What Are Antioxidants And How Much Should You Eat?

A wide variety of foods, ranging from ketchup to pomegranate juice, are recognized for having antioxidants. You’ve undoubtedly heard that those chemicals can do a lot for your health—they’ve been recommended for anything from heart disease prevention to cancer prevention—but are they really as beneficial as people claim? What precisely are these allegedly miraculous chemicals, and why does everyone seem to be making such a huge deal about them all of the time?

“Antioxidants” is one of the many nutrition-related buzzwords that exist, and it is certainly one of the most popular. But, what exactly are antioxidants, and how do they impact your body’s functions? A wide variety of foods, ranging from ketchup to pomegranate juice, are recognized for having antioxidants. You’ve undoubtedly heard that those chemicals can do a lot for your health—they’ve been recommended for anything from heart disease prevention to cancer prevention—but are they really as beneficial as people claim? What precisely are these allegedly miraculous chemicals, and why does everyone seem to be making such a huge deal about them all of the time?

“Antioxidants” is one of many nutrition buzzwords. The question is, what are antioxidants and how do they work?

Plenty of foods contain antioxidants, from ketchup to pomegranate juice. Do many people claim those compounds can help your health, from heart disease to cancer prevention, but are they really that beneficial? And why is it that everyone is always talking about these supposedly magical compounds?

Antioxidants, like many other topics in nutrition, have many facets to explore. While they are marketed as a panacea, they are not. And yet, antioxidants have a lot to offer.

Antioxidants are a type of nutrient that can help us fight disease.

photo: Jesse Morrow/Adobe Stock
photo: Jesse Morrow/Adobe Stock

What are antioxidants?

Let’s first define a wellness buzzword: “free radical” before discussing what an antioxidant is.

According to Edward Giovannucci, M.D., professor of nutrition and epidemiology at Harvard T.H. Chan School of Public Health, free radicals are highly reactive compounds that can attach and bind to normal cells in the body, causing damage such as DNA strand breaks. An unpaired electron in a molecule makes it unstable and constantly seeks out other molecules to bind to.

Diet and vigorous exercise produce free radicals, as do UV light, pollution and smoking. Dr. Chwan-Li (Leslie) Shen, associate dean for research at Texas Tech. The occurrence of free radicals in the body can be caused by other environmental toxins, like ionizing radiation and certain metals (NCI).

As natural byproducts of metabolic processes (like eating and exercising), free radicals aren’t always harmful in themselves. The body uses them for important functions like cell communication.

Excessive production of free radicals can cause issues. Their high reactivity causes oxidative stress, which damages cells. Oncology, cardiovascular disease, type 2 diabetes, Alzheimer’s, Parkinson’s, cataracts, and age-related macular degeneration are all thought to be caused by oxidative stress, according to the National Institutes of Health’s National Center for Complementary and Integrative Health.

Antioxidants come into play here. Antioxidants can help fight free radicals. Antioxidants help neutralize free radicals and other molecules in your body that can damage cells and tissues, according to the NCI. (They do this by lending an electron to a free radical to make it less reactive or binding to a substance to prevent further reactions.)

Antioxidants help your immune system by stabilizing free radicals, which are linked to chronic inflammation, which is linked to many diseases, like heart disease and cancer. Antioxidants may also help repair DNA and cell membranes through different mechanisms.

Where can I get them?

It makes antioxidants, but not enough. As a result, Dr. Shen advises taking external antioxidants.

Antioxidants are “compounds found in foods that stop or delay cell damage,” says Lauri Wright, Ph.D., R.D., L.D., chair of the department of nutrition and dietetics at the University of North Florida. In Dr. Wright’s words, “antioxidants are released from foods we eat through digestion and travel through the bloodstream and into cells.”

Aside from the hyped-up “superfoods,” antioxidants are abundant in nature. Antioxidants are found in many foods, including fruits, vegetables, seafood, whole grains, and meats. (More on suppléments!)

Some antioxidants are vitamins, while others are minerals that your body requires to function. An example of an antioxidant is vitamin C (found in Brussels sprouts, red cabbage, and peppers), which your body makes from beta carotene (found in collard greens, sweet potatoes, and cantaloupe). Selenium (found in Brazil nuts, pork, and turkey) and zinc are examples of antioxidant minerals (found in oysters, beef, and pumpkin seeds).

Antioxidants that aren’t essential nutrients can still affect cells and tissues, says Bradley Bolling, Ph.D., assistant professor of food science at the University of Wisconsin-Madison. Plants, animals, and other foods contain these.

Lycopene (found in watermelon, tomato sauce, and ketchup), lutein and zeaxanthin (found in spinach, Romaine lettuce, and Swiss chard), chlorogenic acid (found in coffee, apples, and eggplants), and ergothioneine (found in berries, teas, and citrus fruits) are a few examples of antioxidants that have been linked to improved health (found in mushrooms).

Antioxidants’ health benefits

These nutrients combat oxidative stress, which is linked to the wide range of health issues listed above.

The risk of disease is determined by many factors, including oxidative stress. Increasing antioxidant intake has been linked to a variety of health benefits, but the NCCIH cautions that the benefits may be due to a combination of substances rather than specific antioxidants, as well as other lifestyle or dietary factors.

Reviewing the evidence linking high antioxidant intake to lower disease risk.

Based on their antioxidant intake, researchers divided 23,595 Americans into four groups. Surveillance revealed that those who consumed the most antioxidants had a 21% lower risk of death over a 13-year period than those who consumed the least. Also, keep in mind that this study relied on only one day’s worth of eating.

Dietary antioxidants may also reduce your risk of type 2 diabetes and stroke, according to research findings. A diet rich in antioxidants may also reduce the risk of cancer, with significant reductions seen in colorectal, endometrial, and gastric cancers, according to a meta-analysis published in Critical Reviews in Oncology/Hematology.

A few antioxidants may even be linked to a reduced risk of certain diseases, though the evidence is mixed. A recent study in the American Journal of Clinical Nutrition suggests a link between flavonoids and a reduced risk of Alzheimer’s disease. On the other hand, Dr. Giovannucci says that eating lycopene (found in tomatoes) may help prevent aggressive prostate cancer, while eating beta-carotene (found in carrots) may help protect against breast cancer (source) (particularly, estrogen receptor negative breast cancer).

Much of the research we’ve covered has focused on total antioxidant intake, and researchers found correlations rather than cause-and-effect relationships. While plenty of research shows a link between higher antioxidant intake and lower disease risk, we can’t guarantee that consuming certain antioxidants (or antioxidants in general) will improve your health. Many factors contribute to the development of these diseases (some of which you can control and others you can not). Talk to your doctor about your specific health history and risk factors, as well as the role that certain antioxidants may play in your health.

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Food antioxidants

Experts recommend getting antioxidants from food rather than supplements for several reasons.

Studies can’t really tell us if the positive health benefits are due to antioxidants alone, or a synergistic combination of antioxidants and other nutrients (like vitamins and minerals). Along with the many other phytochemicals present in plants, Dr. Giovannucci points out that there are many lesser-known compounds in foods—possibly thousands—that have been shown to have antioxidant properties. So, different antioxidants and other substances in, say, a tomato, may work together.

Eating a variety of whole foods provides all the benefits associated with each phytonutrient, regardless of their specific roles.

Aside from that, whole-food packages (berries, greens, root veggies) are incredibly healthy. Antioxidant-rich foods like fruits and vegetables also contain essential vitamins and minerals (not antioxidants), carbohydrates (including fiber and natural sugars), and water. That is, there are many reasons for eating an abundance of antioxidant-rich foods every day.

How much of each should you eat to get enough antioxidants? There are recommended daily allowances (RDAs) for antioxidants that are essential nutrients. The RDA for selenium is 55 micrograms. The Dietary Guidelines for Americans provide RDAs for some nutrients, such as zinc and vitamins A, C, and E. (Women aged 31-50 should aim for 8 mg zinc, 700 micrograms A, 15 mg E, and 75 mg C per day.) Some essential nutrients, like vitamin C and A, are listed on food labels, making tracking your intake simple.

There is no standard recommended amount to consume for antioxidants that aren’t essential nutrients. This is still being researched, says Dr. Bolling. Neither will the antioxidant dose be listed on the labels of foods containing them.

Rather than trying to consume a specific number of antioxidants, focus on increasing your intake of antioxidant-rich foods. “Eating berries for breakfast, or drinking citrus or green tea is enough to put people into higher level consumption patterns,” says Dr. Bolling.

Dr. Garelnabi recommends eating two and a half cups of vegetables and two cups of fruit per day to get enough antioxidants. Dr. Shen recommends lean meats, whole grains, dark chocolate, tea, and nuts as antioxidant sources.

Again, Dr. Garelnabi emphasizes dietary diversity because some antioxidants work better together. Dr. Wright advises aiming for color. A study published in Current Research in Food Science suggests that the color of fruits and vegetables can indicate their antioxidant content. Apples, strawberries, sour cherries, red cabbage, and red peppers are high in anthocyanins, while mangos, yellow peppers, oranges, bananas, and nectarines are high in vitamin C.


So, supplements? Dr. Garelnabi says most people get enough antioxidants from a balanced diet and don’t need to take antioxidant supplements.

While eating plenty of fruits and vegetables is proven to be healthy, the NCCIH says the same can not be said for antioxidant supplements. According to the NCCIH, many studies on antioxidant supplements have found that they do not reduce the risk of developing diseases like heart disease and cancer. The use of antioxidant supplements to prevent chronic diseases or mortality is not supported by research, according to a 2014 review. The NCI proposes that the purified chemical versions of these antioxidants are too different from the complex combinations of compounds obtained from foods.

Unlike foods, antioxidant supplements may be harmful in high doses. According to the NCI, high doses of certain antioxidant supplements have been linked to an increased risk of certain diseases (like beta-carotene and lung cancer). While correlation does not equal causation, it is cause for concern given that people take these supplements to reduce their risk of disease. The NCCIH warns that antioxidant supplements can interact with medications. (For example, vitamin E and blood thinners may increase bleeding risk.)

You should always consult your doctor before taking any supplements. They may interact with other medications you are taking. Also, keep in mind that supplements are not regulated like pharmaceutical drugs, so you may not know what you’re getting.

Otherwise, if you’re focusing on variety and trying new fruits or veggies to broaden your intake, you’re probably doing fine on the antioxidant front.

Add increasing your body’s antioxidant supply to the already long list of reasons to exercise. Dr. Garelnabi says that moderate exercise can help your body produce more natural antioxidants.

Do you know that Green tea also has antioxidants?


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