A glass of orange juice. A side dish of steamed broccoli. Corn on the cob. All of these are simple pleasures that you may enjoy now and then without realizing that these and other common foods and beverages are brimming with antioxidants, which are critical disease fighters.
Remember antioxidants? Back in the 1990s, pills packed with these vitamins, minerals, and other natural compounds were touted as medical wonders. Many books, including bestsellers such as Dr. Kenneth H. Cooper’s Antioxidant Revolution and The Antioxidant Miracle, insisted that antioxidant supplements could dramatically slash the risk of heart attacks and cancer and even slow the aging process.
Fast-forward to today: Mounting research suggests that the preventive and healing powers of antioxidants may extend beyond heart disease and cancer to include a wide range of chronic, painful, and potentially devastating conditions. For example, doctors once believed that daily wear and tear on the joints caused osteoarthritis, the most common type of this degenerative condition. However, recent studies show that damage by free radicals—the villainous molecules antioxidants were born to battle—may speed up the onset of osteoarthritis by attacking the cells that form cartilage. Studies also show that certain antioxidant compounds can slash the risk of cataracts and macular degeneration.
What has changed since the first “antioxidant revolution” — besides our knowledge that antioxidants are even more important than we thought—is that high dose antioxidant supplements aren’t the answer anymore. The answer is food.
In sync: Antioxidants work better together
There is no doubt about it: Many studies show that people who eat plenty of antioxidant-rich foods seem to lower their risk of heart attacks, cancer, and various chronic and debilitating diseases. This promising research led scientists to wonder whether high doses of these same antioxidants—extracted from food and packed into pills—would provide even greater disease protection.
Studies evaluating the benefit of antioxidant supplements have had mixed results. Take vitamin E, for example. Past research shows that people who consumed a lot of it from food had 30 to 40 percent fewer heart attacks than others whose diets included little. Yet several teams of scientists have compared large groups of people who took vitamin E supplements with other who took placebos. Most of these studies have found that people in both groups had the same risk of cardiovascular disease, raising doubts about whether vitamin E protects the heart.
There are several possible explanations for these disappointing results. For example, in some studies, people at high risk for heart disease may have started taking the supplement too late for the pills to do much good. However, mounting research suggests that antioxidants simply work better as a team. That is, individual antioxidant such as vitamin E may be more potent when you toss them down the hatch with other antioxidants—the way they occur naturally in food. “Antioxidants interact in a very dynamic interrelationship,” says nutrition scientist Jeffrey Blumberg, Ph.D., chief of antioxidant research at Tufts University in Boston. “It may be that for optimal health, we need to eat foods that have these complex mixtures of compounds.” His research shows, for example, that vitamin E’s antioxidant punch increases up to 300 percent when the vitamin in combined in a test tube with certain flavonoids found in almonds.
That doesn’t mean Dr. Blumberg and other scientists have given up on vitamin E pills or any other antioxidant supplements. In recent years, the National Institutes of Health has sponsored research on the use of antioxidant therapy to prevent or treat a long list of conditions. But the most powerful evidence on the books today suggests that eating foods rich in antioxidants is the best way to defend yourself against diseases that are caused or worsened by the daily assaults of free radicals.
For instance, drinking a cool glass of orange juice at least three times a week may help reduce the risk of Alzheimer’s disease by up to 76 percent, thanks to its high content of antioxidants content polyphenols, according to a study by Vanderbilt University researchers. Meanwhile, a study in the Archives of ophthalmology found that women who eat plenty of corn, squash, and other yellow vegetables—which are full of antioxidants called carotenoids that protects the eyes from free radicals—halved their risk of macular degeneration, which can cause blindness. And an Italian study recently found that a small daily dose of antioxidants from a surprising source dark chocolate lowered blood pressure better than most standard medications. How sweet is that?
Free radicals: Necessary evils
Here’s news that may leave you holding your breath: oxygen is toxic. You can’t live without it, of course, since very cell in your body requires oxygen to spark metabolism, or the production of energy. However, 1 to 3 percent of the oxygen you inhale never gets burned. Instead, it reacts with naturally occurring metal compounds in your body to produce renegade molecules called free radicals.
There are many different types of free radicals, but they all share one thing in common: Unlike normal molecules, they are missing a pair of electrons. This defect makes them dangerous, since they will attack anything in their path in order to replace their missing parts. Free radicals aren’t entirely bad, though. In fact, your immune system produces them as part of your body’s overall defense scheme, since free radicals kills bacteria and defuse viruses. However, in their quest for electrons, free radicals may also destroy healthy molecules, including protein in cell membranes, fats, and even DNA.
In addition to the free radicals your body makes on purpose, exposure to certain triggers in the environment, including sunlight, air pollution, tobacco smoke, and radiation (from microwave ovens or computers, for example), can produce these unstable molecules. It’s also clear that the hormones that flood your body when you feel emotionally stressed produce free radicals.
Your body tries to keep these oxygen-borne baddies under control, but when levels rise too high, you experience a condition scientists call oxidative stress. Everyone undergoes at least a little oxidative stress now and then, but living in a chronic state of overwhelming stress seems to contribute to a long list of diseases.
Antioxidants to the rescue
If free radicals are reckless marauders that disturb the peace in your body, antioxidants are the riot police. These various vitamins, minerals, and other natural compounds curb the chaos with generosity instead of brute force. An antioxidant neutralizes a free radical by first surrounding it, then giving it a pair of its own electrons, ending the destructive behavior. This gesture turns the antioxidant itself into a free radical since its now missing a pair of electrons, but new molecule is toothless and does not harm.
As mentioned earlier, your body produces its own lineup of antioxidants. Many have name that sound as if they came straight out of a scientific novel, such as superoxide dismutase and coenzyme Q10. These homegrown antioxidants are a talented lot: one, called lipoic acid, is particular versatile, capable of recycling used-up antioxidants and thus restoring their effectiveness. Bu your body makes only a portion of the antioxidant force needed to keep free radicals from taking over. What’s more, your naturally occurring levels of antioxidants decline with age. That’s why it’s critical to get reinforcements from antioxidant-rich foods and in some cases, dietary supplements. Many dietary antioxidants have been well studied and have familiar names, like vitamin C. Others belong to an emerging class of compounds that scientists are just beginning to identify and understand. All belong in your diet.
Vitamins and minerals
Your body can perform remarkable feats of chemistry, but it has limitations. While your inner chemist can build protein and amino acids, for instance, it can’t whip up many of the raw compounds needed to maintain daily functions and prevent disease. Instead, we rely on foods for these critical compounds, known as vitamins and minerals. Not only is your body incapable of manufacturing its own vitamins and minerals, but it also has a limited capacity for storing them. That’s why you must restock your inventory frequently by eating a well-balanced diet.
Most individual vitamins and minerals perform a lengthy list of chores. For instance, your body needs vitamin C to build a healthy immune system, brain cells, and bones, to just name a few of its roles. Vitamin E, meanwhile, is necessary for many tasks, such as forming red blood cells and muscles, lung, and nerve tissue. Both of these vitamins are powerful antioxidants, too. A healthy diet must also include a variety of minerals. . One mineral, selenium, is needed to form certain enzymes that act as antioxidants.
You may be surprised to learn just how much you have in common with a tomato vine or blueberry bush. Just as your body makes antioxidants to fend off illness, plants produce chemicals that protect them against disease. Scientists have identified thousands of so-called phytochemicals. While they are not technically nutrients, many phytochemicals are now known to be critical for keeping your body up and running.
Growing evidence shows that phytochemicals play a wide variety of roles in the body, such as preventing blood clots and slowing the spread of cancer cells. But perhaps the most attention has been focused on their potential as antioxidants. There are two main categories of phytochemicals that acts as antioxidants.
- Carotenoids: Fruits and vegetables that are yellow, orange, or red tend to be good sources of these antioxidant plant chemicals. Think tomatoes, oranges, carrots, and pink grapefruit. Some green vegetables, such as spinach and kale, are full of carotenoids, too. Everyone has heard of beta-carotene, which your body converts to vitamin A, but studies show that several carotenoids with less familiar names are critical to human health, too.
- Flavonoids: These blue, blue-red, and violet pigments are another important category of antioxidants (which technically belongs to a larger category called polyphenols) that may be particularly important in helping us fight diseases ranging allergies to heart disease to cancer. One type of flavonoid, known as quercetin, appears to be particularly good for the cardiovascular system, since it prevents LDL cholesterol from being oxidized (making it less sticky to artery walls). Red and yellow onions, kale, broccoli, red grapes, and apples are all good sources of quercetin. Cocoa contains flavonoids called epicatechins, also thought to benefit the heart. These compounds, also fight found in tea, prevent blood clots, slow the oxidation of LDL cholesterol, improve blood vessel function, and even reduce inflammation.
Antioxidants in action: The benefits of defusing free radicals
Free radicals don’t sleep or take vacations. One expert quoted in The Antioxidant Miracle estimated that the DNA in every cell in the human body suffers about 10,000 “hits” from free radicals each day. It’s not surprising then the oxidative stress that can result when your antioxidant support isn’t up to full strength can produce an array of debilitating conditions. However, if you choose your diet wisely and use supplements as necessary (always under your physicians guidance), antioxidants may do the following.
Protect your heart
Even though studies haven’t shown conclusively that antioxidant supplements prevent heart disease, there is no doubt that your diet must include frequently doses of antioxidants to keep LDL cholesterol, the “bad” stuff, from turning even worse. Oxidized cholesterol—that is, cholesterol that’s been attacked by free radicals—is more likely to burrow into artery walls. Once cholesterol makes its way there, it’s even more likely to become oxidized. When this happens, your immune system senses trouble and responds by sending white blood cells to the scene. These defender cells devour cholesterol, turning into frothy blobs called foam cells. As these fat-filled cells accumulate, they form raised patches called plaques, which narrows arteries. Plaques can erupt, blocking the artery and causing a heart attack.
People who eat plenty of antioxidant-rich fruits and vegetables have a low risk of heart diseases, many studies have shown. Other good sources of heart- healthy antioxidants include tea and wine; both beverages contain high concentrations of flavonoids. Studies suggest that eating a diet high in flavonoids may lower the risk of heart disease by up to 65 percent.
Want to lower the workload for your body’s homegrown crew of antioxidant? Eat fewer sweets and starches, which seem to raise levels of free radicals. A study by the University of California researchers found that people whose diets included the most high-GI foods had the highest levels of oxidized cholesterol, the kind most likely to cause heart attack.
Protect your DNA
Free radicals can damage the DNA in healthy cells, which may alter their operating instructions and cause them to reproduce uncontrollably and form cancerous tumors. People who eat lots of fruits and vegetables have a low risk for some types of cancer. Lab studies show that phytochemicals stifle the growth of tumors in various ways, including by scavenging and demobilizing free radicals.
This news should have you seeing red—and orange and yellow—when you shop for vegetables, since carotenoids (which tend to have these pigments) may be one of the most potent types of antioxidants for fighting cancer. In particular, studies have revealed low rates of prostate cancer among men who consume a lot of tomatoes and cooked tomato products, which contain the carotenoid lycopene. One study found a 64 percent reduction in prostate cancer among men who consumed the most beta-carotene, a carotenoid that’s found in carrots and other yellow or orange fruits and vegetables.
Control diabetes complications
High blood sugar seems to speed up production of some unusually nasty free radicals. These destructive molecules probably cause many of the complications that makes diabetes so frightening, such as blindness, nerve damage, and kidney failure.
Some promising signs suggest that antioxidants could alleviate some diabetes symptoms. For instance, European studies have shown that dietary supplements containing alpha-lipoic acid (found in spinach, broccoli, and beef) may relieve the pain and discomfort of diabetic neuropathy. Scientist in India have shown that antioxidant compound curcumin, which gives the spice turmeric its yellow color, slowed kidney damage in diabetic rats. The antioxidant resveratrol (found in red wine) and quercetin (apples and onions are good sources) had a similar effect.
Some phytochemicals may even offer protection against diabetes itself. In a Finish study of more than 4,300 non-diabetic men and women whom researchers followed for 23 years, those who ate the most of a type of carotenoid found in citrus fruits, red bell peppers, papaya, cilantro, corn, and watermelon cut their risk of type 2 diabetes by 42 percent.
Defend against dementia
Brain cells of people diagnosed with devastating cognitive conditions show evidence of damage by free radicals. What’s more, free radicals seem to be one cause of the clumps of protein in the brain, called amyloids that are characterized of Alzheimer’s disease.
No one is sure how to prevent Alzheimer’s, but eating more oranges and whole-grain bread could be a good start. Human studies offer clues that vitamin C and E may be your brain’s defense. Dutch researchers asked more than 5,000 people over the age of 55 about their diets, then followed them for six years. In the end, people who consumed the most vitamin C reduced their risk of Alzheimer’s by 34 percent, while diets rich in vitamin E appeared to be more protective, slashing the threat of dementia by nearly half.
It’s less clear whether taking high doses of antioxidants will do an even better job of safeguarding the brain. One study published in the New England Journal of Medicine found that taking daily supplements containing 2,000 IU of vitamin E—or about 66 times more than you’ll find in a multivitamin – appeared to slow the onset of Alzheimer’s. However, other studies have failed to show that vitamin E pills protect the brain. (The Alzheimer’s Association doesn’t recommend the use of antioxidant supplement.)
Save your sight
Tired of jokes about rabbits not wearing eyeglasses aside, carrots are indeed good for your eye health (although they won’t do anything to sharpen your eyesight). As anyone who tends a garden knows, rabbits eat many other plants besides carrots, and so should you. Here’s why. Carrots are loaded with beta-carotene, which the body converts into vitamin A—an essential nutrient for healthy eyes. But the latest research suggests that other antioxidant phytochemicals may also be critical for preserving vision. Take lutein, another carotenoid like beta-carotene, which is found in hefty amounts in spinach, kale, and collard greens. Retina cells at the back of the eyeball soak up lutein, apparently to ward off free radicals. When researchers analyzed the diets of more than 1,700 female volunteers in Iowa, Oregon, and Wisconsin, they found that women under 75 who ate plenty of foods rich in lutein and zeaxanthin, another carotenoid, appeared to halve their risk of macular degeneration, a leading cause of vision loss in older folks.
Consuming lots of foods filled with these antioxidants may help prevent cataracts, too. So eat your carrots, but don’t skimp on leafy greens, squash, corn, or peas, all of which are good sources of lutein and zeaxanthin, as are egg yolks, honeydew, and kiwifruit.