Antioxidants Against Cancer

By William W. Li, M.D. President and Medical Director, The Angiogenesis Foundation

Antioxidants Against Cancer

Cancer Fighting Antioxidants – What You Need to Know

Antioxidants are being touted almost everywhere you look – the grocery store, on TV and all over the Internet. So, what are antioxidants really, and how do they work?

First off, antioxidants aren’t just a handful of natural substances found in a few fruits and vegetables – there are literally thousands of molecules that properly fall under the heading of “antioxidant” – and they are common in the produce aisle, market stand, and very likely, in your refrigerator at home. 

Although there are many different kinds of antioxidants, they all do something in common: they protect the DNA in our healthy cells from damage caused by free radicals, which come from harmful chemicals that we absorb from things like cigarette smoke, pollution, fried foods, and other environmental sources. Too many free radicals running around the body can cause mutations in DNA that can lead to cancer.  Antioxidants are a gift from Mother Nature, which she’s incorporated into many different types of foods that we can eat. By choosing these foods when we shop or select a meal, we can boost our own defense systems against cancer. 

Foods vs. Pills

Since many antioxidants are sold as pills, it’s important to ask: What’s better – getting antioxidants from foods or in pill form? The honest answer is that we just don’t know. There haven’t been head-to-head clinical studies comparing the two options.  What is very clear to cancer researchers, though, is that human studies of supplement pills alone haven’t yet proven that any single antioxidant supplement is a magic bullet against cancer.

When it comes to food, however, there are many population studies examining the diets of thousands of individuals, and these have revealed time and time again that specific foods (which are loaded with antioxidants) are linked to reduced cancer risk. While supplement pills are probably helpful, the verdict so far is: It’s very hard to beat Mother Nature at her own game. Foods are probably the best way to go. They taste a whole lot better than pills, too.

Should You Buy Organic?

Some studies have shown that foods grown using organic methods can have higher levels of antioxidants. This is because antioxidants also help defend plants. Many of them have natural protective properties against fungus and insects, so when plants are cultivated without artificial pesticides, it makes sense that they have to make more of their own defense system. And when we eat them, we get the benefits, too. 

To read more about the benefits of wild or organically grown plants, click here.

Antioxidant AND Anti-Angiogenic 

Here’s a new fact about antioxidants: many of them also protect against cancer because they can starve cancer cells. This is a property called anti-angiogenesis.

Angiogenesis is the process our bodies use to grow new blood vessels. Cancer cells hijack this process to recruit their own private blood supply to feed themselves. Without these blood vessel lifelines, cancers remain microscopic and simply can’t grow. Antioxidants that are anti-angiogenic also fight cancer by starving cancer. This effect is as important as the free-radical effect.

Doctors recognize the importance of stopping blood vessels in cancer. Some of the most advanced cancer drugs have actually been designed to cut off the blood supply to tumors when cancer has been diagnosed. To learn more about angiogenesis, click here.

To read more about foods known to starve cancer, click here.

Cancer-Fighting Antioxidants in Food

Which cancer-fighting antioxidants should you know about? There are many, but let’s start with three specific groups:

Carotenoids - These are a group of more than 600 antioxidants that help give fruits and vegetables their red, yellow and orange colors. Some examples are beta-carotene and lycopene. Foods rich in carotenoids include: papaya, persimmon, yellow squash, red pepper and carrots. Research correlating diet and cancer has shown that eating these foods can be protective against cervical cancer, stomach cancer, lung cancer, head and neck cancer, and kidney cancer, among others.

Isothiocyanates - The name’s a tongue twister, so let’s call them ITCs. These are a group of 1,000-plus natural molecules typically found in cruciferous vegetables – the green ones. Foods rich in ITCs include: chicory, Swiss chard, escarole, endive and parsley. Eating these foods can help protect against ovarian cancer, a deadly cancer that affects more than 200,000 women worldwide each year.

Flavanoids - Probably the most commonly recognized antioxidant, “flavanoids” actually refers to more than 6,000 different molecules. Many of them are pigments, so brightly colored foods are likely to contain them. Some examples are: red cabbage, raspberries, red currants and kumquats. These foods are protective against lung cancer, the number-one cancer killer of women.

What Color Is Your Cancer Fighter?

You don’t need to be a scientist to find foods with antioxidants. You’ve heard about the benefits from “eating the rainbow,” and that’s a great guide. Next time you push your shopping cart in the produce section, pick out some colored vegetables: reds, orange, yellows, greens, blues and purples. Fruits, too. These are sure to contain some of the cancer fighters I mentioned above. Diversity in your diet is good. Over the course of a week, eat as many colors as you can.

More Practical Tips for the Health Conscious


Here are some other assorted tips to get the most out of dietary cancer fighters:

  • If you drink tea, dunk your tea bag – doing this over and over releases up to 50% more cancer-fighting polyphenols from the tea leaves compared to letting the bag sit at the bottom of the cup. 
  • Chew your vegetables – the physical action of chewing releases more ITCs from green vegetables.
  • Steam, sauté, or stir-fry – all of these cooking methods makes food taste better than boiling, and keeps the cancer fighters in foods more intact.
  • Eat roasted – peanuts, that is. Roasting increases their levels of antioxidants.
  • Combine certain foods together – tomatoes and broccoli are two examples of foods with additive powers for cancer fighting when consumed together (they can be separate dishes). For more dynamic food duos, click here.

Eating to Defeat Cancer: Spreading the Word Around the World

The non-profit Angiogenesis Foundation’s Eat to Defeat Cancer campaign is aimed at informing people about the evidence that eating certain foods reduces the risk of cancer. You can get more practical tips on how to use food to fight and prevent cancer by joining the campaign, and spreading the word. To learn more about cancer-fighting foods, and to get food facts and recipes you can use today, click here

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