The global antioxidant supplement market was close to four billion dollars in 2020, and is projected to hit six billion by 2027.

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To understand what antioxidants do, you have to start with a little molecule called a free radical. Free radicals are naturally made in your body when your cells make energy from foods you eat and when you use energy during exercise. Free radicals can also occur when your cells are exposed to sunlight, air pollution, or cigarette smoke. These molecules are unstable because they have lost an electron. Electrons rotate around a molecule. When a molecule loses an electron it goes in search of a replacement, this hungry molecule is then a free radical. Free radicals may steal an electron from another cell and damage the cell’s DNA.

What Is Oxidative Stress?

Oxidative stress is damage done to your body when it is overwhelmed by free radicals. According to the National Institutes of Health (NIH), oxidative stress has been linked to an increased risk for chronic diseases that include heart disease, cancer, diabetes, Alzheimer’s disease, Parkinson’s disease, cataracts, and macular degeneration.

What Is an Antioxidant?

An antioxidant is a molecule that has a spare electron it can give to a free radical. Laboratory experiments show that this can stabilize a free radical and prevent oxidative stress. The body naturally produces some antioxidants to prevent oxidative stress, which makes sense, otherwise you would get weaker after exercise instead of stronger. Your body also extracts antioxidants from foods, especially fruits and vegetables.

Many diet studies over the years have found that people who eat lots of fruits and vegetables have a lower risk of chronic diseases caused by oxidative stress. Assuming that this is probably due to the antioxidant effects of these foods, researchers began to study the effects of antioxidant supplements in large clinical trials lasting several years. They hoped to find out if antioxidants supplements can reduce the risk of cancer, heart disease, and the other diseases linked to oxidative stress.

What Did the Research on Antioxidant Supplements Find?

The global antioxidant supplement market was close to four billion dollars in 2020, and is projected to hit six billion by 2027. You would expect that this expanding demand is responding to positive results from all the antioxidant supplement studies. You would be wrong. According to NIH, most of the studies have found that antioxidant supplements do not help prevent diseases. The Harvard T.H. Chan School of Public Health says these disappointing studies have not stopped the media and supplement companies from hyping the benefits of antioxidants. Antioxidants have been added to cereals, energy drinks, and other processed foods. But antioxidants aren’t recommended for everybody.

What About Ascorbic Acid and Other Antioxidant Vitamins?

There are hundreds of antioxidants, but some of the most familiar ones are ascorbic acid (vitamin C), vitamin E, and beta-carotene, which is converted to vitamin A in the body.  Studies on vitamins C, E, and beta-carotene supplements have also been disappointing. In fact, according to Harvard, the results from the largest trials have been negative. Vitamin E supplements may increase the risk of recurrent prostate cancer, and beta carotene may increase the risk of lung cancer in smokers.

Why Do Antioxidants in Foods Work, But Not in Supplements?

First of all, the evidence that antioxidants in fruits and vegetables help prevent many chronic diseases is not absolute. It may be that the people in these studies who ate the most fruits and vegetables also got more exercise and made other good lifestyle choices. The people eating lots of fruits and vegetables were probably not the ones eating lots of fast foods and junk foods.

The probable reason that foods work when supplements don’t is that antioxidants work best as a cocktail mixed with other nutrients and other antioxidants. When your body gets antioxidants from foods it uses them at the right dose and the right mixture. Most of the supplement studies looked at just one antioxidant given at a high dose. That may be like taking one instrument out of an orchestra, playing it loud, and expecting to hear a symphony.

What to Do About Antioxidant Supplements

There may still be hope for antioxidant supplements. It may be that we need longer studies or that we need to study antioxidants in people who actually have an oxidative stress. One study has found that a combination of ascorbic acid, vitamin E, beta-carotene, and zinc reduced the risk of advanced age-related macular degeneration by 25 percent. Macular degeneration is a common eye disease.

Until more studies have found the right mix and dose of antioxidants that work in supplements, eat your fruits and vegetables. Your body knows how to extract what it needs from these foods. It could be antioxidants, minerals, vitamins, fiber, or other nutrients. Whatever the magic formula is, it seems to work. People who eat more fruits and vegetables are healthier.