Should People with Cancer Avoid Antioxidants?

Does it sometimes seem like the more we learn the less we know? That certainly appears to be the case when we look at the effects of antioxidants on cancer. For years, we have been hearing about the health-enhancing benefits of eating fresh fruits and vegetables, and one of the main rationales for that is because they contain antioxidants. These powerful substances protect our cells from unstable molecules known as free radicals, which are linked to cancer.

Free radicals have incomplete electron shells which are usually the result of exposure to something in the food we eat, the air we breathe, the medicines we take and the water we drink. Some of the more common contributors are fried foods, alcohol, tobacco smoke, pesticides and air pollutants. In the body, this process occurs most often when oxygen molecules become “radicalized” and try to steal electrons from other molecules which can lead to DNA damage. Over time, unless checked, this can result in cancer. As part of the normal processes that take place within the cells, the bodies antioxidants neutralize free radicals and prevent them from reaching the level sufficient to create cancerous cells.

This is all good, right? Antioxidants were hailed as super heroes by the health gurus, and supplement makers rushed to fill the gap for those who do not regularly consume the recommended antioxidant-containing fruits and vegetables. Even for those who didn’t naturally gravitate toward kale and spinach could appreciate something as vicious as cancer being held at bay by carrots and mangos.

So, the answer to “Should people with cancer avoid antioxidants?” should be an easy “no”, right? When it comes to cancer and, actually, with most things that have to do with disease and the human body, the answers are seldom easy and rarely clear-cut. Yes, the antioxidant properties found in beta-carotene, lycopene, lutein, vitamins C, E, and A can be very effective in counteracting free radical damage to the body’s DNA and, as a direct result, reduce the incidence of cancer. However, there have been studies over the past several decades that have indicated that antioxidants can actually accelerate cancer progression by short-circuiting one of the body’s own immune system responses to cells that have become malignant.

Dr. Martin Bergo, senior author of a Swedish study conducted on the effects of antioxidants on cancer tumors in mice wrote, “We found that antioxidants caused a threefold increase in the number of tumors, and caused tumors to become more aggressive. Antioxidants caused the mice to die twice as fast, and the effect was dose-dependent. If we gave a small dose, tumors grew a little. If we gave a high dose, tumors grew a lot.”

While supplementing the antioxidants that naturally occur in the body can help prevent cancer, the current research seems to indicate that the body’s immune system already has an intricate system in place to deal with precancerous cells. Flooding it with antioxidants when cancerous cells are already present can suppress the signals necessary to turn that system on which, in turn, allows these damaged cells to multiply.

Because of their wide-ranging health benefits, no one is recommending that we stop eating antioxidant-rich fruits and vegetables. They may very well prevent cancerous cells from ever taking hold. If, however, you have been diagnosed with cancer or are especially vulnerable, it would be a good idea to discuss this with your doctor. Medical research makes new discoveries every day. It is more important than ever to have regular check-ups and discuss current thinking with your healthcare professional.

For those who wish to learn more about antioxidants, the following list comes from the National Institutes of Health as posted on the U.S. Department of Health & Human Resources website:

Beta-carotene is found in many foods that are orange in color, including sweet potatoes, carrots, cantaloupe, squash, apricots, pumpkin, and mangos. Some green leafy vegetables including collard greens, spinach, and kale are also rich in beta-carotene.

Lutein, best known for its association with healthy eyes, is abundant in green, leafy vegetables such as collard greens, spinach, and kale.

Lycopene is a potent antioxidant found in tomatoes, watermelon, guava, papaya, apricots, pink grapefruit, blood oranges, and other foods. Estimates suggest 85 percent of American dietary intake of lycopene comes from tomatoes and tomato products.

Selenium is a mineral, not an antioxidant nutrient. However, it is a component of antioxidant enzymes. Plant foods like rice and wheat are the major dietary sources of selenium in most countries. The amount of selenium in soil, which varies by region, determines the amount of selenium in the foods grown in that soil. Animals that eat grains or plants grown in selenium-rich soil have higher levels of selenium in their muscle. In the United States, meats and bread are common sources of dietary selenium. Brazil nuts also contain large quantities of selenium.

Vitamin A is found in three main forms: retinol (Vitamin A1), 3,4-didehydroretinol (Vitamin A2), and 3-hydroxy-retinol (Vitamin A3). Foods rich in vitamin A include liver, sweet potatoes, carrots, milk, egg yolks and mozzarella cheese.

Vitamin C is also called ascorbic acid, and can be found in high abundance in many fruits and vegetables and is also found in cereals, beef, poultry and fish.

Vitamin E, also known as alpha-tocopherol, is found in almonds, in many oils including wheat germ, safflower, corn and soybean oils, and also found in mangos, nuts, broccoli and other foods.

If you would like to learn about what foods contain the most antioxidants, please watch the following video: