All organisms use oxygen to convert food into energy, just as burning wood in a fireplace produces heat. At the same time, oxygen is involved in the production of free radicals that are often very similar to compounds needed by a cell to stay healthy. Imagine free radicals as being like a friendly dog that’s just been out in the mud. If you play with the dog while wearing a white suit, the dog is going to jump up on you and leave muddy paw prints all over your white suit. Unfortunately, the dirt may permanently stain the suit. It’s not as if the dog meant to hurt you, after all, it didn’t try to bite you. It merely wanted to bond with you.
Similarly, free radicals can bond with molecules in a cell, changing the molecules into forms that aren’t as useful or good for the cell as the originals were. For example, free radicals can attack lipids—molecules that form a fence around cells to allow only certain chemicals to travel in and out of cells. They can also damage DNA, the genetic material that serves as the master plan for a cell and governs how it works. Proteins, the molecules in a cell that actually do the work of processing food, also face problems if they run into free radicals. In general, free radicals can keep a cell from functioning properly.
Our bodies have natural defenses for fighting off free radicals. The body makes certain molecules, known as antioxidants or repair enzymes that stop free radicals before they can harm us. It’s like a war between opposing chemical reactions in which good-guy repair enzymes battle terrorist free radicals for control of cell and body.
While we’re young, our defenses are pretty strong. However, our natural defenses get weaker as we get older. The body’s built-in defenses can only go so far without extra help. Sometimes we see the effects of free-radical, or oxidative, damage directly. Wrinkled skin, for example, is one sign of skin-cell damage. Certain cancers and heart disease are linked to free radicals. Overeating and obesity are also linked to oxidative damage.
We can help by sending in reinforcements: antioxidants. For people, this means a lifestyle of consistently eating a variety of fruits and vegetables with intense colors. Recently, the U.S. Department of Agriculture released new guidelines that recommended we eat five to nine servings of fruits and vegetables each day.
The key to fighting free radicals with fruits and vegetables is to mix and match colors. Go for very bright colors and for many different colors. If you’re looking for greens, spinach, broccoli, and dark green lettuces do the job. Pale iceberg lettuce packs little chemical bang per bite. For reds, strawberries and other berries are best, and tomatoes are tremendous. Carrots, oranges, sweet potatoes, and squash all shine among the yellow/orange foods. Blue or purple foods, in particular, can be very beneficial. Have blueberries, Concord
grapes, and eggplant, for example, on your menu as often as you can. These blue foods contain hundreds of healthful chemicals not found anywhere else.