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Antioxidants and Cancer

Answers to common questions


Antioxidants and Cancer

Free radical damage has been associated with cancer. Increase your intake of coloured fruits and veggies for anticancer and immune support.

The word “antioxidant” seems to be everywhere: on supplement bottles, food labels, even skin care products. While most people are familiar with antioxidants, many have questions about them. How do they work? Why do we need them to stay healthy? Here’s a short review to help answer some common antioxidant questions.  

What do they do?

To understand antioxidants, it is helpful to first understand free radicals—how they are made and why they can be a detriment to our health.

Free radicals can cause damage

Free radicals are continually generated in our bodies as byproducts of our normal, healthy metabolic activities. They are also generated in response to exposure to environmental pollutants, various medications, and a variety of chemicals.

Free radicals have an uneven number of electrons, a condition which makes them unstable. In their quest to stabilize themselves, they grab electrons from other nearby molecules. In the body, these nearby molecules are part of our own tissues. As free radicals take electrons from other molecules, those molecules then become unstable. In the body, this can result in cell and tissue damage, which, if widespread enough, can lead to disease.

Antioxidants “donate” electrons

Antioxidants work by donating electrons to free radicals, therefore stabilizing them and halting their destructive potential. Antioxidants also work together to complement one another so that they can remain stable and continue to control free-radical production.

ORAC values

You may have heard of ORAC values or perhaps have seen references to them on foods or supplement bottles. ORAC is short for Oxygen Radical Absorbance Capacity. It is used to measure a nutrient’s ability to reduce free-radical activity occurring in a test tube. This measure has been used to rank foods by antioxidant capacity and to promote them for their health benefits.

Although ORAC provides some interesting information about the potential antioxidant abilities of a food, it does have some problems. One of the main concerns is that there is no established link between these values and specific health benefits. ORAC also does not take into consideration the difference between a test tube environment and our own bodies or the impact that other nutrients within foods may have.

Increasingly, researchers have been expressing concern over the misuse of ORAC values for marketing purposes, and the potential to overemphasize the nutritional value of a food based solely on its ORAC value. There are many important variables to consider when it comes to nutrition, and a higher ORAC value is not the final word when it comes to nutritional superiority of one food or supplement over another.

Citing many of these concerns, the United States Department of Agriculture (USDA) recently removed from its website a listing of foods ranked by ORAC values and emphasized the limits of ORAC for predicting overall health benefits of any food.

In conclusion, although ORAC can provide some potentially useful information about a food, it is far from being a complete picture of its nutritional value, and more research needs to be done.

Antioxidants and cancer

Antioxidants are often promoted for the prevention of chronic diseases, including cancer. The US-based National Cancer Institute (NCI) has recognized the importance of antioxidants in the prevention of cancers, but it emphasizes the need for further research when it comes to specific antioxidant supplementation.

The NCI states that cancer is associated with free-radical damage and that antioxidants have an important role in their ability to prevent free-radical damage in the body. However, research findings in human trials of antioxidant supplements in cancer prevention are conflicting and ongoing, with many questions still to be answered.

For this reason, it is important to focus on good nutrition and to emphasize intake of a wide range of antioxidant-rich foods, which may contain additional cancer-preventing nutrient combinations that cannot be replaced by supplements.

Food based antioxidants: where to look

To increase the antioxidant content of your diet, reach for a variety of brightly coloured fruits and vegetables. Foods such as leafy greens, beets, carrots, and berries are rich in antioxidants—as well as other health-promoting nutrients.

Here’s a list of some of the top health-promoting antioxidants, and where we can find them.

Vitamin C: bell peppers, broccoli, guava, papaya, berries, and kiwi fruit (most fruit and greens are a decent source of vitamin C)

Vitamin E: wheat germ oil; nuts and seeds such as almonds, sunflower seeds, and hazelnuts

Selenium: nothing beats the Brazil nut; coming in a far second are sunflower seeds, turkey, cod, and tuna

Lycopene: tomatoes, watermelon, guava, papaya, pink grapefruit, and apricots

Lutein: dark leafy greens such as kale, collards, and spinach

Antioxidant supplements: what to look for

Because antioxidants work together and support one another in the body, and our foods generally contain a mix of different antioxidants, look for this in your supplements as well.

You can also look for products containing antioxidants that have been associated with the health benefits that are of most relevance to you:

  • CoQ10: cardiovascular support
  • Pycnogenol: support for diabetes-related ulcers, chronic venous insufficiency, and microangiopathy
  • vitamin C: immune support
  • lycopene: prostate and lung health
  • lutein: vision and eye health
  • green tea: cardiovascular health, skin, anticancer support

As always, check with your health care practitioner to make sure a supplement is right for you.

Antioxidants play a crucial role in the prevention of disease by preventing free-radical damage. Antioxidant-rich foods are key, so reach for them first, and then choose wisely from available supplements and topical products for an extra boost when needed.

Topical use of antioxidants


In the past decade, the addition of antioxidants to facial and body care products has become very popular. This is not without good reason; research has shown topical antioxidants and/or antioxidant-rich plant extracts to benefit skin health and appearance. Here are a few examples.

Vitamin C cremes: these cremes can help improve the appearance of photo-aged skin—in other words, they may repair some of the damage caused by those days you forgot to wear sunscreen.

Alpha-lipoic acid: this water- and fat-soluble antioxidant is another good candidate for reducing the effects of sun damage on the skin.

Green tea extract: this may help in the treatment of mild to moderate acne.



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