Can Nutrition Come in a Can?

Eating some canned foods, such as vitamin-packed pumpkin, is just one surprising way to get more fuel from your fruits and vegetables.

Leslie Barnett, a 28-year-old architect, wondered how healthy her diet was, so she went to a nutritionist. She figured she would fare well in the exam. Although she is sometimes under a lot of stress, she takes good care of herself, eats a vegetarian diet, avoids junk food, and exercises vigorously three or four times a week. The results of the consultation and hair analysis came as a surprise: She was starved for the minerals chromium, selenium, and zinc and was low on protein, too.

Barnett's story is not unusual. Getting all the nutrients we need is not always as simple as just eating five fruits and vegetables a day. Variables such as storage and preparation can rob us of the vitamins and minerals we need. That's why it's so important to make every bite count. You may be surprised to find that some things you think are good for you aren't that great, and others are better than you think. Below we separate fact from fiction and help you get the nutrients you need.

Surprise #1: Fresh Isn't Always Fresh

Nutritionists agree that food picked at the peak of ripeness contains the most nutrients. But most produce found in supermarkets is fairly old. "What most of us think of as fresh vegetables are likely to have been on the road for two weeks," says Barbara Klein, Ph.D., professor of foods and nutrition at the University of Illinois at Urbana-Champaign. "We're not really getting what we think we are."

Typically after harvest, Klein says, domestic food spends several days being sorted and packaged. Then refrigerated trucks take it on a several-day journey to a distribution center, where it may sit for up to two days. Finally it arrives at the store, where it may remain in a cooler or produce case for as long as a week. Fluctuations in temperature, exposure to air and light, and time rob the produce of nutrients along the way.

Klein has conducted studies in which she grew green beans, tested them for nutrient content, and then subjected them to the same insults as grocery store produce. "Green beans lose about 40 percent of their vitamin C in the first two or three days," she says. "By the time most of us would eat them, they have negligible amounts."

The farther a food has to travel, the worse off it is. Food that travels a great distance may have been harvested too early. "If it's picked fairly unripe, then it doesn't reach its maximum nutrient density," says Kristin Baker, a researcher at the Human Nutrition Research Center at Tufts University in Boston.

What should you do? "Buy locally grown stuff," Baker says. "Vary what you buy, and buy what's in season." (For example, purchase McIntosh apples one week and Granny Smith the next.) Because locally grown produce travels a shorter distance, it can be picked when ripe and you get it a lot sooner. Many supermarkets and natural food stores identify the produce from local farms.

Baker also recommends eating fresh produce as soon as possible. Storing food in the refrigerator's vegetable drawer, where it's protected from temperature fluctuations and light, also helps maintain nutrients. Of course, when local produce isn't available, you should continue to eat a variety of fresh foods, as well as frozen and canned goods.

Surprise #2: Canned Foods Can Reign Supreme

Some vegetables and fruits are cooked at high heat before being canned, and many nutritionists assume this processing degrades all their vitamin, mineral, and fiber content. However, while some nutrients, such as vitamin C, are damaged by heat, Klein's studies have found that many canned foods are comparable in nutritional value to frozen and fresh--and, in a few cases, are actually far better. Canned produce, as well as frozen, is typically processed within three or four hours of harvest, locking in nutrients at their peak. Canned pumpkin, for instance, has 20 times as much vitamin A as fresh pumpkin because, among several reasons, the intense heat of canning breaks the fruit's beta carotene (a precursor to vitamin A) away from the protein to which it is normally bound. This makes it easier for the body to absorb.

Canned beans match home-cooked beans in terms of fiber and nutrients. If you add canned beans to your dishes, consider not draining the liquid or rinsing the beans. The brine contains some of the beans' soluble fiber, minerals, and thiamin (vitamin [B.sub.1]). Many brands of canned beans are flavored with salt, so leave salt out of any recipes in which you use brine, or buy low-sodium and no-sodium brands.

Surprise #3: Raw Foods Aren't Always Better Than Cooked

Most of us assume that uncooked fruits and vegetables are the most nutritious--even if they aren't always the tastiest. However, while cooking can damage some nutrients (such as vitamin C), it actually helps unlock others. "There's a fair amount of evidence that cooking carrots releases more of the carotene in a bioavailable form," Klein explains. Epidemiological studies have linked the carotenoid lycopene to a lower risk of prostate cancer, and research has shown that cooked tomato products are a better source of lycopene than raw. And the body can more easily access the potassium in spinach when it's cooked, according to Esther Blum, R.D., a dietitian and nutritionist in New York City.