Being hard of head and body, I'm a certified hunk of health. Nutrients spring from my pores, and my nostrils flare with vitality. My arms are so strong, my hugs are homicidal.

I owe it all to my refrigerator, the convenient cooler in the corner of my kitchen. Without it the nutrients in my food supply would quickly fade, putting me on a diet of dead food that would make my flesh wilt and my skeleton eventually collapse.

It's not hard to kill your food; in a microwave minute you can destroy almost all of its nutritional value. With the exception of carbohydrates nutrients lose their effectiveness when exposed to air, heat or water, the elements that alter their molecular structures. As the nutrient molecule becomes "unglued," it loses its essence; i.e., it dies. Thus, the dark chill of a refrigerator extends the life of food by helping nutrients keep their molecules together.

Even in a deep freeze, however, the stability of nutrients varies from food to food. Take vitamin C, the architect of the human body, for example. Because this vitamin, which is also known as ascorbic acid, is the most difficult nutrient to safeguard, its conservation is often used as an index for the retention of other nutrients. What destroys vitamin C usually destroys the others. Although the C is killed by brief contact with a copper skillet or a jet of steam, it's retained well in citrus fruits and their juices, as well as tomatoes.

To up your nutritional intake, practice the following guidelines:

Buying

Go for the darkest, deepest-colored fruits and vegetables. Assuming that the color is natural, the most vivid greens, reds, yellows and oranges indicate nutrient density. Buy the darkest greens, the brightest vegetables and the ripest, most colorful Fruits. Fruits are ripest when you can smell their sweet pulp through their skins.

Cutting

As a rule the leafy parts of fibrous plants contain more nutrients than the stems or midribs, so plan to eat the leaves. The leaves of broccoli, for example, contain much more vitamin A than the stalks or buds do.

On a head of lettuce the outer, coarser leaves contain more nutrients than the inner, tender leaves. Cabbage, although shaped the same, is different-both the core and the leaves are high in vitamin C.

Storing

Since most greens thrive in near-freezing temperatures and high humidity, they require prompt refrigeration. Although cabbage retains vitamin C better than the majority of leafy vegetables, you shouldn't let it dry out. Wrap and store cabbage in the crisper of your refrigerator, where high humidity prevails.

Keep legumes in their pods as long as possible. If they're already shelled, seal them in a plastic bag and refrigerate.

Tomatoes should be ripened out of the sun at temperatures from 60 to 70 degrees Fahrenheit, not on a hot window sill or in the refrigerator. (In summer buy tomatoes that have been vine ripened in the sunlight; they have twice the vitamin C as the winter, hothouse variety.) Store ripe tomatoes in the refrigerator or in a cool room. Tomatoes lose vitamin C rapidly when they become overripe.

Roots and tubers such as carrots and tomatoes should be kept cool and moist to prevent withering. Store them in the crisper. Mushrooms, which are a fungus, must be refrigerated in open containers; otherwise they'll blacken and become very slimy.

Keep canned foods cool. Canned food loses only about 10 percent of its nutrients after being stored at 65 degrees Fahrenheit, but 25 percent when stored at 80 degrees. Because nutrients escape through water, the liquid in water-packed cans is nutrient—rich-don't throw it out.

Milk must be kept in the dark and stored in opaque containers in order for the riboflavin to survive.

And last but not least, before locking food in plastic bags, squeeze all the air out of the bags.

Cooking

When steaming or boiling, use just enough water to keep food from scorching and cook only until tender. Cover the pan with a tight-fitting lid to prevent steam and water-soluble nutrients from escaping.

The less water you use for cooking, the more food value your cooked vegetables will retain. Larger vegetable pieces retain more nutrients than smaller ones do, and boiling or baking tubers—such as carrots, potatoes and yams—whole with the skin intact yields significantly more nutrients than cooking these vegetables skinned and cut. (The skin of an average-size potato contains three times the vitamin C of a Valencia orange.) Likewise for bread—a thick slice of bread loses only half the nutrients during toasting that a thin slice loses.

Whereas steaming plant foods under pressure in a pressure cooker can cause a great loss of nutrients, especially if the food is overcooked, steaming them in a microwave oven produces the least nutrient loss.

Although animal meats shrink in size and weight when cooked, their protein values remain surprisingly intact. Even when the meat is boiled, not more than 10 percent of its protein escapes into the broth.

To retain the nutrients in enriched rice, don't rinse it before or drain it after cooking.

Reheating

Unless leftovers are blast-frozen, refrigerating them to reheat at a later date can cost you a lot of nutrients. For every day that cooked vegetables sit in the fridge—and are then reheated—they lose 25 percent of their vitamin C.

Storing Supplements

Keep a week's supply on hand in a cool cupboard and store the remaining supplements in a freezer where you can maintain a temperature of 0 degrees Fahrenheit. To reduce air space, tuck cotton in each bottle. Cap tightly.

By Teagan Olive