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Can You Have Too Many Antioxidants?

A lot of focus regarding antioxidants is on how great they are for your health. While this is, generally speaking, true, it is also possible to have too much of a good thing. This article explains what antioxidants are and the potential risks associated with consuming too many.

What are antioxidants?

Our bodies undergo many threats daily. One of these comes from atoms referred to as ‘free radicals’, which can harm the cells and genetic material within us1. As food is turned into energy, free radicals are created. They can also be produced when the body is exposed to high levels of pollution, tobacco smoke, and sunlight2.

The harm caused by free radicals is from them taking the electrons from other nearby atoms that make up our cells1. This causes a condition called ‘oxidative stress’, which has the potential to lead to chronic diseases such as cancer and coronary heart failure3. Antioxidants are the body’s means of combatting free radicals1. They are naturally produced in the body but can also be found in certain foods and are commonly available as supplements. Antioxidants operate by donating electrons to free radicals, meaning that the free radicals stop taking electrons from other cells in the body1.

Do we need free radicals?

Although having free radicals in your body indicates that you are, in fact, alive4, they are still not a positive thing. While they are created by natural processes - such as metabolizing food and exercising - they can do great harm to your cells. This is why your body produces antioxidants to combat the free radicals. Having more antioxidants, therefore, helps to reduce your free radical count. However, there are still risks regarding antioxidant consumption (see below).

Aren’t antioxidants good for you?

Yes, antioxidants are good for you. But, the key is to take on a variety of them, preferably through food rather than as supplements. This is because different antioxidants have varying properties, meaning that consuming a lot of one type cannot do all the work, and may even be harmful1.

Oxidation stress caused by having a high amount of free radicals in the body has been associated with myriad health conditions, including cancer, cataracts, and heart disease1. However, research into the benefits associated with consuming antioxidants to reduce these risks has been mixed. Some academics have proven that antioxidant supplements don’t protect against chronic diseases after all5. One study even showed that certain supplements actually increased the risk of lung cancer in smokers6, rather than reduced it.

This isn’t always the case, as some supplements have been successful. For example, it has been demonstrated that vitamin E supplements can reduce the risk of deaths related to cardiovascular conditions7. In addition, people with pre-existing heart and circulatory issues have been shown to benefit from taking additional vitamin E8, as have sufferers of type 2 diabetes9.

Additionally, cancer risk can be reduced in men by them taking a mixture of antioxidant supplements, although the findings for women have been inconclusive10. Regarding the eyes, antioxidant supplements have also been shown to reduce the likelihood of encountering difficulties such as cataracts or age-related deterioration11. That being said, research also demonstrates that taking only one antioxidant supplement has limited positive effects in terms of vision and eye health12.

Improvements in brain function have also been witnessed when people take antioxidant supplements for a significant period of time (e.g., at least 15 years)6. Conversely, evidence in favor of antioxidants being able to reduce the risk of developing cognitive deficiencies, such as dementia, is inconclusive13.

To put it simply, it is abundantly clear that the balance of antioxidants, vitamins, minerals, and fiber in fruits and vegetables is beneficial to human health1. Unfortunately, on the other hand, it is unlikely that antioxidant supplements can provide the same benefits. As such, it is crucial to ensure that you are eating foods rich in antioxidants in order to see their positive impacts. But, even with eating the right foods, there are still potential risks.

What are the risks associated with antioxidants?

There are scientific studies that show a heightened risk of early death in people taking antioxidant supplements. For example, a meta-analysis combining almost 70 supplement trials found that the risk of dying was increased for people taking vitamin A, vitamin E, and beta-carotene supplements14.

In terms of specific conditions, research has shown that heavy smokers become even more likely to develop lung cancer when taking beta-carotene antioxidant supplements15. A further example is a study that saw increased lung cancer in smokers who were given a combination of beta-carotene and vitamin A16. However, it should be noted that no increased lung risks have been found in non-smokers taking these antioxidant supplements17.

Another trial-based study - in which women were given a cocktail of vitamin E, zinc, selenium, vitamin C, and beta-carotene - showed a heightened risk of skin cancer18. Additionally, vitamin E supplements were found to increase the risk of prostate cancer by 17% in previously healthy men19.

All of these examples highlight potential risks associated with antioxidant supplements or simply having too much of the same thing. As previously stated, it is vital to consume a variety of antioxidants and preferably to have them in their natural form. That is, eat fresh fruits, vegetables, seeds, pulses, and whole grains. These products contain natural antioxidants and other chemicals - such as polyphenols - that work together to combat oxidation stress and your body being overwhelmed by free radicals1.


Antioxidants are naturally occurring molecules that help to combat free radicals in your body. Free radicals are created as your body processes food and exercises, meaning that you’ll consistently produce them. Unfortunately, excess free radicals can lead to severe health conditions, some of which are fatal.

Therefore, it is apparent that consuming additional antioxidants is beneficial for reducing the number of free radicals within your body. However, there are also risks associated. Taking supplements is less profitable than consuming antioxidants in their natural state (i.e., in fruit, vegetables, and legumes). Moreover, supplements may actually be harmful to your health, especially if they are taken over an extended period of time.

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