The Best Defense Is a Good Offense
You buy a lovely two-story house. You paint it, decorate it and make it special. But right under your very nose, or more specifically, under the woodwork, a colony of termites has moved in.
So while you're enjoying your domestic bliss, these hidden invaders are slowly but surely making mincemeat of your happy home. When you finally realize it, the damage has been done. Your floorboards are cracking, your foundation is collapsing and your house is leaning like the Tower of Pisa. Time to call an exterminator--and a contractor.
In real life, your aging body is besieged not by voracious creepy-crawlies but by harmful, unbalanced molecules called free radicals. These marauding substances roam your body looking for healthy cells. Once they find something to latch on to and destroy, they multiply, causing a domino effect of destruction.
So where's your body's exterminator? It could be in your refrigerator. Or in your medicine cabinet. Certain nutrients have shown the ability to stop these free radicals dead in their tracks. These age-erasing nutrients--vitamins C and E and beta-carotene--are called antioxidants.
Oxygen: The Root of the Problem
It's one of the great ironies. Oxygen--the glorious stuff that fills our lungs and keeps us alive--is involved in a process that can seriously hurt us.
To get the energy they need, the body's cells use oxygen to burn fuels such as glucose (blood sugar) and, in the process, some oxygen molecules may lose an electron. Such a molecule is now a free radical, hell-bent on replacing its lost electron by raiding the other molecules making up the cell.
By swiping an electron, this larcenous free radical transforms the unsuspecting molecule into a new free radical. "Soon a chain reaction of electron theft begins that can produce widespread damage to the chemistry and function of the cell," says Denham Harman, M.D., Ph.D., professor emeritus of medicine and biochemistry at the University of Nebraska College of Medicine in Omaha. "This biochemical oxidation process is not far removed from that which turns a shiny piece of metal into rust."
Wrinkled skin, shrinking muscles and weak bones--some of the signs of growing old that a woman most fears--could be due in part to this destructive oxidation process, the sum of millions of continuous free radical reactions. But of even greater concern to researchers is the notion that these free radicals are causing some of aging's most insidious diseases.
For example, atherosclerosis (hardening of the arteries), the leading cause of heart disease and stroke, is caused by the build-up of LDL (low-density lipoprotein) cholesterol, the so-called bad cholesterol. But it probably isn't until free radicals oxidize the LDL cholesterol that it assumes its potentially deadly form, according to Balz Frei, Ph.D., associate professor of medicine and biochemistry at the Boston University Medical Center.
If we could stop or slow down the free radical chain reaction before it starts, then LDL cholesterol may never go "bad" in the first place, says Dr. Frei. Or DNA, the genetic material within our cells, may never mutate to lead to the formation of cancer. Or tissues in the eye may be more resistant to cataracts. In other words, it would be possible to slow the aging process, extend life expectancy and improve the quality of life.
Antioxidants to the Rescue
Your body isn't entirely helpless when free radicals go on the warpath. In fact, it actually starts producing certain enzymes to combat the invading free radicals. The problem is that it just doesn't produce enough to stop them all. It needs outside help--fast.
Enter dietary antioxidants--nutritional "scavengers" that patrol our bodies for free radicals, squelching the offending particles. "Because of their unique molecular structures, antioxidants can give up one or more of their electrons to free radicals without becoming harmful themselves," Dr. Frei says. "They actually render the free radical harmless and head off the destructive chain reaction before damage can occur or spread out."
Most researchers have focused their attentions on three antioxidant nutrients: vitamin C, vitamin E and beta-carotene, a substance the body converts to vitamin A. Study after study has shown that high dosages of each of these nutrients results in low instances of many chronic diseases.
In his research, Dr. Frei has found that vitamins C and E can protect LDLs from oxidative damage. "These studies suggest that antioxidant nutrients, vitamin C in particular, are capable of preventing heart disease or at least slowing down its progression," he says.
Scientists have also noticed a relationship between antioxidants and the incidence of cataracts. A study by Canadian researchers suggested that dietary supplementation of vitamins C and E can reduce your risk of cataracts by at least 50 percent.
Paul F. Jacques, Sc.D., an epidemiologist at the U.S. Department of Agriculture (USDA) Human Nutrition Research Center on Aging at Tufts University in Boston, observed that the risk of developing cataracts was five times higher in those with "lower levels of all types of carotene, including beta-carotene" in their blood.
Dr. Jacques has also studied the role of the antioxidant vitamin C in fighting high blood pressure. According to his research, rates of high blood pressure are approximately two times higher in those with a low intake of vitamin C in their diets (less than the Recommended Dietary Allowance, or RDA, of 60 milligrams).
There is also a growing body of evidence that antioxidants may be our best source of cancer protection as well. Researchers at the Harvard School of Dental Medicine have shown in recent experiments on hamsters that a mixture of beta-carotene, vitamin E and vitamin C produced significant protection against oral cancer.
And the research doesn't stop there. Cancer epidemiologist Gladys Block, Ph.D., professor of public health nutrition at the University of California, Berkeley, has reviewed 180 studies comparing the effect of fruits and vegetables and their antioxidant nutrients on various cancers. "One-hundred fifty-six of these studies have shown a statistically significant reduced risk of cancer at virtually all cancer sites," she says.
Among Dr. Block's findings are that a low intake of vitamin C doubles your risk of developing oral, esophageal and stomach cancer. Vitamin E and beta-carotene may be protective against lung and stomach cancer. She also notes that dietary vitamin C found in fruits and vegetables may be as strong a protective factor against breast cancer as saturated fat is a harmful one, and that there is evidence that vitamins C and E and beta-carotene may have a protective effect against cervical cancer.
A Word about Vitamin A
Besides being an antioxidant protector, beta-carotene is a great source of another important nutrient, vitamin A. The body converts beta-carotene into vitamin A on an as-needed basis.
But be aware that vitamin A and beta-carotene are not the same thing. Vitamin A will not give you the same antioxidant protection as beta-carotene, and too much vitamin A can be highly toxic.
For this reason nutritionists recommend that you don't go beyond the daily Recommended Dietary Allowances (RDAs) for vitamin A (800 micrograms retinol equivalents or 4,000 IU) and avoid all single vitamin A supplements or supplements containing more than 100% of the RDA for vitamin A unless prescribed by a doctor. "We get all the vitamin A we need from meats and vegetables or from foods containing beta-carotene," says Jeffrey Blumberg, Ph.D., professor of nutrition and associate director of the U.S. Department of Agriculture Human Nutrition Research Center on Aging at Tufts University in Boston.
Excessive doses of beta-carotene are not nearly as dangerous as those of vitamin A, says Dr. Blumberg. He says it is almost impossible to consume toxic levels of beta-carotene, but too much can produce an unusual side effect: It can make your skin turn orange.
How Much Does a Woman Need?
The National Research Council's Food and Nutrition Board has established the RDAs as guidelines for how much of each nutrient we need to consume each day to meet our basic health needs and prevent deficiency diseases. For women ages 25 to 50, the daily numbers are 60 milligrams of vitamin C, 8 milligrams alpha-tocopherol equivalents (or 12 IU) of vitamin E, and 800 micrograms retinol equivalents (or 4,000 IU) of vitamin A or 4.8 milligrams of beta-carotene.
A balanced diet consisting of a wide variety of fruits and vegetables is the best way to guarantee that you meet your antioxidant RDAs every day. "Four to five servings of fruits and vegetables per day should easily provide you with most, if not all, of the RDAs for the antioxidants as well as other important vitamins and minerals," says Diane Grabowski, R.D., nutrition educator at the Pritikin Longevity Center in Santa Monica, California.
That's fine for basic health, but in order to achieve the kind of disease-fighting results seen in scientific studies, you need to surpass the current RDAs. Even the healthiest of diets falls short in supplying the same amount of antioxidants used in laboratory experiments.
That's where vitamin supplements can play a role. A supplement can ensure maximum antioxidant protection as well as correct any deficiencies in your diet. But popping a vitamin tablet alone isn't the answer. "These nutrients are not 'magic bullets' and work best in conjunction with other healthy nutritional practices such as eating low-fat, high-fiber meals," says Jeffrey Blumberg, Ph.D., professor of nutrition and associate director of the USDA Human Nutrition Research Center on Aging at Tufts.
More research is being conducted to determine the exact form and amount of the antioxidants needed for optimal health and disease protection. Until then, most researchers believe we can best protect ourselves with a combination of diet and supplements. Dr. Blumberg suggests that you try to get all or as many of your RDAs as possible of each antioxidant from the food you eat. For added protection, he suggests that you take daily supplements containing between 100 and 400 IU of vitamin E, between 500 and 1,000 milligrams of vitamin C and between 6 and 30 milligrams of beta-carotene.
|A GARDENFUL OF DELIGHTS
Much of your antioxidant protection can come from the foods you already love to eat. "A good rule of thumb is to eat from a rainbow of colorful fruits and vegetables," says Diane Grabowski, R.D., nutrition educator at the Pritikin Longevity Center in Santa Monica, California. "In general, the darker green or more vibrantly colorful fruits and vegetables have the richest antioxidant content."
Here are some of the very best sources available.
Sources of Vitamin C
Sources of Vitamin E
Sources of Beta-Carotene
Maximizing Your Defenses
Here's how women can best put antioxidants to work and prevent the harmful effects of free radicals.
Eat fewer calories. Digestion requires oxygen--lots of it. The more calories we consume, the more oxygen is required and the greater our chances for free radical formation. Cutting back on the amount we eat can trim our risk of oxidative damage, says Dr. Harman. That doesn't mean you should starve yourself or do anything to reduce your intake of the essential nutrients, he warns. Instead, focus on trimming those nonessential calories from your diet like desserts, candy and soda.
Get some air. Free radicals are also generated in the environment by industrial chemicals, heavy metals, fumes, car exhaust, air conditioning and other airborne pollutants. While we can't escape all these man-made contaminants, anything that limits our exposure to them is beneficial, says Dr. Harman. For example, if you work in a factory or an office, you can take a walk at lunchtime to briefly get away from impurities that may be circulating around your workplace. Open windows. Or use a commercial air-purifying device.
Dowse the cigs. Cigarette smoke contributes huge amounts of free radicals with every puff. Antioxidants can prevent much of the oxidative damage caused by smoking, says Dr. Frei. But if you avoid the habit in the first place, those antioxidants will be available to fight free radicals elsewhere in the body.
Lose the booze. The occasional cocktail isn't going to cause any harm and may actually lower your risk of heart disease, but frequent alcohol consumption can increase the number of free radicals in the body, says Dr. Frei. Not only that, but people with alcoholism show reduced levels of antioxidants in their systems. According to a study at the King's College School of Medicine and Dentistry in London, alcoholic patients showed significantly lower levels of vitamin E and beta-carotene, which coincided respectively with higher incidences of cirrhosis and liver damage.
Don't overdo your workouts. When it comes to exercise, remember the adage "train, don't strain." As beneficial as exercise is to our health, the extra oxygen we take in whenever we work out subjects muscles and other tissues to additional oxidative damage. Pushing the body beyond its limits can lead to an overproduction of free radicals and that can have a devastating effect on the way you look and feel. "This may be why athletes who overtrain find that their performance suffers or they become sick," says Robert R. Jenkins, Ph.D., professor of biology at Ithaca College in New York.
Does this mean you shouldn't exercise? No! Most doctors and scientists believe that any oxidative damage is minimal with normal exercise and offset by the added benefits that exercise provides. According to a British study of endurance runners, regular, nonexhaustive exercise enhances the levels of some antioxidant enzymes in the blood. And a study conducted at the Washington University School of Medicine in St. Louis found that high doses of vitamin C, vitamin E and beta-carotene, while not preventing the body from undergoing any exercise-induced oxidative stress, do seem to lower the signs of oxidative damage in the body.
Regular, moderate exercise seems to strike the perfect balance, says Dr. Harman. And no matter what, keep up your intake of antioxidant vitamins.