At the same time, though, cooking may decrease the amount of polyphenols -- another beneficial plant chemical -- in carrots.
There are many other similar examples where a cooking o processing technique can have both advantages and disadvantages.
For example, breaking down a fruit or vegetable by mashing or puréeing it can make certain nutrients more available, but may also diminish the benefits from dietary fiber in the food.
Plus, if the nutritional content of a fruit or vegetable is diminished by cooking, the effect can vary by the method of cooking used.
For example, boiling a vegetable can cause substantial nutrient loss if nutrients leach into the cooking water. Water-soluble vitamins such as the B vitamins and vitamin C may also be destroyed by heat. So, the longer the food is boiled, the more nutritional value may be lost.
Steaming in the smallest amount of water for the shortest time possible can help minimize nutrient loss. If nutrients do leach into the cooking water, using that water to make soup or mixing it into another food can be one way to save at least some of the vitamins and minerals.
There are many other ways to maximize the nutritional value of the fruits and vegetables you eat, too. For example:
- Buy foods that are in season and grown locally. They're more likely to have been picked at peak ripeness and less likely to have lost nutritional value in transit to the store or your kitchen. Frozen is as good as fresh.
- Conserve nutrients when you can. If you cook, use a variety of quick-cooking methods that require minimal added fluids. Steam, sauté, stir-fry or cook in a microwave oven, for example. Cook vegetables until they are tender but not mushy.
- Leave the peels on produce grown organically -- cucumbers, carrots, apples -- to get the benefits of the added fiber.
- Diversify your choices. Fresh and frozen are better for you than canned, but canned is much better than no vegetables at all. Eating a variety of cooked, raw, mashed, whole, fresh, frozen and canned fruits and vegetables can help you get a wide range of nutrients in a number of tasty forms.
The bottom line: Eat more fruits and vegetables. Eating them in different forms can help ensure you get the widest possible range of nutrients.And if the variety encourages you to eat more of them more often, all the better.
BY SUZANNE HAVALA HOBBS, Correspondent
The News Observer - http://www.newsobserver.com
