Antioxidant Supplements

Can Antioxidant Supplements Prevent Heart Disease?

Do you take antioxidants to prevent heart disease and cancer?

Millions of people do. Antioxidants such as vitamin C, vitamin E, selenium, beta-carotene, and coenzyme Q10 are among the most common supplements I see on my patients’ medication records. The typical reasons for taking antioxidants include promoting health, slowing aging, and preventing heart disease and cancer.

But do they really work?

High-Antioxidant Foods to Try

photo of tomatoes
1/12TomatoesAntioxidants, chemicals that help “clean up” cell-damaging molecules in your body called free radicals, come in many forms. Tomatoes are chock-full of lycopene, which is one type of a group of antioxidants called carotenoids. You’ll get plenty of it by eating raw tomatoes. But you can bump up your intake by cooking them into a sauce or eating them with a little oil.
photo of garlic
2/12GarlicWhen it comes to antioxidant power, raw garlic packs a punch. Allicin, garlic’s antioxidant workhorse, needs a few minutes to start working after you crush or chop the seasoning. Let minced garlic sit before adding it to a dish. If you plan to cook it, keep the temp below 140 F, or wait until you’re nearly done to add it to the pan. Don’t overdo it! Too much garlic can sour your stomach, breath, and body odor.
photo of dark chocolate
3/12Dark ChocolateChocolate lovers, rejoice. Your favorite sweet treat delivers antioxidants. The key is to nosh on chocolate with a high cocoa content. Choose dark types over milk or white chocolate. Enjoy it in moderation, though. Chocolate candy is high in both fat and sugar. For a sugar-free fix, sprinkle unsweetened cocoa powder into your oatmeal or smoothie.
photo of liver
4/12LiverCow, chicken, and other animal liver is rich in vitamin A, a powerful antioxidant that helps with bone health and vision, and boosts your body’s defenses against illness. If you find the taste too strong, soak it in milk before cooking or mix small pieces into ground beef for chili or tacos. But go easy if you’re pregnant or watching your cholesterol. Too much vitamin A isn’t good for growing babies. And liver is high in cholesterol.
photo of kale
5/12KaleThis leafy green gives you beta-carotene, vitamin E, and vitamin C, all of which are antioxidants. Toss kale in salads or blend it into smoothies to get your daily dose. You can also serve it in soups and stews or bake it into crunchy “chips.” But know that heat lowers its antioxidant power slightly.
photo of coffee
6/12CoffeeThat morning cup of joe does more than wake you up. The antioxidants inside can help ward off cell damage. Don’t load up on cream or sugar, which add calories. To avoid caffeine overload, limit yourself to three to four 8-ounce cups a day.
photo of walnuts
7/12WalnutsCompared to most other common nuts, walnuts have the most polyphenols, a type of antioxidant. You only have to eat about seven to get the health benefits. Raw is best. Roasting can keep the antioxidants from working well.
photo of berries
8/12BerriesName a berry, and it’s probably a good source of antioxidants. Blueberries, cranberries, strawberries, blackberries, raspberries, even goji berries, are all at the top of the list of antioxidant-rich fruits. Berries are low in calories and high in fiber. One cup of fresh or frozen berries a day should do you right.
photo of red pepper
9/12Red PepperBell peppers are all good sources of antioxidants, but red peppers take the prize. They’re full of carotenoids that can help prevent certain cancers. They’re sweet enough to snack on raw, which is how they deliver their antioxidants best.
photo of artichokes
10/12ArtichokesThe U.S. Department of Agriculture ranks artichokes No. 7 on its list of antioxidant-rich foods. Unlike some other veggies, artichokes actually give you more antioxidants after you cook them.  Try steaming them whole or roasting them in the oven. 
photo of sweet potatoes
11/12Sweet PotatoesSweet potatoes’ orange hue makes them a great source of beta-carotene, an antioxidant that helps ward off disease. Keep your portions sensible, since carb-filled potatoes can quickly raise your blood sugar levels. Bake or microwave with the skins on to unlock their power to fight free radicals.
photo of couple drinking wine
12/12WineA substance in red wine called resveratrol may help protect your heart by preventing damage to blood vessels. You can get the same benefit without alcohol by eating red grapes. But if a nightly glass of merlot is part of your routine, it’s nice to know it could be giving you an antioxidant boost. Just keep it to one glass if you’re a woman, or two if you’re a man.

Reviewed by Kathleen Zelman on 2/17/2020

The Antioxidant Story

The reasoning behind our enthusiasm for antioxidants makes a lot of sense. Our normal metabolism creates potentially dangerous substances called free radicals. We can also be exposed to free radicals from toxins like cigarette smoke, excessive sun exposure, and pollution.

The problem with free radicals is that they can cause cell damage (called oxidative stress), leading to health problems like heart disease, dementia, diabetes, and cancer.

Antioxidants are potentially helpful because they have been shown in laboratory studies to neutralize free radicals. Also, many healthy foods like vegetables, fruits, nuts, and berries are high in antioxidants. This information led to the idea that antioxidant supplements could help prevent heart disease and cancer.

Early in my medical career, the antioxidant idea was trendy among physicians based on some early observational studies that were promising. During my training, I was blessed to have some of the brightest physicians in medicine as teachers. And several of them regularly recommended antioxidants to their patients, such as vitamin E, vitamin C, coenzyme Q10, and resveratrol.

However, physicians know that observational studies are not strong science. The findings can be wrong because there are too many uncontrolled variables that can change the outcome. We have also learned many times that logical ideas about how the body works don’t always prove correct in real life.

Therefore, to truly test the idea that antioxidants promoted better health, we needed well-designed research studies to know for sure.

The results were a surprise to many.

Antioxidant Research

Dozens of randomized trials looking at the antioxidants have now been completed. A few examples include:

  • study of over 14,000 male physicians showed no difference in prostate cancer or other cancers in those taking vitamins C and E.
  • study of over 35,000 men showed selenium had no effect — and vitamin E increased prostate cancer.
  • study of over 39,000 women showed no effect on heart disease or cancer in those taking vitamin E.
  • study of over 8,000 women showed no difference in developing diabetes in those taking vitamin C, vitamin E, and beta-carotene.
  • study of over 29,000 male smokers showed no difference in lung cancer with vitamin E, but an INCREASE in lung cancer in those taking beta-carotene.

Despite the promise, higher-quality studies have not shown any benefit to antioxidant supplements as they are currently used (and in some cases, these supplements have resulted in harm).

The full story of antioxidants is not known yet. Although the evidence is solid that vitamin C, vitamin E, and beta-carotene do NOT improve health outcomes (and in the case of beta-carotene and vitamin E, maybe increase risk), there are still several unknowns about antioxidants. Would other antioxidants be effective? Are we giving the right dose to the right people?

Until we have those answers, here is my advice for my patients about antioxidants:

  • Get your antioxidants from real food. There is magic in real food we can’t create in a pill.
  • Be wary of health claims for antioxidant supplements. Be especially wary when the claims come from those who financially benefit from you taking supplements.
  • There are proven ways to dramatically lower your heart disease and cancer risk. They just don’t come in a pill. The remarkable health-promoting benefits of regular physical activity, eating nutritious food, getting adequate sleep, and avoiding toxins such as tobacco and excess alcohol are proven.

If you are taking antioxidant supplements or considering it, I recommend talking to your doctor to understand the risks and benefits for you.

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